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| The braincase in Paleozoic symmoriiform and cladoselachian sharks ; Bulletin of the American Museum of Natural History, no. 307 |
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| Title: | The braincase in Paleozoic symmoriiform and cladoselachian sharks ; Bulletin of the American Museum of Natural History, no. 307 |
| Other Titles: | Braincase in Paleozoic sharks |
| Authors: | Maisey, John G. |
| Issue Date: | 2007 |
| Publisher: | New York, NY : American Museum of Natural History |
| Series/Report no.: | Bulletin of the American Museum of Natural History, no. 307 |
| Abstract: | "The concepts of platytrabia/platybasia and tropibasia/tropitrabia in gnathostomes are reviewed. The terms platytrabia and tropitrabia refer to developmental states of the embryonic trabecular cartilages that can be determined only by ontogenetic studies. The terms platybasia and tropibasia originally had this meaning, but have subsequently taken on additional descriptive connotations involving morphological features in the prechordal part of the adult chondrocranium. However, platybasia and tropibasia are not synonymous with platytrabia and tropitrabia. In gnathostomes, platytrabia usually gives rise to a platybasic adult condition (but not invariably; e.g., Lepisosteus), and tropitrabia usually gives rise to the tropibasic condition (modern elasmobranchs may be an exception). Thus, ontogeny does not provide an absolute guide to the adult condition, nor does adult morphology provide an accurate means to assess the prior ontogenetic condition in gnathostomes. Platybasia and tropibasia ... |
| Description: | 122 p. : ill. (some col.) ; 26 cm. Includes bibliographical references (p. 116-122). |
| URI: | http://hdl.handle.net/2246/5883 |
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