@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.} }