@article {1506266, title = {Modularity, homology, heterochrony:Gavin de Beer{\textquoteright}s legacy to themammalian skull}, journal = {The Royal Society}, year = {2023}, author = {Brian K Hall and James Hanken} } @article {1383896, title = {New Species of Leaf-litter Toad of the Rhinella margaritifera Species Group (Anura: Bufonidae) from Amazonia}, journal = {Copeia}, volume = {108}, year = {2020}, pages = {967-986}, author = {Miqu{\'e}ias Ferr{\~a}o and Albertina Pimentel Lima and Santiago Ron and Sueny Paloma dos Santos and James Hanken} } @article {1327515, title = {A new species of Dendropsophus (Anura, Hylidae) from southwestern Amazonia with a green bilobate vocal sac}, journal = {ZooKeys}, volume = {942}, year = {2020}, pages = {77}, abstract = {Recent studies have shown that species diversity of the South American frog genus Dendropsophus is significantly underestimated, especially in Amazonia. Herein, through integrative taxonomy a new species of Dendropsophus from the east bank of the upper Madeira River, Brazil is described. Based on molecular phylogenetic and morphological analyses, the new species is referred to the D. microcephalus species group, where it is differentiated from its congeners mainly by having a green bilobate vocal sac and an advertisement call comprising 1{\textendash}4 monophasic notes emitted with a dominant frequency of 8,979{\textendash}9,606 Hz. Based on intensive sampling conducted in the study area over the last ten years, the new species is restricted to the east bank of the upper Madeira River, although its geographic range is expected to include Bolivian forests close to the type locality.}, author = {Miqu{\'e}ias Ferr{\~a}o and Jir{\'\i} Moravec and James Hanken and Albertina Pimental Lima} } @article {1309918, title = {Descriptions of five new species of the salamander genus Chiropterotriton (Caudata: Plethodontidae) from eastern Mexico and the status of three currently recognized taxa}, journal = {PeerJ}, volume = {8}, year = {2020}, author = {Gabriela Parra Olea and Mirna G. Garcia-Castillo and Sean M. Rovito and Jessica A. Maisano and James Hanken and David B. Wake} } @article {1302518, title = {Ontogeny of the anuran urostyle and the developmental context of the evolutionary novelty}, journal = {PNAS}, volume = {117}, year = {2020}, pages = {3034-3044}, author = {Gayani Senevirathne and Stephanie Baumgart and Nathaniel Shubin and James Hanken and Neil H Shubin} } @article {1302489, title = {Development and evolution of the tetrapod skull-neck boundary}, journal = {Biological Reviews}, volume = {95}, year = {2020}, pages = {573-591}, abstract = {

\ The origin and evolution of the vertebrate skull have been topics of intense study for more than two centuries. Whereas early theories of skull origin, such as the infl uential vertebral theory, have been largely refuted with respect to the anterior (pre-otic) region of the skull, the posterior (post-otic) region is known to be derived from the anteriormost paraxial segments, i.e. the somites. Here we review the morphology and development of the occiput in both living and extinct tetrapods, taking into account revised knowledge of skull development by augmenting historical accounts with recent data. When occipital composition is evaluated relative to its position along the neural axis, and specifi cally to the hypoglossal nerve complex, much of the apparent interspecifi c variation in the location of the skull{\textendash} neck boundary stabilizes in a phylogenetically informative way. Based on this criterion, three distinct conditions are identifi ed in (i ) frogs, (ii ) salamanders and caecilians, and (iii ) amniotes. The position of the posteriormost occipital segment relative to the hypoglossal nerve is key to understanding the evolution of the posterior limit of the skull. By using cranial foramina as osteological proxies of the hypoglossal nerve, a survey of fossil taxa reveals the amniote condition to be present at the base of Tetrapoda. This result challenges traditional theories of cranial evolution, which posit translocation of the occiput to a more posterior location in amniotes relative to lissamphibians (frogs, salamanders, caecilians), and instead supports the largely overlooked hypothesis that the reduced occiput in lissamphibians is secondarily derived. Recent advances in our understanding of the genetic basis of axial patterning and its regulation in amniotes support the hypothesis that the lissamphibian occipital form may have arisen as the product of a homeotic shift in segment fate from an amniote-like condition.

Key words : skull, development, tetrapod, occiput, somites, skull{\textendash} neck, homeotic transformation

}, author = {Hillary C. Maddin and Nadine Piekarski and Robert R. Reisz and James Hanken} } @article {1218110, title = {Environmental Oxygen Exposure Allows for the Evolution of Interdigital Cell Death in Limb Patterning}, journal = {Developmental Cell}, volume = {50}, year = {2019}, pages = {155-166e1-e4}, url = {https://www.sciencedirect.com/science/article/pii/S153458071930423X}, author = {Cordeiro, Ingrid Rosenburg and Kabashima, Kaori and Ochi, Haruki and Munakata Keijiro and Nishimori, Chika and Mara Laslo and James Hanken and Tanaka, Mikiko} } @article {1166362, title = {Diversification of shrub frogs (Rhacophoridae, Pseudophilautus) in Sri Lanka{\textendash} Timing and geographic context}, journal = {Molecular Phylogenetics and Evolution}, volume = {Volume 132}, year = {2019}, pages = {14-24}, url = {https://www.sciencedirect.com/science/article/pii/S1055790318304159}, author = {Madhava Meegaskumbura and Gayani Seneviranthne and Kelum Manamendra-Arachchi and Rohan Pethiyagoda and James Hanken and Christopher J. Schneider} } @article {1166352, title = {Evolutionary Conservation of ThyroidHormone Receptor and DeiodinaseExpression Dynamics in ovo in aDirect-Developing Frog,Eleutherodactylus coqui}, journal = {Frontiers in Endocrinology}, volume = {10 (article 307)}, year = {2019}, url = {https://www.frontiersin.org/articles/10.3389/fendo.2019.00307/full}, author = {Mara Laslo and Robert J. Denver and James Hanken} } @article {1142365, title = {Expression of a novel surfactant protein gene is associated with sites of extrapulmonary respiration in a lungless salamander}, journal = {Proc. R. Soc. B}, volume = {285}, year = {2018}, author = {Zachary R. Lewis and Jorge A. Dorantes and James Hanken} } @article {1132726, title = {Early limb patterning in the direct-developing salamanderPlethodon cinereus revealed by sox9 and col2a1}, journal = {Evolution \& Development}, volume = {20}, year = {2018}, pages = {100-107}, url = {https://onlinelibrary.wiley.com/doi/10.1111/ede.12250}, author = {Ryan R. Kerney and James Hanken and David C. Blackburn} } @article {1158219, title = {Evolution of the head-trunk interface in tetrapod vertebrates}, journal = {eLIFE}, volume = {5}, year = {2016}, url = {https://elifesciences.org/articles/09972}, author = {Elizabeth M Sefton and Bhart-Anjan S Bhullar and Zahra Mohaddes and James Hanken} } @article {599451, title = {Patterns of reproductive-mode evolution in Old World tree frogs (Anura, Rhacophoridae)}, journal = {Zoologica Scripta}, volume = {doi:10.1111/zsc.12121}, year = {2015}, author = {Meegaskumbura, M. and Senevirathne, G. and Biju, S.D. and Garg, S. and Meegaskumbura, S. and Pethiyagoda, R. and Hanken, J. and Schneider, C. J.} } @article {593876, title = {YesWorkflow: A User-Oriented, Language-Independent Tool for Recovering Workflow Information from Scripts}, journal = {International Journal for Digital Curation}, volume = {10}, year = {2015}, pages = {298-313}, author = {McPhillips, T. and Song, T. and Kolisnik, T. and Aulenbach, S. and Belhajjame, K. and Bocinsky, R.K. and Cao, Y. and Cheney, J. and Chirigati, F. and Dey, S. and Freire, J. and Jones, C. and Hanken, J. and Kintigh, K.W. and Kohler, T.A. and Koop, D. and Macklin, J. A. and Missier, P. and Schildhauer, M. and Schwalm, C. and Wei, Y. and Bieda, M. and Ludascher, B.} } @article {590396, title = {Dual embryonic origin and patterning of the pharyngeal skeleton in the axolotl (Ambystoma mexicanum)}, journal = {Evolution \& Development}, volume = {17}, year = {2015}, pages = {175-184}, author = {Sefton, E. M. and Piekarski, N. and Hanken, J.} } @article {584901, title = {Development of neuroendocrine components of the thyroid axis in the direct-devoloping frog Eleutherodactylus coqui: formation of the median eminence and the onset of pituitary TSH production}, journal = {Gen. Comp. Endocrinol.}, volume = {214}, year = {2015}, pages = {62-67}, author = {Jennings, D. H. and Evans, B. and Hanken, J.} } @inbook {584911, title = {Is heterochrony still an effective paradigm for contemporary studies of evo-devo?}, booktitle = {Conceptual Change in Biology: Scientific and Philosophical Perspectives on Evolution and Development. Boston Studies in the Philosophy and History of Science}, volume = {307}, year = {2015}, pages = {97-110}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {Berlin}, author = {Hanken, J.}, editor = {Love, A.C.} } @article {586236, title = {Review of A. Channing, M.-O. R{\"o}del, and J. Channing, Tadpoles of Africa: The Biology and Identification of all Known Tadpoles in Sub-Saharan Africa}, journal = {Copeia}, volume = {2014}, year = {2014}, pages = {400-402}, author = {Hanken, J.} } @article {584926, title = {Toward automated design, analysis, and optimization of declarative curation workflows}, journal = {Internat. J. Dig. Curat.}, volume = {9}, year = {2014}, pages = {111-122}, author = {Song, T. and K{\"o}hler, S. and Lud{\"a}scher, B. and Hanken, J. and Kelly, M. and Lowery, D. and Macklin, A. and Morris, P. J. and Morris, R. A.} } @article {561701, title = {Evolutionary innovation and conservation in the embryonic derivation of the vertebrate skull}, journal = {Nature Communications}, volume = {5}, year = {2014}, note = {

Ax9naTimes Cited:0Cited References Count:47

}, month = {Dec}, pages = {5661}, abstract = {

Development of the vertebrate skull has been studied intensively for more than 150 years, yet many essential features remain unresolved. One such feature is the extent to which embryonic derivation of individual bones is evolutionarily conserved or labile. We perform long-term fate mapping using GFP-transgenic axolotl and Xenopus laevis to document the contribution of individual cranial neural crest streams to the osteocranium in these amphibians. Here we show that the axolotl pattern is strikingly similar to that in amniotes; it likely represents the ancestral condition for tetrapods. Unexpectedly, the pattern in Xenopus is much different; it may constitute a unique condition that evolved after anurans diverged from other amphibians. Such changes reveal an unappreciated relation between life history evolution and cranial development and exemplify {\textquoteright}developmental system drift{\textquoteright}, in which interspecific divergence in developmental processes that underlie homologous characters occurs with little or no concomitant change in the adult phenotype.

}, keywords = {axolotl, cells, cranial neural-crest, fate, head, mesoderm, origins, ossification, transplantation, xenopus-laevis}, isbn = {2041-1723}, author = {Piekarski, N. and Gross, J. B. and Hanken, J.} } @article {561186, title = {Natural History Collections as Emerging Resources for InnovativeEducation}, journal = {Bioscience}, volume = {64}, number = {8}, year = {2014}, note = {

Am6pvTimes Cited:0Cited References Count:45

}, month = {Aug}, pages = {725-734}, abstract = {

There is an emerging consensus that undergraduate biology education in the United States is at a crucial juncture, especially as we acknowledge the need to train a new generation of scientists to meet looming environmental and health crises. Digital resources for biology now available online provide an opportunity to transform biology curricula to include more authentic and inquiry-driven educational experiences. Digitized natural history collections have become tremendous assets for research in environmental and health sciences, but, to date, these data remain largely untapped by educators. Natural history collections have the potential to help transform undergraduate science education from passive learning into an active exploration of the natural world, including the exploration of the complex relationships among environmental conditions, biodiversity, and human well-being. By incorporating natural history specimens and their associated data into undergraduate curricula, educators can promote participatory learning and foster an understanding of essential interactions between organisms and their environments.

}, keywords = {achievement, climate-change, databases, distributions, Ecology, Habitat, inquiry driven, Mammals, museum, museum collections, niche, place based, specimens, undergraduate education}, isbn = {0006-3568}, author = {Cook, J. A. and SV Edwards and Lacey, E. A. and Guralnick, R. P. and Soltis, P. S. and Soltis, D. E. and Welch, C. K. and Bell, K. C. and Galbreath, K. E. and Himes, C. and Allen, JM and Heath, T. A. and Carnaval, A. C. and Cooper, K. L. and Liu, M. and Hanken, J. and Ickert-Bond, S.} } @proceedings {586251, title = {Implementation plan for the Network Integrated Biocollections Alliance}, year = {2013}, publisher = {[JH co-chaired the writing committee]}, address = {Reston, VA} } @article {586246, title = {A scientist in full: the fruitful, flawed Louis Agassiz [review of C. Irmscher, Louis Agassiz: Creator of American Science]}, journal = {Harvard Magazine}, volume = {115}, year = {2013}, pages = {22-24}, author = {Hanken, J.} } @article {561751, title = {Adaptive radiation in miniature: the minute salamanders of the Mexican highlands (Amphibia: Plethodontidae: Thorius)}, journal = {Biological Journal of the Linnean Society}, volume = {109}, number = {3}, year = {2013}, note = {

164FOTimes Cited:3Cited References Count:96

}, month = {Jul}, pages = {622-643}, abstract = {

The small size and apparent external morphological similarity of the minute salamanders of the genus Thorius have long hindered evolutionary studies of the group. We estimate gene and species trees within the genus using mitochondrial and nuclear DNA from nearly all named and many candidate species and find three main clades. We use this phylogenetic hypothesis to examine patterns of morphological evolution and species coexistence across central and southern Mexico and to test alternative hypotheses of lineage divergence with and without ecomorphological divergence. Sympatric species differ in body size more than expected after accounting for phylogenetic relationship, and morphological traits show no significant phylogenetic signal. Sympatric species tend to differ in a combination of body size, presence or absence of maxillary teeth, and relative limb or tail length, even when they are close relatives. Sister species of Thorius tend to occupy climatically similar environments, which suggests that divergence across climatic gradients does not drive species formation in the genus. Rather than being an example of cryptic species formation, Thorius more closely resembles an adaptive radiation, with ecomorphological divergence that is bounded by organism-level constraints.(c) 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 622-643.

}, keywords = {bayesian-inference, biogeography, climatic zonation, cranial morphology, diversification, diversification rates, genus chiropterotriton caudata, morphological evolution, Morphology, mountain passes, nonadaptive radiation, phylogenetic-relationships, Phylogeny, species formation, species trees, Systematics}, isbn = {0024-4066}, author = {Rovito, S. M. and Parra-Olea, G. and Hanken, J. and Bonett, R. M. and Wake, D.B.} } @article {561381, title = {Biodiversity Online: Toward a Network Integrated Biocollections Alliance}, journal = {Bioscience}, volume = {63}, number = {10}, year = {2013}, note = {

235TPTimes Cited:0Cited References Count:1

}, month = {Oct}, pages = {789-790}, isbn = {0006-3568}, author = {Hanken, J.} } @article {561136, title = {Developmental origins of a novel gut morphology in frogs}, journal = {Evolution \& Development}, volume = {15}, number = {3}, year = {2013}, note = {

134QRTimes Cited:5Cited References Count:72

}, month = {May}, pages = {213-223}, abstract = {

Phenotypic variation is a prerequisite for evolution by natural selection, yet the processes that give rise to the novel morphologies upon which selection acts are poorly understood. We employed a chemical genetic screen to identify developmental changes capable of generating ecologically relevant morphological variation as observed among extant species. Specifically, we assayed for exogenously applied small molecules capable of transforming the ancestral larval foregut of the herbivorous Xenopus laevis to resemble the derived larval foregut of the carnivorous Lepidobatrachus laevis. Appropriately, the small molecules that demonstrate this capacity modulate conserved morphogenetic pathways involved in gut development, including downregulation of retinoic acid (RA) signaling. Identical manipulation of RA signaling in a species that is more closely related to Lepidobatrachus, Ceratophrys cranwelli, yielded even more similar transformations, corroborating the relevance of RA signaling variation in interspecific morphological change. Finally, we were able to recover the ancestral gut phenotype in Lepidobatrachus by performing a reverse chemical manipulation to upregulate RA signaling, providing strong evidence that modifications to this specific pathway promoted the emergence of a lineage-specific phenotypic novelty. Interestingly, our screen also revealed pathways that have not yet been implicated in early gut morphogenesis, such as thyroid hormone signaling. In general, the chemical genetic screen may be a valuable tool for identifying developmental mechanisms that underlie ecologically and evolutionarily relevant phenotypic variation.

}, keywords = {actin bundles, chemical genetics, eye morphogenesis, heart tube, left-right asymmetry, neural crest cells, pancreas development, retinoic acid, sonic hedgehog, xenopus-laevis}, isbn = {1520-541X}, author = {Bloom, S. and Ledon-Rettig, C. and Infante, C. and Everly, A. and Hanken, J. and Nascone-Yoder, N.} } @article {561876, title = {Morphology of the cranial skeleton and musculature in the obligate carnivorous tadpole of Lepidobatrachus laevis (Anura: Ceratophryidae)}, journal = {Acta Zoologica}, volume = {94}, number = {1}, year = {2013}, note = {

054KFTimes Cited:3Cited References Count:33

}, month = {Jan}, pages = {101-112}, abstract = {

Ziermann, J.M., Infante, C., Hanken, J. and Olsson, L. 2011. Morphology of the cranial skeleton and musculature in the obligate carnivorous tadpole of Lepidobatrachus laevis (Anura: Ceratophryidae). Acta Zoologica (Stockholm) 00:112. Lepidobatrachus laevis (Ceratophryidae: Ceratophryinae) is a bizarre frog endemic to the Chacoan desert of central South America. Its tadpole is an obligate carnivore that can catch and consume live prey nearly its own size. Morphological adaptations associated with this unique feeding mode, including the larval skull anatomy and associated cranial musculature, have only been partly described. We studied the head of Stages 2627 larvae using gross dissection, immunohistochemistry, and standard histology. Derived features of this tadpole compared to the microphagous, herbivorous larvae of most other anurans include simplified chondrocranial cartilages and very robust jaw muscles. The mm. suspensorio- et quadratoangularis do not take their origin from the processus muscularis of the palatoquadrate, as in most other tadpoles, but instead originate from the corpus of the palatoquadrate caudal to this process. The jaw levators are unusually large. The tadpole of Ceratophrys, another member of the ceratophryine clade, also consumes large animal prey, but its morphology is very different. It probably has evolved independently from a generalized, mainly herbivorous tadpole similar to the larva of Chacophrys, the third ceratophryine genus. Most specialized features of the larval head of Lepidobatrachus laevis are adaptations for megalophagyingestion of whole, very large animal prey.

}, keywords = {amphibia, cranial cartilages, cranial muscles, Evolution, frog, hylidae, Larva, leptodactylidae, muscles, neobatrachia, Skull}, isbn = {0001-7272}, author = {Ziermann, J. M. and Infante, C. and Hanken, J. and Olsson, L.} } @article {561836, title = {Pseudotyped retroviruses for infecting axolotl in vivo and in vitro}, journal = {Development}, volume = {140}, number = {5}, year = {2013}, note = {

089AKTimes Cited:5Cited References Count:40

}, month = {Mar 1}, pages = {1137-1146}, abstract = {

Axolotls are poised to become the premiere model system for studying vertebrate appendage regeneration. However, very few molecular tools exist for studying crucial cell lineage relationships over regeneration or for robust and sustained misexpression of genetic elements to test their function. Furthermore, targeting specific cell types will be necessary to understand how regeneration of the diverse tissues within the limb is accomplished. We report that pseudotyped, replication-incompetent retroviruses can be used in axolotls to permanently express markers or genetic elements for functional study. These viruses, when modified by changing their coat protein, can infect axolotl cells only when they have been experimentally manipulated to express the receptor for that coat protein, thus allowing for the possibility of targeting specific cell types. Using viral vectors, we have found that progenitor populations for many different cell types within the blastema are present at all stages of limb regeneration, although their relative proportions change with time.

}, keywords = {a avian-leukosis, adult vertebrate, axolotl, cells, expression, gene, growth-factor, neural crest, newt, regeneration, retrovirus, tissue specific, vectors, vertebrate limb regeneration}, isbn = {0950-1991}, author = {Whited, J. L. and Tsai, S. L. and Beier, K. T. and White, J. N. and Piekarski, N. and Hanken, J. and Cepko, C. L. and Tabin, C. J.} } @article {561656, title = {Semantic Annotation of Mutable Data}, journal = {Plos One}, volume = {8}, number = {11}, year = {2013}, note = {

245ZCTimes Cited:0Cited References Count:70

}, month = {Nov 4}, abstract = {

Electronic annotation of scientific data is very similar to annotation of documents. Both types of annotation amplify the original object, add related knowledge to it, and dispute or support assertions in it. In each case, annotation is a framework for discourse about the original object, and, in each case, an annotation needs to clearly identify its scope and its own terminology. However, electronic annotation of data differs from annotation of documents: the content of the annotations, including expectations and supporting evidence, is more often shared among members of networks. Any consequent actions taken by the holders of the annotated data could be shared as well. But even those current annotation systems that admit data as their subject often make it difficult or impossible to annotate at fine-enough granularity to use the results in this way for data quality control. We address these kinds of issues by offering simple extensions to an existing annotation ontology and describe how the results support an interest-based distribution of annotations. We are using the result to design and deploy a platform that supports annotation services overlaid on networks of distributed data, with particular application to data quality control. Our initial instance supports a set of natural science collection metadata services. An important application is the support for data quality control and provision of missing data. A previous proof of concept demonstrated such use based on data annotations modeled with XML-Schema.

}, keywords = {provenance}, isbn = {1932-6203}, author = {Morris, R. A. and Dou, L. and Hanken, J. and Kelly, M. and Lowery, D. B. and Ludascher, B. and Macklin, J. A. and Morris, P. J.} } @article {561871, title = {Significance of pre-Quaternary climate change for montane species diversity: Insights from Asian salamanders (Salamandridae: Pachytriton)}, journal = {Molecular Phylogenetics and Evolution}, volume = {66}, number = {1}, year = {2013}, note = {

055LMTimes Cited:4Cited References Count:92

}, month = {Jan}, pages = {380-390}, abstract = {

Despite extensive focus on the genetic legacy of Pleistocene glaciation, impacts of earlier climatic change on biodiversity are poorly understood. Because amphibians are highly sensitive to variations in precipitation and temperature, we use a genus of Chinese montane salamanders (Salamandridae: Pachytriton) to study paleoclimatic change in East Asia, which experienced intensification of its monsoon circulation in the late Miocene associated with subsequent Pliocene warming. Using both nuclear and mitochondrial DNA sequences, we reconstruct the species tree under a coalescent model and demonstrate that all major lineages originated before the Quaternary. Initial speciation within the genus occurred after the summer monsoon entered a stage of substantial intensification. Heavy summer precipitation established temporary water connectivity through overflows between adjacent stream systems, which may facilitate geographic range expansion by aquatic species such as Pachytriton. Species were formed in allopatry likely through vicariant isolation during or after range expansion. To evaluate the influence of Pliocene warming on these cold-adapted salamanders, we construct a novel temperature buffer-zone model, which suggests widespread physiological stress or even extinction during the warming period. A significant deceleration of species accumulation rate is consistent with Pliocene range contraction, which affected P. granulosus and P. archospotus the most because they lack large temperature buffer zones. In contrast, demographic growth occurred in species for which refugia persist. The buffer-zone model reveals the Huangshan Mountain as a potential climatic refugium, which is similar to that found for other East Asian organisms. Our approach can incorporate future climatic data to evaluate the potential impact of ongoing global warming on montane species (particularly amphibians) and to predict possible population declines. (C) 2012 Elsevier Inc. All rights reserved.

}, keywords = {amphibians, bayesian-inference, china amphibia, diversification rates, east asian summer monsoon, family salamandridae, global patterns, high-resolution, historical demography, phylogenetic analysis, pliocene warming, populations, range expansion, south china, temperature buffer-zone model}, isbn = {1055-7903}, author = {Wu, Y. K. and Wang, Y. Z. and Jiang, K. and Hanken, J.} } @article {561856, title = {Comparative Osteology of the Genus Pachytriton (Caudata: Salamandridae) from Southeastern China}, journal = {Asian Herpetological Research}, volume = {3}, number = {2}, year = {2012}, note = {

980FKTimes Cited:3Cited References Count:39

}, month = {Jun 25}, pages = {83-102}, abstract = {

Osteological evidence provides invaluable insights into patterns of amphibian biodiversity. In small montane streams of southeastern China, an endemic genus of salamanders (Pachytriton) displays remarkable aquatic specializations, many of which are reflected in skeletal morphology, but these specializations remain to be studied in an integrated perspective. Attempts to fully resolve the taxonomy within the genus also can benefit from knowledge of internal morphology. We present a detailed description of the adult skeleton of P. brevipes, P. inexpectatus and P. archospotus by analyzing both cleared-and-stained and radiographed specimens in a comparative framework. Compared to terrestrial and amphibious salamanders, the most distinctive osteological features of Pachytriton include a modified hyobranchial apparatus, a reduced frontosquamosal arch, and deep neural and haemal arches of the caudal vertebrae. The hyobranchial apparatus of P. archospotus is distinctly different from that of congeners and likely secondarily derived. Patterns of interspecific variation suggest that northeastern P. inexpectatus is more closely related to P. brevipes than it is to southwestern P. inexpectatus, thereby reinforcing results from earlier molecular phylogenetic analyses. We advocate assigning northeastern P. inexpectatus to P. brevipes.

}, keywords = {amphibia, anatomy, aquatic specialization, Evolution, family salamandridae, growth, interspecific variation, montane amphibian, newts, Phylogeny, Population, Taxonomy, urodela}, isbn = {2095-0357}, author = {Wu, Y. K. and Wang, Y. Z. and Hanken, J.} } @article {561206, title = {Kurator: A Kepler Package for Data Curation Workflows}, journal = {Proceedings of the International Conference on Computational Science, Iccs 2012}, volume = {9}, year = {2012}, note = {

Bba26Times Cited:1Cited References Count:10Procedia Computer Science

}, pages = {1614-1619}, abstract = {

Data curation is critical for scientific data digitization, sharing, integration, and use. This paper presents Kurator, a software package for automating data curation pipelines in the Kepler scientific workflow system. Several curation tools and services are integrated into this package as actors to enable construction of workflows to perform and document various data curation tasks. The integration of Google cloud services (e. g., Google spreadsheets), allows workflow steps to invoke human experts outside the workflow in a manner that greatly simplifies the complex data handling in distributed, multi-user curation workflows. The Kepler platform provides the modeling, execution and management ability, including a collection-oriented model of computation (COMAD), and provenance tracking and browsing for the curation package. These features not only allow workflows to be easily modeled, maintained, and evolved, but also QA/QC of curation results is facilitated through examination of provenance information recorded during workflow execution. Effectiveness of the Kurator package is demonstrated through a workflow for data curation of natural science collections.

}, keywords = {biodiversity informatics, data curation, scientific workflows}, isbn = {1877-0509}, author = {Dou, L. and Cao, G. and Morris, P. J. and Morris, R. A. and Ludascher, B. and Macklin, J. A. and Hanken, J.} } @article {561831, title = {Mapping the biosphere: exploring species to understand the origin, organization and sustainability of biodiversity}, journal = {Systematics and Biodiversity}, volume = {10}, number = {1}, year = {2012}, note = {

962AXTimes Cited:28Cited References Count:90

}, pages = {1-20}, abstract = {

The time is ripe for a comprehensive mission to explore and document Earth{\textquoteright}s species. This calls for a campaign to educate and inspire the next generation of professional and citizen species explorers, investments in cyber-infrastructure and collections to meet the unique needs of the producers and consumers of taxonomic information, and the formation and coordination of a multi-institutional, international, transdisciplinary community of researchers, scholars and engineers with the shared objective of creating a comprehensive inventory of species and detailed map of the biosphere. We conclude that an ambitious goal to describe 10 million species in less than 50 years is attainable based on the strength of 250 years of progress, worldwide collections, existing experts, technological innovation and collaborative teamwork. Existing digitization projects are overcoming obstacles of the past, facilitating collaboration and mobilizing literature, data, images and specimens through cyber technologies. Charting the biosphere is enormously complex, yet necessary expertise can be found through partnerships with engineers, information scientists, sociologists, ecologists, climate scientists, conservation biologists, industrial project managers and taxon specialists, from agrostologists to zoophytologists. Benefits to society of the proposed mission would be profound, immediate and enduring, from detection of early responses of flora and fauna to climate change to opening access to evolutionary designs for solutions to countless practical problems. The impacts on the biodiversity, environmental and evolutionary sciences would be transformative, from ecosystem models calibrated in detail to comprehensive understanding of the origin and evolution of life over its 3.8 billion year history. The resultant cyber-enabled taxonomy, or cybertaxonomy, would open access to biodiversity data to developing nations, assure access to reliable data about species, and change how scientists and citizens alike access, use and think about biological diversity information.

}, keywords = {Biodiversity, bioinformatics, biomimicry, biosphere, challenges, Conservation, cyberinfrastructure, Ecology, Evolution, hippopotamus, information, infrastructure, international collaboration, life, organization of science, origins, red sweat, species, sustainability, systematic biology, Systematics, Taxonomy, team work, tree}, isbn = {1477-2000}, author = {Wheeler, Q. D. and Knapp, S. and Stevenson, D. W. and Stevenson, J. and Blum, S. D. and Boom, B. M. and Borisy, G. G. and Buizer, J. L. and De Carvalho, M. R. and Cibrian, A. and Donoghue, M. J. and Doyle, V. and Gerson, E. M. and Graham, C. H. and Graves, P. and Graves, S. J. and Guralnick, R. P. and Hamilton, A. L. and Hanken, J. and Law, W. and Lipscomb, D. L. and Lovejoy, T. E. and Miller, H. and Miller, J. S. and Naeem, S and Novacek, M. J. and Page, L. M. and Platnick, N. I. and Porter-Morgan, H. and Raven, P. H. and Solis, M. A. and Valdecasas, A. G. and Van Der Leeuw, S. and Vasco, A. and Vermeulen, N. and Vogel, J. and Walls, R. L. and Wilson, E. O. and Woolley, J. B.} } @article {561851, title = {New species of Pachytriton (Caudata: Salamandridae) from the Nanling Mountain Range, southeastern China}, journal = {Zootaxa}, number = {3388}, year = {2012}, note = {

973YYTimes Cited:0Cited References Count:35

}, month = {Jul 13}, pages = {1-16}, abstract = {

New species of amphibians are being reported at an astonishingly fast rate. These include some that have been known to the commercial pet trade for years but have not been formally described due to uncertain origin. The distinctive phenotype of "Pachytriton B" among the Chinese stout newts (also known as paddle-tailed newts) is one such example. Through examination of museum specimens, we locate a population from Mt. Mang within the Nanling Mountain Range with morphology and coloration similar to Pachytriton B. Molecular phylogenetic analyses strongly suggest that this population and Pachytriton B belong to the same species, which differs from congeners morphologically and chromatically and is described here as a new species. This species is characterized by a large and stout body, uniformly light brown dorsum, and orange spots or blotches that extend ribbon-like along the dorsolateral sides of the body. A mitochondrial genealogy suggests that the new species is the sister taxon to the group (P. brevipes + P. feii). Morphologically, this species is significantly stouter than P. feii and has significantly longer limbs than P. brevipes.

}, keywords = {amphibia urodela salamandridae, chinese stout newt, guangxi, labiatus, maximum-likelihood, mitochondrial genealogy, molecular phylogeny, pachytriton xanthospilos sp nov., principal-components analysis, province, salamander}, isbn = {1175-5326}, author = {Wu, Y. K. and Wang, Y. Z. and Hanken, J.} } @article {561816, title = {Taxonomic status of the enigmatic salamander Cryptotriton adelos (Amphibia: Plethodontidae) from northern Oaxaca, Mexico, with observations on its skull and postcranial skeleton}, journal = {Zootaxa}, number = {3579}, year = {2012}, note = {

050RGTimes Cited:2Cited References Count:16

}, month = {Dec 11}, pages = {67-70}, keywords = {genus thorius amphibia, minute salamanders, Morphology}, isbn = {1175-5326}, author = {Wake, D.B. and Rovito, S. M. and Maisano, J. A. and Hanken, J.} } @article {561881, title = {Terrestrialization, Miniaturization and Rates of Diversification in sub-Saharan Frogs (Anura: Phrynobatrachidae)}, journal = {Plos One}, volume = {7}, number = {4}, year = {2012}, note = {

959FETimes Cited:3Cited References Count:80

}, month = {Apr 10}, pages = {1-11 e35118}, abstract = {

Terrestrialization, the evolution of non-aquatic oviposition, and miniaturization, the evolution of tiny adult body size, are recurring trends in amphibian evolution, but the relationships among the traits that characterize these phenomena are not well understood. Furthermore, these traits have been identified as possible "key innovations{\textquoteright}{\textquoteright} that are predicted to increase rates of speciation in those lineages in which they evolve. We examine terrestrialization and miniaturization in sub-Saharan puddle frogs (Phrynobatrachidae) in a phylogenetic context to investigate the relationship between adaptation and diversification through time. We use relative dating techniques to ascertain if character trait shifts are associated with increased diversification rates, and we evaluate the likelihood that a single temporal event can explain the evolution of those traits. Results indicate alternate reproductive modes evolved independently in Phrynobatrachus at least seven times, including terrestrial deposition of eggs and terrestrial, non-feeding larvae. These shifts towards alternate reproductive modes are not linked to a common temporal event. Contrary to the "key innovations{\textquoteright}{\textquoteright} hypothesis, clades that exhibit alternate reproductive modes have lower diversification rates than those that deposit eggs aquatically. Adult habitat, pedal webbing and body size have no effect on diversification rates. Though these traits putatively identified as key innovations for Phrynobatrachus do not seem to be associated with increased speciation rates, they may still provide opportunities to extend into new niches, thus increasing overall diversity.

}, keywords = {ancestral character states, body-size, discrete characters, Evolution, life-history, maximum-likelihood, reproductive mode, skeletal morphology, species-richness, taxonomic diversity}, isbn = {1932-6203}, author = {Zimkus, B. M. and Lawson, L. and Loader, S. P. and Hanken, J.} } @article {586256, title = {Review of M.D. Laublichler and J. Maienschein, eds., Form and Function in Direct Developmental Evolution}, journal = {Quart. Rev. Biol.}, volume = {86}, year = {2011}, pages = {142-143}, author = {Hanken, J.} } @article {561616, title = {Do Larval Traits Re-Evolve? Evidence from the Embryogenesis of a Direct-Developing Salamander, Plethodon cinereus}, journal = {Evolution}, volume = {66}, number = {1}, year = {2011}, note = {

871LHTimes Cited:4Cited References Count:79

}, month = {Jan}, pages = {252-262}, abstract = {

Recent molecular phylogenies suggest the surprising reacquisition of posthatching metamorphosis within an otherwise direct-developing clade of lungless salamanders (family Plethodontidae). Metamorphosis was long regarded as plesiomorphic for plethodontids, yet the genus Desmognathus, which primarily includes metamorphosing species, is now nested within a much larger clade of direct-developing species. The extent to which the putative reacquisition of metamorphosis in Desmognathus represents a true evolutionary reversal is contingent upon the extent to which both larva-specific features and metamorphosis were actually lost during the evolution of direct development. In this study we analyze development of the hyobranchial skeleton, which is dramatically remodeled during salamander metamorphosis, in the direct-developing red-backed salamander, Plethodon cinereus. We find dramatic remodeling of the hyobranchial skeleton during embryogenesis in P. cinereus and the transient appearance of larva-specific cartilages. Hyobranchial development in this direct-developing plethodontid is highly similar to that in metamorphosing plethodontids (e.g., Desmognathus). The proposed reacquisition of hyobranchial metamorphosis within Desmognathus does not represent the re-evolution of a lost phenotype, but instead the elaboration of an existing developmental sequence.

}, keywords = {amphibia, body-size, Development, direct development, dollo{\textquoteright}s law, dollos law, eurycea-bislineata, evolutionary developmental biology, life history evolution, life-history evolution, lungless salamanders, marsupial frogs, phylogenetic-relationships, plethodontidae, skeletal morphogenesis, urodele skull}, isbn = {0014-3820}, author = {Kerney, R. R. and Blackburn, D. C. and Muller, H. and Hanken, J.} } @article {561226, title = {Molecular anatomy of the developing limb bud in the coqui frog, Eleutherodactylus coqui}, journal = {Developmental Biology}, volume = {356}, number = {1}, year = {2011}, note = {

792XT487Times Cited:0Cited References Count:0

}, month = {Aug 1}, pages = {248-248}, isbn = {0012-1606}, author = {Gross, J. and Kerney, R. and Hanken, J. and Tabin, C.} } @article {561261, title = {Molecular anatomy of the developing limb in the coqui frog, Eleutherodactylus coqui}, journal = {Evolution \& DevelopmentEvolution \& DevelopmentEvolution \& Development}, volume = {13}, number = {5}, year = {2011}, note = {

827KHTimes Cited:1Cited References Count:66

}, month = {Sep-Oct}, pages = {415-426}, abstract = {

The vertebrate limb demonstrates remarkable similarity in basic organization across phylogenetically disparate groups. To gain further insight into how this morphological similarity is maintained in different developmental contexts, we explored the molecular anatomy of size-reduced embryos of the Puerto Rican coqui frog, Eleutherodactylus coqui. This animal demonstrates direct development, a life-history strategy marked by rapid progression from egg to adult and absence of a free-living, aquatic larva. Nonetheless, coqui exhibits a basal anuran limb structure, with four toes on the forelimb and five toes on the hind limb. We investigated the extent to which coqui limb bud development conforms to the model of limb development derived from amniote studies. Toward this end, we characterized dynamic patterns of expression for 13 critical patterning genes across three principle stages of limb development. As expected, most genes demonstrate expression patterns that are essentially unchanged compared to amniote species. For example, we identified an EcFgf8-expression domain within the apical ectodermal ridge (AER). This expression pattern defines a putatively functional AER signaling domain, despite the absence of a morphological ridge in coqui embryos. However, two genes, EcMeis2 and EcAlx4, demonstrate altered domains of expression, which imply a potential shift in gene function between coqui frogs and amniote model systems. Unexpectedly, several genes thought to be critical for limb patterning in other systems, including EcFgf4, EcWnt3a, EcWnt7a, and EcGremlin, demonstrated no evident expression pattern in the limb at the three stages we analyzed. The absence of EcFgf4 and EcWnt3a expression during limb patterning is perhaps not surprising, given that neither gene is critical for proper limb development in the mouse, based on knockout and expression analyses. In contrast, absence of EcWnt7a and EcGremlin is surprising, given that expression of these molecules appears to be absolutely essential in all other model systems so far examined. Although this analysis substantiates the existence of a core set of ancient limb-patterning molecules, which likely mediate identical functions across highly diverse vertebrate forms, it also reveals remarkable evolutionary flexibility in the genetic control of a conserved morphological pattern across evolutionary time.

}, keywords = {apical ectodermal ridge, developing chick limb, digit identity, feedback loop, gene-expression, pattern-formation, polarizing activity, signaling pathway, sonic-hedgehog, vertebrate limb}, isbn = {1520-541X}, author = {Gross, J. B. and Kerney, R. and Hanken, J. and Tabin, C. J.} } @article {584996, title = {Taruga (Anura: Rhacophoridae), a new gnus of foam-nesting tree frogs endemic to Sri Lanka}, journal = {Cey. J. Sci. (Bio. Sci.)}, volume = {39}, year = {2010}, pages = {75-94}, author = {Meegaskumbura, M. and Meegaskumbura, S. and Bowatte, G. and Manamendra-Arachchi, K. and Pethiyagoda, R. and Hanken, J. and Schneider, C. J.} } @inbook {585001, title = {The Encyclopedia of Life: a new digital resource for taxonomy}, booktitle = {Systema Naturae 250: The Linnaean Ark}, year = {2010}, pages = {127-135}, publisher = {Taylor \& Francis}, organization = {Taylor \& Francis}, address = {Boca Raton}, author = {Hanken, J.}, editor = {Polaszek, A.} } @article {584986, title = {VertNet: A new model for biodiversity data sharing}, journal = {PLoS Biology}, volume = {8}, year = {2010}, pages = {e1000309}, author = {Constable, H. and Guralnick, R. and Wieczorek, J. and Spencer, C. and Peterson, T. and Bart, H. and Bates, J. and Cotter, G. and Hanken, J. and Mortiz, C. and Simmons, N. and Trueb, L.} } @article {561591, title = {Early cranial patterning in the direct-developing frog Eleutherodactylus coqui revealed through gene expression}, journal = {Evolution \& Development}, volume = {12}, number = {4}, year = {2010}, note = {

619OZTimes Cited:14Cited References Count:64

}, month = {Jul-Aug}, pages = {373-382}, abstract = {

P\>Genetic and developmental alterations associated with the evolution of amphibian direct development remain largely unexplored. Specifically, little is known of the underlying expression of skeletal regulatory genes, which may reveal early modifications to cranial ontogeny in direct-developing species. We describe expression patterns of three key skeletal regulators (runx2, sox9, and bmp4) along with the cartilage-dominant collagen 2 alpha 1 gene (col2a1) during cranial development in the direct-developing anuran, Eleutherodactylus coqui. Expression patterns of these regulators reveal transient skeletogenic anlagen that correspond to larval cartilages, but which never fully form in E. coqui. Suprarostral anlagen in the frontonasal processes are detected through runx2, sox9, and bmp4 expression. Previous studies have described these cartilages as missing from Eleutherodactylus cranial ontogeny. These transcriptionally active suprarostral anlagen fuse to the more posterior cranial trabeculae before they are detectable with col2a1 staining or with the staining techniques used in earlier studies. Additionally, expression of sox9 fails to reveal an early anterior connection between the palatoquadrate and the neurocranium, which is detectable through sox9 staining in Xenopus laevis embryos (a metamorphosing species). Absence of this connection validates an instance of developmental repatterning, where the larval quadratocranial commissure cartilage is lost in E. coqui. Expression of runx2 reveals dermal-bone precursors several developmental stages before their detection with alizarin red. This early expression of runx2 correlates with the accelerated embryonic onset of bone formation characteristic of E. coqui and other direct-developing anurans, but which differs from the postembryonic bone formation of most metamorphosing species. Together these results provide an earlier depiction of cranial patterning in E. coqui by using earlier markers of skeletogenic cell differentiation. These data both validate and modify previously reported instances of larval recapitulation and developmental repatterning associated with the evolution of anuran direct development.

}, keywords = {anura, bone, chondrogenesis, Evolution, ii collagen, life-history, limb, neural crest development, skeletal development, xenopus-laevis}, isbn = {1520-541X}, author = {Kerney, R. and Gross, J. B. and Hanken, J.} } @article {561861, title = {Homoplastic evolution of external colouration in Asian stout newts (Pachytriton) inferred from molecular phylogeny}, journal = {Zoologica Scripta}, volume = {39}, number = {1}, year = {2010}, note = {

541DBTimes Cited:12Cited References Count:62

}, month = {Jan}, pages = {9-22}, abstract = {

Wu, Y., Wang, Y., Jiang, K., Chen, X. \& Hanken, J. (2010). Homoplastic evolution of external colouration in Asian stout newts (Pachytriton) inferred from molecular phylogeny.-Zoologica Scripta, 39, 9-22.The Asian stout newts of the genus Pachytriton (Salamandridae) inhabit montane streams in south-eastern China. Despite their abundance in the pet trade, the phylogeny and systematics of this genus are poorly understood. Colouration is often used to delimit species under the assumption that consistent chromatic differences characterize independent evolutionary lineages. We present the first phylogenetic study of Pachytriton that incorporates 2.35 kb of mitochondrial DNA (ND2, cytb) and 1.2 kb of nuclear sequence data (RAG-1) along with morphometric characters to infer evolutionary relationships and patterns of colour evolution among the three described species: Pachytriton brevipes, Pachytriton labiatus and Pachytriton archospotus. Our results support the monophyly of Pachytriton and recover P. archospotus as the sister taxon to P. brevipes. Monophyly of P. labiatus is significantly rejected: south-western populations are sister to the group of P. brevipes plus P. archospotus, whereas north-eastern populations nest with P. brevipes. The two geographic units are further separated by multivariate morphological analyses. South-western P. labiatus is the type species; misidentification of north-eastern populations as P. labiatus results from their similar colouration. An unspotted, dark brown dorsum is the likely ancestral state for the genus, whereas black-spotted colouration characterized the common ancestor of P. brevipes, P. archospotus, and north-eastern P. labiatus and was secondarily lost in the latter group. Homoplastic evolution and intraspecific variation render colour pattern in Pachytriton an unreliable character for delimiting species boundaries. North-eastern populations of P. labiatus are declining as the result of human collection and habitat destruction and are in urgent need of conservation protection.

}, keywords = {caudata, China, complete mitochondrial genomes, DNA, family salamandridae amphibia, inference, malagasy poison frogs, patterns, species-level, trees}, isbn = {0300-3256}, author = {Wu, Y. K. and Wang, Y. Z. and Jiang, K. and Chen, X. and Hanken, J.} } @article {561866, title = {A new newt of the genus Cynops (Caudata: Salamandridae) from Fujian Province, southeastern China}, journal = {Zootaxa}, number = {2346}, year = {2010}, note = {

548SNTimes Cited:8Cited References Count:20

}, month = {Jan 28}, pages = {42-52}, abstract = {

A new species of fire-bellied newt, Cynops fudingensis, is described from northeastern Fujian Province, southeastern China. This species forms a well-supported clade with C. orientalis and C. orphicus based on molecular phylogenetic analysis of nucleotide sequences from mitochondrial DNA subunit two of NADH dehydrogenase and its two flanking tRNAs. Further, its genetic distance to each of the two previously described species is large. Principal-components analysis of external linear measurements differentiates the new species from C. orientalis and C. orphicus in morphological space. Geographically, C. fudingensis occupies the distribution gap between C. orientalis and C. orphicus.

}, keywords = {amphibia, molecular phylogeny, new species, Phylogeny, salamanders, Taxonomy}, isbn = {1175-5326}, author = {Wu, Y. K. and Wang, Y. Z. and Jiang, K. and Hanken, J.} } @article {561841, title = {A new species of newt of the genus Paramesotriton (Salamandridae) from southwestern Guangdong, China, with a new northern record of P. longliensis from western Hubei}, journal = {Zootaxa}, number = {2494}, year = {2010}, note = {

607FVTimes Cited:5Cited References Count:33

}, month = {Jun 4}, pages = {45-58}, abstract = {

We report two previously unknown populations of Asian warty newts (Salamandridae: Paramesotriton) in China. The first population, from southwestern Guangdong, is described as a new species, which is closely related to P. guangxiensis based on morphological and molecular data. The second new population, from western Hubei, is assigned to P. longliensis, which extends the known range of this species 400 km northwards. Limited genetic differentiation between P. longliensis and P. zhijinensis suggests that these two names may refer to the same (single) species.

}, keywords = {amphibia, biogeography, caudata salamandridae, complete mitochondrial genomes, Evolution, mitochondrial DNA, molecular phylogeny, phylogenetics, province, salamander, Taxonomy, trees}, isbn = {1175-5326}, author = {Wu, Y. K. and Jiang, K. and Hanken, J.} } @article {561596, title = {Regulatory elements of Xenopus col2a1 drive cartilaginous gene expression in transgenic frogs}, journal = {International Journal of Developmental Biology}, volume = {54}, number = {1}, year = {2010}, note = {

562RKTimes Cited:7Cited References Count:71

}, pages = {141-150}, abstract = {

This study characterizes regulatory elements of collagen2 alpha 7 (col2a1) in Xenopus that enable transgene expression in cartilage-forming chondrocytes. The reporters described in this study drive strong cartilage-specific gene expression, which will be a valuable tool for further investigations of Xenopus skeletal development. While endogenous col2a1 mRNA is expressed in many embryonic tissues, its expression becomes restricted to tadpole and adult chondrocytes. This chondrocyte-specific expression is recapitulated by col2a1 reporter constructs, which were tested through I-Scel meganuclease-mediated transgenesis. These constructs contain a portion of the Xenopus tropicalis col2a1 intron, which aligns to a cartilage-specific intronic enhancer that has been well characterized in mammals. Two overlapping regions of the first intron that are 1.5-Kb and 665-bp long, both of which contain this enhancer sequence, drove EGFP expression in both larval and adult chondrocytes when connected to an upstream promoter. However, neither a truncated 155-bp region that also contains the enhancer, nor a separate 347-bp intronic region that lacks it, was able to drive cartilaginous transgene expression. The two cartilage-specific transgenes are heritable in F1 progeny, which exhibit none of the background expression observed in the injected founders. This study is the first to use the I-Scel technique to characterize an enhancer element in Xenopus, and the first to generate chondrocyte-specific gene expression in a non-mammalian vertebrate. The creation of novel cartilage-specific gene expression provides a new tool for further studies of anuran skeletal development.

}, keywords = {chondrocyte, chondrocyte-specific enhancer, col2a1, col2a1 gene, connective-tissue, factor sox9, highly efficient transgenesis, i-scei meganuclease, meganuclease, neural crest development, pro-alpha-1(ii) collagen gene, sox9, tissue-specific expression, transient expression, xenopus}, isbn = {0214-6282}, author = {Kerney, R. and Hall, B. K. and Hanken, J.} } @inbook {586271, title = {David B. Wake}, booktitle = {Evolution: The First Four Billion Years}, year = {2009}, pages = {901-902}, publisher = {Harvard University Press}, organization = {Harvard University Press}, address = {Cambridge}, author = {Hanken, J.}, editor = {Ruse, M. and Travis, J.} } @article {586266, title = {Rx for human (and planetary) health [review of E. Chivian and A Bernstein, eds.; Sustaining Life: How Human Health Depends on Biodiversity}, journal = {ReVista [Harvard Review of Latin America]}, volume = {8}, year = {2009}, pages = {64-66}, author = {Hanken, J.} } @article {561846, title = {A new species of the genus Paramesotriton (Caudata: Salamandridae) from Guangxi Zhuang Autonomous Region, southern China}, journal = {Zootaxa}, number = {2060}, year = {2009}, note = {

426PHTimes Cited:9Cited References Count:26

}, month = {Apr 1}, pages = {59-68}, abstract = {

A new species of Asian warty newt, Paramesotriton ermizhaoi, is described from Guangxi Zhuang Autonomous Region in southern China. This species is easily distinguished from other congeners by external morphology and osteology. Phylogenetic analyses based on mitochondrial data place P. ermizhaoi as a possible sister taxon to P. hongkongensis and P. chinensis. The number of trunk vertebrae varies from 12 to 13 in the new species. The relationship between P. ermizhaoi and a potentially new Pachytriton species (Pachytriton C), and the Guangxi population of P. chinensis is briefly discussed.

}, keywords = {amphibia, caudata, family salamandridae, new species, paramesotriton ermizhaoi, Phylogeny, salamandridae, southern china}, isbn = {1175-5326}, author = {Wu, Y. K. and Rovito, S. M. and Papenfuss, T. J. and Hanken, J.} } @inbook {587211, title = {Bolitoglossa bramei}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Wake, D. and Hanken, J. and Bola{\~n}os, F.} } @inbook {587241, title = {Bolitoglossa copia}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Ib{\'a}{\~n}ez, R. and Wake, D.} } @inbook {587216, title = {Bolitoglossa gomezi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Wake, D. and Hanken, J. and Bola{\~n}os, F.} } @inbook {587246, title = {Bolitoglossa magnifica}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Ib{\'a}{\~n}ez, R. and Wake, D.} } @inbook {587256, title = {Bolitoglossa obscura}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Wake, D. and Bola{\~n}os, F.} } @inbook {587251, title = {Bolitoglossa sombra}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Ib{\'a}{\~n}ez, R. and Wake, D. and Bola{\~n}os, F. and Chaves, G.} } @inbook {587181, title = {Chiropterotriton arboreus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Papenfuss, T. and Hanken, J.} } @inbook {587191, title = {Chiropterotriton larvae}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Raffaelli, J. and Hanken, J.} } @inbook {587231, title = {Pseudoeurycea boneti}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Wake, D. and Parra-Olea, G. and Hanken, J.} } @inbook {587226, title = {Pseudoeurycea maxima}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Wake, D. and Papenfuss, T. and Hanken, J.} } @inbook {587201, title = {Psudoeurycea tlilicxitl}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Wake, D. and Hanken, J.} } @inbook {587036, title = {Thorius arboreus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587041, title = {Thorius aureus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587046, title = {Thorius boreas}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587051, title = {Thorius lunaris}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587011, title = {Thorius omiltemi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {587056, title = {Thorius papaloae}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587196, title = {Thorius pennatulus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Raffaelli, J. and Hanken, J.} } @inbook {587016, title = {Thorius pulmonaris}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {587021, title = {Thorius schmidti}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {587026, title = {Thorius smithi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {587061, title = {Thorius spilogaster}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J. and Garc{\'\i}a-Par{\'\i}s, M.} } @inbook {587031, title = {Thorius troglodytes}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586496, title = {Chiropterotriton chiropterus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586491, title = {Bolitoglossa macrinii}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586501, title = {Chiropterotriton magnipes}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586506, title = {Cryptotriton adelos}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586511, title = {Cryptotriton alvarezdeltoroi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586516, title = {Pseudoeurycea ahuitzotl}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586521, title = {Pseudoeurycea amuzga}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.q} } @inbook {586526, title = {Pseudoeurycea anitae}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586531, title = {Pseudoeurycea conanti}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586536, title = {Pseudoeurycea mixcoatl}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586461, title = {Pseudoeurycea obesa}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Wake, D.} } @inbook {586466, title = {Pseudoeurycea papenfussi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, edition = {Version 2012.2}, url = {http://www.iucnredlist.org}, author = {Hanken, J. and Wake, D. and Papenfuss, T.} } @inbook {586541, title = {Pseudoeurycea robertsi}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586546, title = {Pseudoeurycea ruficauda}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586551, title = {Pseudoeurycea tenchalli}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586556, title = {Pseudoeurycea teotepec}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586566, title = {Pseudoeurycea tlahcuiloh}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586571, title = {Pseudoeurycea unguidentis}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586576, title = {Thorius dubitus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586476, title = {Thorius grandis}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D.} } @inbook {586481, title = {Thorius infernalis}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Garc{\'\i}a-Par{\'\i}s, M. and Hanken, J.} } @inbook {586591, title = {Thorius insperatus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586596, title = {Thorius macdougalli}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586601, title = {Thorius magnipes}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586606, title = {Thorius minutissimus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586611, title = {Thorius minydemus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {586486, title = {Thorius narismagnus}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Garc{\'\i}a-Par{\'\i}s, M. and Hanken, J.} } @inbook {586616, title = {Thorius narisovalis}, booktitle = {IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2}, year = {2008}, url = {http://www.iucnredlist.org}, author = {Parra-Olea, G. and Wake, D. and Hanken, J.} } @inbook {585011, title = {Pickled frogs help biodiversity assessment}, booktitle = {Threatened Amphibians of the World}, year = {2008}, pages = {45}, publisher = {Lynx Edicions, IUCN, and Conservation International}, organization = {Lynx Edicions, IUCN, and Conservation International}, address = {Barcelona, Gland, Arlington}, author = {Meegaskumbura, M. and Pethiyagoda, R. and Chanson, J. and Wake, D. and Hanken, J.}, editor = {Stuart, S. and Hoffmann, M. and Chanson, J. and Cox, N. and Berridge, R. and Ramani, P. and Young, B.} } @article {561121, title = {Concealed weapons: erectile claws in African frogs}, journal = {Biology Letters}, volume = {4}, number = {4}, year = {2008}, note = {

322TRTimes Cited:5Cited References Count:18

}, month = {Aug 23}, pages = {355-357}, abstract = {

Vertebrate claws are used in a variety of important behaviours and are typically composed of a keratinous sheath overlying the terminal phalanx of a digit. Keratinous claws, however, are rare in living amphibians; their microstructure and other features indicate that they probably originated independently from those in amniotes. Here we show that certain African frogs have a different type of claw, used in defence, that is unique in design among living vertebrates and lacks a keratinous covering. These frogs have sectorial terminal phalanges on their hind feet that become functional by cutting through the skin. In the resting state, the phalanx is subdermal and attached to a distal bony nodule, a neomorphic skeletal element, via collagen-rich connective tissue. When erected, the claw breaks free from the nodule and pierces the ventral skin. The nodule, suspended by a sheath attached to the terminal phalanx and supported by collagenous connections to the dermis, remains fixed in place. While superficially resembling the shape of claws in other tetrapods, these are the only vertebrate claws known to pierce their way to functionality.

}, keywords = {anura, arthroleptidae, functional morphology, limb anatomy, morphological novelty, regeneration, Vertebrates, xenopus}, isbn = {1744-9561}, author = {Blackburn, D. C. and Hanken, J. and Jenkins, F. A.} } @article {561886, title = {DNA damage in preserved specimens and tissue samples: a molecular assessment}, journal = {Frontiers in Zoology}, volume = {5}, year = {2008}, note = {

371KPTimes Cited:22Cited References Count:37

}, month = {Oct 23}, abstract = {

The extraction of genetic information from preserved tissue samples or museum specimens is a fundamental component of many fields of research, including the Barcode of Life initiative, forensic investigations, biological studies using scat sample analysis, and cancer research utilizing formaldehyde-fixed, paraffin-embedded tissue. Efforts to obtain genetic information from these sources are often hampered by an inability to amplify the desired DNA as a consequence of DNA damage. Previous studies have described techniques for improved DNA extraction from such samples or focused on the effect of damaging agents - such as light, oxygen or formaldehyde - on free nucleotides. We present ongoing work to characterize lesions in DNA samples extracted from preserved specimens. The extracted DNA is digested to single nucleosides with a combination of DNase I, Snake Venom Phosphodiesterase, and Antarctic Phosphatase and then analyzed by HPLC-ESI-TOF-MS. We present data for moth specimens that were preserved dried and pinned with no additional preservative and for frog tissue samples that were preserved in either ethanol, or formaldehyde, or fixed in formaldehyde and then preserved in ethanol. These preservation methods represent the most common methods of preserving animal specimens in museum collections. We observe changes in the nucleoside content of these samples over time, especially a loss of deoxyguanosine. We characterize the fragmentation state of the DNA and aim to identify abundant nucleoside lesions. Finally, simple models are introduced to describe the DNA fragmentation based on nicks and double-strand breaks.

}, keywords = {ancient DNA, bases, degradation, depurination, endocyclic imino groups, formaldehyde, formalin, nucleotide-sequence, probe, real-time pcr}, isbn = {1742-9994}, author = {Zimmermann, J. and Hajibabaei, M. and Blackburn, D. C. and Hanken, J. and Cantin, E. and Posfai, J. and Evans, T. C.} } @article {561601, title = {Gene expression reveals unique skeletal patterning in the limb of the direct-developing frog, Eleutherodactylus coqui}, journal = {Evolution \& Development}, volume = {10}, number = {4}, year = {2008}, note = {

325JTTimes Cited:10Cited References Count:53

}, month = {Jul-Aug}, pages = {439-448}, abstract = {

The growing field of skeletal developmental biology provides new molecular markers for the cellular precursors of cartilage and bone. These markers enable resolution of early features of skeletal development that are otherwise undetectable through conventional staining techniques. This study investigates mRNA distributions of skeletal regulators runx2 and sox9 along with the cartilage-dominant collagen 2(alpha)1 (col2a1) in embryonic limbs of the direct-developing anuran, Eleutherodactylus coqui. To date, distributions of these genes in the limb have only been examined in studies of the two primary amniote models, mouse and chicken. In E coqui, expression of transcription factors runx2 and sox9 precedes that of col2a1 by 0.5-1 developmental stage (approximately 12-24 h). Limb buds of E. coqui contain unique distal populations of both runx2- and sox9-expressing cells, which appear before formation of the primary limb axis and do not express col2a1. The subsequent distribution of col2a1 reveals a primary limb axis similar to that described for Xenopus laevis. Precocious expression of both runx2 and sox9 in the distal limb bud represents a departure from the conserved pattern of proximodistal formation of the limb skeleton that is central to prevailing models of vertebrate limb morphogenesis. Additionally, runx2 is expressed in the early joint capsule perichondria of the autopod and in the perichondria of long bones well before periosteum formation. The respective distributions of sox9 and col2a1 do not reveal the joint perichondria but instead are expressed in the fibrocartilage that fills each presumptive joint capsule. These distinct patterns of runx2- and sox9-expressing cells reveal precursors of chondrocyte and osteoblast lineages well before the appearance of mature cartilage and bone.

}, keywords = {amphibia, anura, apical ectodermal ridge, chondrogenesis, ii collagen, osteoblast differentiation, runx2, sox9, vertebrate limb, xenopus-laevis}, isbn = {1520-541X}, author = {Kerney, R. and Hanken, J.} } @article {561251, title = {Review of fate-mapping studies of osteogenic cranial neural crest in vertebrates}, journal = {Developmental Biology}, volume = {317}, number = {2}, year = {2008}, note = {

301LVTimes Cited:45Cited References Count:101

}, month = {May 15}, pages = {389-400}, abstract = {

Recent years have witnessed renewed interest in defining the embryonic cell populations that directly contribute to the bony skull. This question lies at the intersection of several important developmental, clinical and evolutionary interests. Until recently, our collective understanding of the embryonic origin of the vertebrate osteocranium has been based on a small number of reports published solely using avian models. As data gradually accumulates from other, distantly related species (e.g., mouse and frog), we can begin to evaluate long-standing assumptions regarding the behavior of osteogenic (bone-forming) neural crest cells within a wider phylogenetic and comparative context. In this review, we summarize data collected to date in three major vertebrate taxa: amphibians, birds and mammals. We highlight three largely unexplored topics within the field of osteogenic neural crest development: 1) disagreements in bone tissue origin within and across current model systems; 2) whether the pattern of neural crest cell contribution to skull bone is evolutionarily conservative or labile; and 3) how our understanding of development and morphology will benefit from fate maps using currently unexamined animal models. (C) 2008 Elsevier Inc. All rights reserved.

}, keywords = {chelydra-serpentina, connective tissues, head skeleton, homology, mammalian skull vault, osteocranium, paraxial mesoderm, plastron bones, quail-chick chimeras, Skull, treacher-collins-syndrome, Vertebrates, visceral skeleton, xenopus-laevis}, isbn = {0012-1606}, author = {Gross, J. B. and Hanken, J.} } @article {561246, title = {Segmentation of the vertebrate skull: neural-crest derivation of adult cartilages in the clawed frog, Xenopus laevis}, journal = {Integrative and Comparative Biology}, volume = {48}, number = {5}, year = {2008}, note = {

373OITimes Cited:10Cited References Count:71

}, month = {Nov}, pages = {681-696}, abstract = {

We utilize a novel, transgenic cell-labeling system to assess the embryonic derivation of cartilages in the post-metamorphic skull of anuran amphibians. Many of these cartilages form de novo at metamorphosis and have no obvious precursors within the larval skeleton. Most adult cartilages are derived from mandibular- or hyoid-stream neural crest, either individually or in combination; branchial-stream neural crest makes a modest contribution. Each stream also contributes to at least one cartilage in the middle ear or external ear. Four cartilages are composite elements; each is derived from at least two distinct cell populations. Many boundaries between adjacent neural-crest territories are cryptic insofar as they do not coincide with anatomical boundaries. The system of adult cranial segmentation revealed by these fate-mapping results differs in important respects from both the segmentation of the ontogenetically earlier larval skull and the cranial segmentation in amniotes. Most striking is the rostral inversion of neural-crest-derived cartilages in Xenopus, such that mandibular stream-derived elements are deployed caudal to those derived from the hyoid stream, which predominate anteriorly. This novel pattern of rostral segmentation may be a consequence of the complex, biphasic life history that is characteristic of most species of living amphibians, and especially anurans, in which cranial architecture is significantly reconfigured at metamorphosis. Neural-crest derivation of the vertebrate skull is not invariant; instead, embryonic derivation of individual components of the cranial skeleton may vary widely among species.

}, keywords = {amphibian metamorphosis, anura, bombina-orientalis, eleutherodactylus-coqui, fate, fire-bellied toad, head, middle-ear, programmed cell-death, skeletal}, isbn = {1540-7063}, author = {Gross, J. B. and Hanken, J.} } @inbook {585041, title = {Systematics and Conservation}, booktitle = {Amphibian Conservation Action Plan}, year = {2007}, pages = {45-48}, publisher = {IUCN/SSC Amphibian Specialist Group}, organization = {IUCN/SSC Amphibian Specialist Group}, address = {Gland and Cambridge}, author = {Parra, G. and Brown, R. and Hanken, J. and Hedges, B. and Heyer, R. and Kuzmin, S. and Lavilla, E. and L{\"o}tters, S. and Pimenta, B. and Richards, S. and R{\"o}del, M.O. and de S{\'a}, R.O. and Wake, D.B.}, editor = {Gascon, C. and Collins, J.P. and Moore, R.D. and Church, D.R. and McKay, J.E. and Mendelson III, J.R.} } @article {561611, title = {Cranial ontogeny in Philautus silus (Anura : Ranidae : Rhacoohorinae) reveals few similarities with other direct-developing anurans}, journal = {Journal of Morphology}, volume = {268}, number = {8}, year = {2007}, note = {

198LUTimes Cited:15Cited References Count:54

}, month = {Aug}, pages = {715-725}, abstract = {

Direct development has evolved in rhacophorine frogs independently from other anuran lineages, thereby offering an opportunity to assess features associated with this derived life history. Using a developmental series of the direct-developing Philautus silus (Ranidae: Rhaeophorinae) from Sri Lanka, we examine features of cranial morphology that are part of a suite of adaptations that facilitate feeding in free-living tadpoles, but have been changed or lost in other direct-developing lineages. Larval-specific upper jaw cartilages, which are absent from many non-rhacophorine direct-developing species (such as Eleutherodactylus coqui), develop in embryos of P. silus. Similarly, lower jaw cartilages initially assume a larval morphology, which is subsequently remodeled into the adult jaw configuration before hatching. However, the cartilaginous jaw suspension and hyobranchial skeleton never assume a typical larval morphology. The palatoquadrate, which suspends the lower jaw, lacks the posterior connections to the braincase found in many metamorphosing species. Unlike in metamorphosing species, bone formation in P. silus begins before hatching. However, the sequence of bone formation resembles that of metamorphosing anurans more than that of other direct developers. In particular, P. silus does not exhibit precocious ossification of the lower jaw, which is characteristic of some frogs and caecilians that lack a free-living tadpole. These data reveal some similarities between Philautus and other direct-developing anurans. However, the departure of Philautus embryos from the generalized tadpole skeletal morphology is less pronounced than that observed in other direct-developing taxa.

}, keywords = {amphibia, anura, developmental biology, direct development, eleutherodactylus-coqui anura, Evolution, frogs, life history evolution, Morphology, ossification, pipa, repatterning, skeletal development, tadpoles}, isbn = {0362-2525}, author = {Kerney, R. and Meegaskumbura, M. and Manamendra-Arachchi, K. and Hanken, J.} } @article {561586, title = {Runx2 is essential for larval hyobranchial cartilage formation in Xenopus laevis}, journal = {Developmental Dynamics}, volume = {236}, number = {6}, year = {2007}, note = {

178MKTimes Cited:19Cited References Count:73

}, month = {Jun}, pages = {1650-1662}, abstract = {

The vertebrate transcription factor protein Runx2 is regarded as a "master regulator" of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre-hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in cartilage differentiation is shared between zebrafish and Xenopus. A combination of morpholino oligonucleotide injections and neural crest transplants indicate that Runx2 is involved in differentiation of the cartilaginous hyobranchial skeleton in the frog, Xenopus laevis. Additionally, in situ hybridizations show runx2 mRNA expression in mesenchymal precursors of the cartilaginous skull, which reveals the earliest pre-patterning of these cartilages described to date. The early distribution of runx2 resolves the homology of the larval suprarostral plate, which is one of the oldest controversies of anuran skull development. Together these data reveal a shift in Runx2 protein function during vertebrate evolution towards its exclusive roles in cartilage hypertrophy and bone differentiation within the amniote lineage.

}, keywords = {cartilage formation, cbfa1, chondrocyte maturation, cleidocranial dysplasia, condylar cartilage, Evolution, expression patterns, ii collagen, neural crest development, osteoblast differentiation, pipidae, runx2, skeletal development, suprarostral, transcription factor, xxenopus laevis}, isbn = {1058-8388}, author = {Kerney, R. and Gross, J. B. and Hanken, J.} } @article {561111, title = {Forelimb-hindlimb developmental timing changes across tetrapod phylogeny}, journal = {Bmc Evolutionary Biology}, volume = {7}, year = {2007}, note = {

252KHTimes Cited:42Cited References Count:34

}, month = {Oct 1}, pages = {182}, abstract = {

Background: Tetrapods exhibit great diversity in limb structures among species and also between forelimbs and hindlimbs within species, diversity which frequently correlates with locomotor modes and life history. We aim to examine the potential relation of changes in developmental timing (heterochrony) to the origin of limb morphological diversity in an explicit comparative and quantitative framework. In particular, we studied the relative time sequence of development of the forelimbs versus the hindlimbs in 138 embryos of 14 tetrapod species spanning a diverse taxonomic, ecomorphological and life-history breadth. Whole- mounts and histological sections were used to code the appearance of 10 developmental events comprising landmarks of development from the early bud stage to late chondrogenesis in the forelimb and the corresponding serial homologues in the hindlimb.Results: An overall pattern of change across tetrapods can be discerned and appears to be relatively clade- specific. In the primitive condition, as seen in Chondrichthyes and Osteichthyes, the forelimb/ pectoral fin develops earlier than the hindlimb/ pelvic fin. This pattern is either retained or re- evolved in eulipotyphlan insectivores (= shrews, moles, hedgehogs, and solenodons) and taken to its extreme in marsupials. Although exceptions are known, the two anurans we examined reversed the pattern and displayed a significant advance in hindlimb development. All other species examined, including a bat with its greatly enlarged forelimbs modified as wings in the adult, showed near synchrony in the development of the fore and hindlimbs.Conclusion: Major heterochronic changes in early limb development and chondrogenesis were absent within major clades except Lissamphibia, and their presence across vertebrate phylogeny are not easily correlated with adaptive phenomena related to morphological differences in the adult fore- and hindlimbs. The apparently conservative nature of this trait means that changes in chondrogenetic patterns may serve as useful phylogenetic characters at higher taxonomic levels in tetrapods. Our results highlight the more important role generally played by allometric heterochrony in this instance to shape adult morphology.

}, keywords = {Evolution, framework, Genes, heterochrony, limb development, origin, patterns, sequences}, isbn = {1471-2148}, author = {Bininda-Emonds, O. R. P. and Jeffery, J. E. and Sanchez-Villagra, M. R. and Hanken, J. and Colbert, M. and Pieau, C. and Selwood, L. and ten Cate, C. and Raynaud, A. and Osabutey, C. K. and Richardson, M. K.} } @article {561821, title = {Montane salamanders from the Costa Rica-Panama border region, with descriptions of two new species of Bolitoglossa}, journal = {Copeia}, number = {3}, year = {2007}, note = {

210WTTimes Cited:9Cited References Count:19

}, month = {Sep 10}, pages = {556-565}, abstract = {

Two new species of lungless salamanders (Plethodontidae) are described from montane habitats of eastern Costa Rica and adjacent western Panama. Bolitoglossa gomezi and B. bramei are distinguished from each other and from other salamander species in this remote area in adult body size, external proportions, foot webbing, tooth counts, and/or external coloration. Both new species are assigned to the B. subpalmata species group, subgenus Eladinea. A newly identified specimen of Bolitoglossa anthracina-only the fourth known specimen of this rare species in collections-is reported from the same region. Salamander species diversity along the border between Costa Rica and Panama is exceptionally large, at present comprising 22 named and two unnamed forms.

}, keywords = {caudata, genus bolitoglossa, large black salamander, plethodontidae}, isbn = {0045-8511}, author = {Wake, D.B. and Savage, J. M. and Hanken, J.} } @proceedings {586281, title = {Overcoming the digitization bottleneck in natural history collections: A summary report on a workshop held 7-9 September 2006 at Harvard University}, year = {2006}, publisher = {Natural Science Collections Alliance, Washington, DC}, author = {Beaman, R. and Macklin, J. and Donoghue, M. and Hanken, J.} } @article {586276, title = {A Savage approach to tropical biology [review of M.A. Donnelly, B.I. Brother, C. Guyer, M.H. Wake, and M.E. White, eds., Ecology and Evolution in the Tropics: A Herpetological Perspective]}, journal = {BioScience}, volume = {56}, year = {2006}, pages = {936-937}, author = {Hanken, J.} } @article {561256, title = {Use of a ROSA26 : GFP transgenic line for long-term Xenopus fate-mapping studies}, journal = {Journal of Anatomy}, volume = {209}, number = {3}, year = {2006}, note = {

076VYTimes Cited:14Cited References Count:39

}, month = {Sep}, pages = {401-413}, abstract = {

Widespread and persistent marker expression is a prerequisite for many transgenic applications, including chimeric transplantation studies. Although existing transgenic tools for the clawed frog, Xenopus laevis, offer a number of promoters that drive widespread expression during embryonic stages, obtaining transgene expression through metamorphosis and into differentiated adult tissues has been difficult to achieve with this species. Here we report the application of the murine ROSA26 promoter in Xenopus. GFP is expressed in every transgenic tissue and cell type examined at post-metamorphic stages. Furthermore, transgenic ROSA26:GFP frogs develop normally, with no apparent differences in growth or morphology relative to wild-type frogs. ROSA26 transgenes may be used as a reliable marker for embryonic fate-mapping of adult structures in Xenopus laevis. Utility of this transgenic line is illustrated by its use in a chimeric grafting study that demonstrates the derivation of the adult bony jaw from embryonic cranial neural crest.

}, keywords = {bone, cells, chimera, cranial neural crest, developmental biology, embryos, expression, green fluorescent protein, laevis, marker, Skull, skull vault, tail regeneration, Vertebrates}, isbn = {0021-8782}, author = {Gross, J. B. and Hanken, J. and Oglesby, E. and Marsh-Armstrong, N.} } @article {586286, title = {Wrangling about reefs [review of D. Dobbs, Reef Madness: Charles Darwin, Alexander Agassiz, and the Meaning of Coral]}, journal = {Harvard Magazine}, volume = {107}, year = {2005}, pages = {20-24}, author = {Hanken, J.} } @article {561241, title = {Cranial neural crest contributes to the bony skull vault in adult Xenopus laevis: Insights from cell labeling studies}, journal = {Journal of Experimental Zoology Part B-Molecular and Developmental Evolution}, volume = {304B}, number = {2}, year = {2005}, note = {

913THTimes Cited:28Cited References Count:34

}, month = {Mar 15}, pages = {169-176}, abstract = {

As a step toward resolving the developmental origin of the ossified skull in adult anurans, we performed a series of cell labeling and grafting studies of the cranial neural crest (CNC) in the clawed frog, Xenopus laevis. We employ an indelible, fixative-stable fluorescent dextran as a cell marker to follow migration of the three embryonic streams of cranial neural crest and to directly assess their contributions to the bony skull vault, which forms weeks after hatching. The three streams maintain distinct boundaries in the developing embryo. Their cells proliferate widely through subsequent larval (tadpole) development, albeit in regionally distinct portions of the head. At metamorphosis, each stream contributes to the large frontoparietal bone, which is the primary constituent of the skull vault in adult anurans. The streams give rise to regionally distinct portions of the bone, thereby preserving their earlier relative position anteroposteriorly within the embryonic neural ridge. These data, when combined with comparable experimental observations from other model species, provide insights into the ancestral pattern of cranial development in tetrapod vertebrates as well as the origin of differences reported between birds and mammals. (c) 2005 Wiley-Liss, Inc.

}, keywords = {anura, head, marker, skeletal, transplantation, urodeles}, isbn = {1552-5007}, author = {Gross, J. B. and Hanken, J.} } @article {561406, title = {Evolution of cranial development and the role of neural crest: insights from amphibians}, journal = {Journal of Anatomy}, volume = {207}, number = {5}, year = {2005}, note = {

980EVTimes Cited:26Cited References Count:57

}, month = {Nov}, pages = {437-446}, abstract = {

Contemporary studies of vertebrate cranial development document the essential role played by the embryonic neural crest as both a source of adult tissues and a locus of cranial form and patterning. Yet corresponding and basic features of cranial evolution, such as the extent of conservation vs. variation among species in the contribution of the neural crest to specific structures, remain to be adequately resolved. Investigation of these features requires comparable data from species that are both phylogenetically appropriate and taxonomically diverse. One key group are amphibians, which are uniquely able to inform our understanding of the ancestral patterns of ontogeny in fishes and tetrapods as well as the evolution of presumably derived patterns reported for amniotes. Recent data support the hypothesis that a prominent contribution of the neural crest to cranial skeletal and muscular connective tissues is a fundamental property that evolved early in vertebrate history and is retained in living forms. The contribution of the neural crest to skull bones appears to be more evolutionarily labile than that of cartilages, although significance of the limited comparative data is difficult to establish at present. Results underline the importance of accurate and reliable homology assessments for evaluating the contrasting patterns of derivation reported for the three principal tetrapod models: mouse, chicken and frog.

}, keywords = {ambystoma-mexicanum, bombina, bone, cells, cephalic mesoderm, connective tissues, embryos, Migration, muscle, origins, quail-chick chimeras, Skull, skull vault, xenopus, xenopus-laevis}, isbn = {0021-8782}, author = {Hanken, J. and Gross, J. B.} } @article {561806, title = {A new species of big black Bolitoglossa (Amphibia : Caudata) from central Panama}, journal = {Copeia}, number = {2}, year = {2005}, note = {

925NRTimes Cited:3Cited References Count:5

}, month = {May 9}, pages = {223-226}, abstract = {

A new species of Bolitoglossa is described from the Cordillera Central of central Panama. This is a large black species, which is likely related to the B. (Eladinea) schizodactyla group of Costa Rica and Panama. The new species, known from a single specimen, differs from other large black Bolitoglossa in having white pigmentation on the lower face and on the ventral portions of the head and chest. It also has more interdigital webbing than most members of the B. (E.) schizodactyla group.

}, keywords = {evolutionary, plethodontidae, salamanders}, isbn = {0045-8511}, author = {Wake, D.B. and Hanken, J. and Ibanez, R.} } @article {561551, title = {A solution to the large black salamander problem (genus Bolitoglossa) in Costa Rica and Panama}, journal = {Copeia}, number = {2}, year = {2005}, note = {

925NRTimes Cited:11Cited References Count:26

}, month = {May 9}, pages = {227-245}, abstract = {

Several populations of large (adult standard length, 43-134 mm) black salamanders of the widespread neotropical genus Bolitoglossa (Plethodontidae) are known from the cordilleras of western Panama and Costa Rica. These populations constitute at least seven species, including two recently described (B. anthracina, B. copia), one described long ago that remains poorly known (B. nigrescens), and three described herein as new. The long recognized, Aide-ranging B. robusta, which is distinguished by a pale, pigmented ring around the tail base and a unique combination of maxillary and vomerine tooth counts, may occur sympatrically with four of the other taxa. Differences in head and body form, adult size, cranial osteology, and maxillary and vomerine tooth counts separate all recognized taxa from one another. These results confirm and indeed increase the exceedingly high diversity of salamander species known from the Cordillera Talamanca-Baru of Costa Rica and Panama, diversity that now rivals that found anywhere else in the tropics.

}, keywords = {genetic differentiation}, isbn = {0045-8511}, author = {Hanken, J. and Wake, D.B. and Savage, J. M.} } @article {561696, title = {Two new species of Pseudoeurycea (Caudata : Plethodontidae) from the mountains of northern Oaxaca, Mexico}, journal = {Copeia}, number = {3}, year = {2005}, note = {

952WDTimes Cited:6Cited References Count:22

}, month = {Aug 2}, pages = {461-469}, abstract = {

We describe two new species of salamanders of the genus Pseudoeurycea from mountains in the northern part of the state of Oaxaca, Mexico. Pseudoeurycea papenfussi, a large, muscular member of the P gadovii group, occurs near the peaks (just below 3000 m) of the highest mountains of the Sierra de Juarez. It is related to P smithi, a more southerly species, and possibly to P aquatica, another species from Oaxaca. Pseudoeurycea obesa, a rotund member of the P leprosa group, is known only from the type locality in the Sierra Mazateca at the northernmost extremity of Oaxaca. It is related to P. werleri and P mystax, which are known from more southern parts of Oaxaca. These descriptions bring to 27 the number of species of salamanders known from Oaxaca. Most of these species are endemic to the state and are known only from regions that are undergoing rapid habitat modification and destruction.

}, keywords = {genus pseudoeurycea, juarez, neotropical salamanders, phylogenetic-relationships, sierra, thorius}, isbn = {0045-8511}, author = {Parra-Olea, G. and Garcia-Paris, M. and Hanken, J. and Wake, D.B.} } @article {561691, title = {A new species of arboreal salamander (Caudata : Plethodontidae : Pseudoeurycea) from the mountains of Oaxaca, Mexico}, journal = {Journal of Natural History}, volume = {38}, number = {16}, year = {2004}, note = {

823AHTimes Cited:6Cited References Count:33

}, month = {Sep}, pages = {2119-2131}, abstract = {

Recent surveys of the plethodontid salamander fauna of Oaxaca, Mexico, disclosed the existence of a new, morphologically distinct arboreal species of the genus Pseudoeurycea. The new species, described here, is from the Sierra Mazateca in northern Oaxaca. Sequences of 1833 base pairs of the 16S, cytochrome b and ND4 mitochondrial DNA ( mtDNA) genes from the new taxon were used to assess its phylogenetic position. Previous phylogenetic analyses based on mtDNA supported recognition of four clades within Pseudoeurycea: P. bellii, P. gadovii, P. juarezi and P. leprosa-Lineatriton species groups. One additional species, P. unguidentis, was not closely allied to any of the four groups. Re-analysis including the additional sequences reported here establishes a sister-group relationship between the new species and P. unguidentis. Moreover, it supports this clade as part of the P. juarezi species group.

}, keywords = {amphibia, bootstrap, caudata, confidence, DNA, likelihood, mexico, mitochondrial genome, model, new species, phylogenetic-relationships, plethodontidae, pseudoeurycea, sequence, substitution, Systematics, Taxonomy}, isbn = {0022-2933}, author = {Parra-Olea, G. and Garcia-Paris, M. and Hanken, J. and Wake, D.B.} } @article {561231, title = {Use of fluorescent dextran conjugates as a long-term marker of osteogenic neural crest in frogs}, journal = {Developmental Dynamics}, volume = {230}, number = {1}, year = {2004}, note = {

816FMTimes Cited:22Cited References Count:38

}, month = {May}, pages = {100-106}, abstract = {

The neural crest is a population of multipotent stem cells unique to vertebrates. In the head, cranial neural crest (CNC) cells make an assortment of differentiated cell types and tissues, including neurons, melanocytes, cartilage, and bone. The earliest understanding of the developmental potentiality of CNC cells came from classic studies using amphibian embryos. Fate maps generated from these studies have been largely validated in recent years. However, a fate map for the most late-developing structures in amphibians, and especially anurans (frogs), has never been produced. One such tissue type, skull bone, has been among the most difficult tissues to study due to the long time required for its development during anuran metamorphosis, which in some species may not occur until several months, or even years, after hatching. We report a relatively simple technique for studying this elusive population of neural crest-derived osteogenic (bone-forming) cells in Xenopus laevis by using fluorescently labeled dextran conjugates. (C) 2004 Wiley-Liss, Inc.

}, keywords = {amphibian, cells, cranial neural crest, embryo, fate, fate map, head, lineage marker, mammalian skull vault, Migration, pattern, transplantation, Vertebrates, xenopus}, isbn = {1058-8388}, author = {Gross, J. B. and Hanken, J.} } @inbook {585456, title = {Direct development}, booktitle = {Keywords \& Concepts in Evolutionary Developmental Biology}, year = {2003}, pages = {97-102}, publisher = {Harvard University Press}, organization = {Harvard University Press}, address = {Cambridge}, author = {Hanken, J.}, editor = {Hall, B. K. and Olson, W.M.} } @article {561786, title = {Developmental basis of evolutionary digit loss in the Australian lizard Hemiergis}, journal = {Journal of Experimental Zoology Part B-Molecular and Developmental Evolution}, volume = {297B}, number = {1}, year = {2003}, note = {

687DWTimes Cited:64Cited References Count:40

}, month = {Jun 15}, pages = {48-56}, abstract = {

Loss of limb skeletal elements is a recurring theme in tetrapod evolution, but the developmental mechanisms underlying this phenomenon remain largely unknown. The Australian lizard genus Hemiergis offers an excellent model system to study limb reduction among closely related, naturally occurring populations with different numbers of digits. Evolutionary digit loss in Hemiergis does not result from simple truncation of a pentadactyl skeletal developmental program. Rather, the duration of embryonic expression of the patterning molecule Sonic hedgehog (SHH) is shortened in limbs with reduced numbers of digits, and is correlated with decreased cell proliferation in the posterior aspect of the limb. Moreover, this comparative analysis suggests an early role for SHH in specification of digit identity and later importance in maintaining cell proliferation and survival. Subtle changes in spatial or temporal regulation of SHH may alter proliferation and patterning of the developing limb, thereby effecting divergence in adult limb morphology among closely related species. In contrast, expression of MSX and Distal-less proteins were similar among embryos from different populations. (C) 2003 Wiley Liss, Inc.

}, keywords = {Apoptosis, chick, expression, feedback loop, heterochrony, limb bud, reduction, shh, sonic-hedgehog, vertebrate}, isbn = {1552-5007}, author = {Shapiro, M. D. and Hanken, J. and Rosenthal, N.} } @article {586291, title = {NEON-V: CRIPTON Workshop (Collections, Research, Inventories, and People for Taxonomic Opportunities) - Final Report}, journal = {National Science Foundation, Washington, DC}, year = {2002}, author = {Sierwald, P. and Bieler, R. and Hanken, J. and Magil, R.} } @inbook {585471, title = {Eric Thomas Brazil Francis and the evolutionary morphology of salamanders. Introduction to the reprint of E.T.B. Francis}, booktitle = {The Anatomy of the salamander}, year = {2002}, pages = {v-xiv}, publisher = {Society for the Study of Amphibians and Reptiles}, organization = {Society for the Study of Amphibians and Reptiles}, address = {Ithaca}, author = {Hanken, J.} } @article {561216, title = {Cranial neural crest emergence and migration in the Mexican axolotl (Ambystoma mexicanum)}, journal = {Zoology (Jena)}, volume = {105}, number = {3}, year = {2002}, note = {

608UJTimes Cited:11Cited References Count:31

}, pages = {195-202}, abstract = {

The timing and pattern of cranial neural crest cell emergence and migration in the Mexican axolotl, Ambystoma mexicanum, are assessed using scanning electron microscopy (SEM). Cranial neural crest cells emerge and begin to migrate at the time of neural fold closure and soon form three distinct streams. The most anterior (mandibular) stream emerges first, at the level of the mesencephalon. Cells in this stream migrate rostroventrally around the optic vesicle. The second (hyoid) and third (branchial) streams emerge in close succession at the level of the rhombencephalon and extend ventrolaterally. Cells forming the hyoid stream migrate rostral to the otic vesicle, whereas the branchial stream divides into two parallel streams, which migrate caudal to the otic vesicle. At later stages (stage 26 onwards) the cranial neural crest cells disperse into the adjacent mesoderm and can no longer be followed by dissection and SEM. The pattern of cranial neural crest emergence and migration, and division into migratory streams is similar to that in other amphibians and in the Australian lungfish (Neoceratodus forsteri). Emergence of crest cells from the neural tube, relative to the time of neural tube closure, occurs relatively late in comparison to anurans, but much earlier than in the Australian lungfish. These results establish a morphological foundation for studies in progress on the further development and fate of cranial neural crest cells in the Mexican axolotl, as well as for studies of the role of cranial neural crest in cranial patterning.

}, keywords = {anuran amphibians, cell migration, direct-developing frog, eleutherodactylus-coqui, Evolution, head, head development, jaw, lampetra-japonica, nerves, pattern, pattern formation, salamander, transplantation}, isbn = {0944-2006}, author = {Falck, P. and Hanken, J. and Olsson, L.} } @article {561681, title = {Cranial neural crest-cell migration in the direct-developing frog, Eleutherodactylus coqui: molecular heterogeneity within and among migratory streams}, journal = {Zoology (Jena)}, volume = {105}, number = {1}, year = {2002}, note = {

592HRTimes Cited:14Cited References Count:86

}, pages = {3-13}, abstract = {

Direct development is a specialized reproductive mode that has evolved repeatedly in many different lineages of amphibians, especially anurans. A fully formed, albeit miniature adult hatches directly from the egg; there is no free-living larva. In many groups, the evolution of direct development has had profound consequences for cranial development and morphology, including many components that are derived from the embryonic neural crest. Yet, the developmental bases of these effects remain poorly known. In order to more fully characterize these changes, we used three molecular markers to analyze cranial neural crest-cell emergence and migration in the direct-developing frog, Eleutherodactylus coqui: HNK-1 immunoreactivity, Dlx protein expression, and cholinesterase activity. Our study validates and extends earlier results showing that the comprehensive changes in embryonic cranial patterning, differentiation, and developmental timing that are associated with direct development in Eleutherodactylus have not affected gross features of cranial neural crest biology: the relative timing of crest emergence and the number, configuration and identity of the principal migratory streams closely resemble those seen in metamorphic anurans. The three markers are variably expressed within and among neural crest-cell populations. This variation suggests that determination of cranial neural crest-cells may already have begun at or soon after the onset of migration, when the cells emerge from the neural tube. It is not known how or even if this variation correlates with differential cell lineage or fate. Finally, although HNK-1 expression is widely used to study neural crest migration in teleost fishes and amniotes, E. coqui is the only amphibian known in which it effectively labels migrating neural crest-cells. There are not enough comparative data to determine whether this feature is functionally associated with direct development or is instead unrelated to reproductive mode.

}, keywords = {anura, anuran amphibians, avian embryos, cell migration, cholinesterase, craniofacial development, developing forebrain, developmental biology, distal-less gene, dlx, head development, hnk-1, homeobox genes, limb development, monoclonal-antibody, pattern-formation}, isbn = {0944-2006}, author = {Olsson, L. and Moury, J. D. and Carl, T. F. and Hastad, O. and Hanken, J.} } @article {561671, title = {Cranial neural crest cells contribute to connective tissue in cranial muscles in the anuran amphibian, Bombina orientalis}, journal = {Developmental Biology}, volume = {237}, number = {2}, year = {2001}, note = {

476CQTimes Cited:48Cited References Count:47

}, month = {Sep 15}, pages = {354-367}, abstract = {

The contribution of cranial neural crest cells to the development and patterning of cranial muscles in amphibians was investigated in the phylogenetically basal and morphologically generalized frog, Bombina orientalis. Experimental methods included fluorescent marking of premigratory cranial neural crest and extirpation of individual migratory streams. Neural crest cells contributed to the connective tissue component, but not the myofibers, of many larval muscles within the first two branchial arches (mandibular and hyoid), and complex changes in muscle patterning followed neural crest extirpation. Connective tissue components of individual muscles of either arch originate from the particular crest migratory stream that is associated with that arch, and this relationship is maintained regardless of the segmental identity-or embryonic derivation-of associated skeletal components. These developmental relations define a pattern of segmentation in the head of larval anurans that is similar to that previously described in the domestic chicken, the only vertebrate that has been thoroughly investigated in this respect. The fundamental role of the neural crest in patterning skeleton and musculature may represent a primitive feature of cranial development in vertebrates. Moreover, the corresponding developmental processes and cell fates appear to be conserved even when major evolutionary innovations-such as the novel cartilages and muscles of anuran larvae-result in major differences in cranial form. (C) 2001 Academic Press.

}, keywords = {bombina, cell fate, cell migration, cranial muscles, craniofacial development, extirpation, fate, head, Migration, neural crest, origin, pattern, Vertebrates, vital dye labeling, xenopus-laevis, zebrafish embryo}, isbn = {0012-1606}, author = {Olsson, L. and Falck, P. and Lopez, K. and Cobb, J. and Hanken, J.} } @article {561386, title = {Limb development in a "non-model" vertebrate, the direct-developing frog Eleutherodactylus coqui}, journal = {Journal of Experimental Zoology (Mol. Dev. Vol.)}, volume = {291}, number = {4}, year = {2001}, note = {

500UMTimes Cited:26Cited References Count:87

}, month = {Dec 15}, pages = {375-388}, abstract = {

Mechanisms that mediate limb development are regarded as highly conserved among vertebrates, especially tetrapods. Yet, this assumption is based on the study of relatively few species, and virtually none of those that display any of a large number of specialized life-history or reproductive modes, which might be expected to affect developmental pattern or process. Direct development is an alternative life history found in many anuran amphibians. Many adult features that form after hatching in metamorphic frogs, such as limbs, appear during embryogenesis in direct-developing species. Limb development in the direct-developing frog Eleutherodactylus coqui presents a mosaic of apparently conserved and novel features. The former include the basic sequence and pattern of limb chondrogenesis, which are typical of anurans generally and appear largely unaffected by the gross shift in developmental timing; expression of Distal-less protein (D1x) in the distal ectoderm; expression of the gene Sonic hedgehog (Shh) in the zone of polarizing activity (ZPA); and the ability of the ZPA to induce supernumerary digits when transplanted to the anterior region of an early host limb bud. Novel features include the absence of a morphologically distinct apical ectodermal ridge, the ability of the limb to continue distal outgrowth and differentiation following removal of the distal ectoderm, and earlier cessation of the inductive ability of the ZPA. Attempts to represent tetrapod limb development as a developmental "module" must allow for this kind of evolutionary variation among species. (C) 2001 Wiley-Liss, Inc.

}, keywords = {apical ectodermal ridge, chick wing bud, distal-less gene, Evolution, expression, leptodactylidae, polarizing activity, regenerating axolotl limbs, sonic-hedgehog, xenopus-laevis}, isbn = {0022-104X}, author = {Hanken, J. and Carl, T. F. and Richardson, M. K. and Olsson, L. and Schlosser, G. and Osabutey, C. K. and Klymkowsky, M. W.} } @article {561146, title = {New species of large black salamander, genus Bolitoglossa (Plethodontidae) from western Panama}, journal = {Copeia}, number = {3}, year = {2001}, note = {

516AQTimes Cited:3Cited References Count:5

}, month = {Aug 6}, pages = {700-704}, abstract = {

A new species of plethodontid salamander is one of several large black species found in the Cordillera Talamanca-Baru of Panama and Costa Rica. Bolitoglossa anthracina sp. nov. differs from others in this group in having a very large number of maxillary teeth and a moderate number of vomerine teeth.

}, isbn = {0045-8511}, author = {Brame, A. H. and Savage, J. M. and Wake, D.B. and Hanken, J.} } @article {561541, title = {A seventh species of minute salamander (Thorius : Plethodontidae) from the Sierra de Juarez, Oaxaca, Mexico}, journal = {Herpetologica}, volume = {57}, number = {4}, year = {2001}, note = {

501TNTimes Cited:7Cited References Count:22

}, month = {Dec}, pages = {515-523}, abstract = {

We describe a new terrestrial species of minute lungless salamander of the Mexican genus Thorius (Plethodontidae) from montane pine-oak forests in the Sierra de Juarez of north central Oaxaca, Mexico. The new species is distinguished from congeners by a combination of body size, external morphology, osteology, and dental traits, and it is well differentiated genetically from other named species for which data are available. This is the seventh endemic species of Thorius reported from the Sierra de Juarez, and known localities are geographically isolated from those of all other species. Discovery of another new species of plethodontid salamander from Oaxaca enhances the state{\textquoteright}s standing as a preeminent center of herpetological diversity within both Mexico and Mesoamerica.

}, keywords = {amphibia, biogeography, miniaturization, Morphology, osteology, Taxonomy}, isbn = {0018-0831}, author = {Hanken, J. and Wake, D.B.} } @article {586301, title = {A review of Tadpoles: the Biology of Anuran Larvae}, journal = {Evol. Devel.}, volume = {2}, year = {2000}, pages = {174-175}, author = {Hanken, J.} } @inbook {561181, title = {Green fluorescent protein used to assess cranial neural crest derivatives in the frog, Xenopus laevis}, booktitle = {Regulatory Processes in Development: The Legacy of Sven H{\"o}rstadius (1898-1996)}, volume = {76}, year = {2000}, note = {

Bu62xTimes Cited:5Cited References Count:29Wenner-Gren International Series

}, pages = {167-172}, publisher = {Wenner-Gren International Series, Portland Press}, organization = {Wenner-Gren International Series, Portland Press}, address = {London}, abstract = {

We used RNA encoding green fluorescent protein (GFP) to study the migration and larval derivatives of cranial neural crest cells in the metamorphosing frog, Xenopus laevis. GFP provides an intrinsic cell-lineage marker that is retained after cell division. Moreover, because GFP label introduced at the one-cell stage continues to be expressed well after hatching, it offers a reliable and effective method for assessing the embryonic derivation of many larval, and possibly even adult, tissues in amphibians as well as other vertebrates. Basic patterns of cranial neural crest migration and derivation in X. laevis defined using GFP (including contributions to many larval cranial cartilages) arc similar to those documented in previous studies that used conventional vital stains, lineage markers, and ablation techniques. However, preliminary results also suggest the neural crest derivation of additional components of the larval anuran head, e.g., cranial bone, whose embryonic origins have proven much more difficult to resolve with other methods.

}, keywords = {cells, embryo, gene-expression, head, markers, Migration, plakoglobin, skeletal, trunk}, author = {Carl, T. F. and Dufton, C. and Vourgourakis, Y. and Klymkowsky, M. and Hanken, J.}, editor = {Jacobson, C.O. and Olsson, L.} } @article {586306, title = {An alternative evolutionary synthesis [review of C.D. Schlichting and M. Pigliucci, Phenotypic Evolution: A Reaction Norm Perspective]}, journal = {Trends Ecol. Evol. }, volume = {14}, year = {1999}, pages = {162-163}, author = {Hanken, J.} } @inbook {585506, title = {Larvae in amphibian development and evolution}, booktitle = {The Origin and Evolution of Larval Forms}, year = {1999}, pages = {61-108}, publisher = {Academic Press}, organization = {Academic Press}, address = {San Diego}, author = {Hanken, J.} } @article {561361, title = {4,780 and counting}, journal = {Natural History}, volume = {108}, number = {6}, year = {1999}, note = {

210YVTimes Cited:0Cited References Count:0

}, month = {Jul-Aug}, pages = {82-82}, isbn = {0028-0712}, author = {Hanken, J.} } @article {561151, title = {Inhibition of neural crest migration in Xenopus using anti-sense-slug RNA}, journal = {Developmental Biology}, volume = {213}, number = {1}, year = {1999}, note = {

233HRTimes Cited:100Cited References Count:71

}, month = {Sep 1}, pages = {101-115}, abstract = {

Based primarily on studies in the chick, it has been assumed that the zinc finger transcription factor Slug is required for neural crest migration. In the mouse, however, Slug is not expressed in the premigratory neural crest, which forms normally in Slug -/- animals. To study the role of Slug in Xenopus laevis, we used the injection of XSlug antisense RNA and tissue transplantation. Injection of Slug antisense RNA did not suppress the early expression of the related gene XSnail, but led to reduced expression of both XSlug and XSnail in later stage embryos, whereas the expression of another neural crest marker, XTwist, was not affected. Down-regulation of XSlug and XSnail was associated with the inhibition of neural crest cell migration and the reduction or loss of many neural crest derivatives. In particular, the formation of rostral cartilages was often highly aberrant, whereas the posterior cartilages were less frequently affected. The effects of Slug antisense RNA on neural crest migration and cartilage formation were rescued by the injection of either XSlug or XSnail mRNA. These studies indicate that XSlug is required for neural crest migration, that XSlug and XSnail may be functionally redundant, and that both genes are required to maintain each other{\textquoteright}s expression in the neural crest development of xenopus laevis. (C) 1999 Academic Press.

}, keywords = {cartilage, cell-adhesion, Drosophila, epithelial to mesenchymal transition, expression, in-vitro, mesoderm, messenger-rna, mutant embryos, neural crest, slug, snail, snail family, wild-type, Xenopus laevis, zinc-finger gene}, isbn = {0012-1606}, author = {Carl, T. F. and Dufton, C. and Hanken, J. and Klymkowsky, M. W.} } @article {561366, title = {Modern museums are far from fossilized}, journal = {Nature}, volume = {400}, number = {6739}, year = {1999}, note = {

213DATimes Cited:0Cited References Count:1

}, month = {Jul 1}, pages = {13-13}, isbn = {0028-0836}, author = {Hanken, J.} } @article {561546, title = {Three new species of minute salamanders (Thorius : Plethodontidae) from Guerrero, Mexico, including the report of a novel dental polymorphism in urodeles}, journal = {Copeia}, number = {4}, year = {1999}, note = {

269NHTimes Cited:7Cited References Count:43

}, month = {Dec 17}, pages = {917-931}, abstract = {

Three new species of minute lungless salamanders of the Mexican genus Thorius (Plethodontidae) are described from montane forests in the Sierra Madre del Sur of Guerrero. Each species is distinguished from congeners by a combination of body size, external morphology, osteology, dental traits, and proteins. Thorius omiltemi and T. grandis are among the largest species within the genus; standard length (SL) approaches or exceeds 30 mm in many adults. Thorius infernalis is much smaller (SL \< 19 mm). Adult T. grandis display an extreme, unique sexual dimorphism involving the presence/absence of maxillary teeth and several related features of cranial osteology. Protein (allozyme) data for T. omiltemi and T. grandis reveal substantial levels of genetic differentiation relative to species in Veracruz, Puebla, and Oaxaca. Comparable genetic data are unavailable for T. infernalis, The three species collectively define a broad elevational range, from high elevation T. omiltemi and T. grandis (2200-2700 m and 2495-3360 m, respectively) to lower montane T. infernalis (1140 m), Description of several additional species of plethodontid salamanders from central montane Guerrero underscores the region{\textquoteright}s rich herpetological diversity, which includes many endemic species of both amphibians and reptiles.

}, keywords = {amphibia, cranial morphology, miniaturization, size, southern mexico}, isbn = {0045-8511}, author = {Hanken, J. and Wake, D.B. and Freeman, H. L.} } @article {561371, title = {Why are there so many new amphibian species when amphibians are declining?}, journal = {Trends in Ecology \& Evolution}, volume = {14}, number = {1}, year = {1999}, note = {

180ZXTimes Cited:41Cited References Count:24

}, month = {Jan}, pages = {7-8}, keywords = {complex}, isbn = {0169-5347}, author = {Hanken, J.} } @article {561356, title = {Beauty beyond belief}, journal = {Natural History}, volume = {107}, number = {10}, year = {1998}, note = {

149AVTimes Cited:0Cited References Count:0

}, month = {Dec-Jan}, pages = {56-59}, isbn = {0028-0712}, author = {Hanken, J.} } @article {561536, title = {Biology of tiny animals: Systematics of the minute salamanders (Thorius : Plethodontidae) from Veracruz and Puebla, Mexico, with descriptions of five new species}, journal = {Copeia}, number = {2}, year = {1998}, note = {

Zn379Times Cited:15Cited References Count:41

}, month = {May 1}, pages = {312-345}, abstract = {

Minute plethodontid salamanders, genus Thorius, are far more diverse taxonomically than has been recognized previously. Populations of these salamanders from the Mexican states of Veracruz and Puebla are assigned to 10 species, five of which are described as new. Combinations of morphological and allozymic characters are used to sort the species and to make initial assessments of relationships. Valid existing names include Thorius pennatulus, T., troglodytes, T. dubitus, and T. schmidti. Thorius narismagnus; from the Sierra de Los Tuxtlas, which previously was considered to be a disjunct subspecies of T., pennatulus, is elevated to species rank. Thorius maxillabrochus is treated as a subjective junior synonym of the sympatric T.:schmidti. New taxa include Thorius lunaris, T. magnipes, T. minydemus, T. munificus, and T. spilogaster: All 10 species can be distinguished by morphological characters, but the distinctiveness of the taxa is bolstered by allozymic characters and by extensive sympatry. As many as three, and possibly four, species occur in sympatry, with some evidence of segregation by microhabitat (arboreal vs terrestrial). Adult body sizes span the range known for the genus, from very small in T., pennatulus (maturing at \< 16 mm standard length) to large in T. lunaris (adults reaching \> 31 mm). Collectively these species display a Hide elevational distribution, from less than 1000 m (T. pennatulus, T. narismagnus) to more than 3000 m (T. lunaris, T., spilogaster). Discovery of these new species adds to the rich herpetological diversity of east-central Mexico and underscores its importance as a principal center of radiation of tropical plethodontid salamanders.

}, keywords = {amphibia, Brain, caudata, consequences, cranial morphology, Evolution, lineage, miniaturization, size, visual-system}, isbn = {0045-8511}, author = {Hanken, J. and Wake, D.B.} } @article {561736, title = {Haeckel, embryos, and evolution}, journal = {Science}, volume = {280}, number = {5366}, year = {1998}, note = {

Zn615Times Cited:11Cited References Count:7

}, month = {May 15}, pages = {983-985}, isbn = {0036-8075}, author = {Richardson, M. K. and Hanken, J. and Selwood, L. and Wright, G. M. and Richards, R. J. and Pieau, C. and Raynaud, A.} } @article {561486, title = {Haeckel{\textquoteright}s embryos}, journal = {Science}, volume = {279}, number = {5355}, year = {1998}, note = {

Yz412Times Cited:1Cited References Count:4

}, month = {Feb 27}, pages = {1288-1288}, isbn = {0036-8075}, author = {Hanken, J. and Richardson, M. K.} } @article {561726, title = {Limb development and evolution: a frog embryo with no apical ectodermal ridge (AER)}, journal = {Journal of Anatomy}, volume = {192}, year = {1998}, note = {

3100XVTimes Cited:33Cited References Count:51

}, month = {Apr}, pages = {379-390}, abstract = {

The treefrog Eleutlrerodactylus coqui is a direct developer-it has no tadpole stage. The limb buds develop earlier than in metamorphosing species (indirect developers, such as Xenopus laevis). Previous molecular studies suggest that at least some mechanisms of limb development in E. coqui are similar to those of other vertebrates and we wished to see how limb morphogenesis in this species compares with that in other vertebrates. We found that the hind limb buds are larger and more advanced than the forelimbs at all stages examined, thus differing from the typical amniote pattern. The limb buds were also small compared to those in the chick. Scanning and transmission electron microscopy showed that although the apical ectoderm is thickened, there was no apical ectodermal ridge (AER). In addition, the limb buds lacked the dorsoventral flattening seen in many amniotes. These findings could suggest a mechanical function for the AER in maintaining dorsoventral flattening, although not all data are consistent with this view. Removal of distal ectoderm from E. coqui hindlimb buds does not stop outgrowth, although it does produce anterior defects in the skeletal pattern. The defects are less severe when the excisions are performed earlier. These results contrast with the chick, in which AER excision leads to loss of distal structures. We suggest that an AER was present in the common ancestor of anurans and amniotes and has been lost in at least some direct developers including E. coqui.

}, keywords = {anurans, bud, direct development, distal-less gene, eleutherodactylus, eleutherodactylus-coqui anura, expression, fgf-4, heterochrony, leptodactylidae, limb bud, xenopus}, isbn = {0021-8782}, author = {Richardson, M. K. and Carl, T. F. and Hanken, J. and Elinson, R. P. and Cope, C. and Bagley, P.} } @article {561581, title = {Mechanistic basis of life history evolution in anuran amphibians: Thyroid gland development in the direct-developing frog, Eleutherodactylus coqui}, journal = {General and Comparative Endocrinology}, volume = {111}, number = {2}, year = {1998}, note = {

106UETimes Cited:35Cited References Count:44

}, month = {Aug}, pages = {225-232}, abstract = {

Direct development is a widespread, alternative life history in Recent amphibians. There is no free-living, aquatic larva; adult features form in the embryo and are present at hatching. The mechanistic bases of direct development remain relatively unexplored. The current study describes the embryonic ontogeny of the thyroid gland in the direct-developing frog Eleutherodactylus coqui (Leptodactylidae) and quantifies histological changes that occur in the gland after its initial appearance. The thyroid gland of E. coqui is first apparent at Townsend-Stewart stage 10, approximately two-thirds of the way through embryogenesis. Soon after this the thyroid begins to accumulate follicular colloid. Quantitative analyses of thyroid histology reveal embryonic peaks in two measures, follicle number and follicle volume, which are followed by declines in these measures prior to hatching. These peaks in thyroid activity in E. coqui are correlated with morphological changes that are directly comparable to metamorphic changes in frogs that retain the ancestral, biphasic life history. In metamorphic taxa, a histologically identifiable thyroid gland does not form until the larval period, well after hatching. Nevertheless, measures of thyroid histology observed in E. coqui follow the pattern reported for metamorphosing amphibians. The present results support the hypothesis that the evolution of direct development in anurans is associated with precocious development and activity of the thyroid axis. (C) 1998 Academic Press.

}, keywords = {leptodactylidae, metamorphosis}, isbn = {0016-6480}, author = {Jennings, D. H. and Hanken, J.} } @article {561741, title = {Phylotypic stage theory}, journal = {Trends in Ecology \& Evolution}, volume = {13}, number = {4}, year = {1998}, note = {

Zd972Times Cited:10Cited References Count:7

}, month = {Apr}, pages = {158-158}, isbn = {0169-5347}, author = {Richardson, M. K. and Minelli, A. and Coates, M. and Hanken, J.} } @article {561721, title = {Somite number and vertebrate evolution}, journal = {Development}, volume = {125}, number = {2}, year = {1998}, note = {

Yx504Times Cited:96Cited References Count:92

}, month = {Jan}, pages = {151-160}, abstract = {

Variation in segment number is an important but neglected feature of vertebrate evolution, Some vertebrates have as few as six trunk vertebrae, while others have hundreds. We examine this phenomenon in relation to recent models of evolution and development. Surprisingly, differences in vertebral number are foreshadowed by different somite counts at the tailbud stage, thought to be a highly conserved (phylotypic) stage, Somite number therefore violates the {\textquoteright}developmental hourglass{\textquoteright} model, We argue that this is because somitogenesis shows uncoupling or dissociation from the conserved positional field encoded by genes of the zootype.Several other systems show this kind of dissociation, including limbs and feathers. Bmp-7 expression patterns demonstrate dissociation in the chick pharyngeal arches, This makes it difficult to recognise a common stage of pharyngeal development or {\textquoteright}pharyngula{\textquoteright} in ail species, Rhombomere number is more stable during evolution than somite number, possibly because segmentation and positional specification in the hindbrain are relatively interdependent, Although developmental mechanisms are strongly conserved, dissociation allows at least some major evolutionary changes to be generated in phylotypic stages.

}, keywords = {bone morphogenetic protein-7, cell lineage analysis, chick-embryo, Evolution, gene-expression, heat-shock, hindbrain segmentation, hox genes, mouse hindbrain, phylotypic stage, quail embryo, segmentation, somite number, vertebrate, xenopus-laevis}, isbn = {0950-1991}, author = {Richardson, M. K. and Allen, S. P. and Wright, G. M. and Raynaud, A. and Hanken, J.} } @article {561451, title = {Jaw muscle development as evidence for embryonic repatterning in direct-developing frogs}, journal = {Proceedings of the Royal Society B-Biological Sciences}, volume = {264}, number = {1386}, year = {1997}, note = {

Xy660Times Cited:36Cited References Count:52

}, month = {Sep 22}, pages = {1349-1354}, abstract = {

The Puerto Rican direct-developing frog Eleutherodactylus coqui (Leptodactylidae) displays a novel mode of jaw muscle development for anuran amphibians. Unlike metamorphosing species, several larval-specific features never form in E. coqui; embryonic muscle primordia initially assume an abbreviated, mid-metamorphic configuration that is soon remodelled to form the adult morphology before hatching. Also lacking are both the distinct population of larval myofibres and the conspicuous, larval-to-adult myofibre turnover that are characteristic of muscle development in metamorphosing species. These modifications are part of a comprehensive alteration in embryonic cranial patterning that has accompanied life history evolution in this highly speciose lineage. Embryonic {\textquoteright}repatterning{\textquoteright} in Eleutherodactylus may reflect underlying developmental mechanisms that mediate the integrated evolution of complex structures. Such mechanisms may also facilitate, in organisms with a primitively complex life cycle, the evolutionary dissociation of embryonic, larval, and adult features.

}, keywords = {Behavior, biology, eleutherodactylus-coqui anura, Evolution, expression, head, leptodactylidae, neural-crest migration, pattern-formation, plethodontid salamanders}, isbn = {0962-8452}, author = {Hanken, J. and Klymkowsky, M. W. and Alley, K. E. and Jennings, D. H.} } @article {561446, title = {Mechanistic basis of life-history evolution in anuran amphibians: Direct development}, journal = {American Zoologist}, volume = {37}, number = {2}, year = {1997}, note = {

Wy611Times Cited:44Cited References Count:77

}, month = {Apr}, pages = {160-171}, abstract = {

The primitive, or ancestral reproductive mode for Recent amphibians involves a complex, biphasic life history, Yet evolutionarily derived, alternate modes are seen in all three living orders and predominate in some clades, Analysis of the consequences and mechanistic bases of one such mode-direct development-can provide insights into the evolutionary opportunities and constraints conferred by the ancestral metamorphic ontogeny, Direct development in the anuran genus Eleutherodactylus involves fundamental alterations to many features of embryonic and posthatching development, At hatching, young emerge as fully formed, albeit tiny versions of the adult; most larval features are absent, Pervasive changes in ontogenetic timing, in particular the precocious (embryonic) formation of many adult structures, appear to be correlated with early development of the thyroid axis, although responsiveness to exogenous thyroid hormone is diminished or even lacking in at least some peripheral tissues, Changes in cranial patterning are likely mediated by the embryonic neural crest, although many gross features of crest biology are highly conserved, Laboratory-based analyses of direct development and other derived reproductive modes in amphibians, using contemporary methods developed for more standard, {\textquoteright}{\textquoteright}model{\textquoteright}{\textquoteright} organisms, may contribute important insights into life-history evolution that complement those derived from analyses of morphology, ecology and phylogeny.

}, keywords = {craniofacial development, eleutherodactylus-coqui anura, expression, forebrain, homeobox gene, hormone, metamorphosis, neural crest development, Vertebrates, xenopus-laevis}, isbn = {0003-1569}, author = {Hanken, J. and Jennings, D. H. and Olsson, L.} } @article {561731, title = {There is no highly conserved embryonic stage in the vertebrates: Implications for current theories of evolution and development}, journal = {Anatomy and Embryology}, volume = {196}, number = {2}, year = {1997}, note = {

Xq780Times Cited:140Cited References Count:81

}, month = {Aug}, pages = {91-106}, abstract = {

Embryos of different species of vertebrate share a common organisation and often look similar. Adult differences among species become more apparent through divergence at later stages. Some authors have suggested that members of most or all vertebrate clades pass through a virtually identical, conserved stage. This idea was promoted by Haeckel, and has recently been revived in the context of claims regarding the universality of developmental mechanisms. Thus embryonic resemblance at the tailbud stage has been linked with a conserved pattern of developmental gene expression - the zootype. Haeckel{\textquoteright}s drawings of the external morphology of various vertebrates remain the most comprehensive comparative data purporting to show a conserved stage. However, their accuracy has been questioned and only a narrow range of species was illustrated. In view of the current widespread interest in evolutionary developmental tal biology, and especially in the conservation of developmental mechanisms, re-examination of the extent of variation in vertebrate embryos is long overdue, We present here the first review of the external morphology of tailbud embryos, illustrated with original specimens from a wide range of vertebrate groups, We find that embryos at the tailbud stage - thought to correspond to a conserved stage - show variations in form due to allometry, heterochrony, and differences in body plan and somite number. These variations foreshadow important differences in adult body form. Contrary to recent claims that all vertebrate embryos pass through a stage when they are the same size, we find a greater than 10-fold variation in greatest length at the tailbud stage. Our survey seriously undermines the credibility of Haeckel{\textquoteright}s drawings, which depict not a conserved stage for vertebrates, but a stylised amniote embryo. In fact, the taxonomic level of greatest resemblance among vertebrate embryos is below the subphylum. The wide variation in morphology among vertebrate embryos is difficult to reconcile with the idea of a phyogenetically-conserved tailbud stage, and suggests that at least some developmental mechanisms are not highly constrained by the zootype, Our study also highlights the dangers of drawing general conclusions about vertebrate development from studies of gene expression in a small number of laboratory species.

}, keywords = {comparative anatomy, Comparative Study, developmental biology, embryology, model systems, Morphogenesis, quail embryo, zebrafish}, isbn = {0340-2061}, author = {Richardson, M. K. and Hanken, J. and Gooneratne, M. L. and Pieau, C. and Raynaud, A. and Selwood, L. and Wright, G. M.} } @article {586311, title = {The shape of evolutionary developmental biology [review of R.A. Taff, The Shape of Life: Genes, Development, and the Evolution of the Animal Form]}, journal = {Trends Ecol. Evol.}, volume = {11}, year = {1996}, pages = {441-442}, author = {Hanken, J. and Carl, T. F.} } @article {561351, title = {The art of the skull}, journal = {Natural History}, volume = {105}, number = {10}, year = {1996}, note = {

Vj907Times Cited:0Cited References Count:0

}, month = {Oct}, pages = {34-39}, isbn = {0028-0712}, author = {Hanken, J.} } @article {561676, title = {Cranial neural crest migration and chondrogenic fate in the oriental fire-bellied toad Bombina orientalis: Defining the ancestral pattern of head development in anuran amphibians}, journal = {Journal of Morphology}, volume = {229}, number = {1}, year = {1996}, note = {

Uq670Times Cited:62Cited References Count:108

}, month = {Jul}, pages = {105-120}, abstract = {

We assess cranial neural-crest cell migration and contributions to the larval chondrocranium in the phylogenetically basal and morphologically generalized anuran Bombina orientalis (Bombinatoridae). Methods used include microdissection, scanning electron microscopy, and vital dye labeling, in conjunction with confocal and fluorescence microscopy. Cranial neural-crest cells begin migrating before neural-fold closure and soon form three primary streams. These streams contribute to all cranial cartilages except two medial components of the hyobranchial skeleton (basihyal and basibranchial cartilages), the posterior portion of the trabecular plate, and the otic capsule, the embryonic origin of which is unknown. Chondrogenic fate is regionalized within the cranial neural folds, with the anterior regions contributing to anterior cartilages and the posterior regions to posterior cartilages. A neural-crest contribution also was consistently observed in several cranial nerves and the connective tissue component of many cranial muscles. Notwithstanding minor differences among species in the initial configuration of migratory streams, cranial neural-crest migration and chondrogenic potential in metamorphosing anurans seem to be highly stereotyped and evolutionarily conservative. This includes a primary role for the neural crest in the evolutionary origin of the paired suprarostral and infrarostral cartilages, two prominent caenogenetic features of the rostral skull unique to anuran larvae. Our results provide a model of the ancestral pattern of embryonic head development in anuran amphibians. This model can serve as a basis for examining the ontogenetic mechanisms that underlie the diversity of cranial morphology and development displayed by living frogs, as well as the evolutionary consequences of this diversity. (C) 1996 Wiley-Liss, Inc.

}, keywords = {discoglossidae, Evolution, expression, mesenchyme, metamorphosis, mouse embryo, ontogeny, quail-chick chimeras, skull development, vertebrate skull}, isbn = {0362-2525}, author = {Olsson, L. and Hanken, J.} } @article {561801, title = {Direct development in the lungless salamanders: What are the consequences for developmental biology, evolution and phylogenesis?}, journal = {International Journal of Developmental Biology}, volume = {40}, number = {4}, year = {1996}, note = {

Ve441Times Cited:59Cited References Count:134

}, month = {Aug}, pages = {859-869}, abstract = {

Direct development is a widespread alternate reproductive mode in living amphibians that is characterized by evolutionary loss of the free-living, aquatic larval stage. Courtship, mating, and oviposition occur on land, and the terrestrial egg hatches as a fully formed, miniature adult. While it is the most common reproductive mode in urodeles, development outside the reproductive tract of the female that proceeds directly to a terrestrial hatchling occurs in only a single lineage, the lungless salamanders of the family Plethodontidae. Evolution of direct development in plethodontids has contributed importantly to the extraordinary evolutionary success of this speciose, geographically widespread, and morphologically and ecologically diverse taxon. Developmental consequences and correlates include increased egg size and embryonic development time, loss of larval structures and ontogenetic repatterning, and altered pattern formation in organogenesis. Evolutionary and phylogenetic consequences and correlates include the loss of larval constraints and origin of morphological novelty, and frequent homoplasy. Analysis of direct development in an evolutionary context illustrates the complex interplay between processes of phylogenetic divergence and developmental biology, and substantiates the prominent role of developmental processes in both constraining phenotypic variation and promoting phenotypic diversity. Despite the proven suitability of direct-developing plethodontid salamanders for laboratory and field study, knowledge of basic features of their developmental biology remains far below that available for many other urodeles. Examination of such features of these {\textquoteright}{\textquoteright}non-model{\textquoteright}{\textquoteright} organisms is an appropriate and deserving goal of future research.

}, keywords = {ambystoma-mexicanum, constraints, direct development, eleutherodactylus-coqui, eurycea-bislineata, Evolution, family plethodontidae, model systems, morphological evolution, ontogeny, plethodontid salamanders, plethodontidae, postembryonic development, skeletal morphogenesis, urodele skull}, isbn = {0214-6282}, author = {Wake, D.B. and Hanken, J.} } @article {561686, title = {Growth and uptake of mineral by embryos of the direct-developing frog Eleutherodactylus coqui}, journal = {Comp. Physiol. Biochem.}, volume = {113A}, number = {4}, year = {1996}, note = {

Uk220Times Cited:5Cited References Count:37

}, month = {Apr}, pages = {343-349}, abstract = {

Embryos of the direct-developing frog Elutherodactylus coqui cake up small quantities of yolk and yolk mineral early in incubation but increase their uptake of yolk reserves at later stages of development. Growth and accumulation of calcium and magnesium by embryos also occur slowly at first and at a higher rate later. Accumulation of calcium and magnesium by embryos is largely a function of variation in size of embryos, but uptake of phosphorus is unrelated to size. Although patterns of growth and uptake of mineral by embryonic coquis resemble those for embryos of oviparous amniotes, embryonic coquis do not deplete the yolk of its nutrients to the same degree. Thus, residual yolk of coqui hatchlings contains a high percentage of the nutrient reserves originally present in the egg. This difference between embryonic coquis and embryos of oviparous amniotes may indicate that transfer of nutrients from yolk to embryo becomes limiting during the growth phase. Alternatively, some aspects of the neurologic system are so poorly developed at hatching that coqui may not be able to find prey effectively. A large nutrient reserve could sustain hatchlings while the neurologic system continues to mature.

}, keywords = {anura, anuran, calcium, calcium mobilization, chelydra-serpentina, cranial ossification, direct development, embryo, frog, leptodactylidae, magnesium, metabolism, mineral, phosphorus, turtles chrysemys-picta, water-balance}, isbn = {1095-6433}, author = {Packard, M. J. and Jennings, D. H. and Hanken, J.} } @inbook {585791, title = {Development and evolution in amphibians}, booktitle = {Exploring Evolutionary Biology: Readings from American Scientist}, year = {1995}, pages = {224-231}, publisher = {Sinauer Assoc., Inc.}, organization = {Sinauer Assoc., Inc.}, address = {Sunderland}, author = {Hanken, J.}, editor = {Slatkin, M.} } @article {561661, title = {Early cranial neural crest migration in the direct-developing frog, Eleutherodactylus coqui}, journal = {Acta Anatomica}, volume = {153}, number = {4}, year = {1995}, note = {

Tv498Times Cited:23Cited References Count:49

}, pages = {243-253}, abstract = {

Direct development is a common reproductive mode in Living amphibians characterized by absence of the free-living, aquatic larval stage. In Eleutherodactylus, a species-rich genus of New World frogs, evolution of direct development from the ancestral biphasic ontogeny is correlated with a comprehensive modification in embryonic cranial patterning, including the loss of many larval-specific components and the precocious formation of many adult (postmetamorphic) structures, We use scanning electron microscopy (SEM) to examine the emergence and early migration of cranial neural crest cells in Eleutherodactylus coqui to begin to assess the possible role of the neural crest in mediating these evolutionary changes. As in metamorphosing frogs, cranial crest cells emerge prior to neural fold closure and assemble into three streams: rostral, rostral otic, and caudal otic. These streams contribute to the face and first visceral (mandibular) arch, to the second (hyoid) arch, and to posterior (branchial) arches, respectively. Rostrocaudal position, morphology, and/or migration patterns distinguish subpopulations of cells within the rostral stream and caudal otic stream. With the possible exception of the small size of the rostral otic and caudal otic streams, evolution of direct development in E. coqui has not altered basic patterns of neural crest emergence or early migration as assessed by SEM. Lf observed evolutionary changes in embryonic cranial patterning are mediated by the neural crest, then they likely involve later aspects of crest migration or more subtle features related to pattern formation such as cell behavior and commitment, or gene expression.

}, keywords = {anura, avian embryo, cell-migration, craniofacial development, direct development, eleutherodactylus, Evolution, head, leptodactylidae, metameric pattern, mouse embryo, movements, neural crest, prospective areas, segments, xenopus-laevis}, isbn = {0001-5180}, author = {Moury, J. D. and Hanken, J.} } @article {561531, title = {Five New Species of Minute Salamanders, Genus Thorius (Caudata, Plethodonitdaee, from Northern Oaxaca, Mexico}, journal = {Copeia}, number = {3}, year = {1994}, note = {

Pd127Times Cited:25Cited References Count:20

}, month = {Aug 17}, pages = {573-590}, abstract = {

Five new species of diminutive salamanders of the endemic Mexican genus Thorius (Plethodontidae) are described from the Sierra de Juarez in northern Oaxaca. The species are diagnosed by adult body size, external proportions, dentition, osteology and coloration. The three species that have been studied using protein electrophoresis are genetically unique; all differ from T. macdougalli, the only species of the genus previously known from these mountains. Each of the six species studied has distinct geographic and elevational ranges, and there is a complex pattern of geographic overlap and replacement. As many as three species co-occur locally at elevations up to 2955 m on Cerro Pelon, and each species is sympatric with at least one other. One species descends to approximately 800 m, which is the lowest known elevational record for the genus. The new taxa include the full size range of the genus, with two large and three small species.

}, keywords = {amphibia, miniaturization, Morphology, plethodontidae}, isbn = {0045-8511}, author = {Hanken, J. and Wake, D.B.} } @article {561776, title = {Type II Collagen Distribution during Cranial Development in Xenopus Laevis}, journal = {Anatomy and Embryology}, volume = {189}, number = {1}, year = {1994}, note = {

Mu867Times Cited:18Cited References Count:38

}, month = {Jan}, pages = {81-89}, abstract = {

Epithelially expressed type II collagen is thought to play a prominent role in the embryonic patterning and differentiation of the vertebrate skull, primarily on the basis of data derived from amniotes. We describe the spatiotemporal distribution of type II collagen in the embryonic head of the African clawed frog, Xenopus laevis, using whole-mount and serial-section immunohistochemical analysis. We studied embryos spanning Nieuwkoop and Faber (1967) stages 21-39, a period including cranial neural crest cell migration and ending immediately before the onset of neurocranial chondrogenesis. Xenopus displays a transient expression of type II collagen beginning at least as early as stage 21; staining is most intense and widespread at stages 33/34 and 35/36 and subsequently diminishes. Collagen-positive areas include the ventrolateral surface of the brain, sensory vesicles, notochord, oropharynx, and integument. This expression pattern is similar, but not identical, to that reported for the mouse and two bird species (Japanese quail, domestic fowl); thus epithelially expressed type II collagen appears to be a phylogenetically widespread feature of vertebrate cranial development. Consistent with the proposed role of type II collagen in mediating neurocranial differentiation, most collagen-positive areas lie adjacent to subsequent sites gf chondrogenesis in the neurocranium but not the visceral skeleton. However, much of the collagen is expressed after the migration of cranial neural crest, including presumptive chondrogenic crest, seemingly too late to pattern the neurocranium by entrapment of these migrating cells.

}, keywords = {amphibia, cartilage, craniofacial development, embryos, extracellular-matrix, interfaces, messenger-rna, neural crest, prepattern, procollagen, Skull, somite chondrogenesis, transient expression, type ii collagen}, isbn = {0340-2061}, author = {Seufert, D. W. and Hanken, J. and Klymkowsky, M. W.} } @inbook {585836, title = {Adaptation of bone growth to miniaturization of body size}, booktitle = {Bone, Volume 7: Bone Growth - B}, year = {1993}, pages = {79-104}, publisher = {CRC Press}, organization = {CRC Press}, address = {Boca Raton}, author = {Hanken, J.}, editor = {Hall, B. K.} } @inbook {585821, title = {Bibliography of skull development: 1937-1989}, booktitle = {The Skull: Vol. 1, Development}, year = {1993}, pages = {378-577}, publisher = {University of Chicago Press}, organization = {University of Chicago Press}, address = {Chicago}, author = {Hall, B. K. and Hanken, J.}, editor = {Hanken, J. and Hall, B. K.} } @inbook {585831, title = {Mechanisms of skull diversity and evolution}, booktitle = {The Skull: Vol. 3, Functional and Evolutionary Mechanisms}, year = {1993}, pages = {1-36}, publisher = {University of Chicago Press}, organization = {University of Chicago Press}, address = {Chicago}, author = {Hanken, J. and Hall, B. K.}, editor = {Hanken, J. and Hall, B. K.} } @book {584886, title = {The Skull: Vol. 1, Development; Vol. 2, Patterns of Structural and Systematic Diversity; Vol. 3, Functional and Evolutionary Mechanisms}, year = {1993}, publisher = {University of Chicago Press}, organization = {University of Chicago Press}, address = {Chicago}, editor = {Hanken, J. and Hall, B. K.} } @article {561516, title = {Evolution and Development of the Vertebrate Skull - the Role of Pattern Formation}, journal = {Trends in Ecology \& Evolution}, volume = {8}, number = {1}, year = {1993}, note = {

Kf108Times Cited:53Cited References Count:38

}, month = {Jan}, pages = {9-15}, abstract = {

The vertebrate skull is anatomically complex and phylogenetically diverse; it presents unique opportunities to examine the role of developmental processes in evolutionary change. Previous studies have largely examined phylogenetic trends in tissue composition or change in the timing of developmental events (heterochrony). Additional important insights may be gained if skull evolution and development are viewed from the standpoint of pattern formation. Contemporary models of pattern formation offer the possibility of linking developmental mechanisms of cranial morphogenesis from the level of genes, through cell biology, to adult form.

}, keywords = {collagen type-ii, craniofacial development, Genes, head, interfaces, Morphogenesis, origin, transient expression}, isbn = {0169-5347}, author = {Hanken, J. and Thorogood, P.} } @article {561526, title = {Miniaturization of Body Size: Organismal Consequences and Evolutionary Significance}, journal = {Annual Review of Ecology and Systematics}, volume = {24}, year = {1993}, note = {

Mj371Times Cited:196Cited References Count:181

}, pages = {501-519}, abstract = {

Miniaturization, or the evolution of extremely small adult body size, is a widespread phenomenon in animals. It has important consequences for both organismal biology and phyletic diversification above the species level. The miniaturized phenotype is a complex combination of ancestral and derived traits, including reduction and structural simplification, increased variability, and morphological novelty. Many features likely represent secondary consequences of size decrease, which may be the result of selection primarily for small body size or some related attribute such as life history characteristics. In some cases, miniaturization has resulted in novel bauplans associated with the origin of higher taxa. Evaluation of causes and consequences of miniaturization should consider obvious features of physical size as well as less obvious, but biologically important, features such as genome and cell size.

}, keywords = {cell-size, cranial morphology, dwarfism, family plethodontidae, feeding adaptations, genome size, genus thorius amphibia, heterochrony, lungless salamanders, morphological novelty, plethodontid salamanders, progenesis, small body size, visual-system}, isbn = {0066-4162}, author = {Hanken, J. and Wake, D.B.} } @article {561346, title = {Model Systems Versus Outgroups: Alternative Approaches to the Study of Head Development and Evolution}, journal = {American Zoologist}, volume = {33}, number = {4}, year = {1993}, note = {

Ne970Times Cited:50Cited References Count:30

}, pages = {448-456}, abstract = {

There is widespread recognition of a recent coming together of developmental and evolutionary biology in the study of problems of mutual interest. Contemporary studies into the development and evolution of the head largely comprise two parallel approaches, or research strategies: the model systems approach and the comparative approach. The two strategies share the same general goal-greater understanding of cranial development and evolution-but typically emphasize different problems, ask different questions, and employ different methods, reflecting the contrasting backgrounds and biases of each group of investigators; there has been relatively little true synthesis. Each strategy is making important and valid contributions, but both have limitations. Resolution. of many fundamental and long-standing problems in cranial development and evolution will require a combined approach that incorporates the technical and conceptual strengths of each discipline.

}, keywords = {expression, frog, laevis, leptodactylidae, ontogeny, Phylogeny}, isbn = {0003-1569}, author = {Hanken, J.} } @article {586316, title = {Body building exercises}, journal = {Curr. Biol.}, volume = {2}, year = {1992}, pages = {83-85}, author = {Thorogood, P. and Hanken, J.} } @article {561461, title = {Cranial Ontogeny in the Direct-Developing Frog, Eleutherodactylus coqui (Anura, Leptodactylidae), Analyzed Using Whole-Mount Immunohistochemistry}, journal = {Journal of Morphology}, volume = {211}, number = {1}, year = {1992}, note = {

Gy542Times Cited:75Cited References Count:69

}, month = {Jan}, pages = {95-118}, abstract = {

Direct development in amphibians is an evolutionarily derived life-history mode that involves the loss of the free-living, aquatic larval stage. We examined embryos of the direct-developing anuran Eleutherodactylus coqui (Leptodactylidae) to evaluate how the biphasic pattern of cranial ontogeny of metamorphosing species has been modified in the evolution of direct development in this lineage. We employed whole-mount immunohistochemistry using a monoclonal antibody against the extracellular matrix component Type II collagen, which allows visualization of the morphology of cartilages earlier and more effectively than traditional histological procedures; these latter procedures were also used where appropriate. This represents the first time that initial chondrogenic stages of cranial development of any vertebrate have been depicted in whole-mounts.Many cranial cartilages typical of larval anurans, e.g., suprarostrals, cornua trabeculae, never form in Eleutherodactylus coqui. Consequently, many regions of the skull assume an adult, or postmetamorphic, morphology from the inception of their development. Other components, e.g., the lower jaw, jaw suspensorium, and the hyobranchial skeleton, initially assume a mid-metamorphic configuration, which is subsequently remodeled before hatching. Thirteen of the adult complement of 17 bones form in the embryo, beginning with two bones of the jaw and jaw suspensorium, the angulosplenial and squamosal. Precocious ossification of these and other jaw elements is an evolutionarily derived feature not found in metamorphosing anurans, but shared with some direct-developing caecilians. Thus, in Eleutherodactylus cranial development involves both recapitulation and repatterning of the ancestral metamorphic ontogeny. These modifications, however, are not associated with any fundamental change in adult morphology and cannot at this time be causally linked to the evolutionary success of this extraordinarily speciose genus.

}, keywords = {amphibians, cartilage, eurycea-bislineata, Evolution, metamorphosis, ossification, salamanders, sea-urchins, sequence, skull development}, isbn = {0362-2525}, author = {Hanken, J. and Klymkowsky, M. W. and Summers, C. H. and Seufert, D. W. and Ingebrigtsen, N.} } @article {561341, title = {Life History and Morphological Evolution}, journal = {Journal of Evolutionary Biology}, volume = {5}, number = {4}, year = {1992}, note = {

Ke392Times Cited:44Cited References Count:0

}, pages = {549-557}, keywords = {amphibians, Evolution, metamorphosis, Morphology, ontogeny}, isbn = {1010-061X}, author = {Hanken, J.} } @article {561796, title = {Skeletal Development in Xenopus laevis (Anura: Pipidae)}, journal = {Journal of Morphology}, volume = {214}, number = {1}, year = {1992}, note = {

Jw302Times Cited:110Cited References Count:55

}, month = {Oct}, pages = {1-41}, abstract = {

Postembryonic skeletal development of the pipid frog Xenopus laevis is described from cleared-and-stained whole-mount specimens and sectioned material representing Nieuwkoop and Faber developmental Stages 46-65, plus postmetamorphic individuals up to 6 months old. An assessment of variation of skeletogenesis within a single population of larvae and comparison with earlier studies revealed that the timing, but not the sequence, of skeletal development in X. laevis is more variable than previously reported and poorly correlated with the development of external morphology. Examination of chondrocranial development indicates that the rostral cartilages of X. laevis are homologous with the suprarostral cartilages of non-pipoid anurans, and suggests that the peculiar chondrocranium of this taxon is derived from a more generalized pattern typical of non-pipoid frogs. Derived features of skeletal development not previously reported for X. laevis include 1) bipartite formation of the palatoquadrate; 2) precocious formation of the adult mandible; 3) origin of the angulosplenial from two centers of ossification; 4) complete erosion of the orbital cartilage during the later stages of metamorphosis; 5) development of the sphenethmoid as a membrane, rather than an endochondral bone; and 6) a pattern of timing of ossification that more closely coincides with that of the pelobatid frog Spea than that recorded for neobatrachian species.

}, keywords = {amphibia, cranial ossification, Evolution, meckels cartilage, metamorphosis, ossification sequence, pipoid frogs, replacement, sexually dimorphic larynx, Vertebrates}, isbn = {0362-2525}, author = {Trueb, L. and Hanken, J.} } @article {584896, title = {Symposium: Experimental approaches to the analysis of form and function}, journal = {Amer. Zool.}, volume = {31}, year = {1991}, pages = {601-756}, editor = {Hanken, J. and Wake, M. H.} } @inbook {561811, title = {Development and Evolution - the Emergence of a New Field}, booktitle = {Unity of Evolutionary Biology: The Proceedings of the Fourth International Congress of Systematic and Evolutionary Biology}, year = {1991}, note = {

Bw25vTimes Cited:10Cited References Count:0

}, pages = {582-588}, publisher = {Dioscorides Press}, organization = {Dioscorides Press}, address = {Portland}, author = {Wake, D.B. and Mabee, P. and Hanken, J. and Wagner, G.}, editor = {Dudley, E.C.} } @article {561561, title = {Introduction to the Symposium: Experimental Approaches to the Analysis of Form and Function}, journal = {American Zoologist}, volume = {31}, number = {4}, year = {1991}, note = {

Gf868Times Cited:4Cited References Count:5

}, pages = {603-604}, keywords = {Morphology}, isbn = {0003-1569}, author = {Hanken, J. and Wake, M. H.} } @inbook {561621, title = {Whole-Mount Staining of Xenopus and Other Vertebrates}, booktitle = {Xenopus laevis: Practical Uses in Cell and Molecular Biology}, year = {1991}, note = {

Mc414Times Cited:163Cited References Count:45

}, pages = {419-441}, publisher = {Academic Press}, organization = {Academic Press}, address = {New York}, keywords = {bone, cartilage, embryos, expression, fluorescence microscopy, laevis oocytes, larvae, microtubules, organization, Proteins}, isbn = {0091-679X}, author = {Klymkowsky, M. W. and Hanken, J.}, editor = {Kay, B.K. and Peng, H.B.} } @article {586321, title = {Review of Thomson, K.S., Morphogenesis and Evolution}, journal = {Copeia}, volume = {1990}, year = {1990}, pages = {247-248}, author = {Hanken, J.} } @article {561201, title = {Amputation Level-Dependent Patterning in Urodele Limb Regeneration}, journal = {Journal of Morphology}, volume = {205}, number = {1}, year = {1990}, note = {

Dq337Times Cited:2Cited References Count:41

}, month = {Jul}, pages = {77-84}, isbn = {0362-2525}, author = {Dinsmore, C. E. and Hanken, J.} } @article {561211, title = {Limb Skeletal Variation in the Jemez Mountains Salamander, Plethodon neomexicanus}, journal = {Canadian Journal of Zoology}, volume = {68}, number = {6}, year = {1990}, note = {

Dp423Times Cited:6Cited References Count:29

}, month = {Jun}, pages = {1281-1287}, isbn = {0008-4301}, author = {Dwyer, C. M. and Hanken, J.} } @article {561746, title = {Miniaturization in Plethodontid Salamanders (Caudata, Plethodontidae) and Its Consequences for the Brain and Visual-System}, journal = {Biological Journal of the Linnean Society}, volume = {40}, number = {2}, year = {1990}, note = {

Dm616Times Cited:28Cited References Count:51

}, month = {Jun}, pages = {165-190}, isbn = {0024-4066}, author = {Roth, G. and Rottluff, B. and Grunwald, W. and Hanken, J. and Linke, R.} } @article {586326, title = {Development and evolution of the neural crest (review of Developmental and Evolutionary Aspects of the Neural Crest)}, journal = {Evolution}, volume = {43}, year = {1989}, pages = {1337-1338}, author = {Hanken, J.} } @inbook {585981, title = {Developmental characters in phylogenetic inference: a test case using amphibians}, booktitle = {Trends in Vertebrate Morphology}, volume = {35}, year = {1989}, pages = {174-179}, publisher = {Fortsch. Zool.}, organization = {Fortsch. Zool.}, author = {Hanken, J.}, editor = {Splechtna, H. and Hilgers, H.} } @article {561336, title = {Development and Evolution in Amphibians}, journal = {American Scientist}, volume = {77}, number = {4}, year = {1989}, note = {

Ae823Times Cited:24Cited References Count:41

}, month = {Jul-Aug}, pages = {336-343}, isbn = {0003-0996}, author = {Hanken, J.} } @inbook {561626, title = {How Are Feeding Systems Integrated and How Have Evolutionary Innovations Been Introduced}, booktitle = {Complex Organismal Functions : Integration and Evolution in VertebratesComplex Organismal Functions : Integration and Evolution in VertebratesComplex Organismal Functions : Integration and Evolution in Vertebrates}, year = {1989}, note = {

Bq55zTimes Cited:18Cited References Count:0Life Sciences Research Report

}, pages = {97-115}, publisher = {John Wiley \& Sons Ltd.}, organization = {John Wiley \& Sons Ltd.}, address = {Chichester}, author = {Lauder, G. V. and Crompton, A. W. and Gans, C. and Hanken, J. and Liem, K. F. and Maier, W. O. and A Meyer and Presley, R. and Rieppel, O. C. and Roth, G. and Schluter, D. and Zweers, G. A.}, editor = {Wake, D.B. and Roth, G.} } @article {561511, title = {Morphological Integration in the Cranium during Anuran Metamorphosis}, journal = {Experientia}, volume = {45}, number = {9}, year = {1989}, note = {

At962Times Cited:12Cited References Count:26

}, month = {Sep 15}, pages = {872-875}, isbn = {0014-4754}, author = {Hanken, J. and Summers, C. H. and Hall, B. K.} } @article {586041, title = {Thorius pennatulus Cope, 1869 (Amphibia, Caudata): proposed confirmation of the specific name}, journal = {Bull. Zool. Nomen.}, volume = {45}, year = {1988}, pages = {210-211}, author = {H. Smith and Hanken, J. and Chiszar, D.} } @article {561436, title = {Skull Development during Anuran Metamorphosis. I. Early Development of the first three Bones to Form - the Exoccipital, the Parasphenoid, and the Frontoparietal}, journal = {Journal of Morphology}, volume = {195}, number = {3}, year = {1988}, note = {

M7941Times Cited:48Cited References Count:30

}, month = {Mar}, pages = {247-256}, isbn = {0362-2525}, author = {Hanken, J. and Hall, B. K.} } @article {561441, title = {Skull Development during Anuran Metamorphosis. II. Role of Thyroid Hormone in Osteogenesis}, journal = {Anatomy and Embryology}, volume = {178}, number = {3}, year = {1988}, note = {

N7552Times Cited:25Cited References Count:52

}, pages = {219-227}, isbn = {0340-2061}, author = {Hanken, J. and Hall, B. K.} } @article {561501, title = {Skull Development during Anuran Metamorphosis. III. Role of Thyroid Hormone in Chondrogenesis}, journal = {Journal of Experimental Zoology}, volume = {246}, number = {2}, year = {1988}, note = {

N5412Times Cited:39Cited References Count:66

}, month = {May}, pages = {156-170}, isbn = {0022-104X}, author = {Hanken, J. and Summers, C. H.} } @article {586331, title = {Review of Biology of the Reptilia, v. 14-15 (Development A \& B)}, journal = {Herp. Rev.}, volume = {18}, year = {1987}, pages = {41-43}, author = {Hanken, J.} } @inbook {586051, title = {Salamander invasion of the tropics.}, booktitle = {Natural History Reader in Evolution}, year = {1987}, pages = {101-107}, publisher = {Colombia University Press}, organization = {Colombia University Press}, address = {New York}, author = {Hanken, J. and Lynch, J. F. and Wake, D.B.}, editor = {Eldredge, N.} } @article {586401, title = {Morphological evolution (Review of Mechanisms of Morphological Evolution)}, journal = {Evolution}, volume = {40}, year = {1986}, pages = {443-444}, author = {Hanken, J.} } @article {586336, title = {Review of Morphometrics in Evolutionary Biology: The Geometry of Size and Shape Change, with Examples from Fishes}, journal = {Quart. Rev. Biol.}, volume = {61}, year = {1986}, pages = {542-543}, author = {Hanken, J.} } @inbook {586056, title = {Bone}, booktitle = {Collier{\textquoteright}s Encyclopedia}, volume = {4}, year = {1986}, pages = {349-351}, publisher = {Macmillan Educational Co.}, organization = {Macmillan Educational Co.}, address = {New York}, author = {Hanken, J.} } @inbook {561331, title = {Developmental Evidence for Amphibian Origins}, booktitle = {Evolutionary Biology}, volume = {20}, year = {1986}, note = {

D3617Times Cited:29Cited References Count:142

}, pages = {389-417}, publisher = {Plenum Publ. Corp.}, organization = {Plenum Publ. Corp.}, address = {New York}, isbn = {0071-3260}, author = {Hanken, J.}, editor = {Hecht, M.K. and Wallace, B. and Prance, G.T.} } @article {561391, title = {Geographic Variation in the Limb Skeleton of the Red-Backed Salamander, Plethodon cinereus}, journal = {Journal of Herpetology}, volume = {20}, number = {1}, year = {1986}, note = {

A8274Times Cited:18Cited References Count:15

}, month = {Mar}, pages = {97-101}, isbn = {0022-1511}, author = {Hanken, J. and Dinsmore, C. E.} } @article {561196, title = {Native Variant Limb Skeletal Patterns in the Red-Backed Salamander, Plethodon cinereus, Are Not Regenerated}, journal = {Journal of Morphology}, volume = {190}, number = {2}, year = {1986}, note = {

E8453Times Cited:13Cited References Count:32

}, month = {Nov}, pages = {191-200}, isbn = {0362-2525}, author = {Dinsmore, C. E. and Hanken, J.} } @article {561326, title = {Small Wonders}, journal = {The Sciences}, volume = {26}, number = {5}, year = {1986}, note = {

D6368Times Cited:4Cited References Count:0

}, month = {Sep-Oct}, pages = {40-43}, isbn = {0036-861X}, author = {Hanken, J.} } @inbook {586061, title = {Forward}, booktitle = {The Development of the Vertebrate Skull}, year = {1985}, pages = {vii-xxviii}, publisher = {University of Chicago Press}, organization = {University of Chicago Press}, address = {Chicago}, author = {Hall, B. K. and Hanken, J.}, editor = {de Beer, G.R.} } @article {561321, title = {Morphological Novelty in the Limb Skeleton Accompanies Miniaturization in Salamanders}, journal = {Science}, volume = {229}, number = {4716}, year = {1985}, note = {

Aph24Times Cited:58Cited References Count:37

}, pages = {871-874}, isbn = {0036-8075}, author = {Hanken, J.} } @article {561266, title = {Repair of Fractured Lower Jaws in the Spotted Salamander - Do Amphibians Form Secondary Cartilage?}, journal = {Journal of Experimental Zoology}, volume = {233}, number = {3}, year = {1985}, note = {

Act81Times Cited:12Cited References Count:35

}, pages = {359-368}, isbn = {0022-104X}, author = {Hall, B. K. and Hanken, J.} } @article {586231, title = {Skeletal pattern variability innative and regenerated limbs of the red-backed salamander, Plethodon cinereus}, journal = {Mt. Desert Is. Biol. Lab. Bull.}, volume = {24}, year = {1984}, pages = {70-71}, author = {Dinsmore, C. E. and Hanken, J.} } @article {561311, title = {Miniaturization and Its Effects on Cranial Morphology in Plethodontid Salamanders, Genus Thorius (Amphibia, Plethodontidae). I. Osteological Variation}, journal = {Biological Journal of the Linnean Society}, volume = {23}, number = {1}, year = {1984}, note = {

Tt323Times Cited:74Cited References Count:61

}, pages = {55-75}, isbn = {0024-4066}, author = {Hanken, J.} } @article {561466, title = {Technique for Revealing the three Dimensional Architecture of Whole Preserved Spiculated Invertebrates}, journal = {Stain Technology}, volume = {59}, number = {2}, year = {1984}, note = {

Te456Times Cited:3Cited References Count:12

}, pages = {65-69}, isbn = {0038-9153}, author = {Hanken, J. and Koehl, M. A. R.} } @article {561421, title = {Variation and Timing of the Cranial Ossification Sequence of the Oriental Fire-Bellied Toad, Bombina orientalis (Amphibia, Discoglossidae)}, journal = {Journal of Morphology}, volume = {182}, number = {3}, year = {1984}, note = {

Tw103Times Cited:64Cited References Count:33

}, pages = {245-255}, isbn = {0362-2525}, author = {Hanken, J. and Hall, B. K.} } @article {561416, title = {Evolution of the Skeleton}, journal = {Natural History}, volume = {92}, number = {4}, year = {1983}, note = {

Qf691Times Cited:4Cited References Count:0

}, pages = {28-39}, isbn = {0028-0712}, author = {Hanken, J. and Hall, B. K.} } @article {561291, title = {Genetic-Variation in a Dwarfed Lineage, the Mexican Salamander Genus Thorius (Amphibia, Plethodontidae): Taxonomic, Ecologic and Evolutionary Implications}, journal = {Copeia}, volume = {1983}, number = {4}, year = {1983}, note = {

Rv870Times Cited:31Cited References Count:53

}, pages = {1051-1073}, isbn = {0045-8511}, author = {Hanken, J.} } @article {561301, title = {High-Incidence of Limb Skeletal Variants in a Peripheral Population of the Red-Backed Salamander, Plethodon cinereus (Amphibia, Plethodontidae), from Nova Scotia}, journal = {Canadian Journal of Zoology}, volume = {61}, number = {8}, year = {1983}, note = {

Rf912Times Cited:31Cited References Count:22

}, pages = {1925-1931}, isbn = {0008-4301}, author = {Hanken, J.} } @article {561296, title = {Miniaturization and Its Effects on Cranial Morphology in Plethodontid Salamanders, Genus Thorius (Amphibia, Plethodontidae). II. The Fate of the Brain and Sense Organs and Their Role in Skull Morphogenesis and Evolution}, journal = {Journal of Morphology}, volume = {177}, number = {3}, year = {1983}, note = {

Rm437Times Cited:78Cited References Count:67

}, pages = {255-268}, isbn = {0362-2525}, author = {Hanken, J.} } @article {561281, title = {Appendicular Skeletal Morphology in Minute Salamanders, Genus Thorius (Amphibia, Plethodontidae): Growth Regulation, Adult Size Determination, and Natural Variation}, journal = {Journal of Morphology}, volume = {174}, number = {1}, year = {1982}, note = {

Pl112Times Cited:51Cited References Count:64

}, pages = {57-77}, isbn = {0362-2525}, author = {Hanken, J.} } @article {561826, title = {Development of the Skull of Dermophis mexicanus (Amphibia, Gymnophiona), with Comments on Skull Kinesis and Amphibian Relationships}, journal = {Journal of Morphology}, volume = {173}, number = {2}, year = {1982}, note = {

Pc167Times Cited:74Cited References Count:64

}, pages = {203-223}, isbn = {0362-2525}, author = {Wake, M. H. and Hanken, J.} } @article {561521, title = {Genetic Differentiation among Plethodontid Salamanders (Genus Bolitoglossa) in Central America and South America: Implications for the South-American Invasion}, journal = {Herpetologica}, volume = {38}, number = {2}, year = {1982}, note = {

Nx498Times Cited:23Cited References Count:0

}, pages = {272-287}, isbn = {0018-0831}, author = {Hanken, J. and Wake, D.B.} } @article {586406, title = {The visible skeleton}, journal = {Funct. Photog.}, volume = {16}, year = {1981}, pages = {22-26, 44}, author = {Hanken, J. and Wassersug, R.J.} } @article {561491, title = {Multiple Paternity in Beldings Ground Squirrel Litters}, journal = {Science}, volume = {212}, number = {4492}, year = {1981}, note = {

Lk031Times Cited:197Cited References Count:56

}, pages = {351-353}, isbn = {0036-8075}, author = {Hanken, J. and Sherman, P. W.} } @article {561471, title = {Salamander Invasion of the Tropics}, journal = {Natural History}, volume = {89}, number = {12}, year = {1980}, note = {

Kr564Times Cited:0Cited References Count:0

}, pages = {47-53}, isbn = {0028-0712}, author = {Hanken, J. and Lynch, J. F. and Wake, D.B.} } @article {561276, title = {Egg Development Time and Clutch Size in two Neotropical Salamanders}, journal = {Copeia}, volume = {1979}, number = {4}, year = {1979}, note = {

Hw535Times Cited:12Cited References Count:9

}, pages = {741-744}, isbn = {0045-8511}, author = {Hanken, J.} } @article {586411, title = {Herpetology at the University of California-Berkeley}, journal = {Herp. Rev.}, volume = {8}, year = {1977}, pages = {74-75}, author = {Wake, D.B. and Hanken, J.} }