THE POSTCRANIAL SKELETON OF THE DEVONIAN TETRAPOD TULERPETON CURTUM LEBEDEV

Citation
Oa. Lebedev et Mi. Coates, THE POSTCRANIAL SKELETON OF THE DEVONIAN TETRAPOD TULERPETON CURTUM LEBEDEV, Zoological journal of the Linnean Society, 114(3), 1995, pp. 307-348
Citations number
88
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Zoology
ISSN journal
0024-4082
Volume
114
Issue
3
Year of publication
1995
Pages
307 - 348
Database
ISI
SICI code
0024-4082(1995)114:3<307:TPSOTD>2.0.ZU;2-Z
Abstract
Postcranial remains of the Russian Late Devonian tetrapod Tulerpeton i nclude the hexadactylous fore limb, hind limb, anocleithral pectoral g irdle, squamation, and associated disarticulated postcranial bones. A cladistic analysis indicates that Tulerpeton is a reptiliomorph stem-g roup amniote and the earliest known crown-group tetrapod: Acanthostega and Ichthyostega are successively more derived plesion stem-group tet rapods and do not consititute a monophyletic ichthyostegalian radiatio n. Previous analyses suggesting a profound split in tetrapod phylogeny are thereby corroborated, and likewise the interpretation of Westloth iana as a stem-group amniote. The divergence of reptiliomorphs from ba trachomorphs occurred before the Devonian-Carboniferous boundary. Tule rpeton originates from an entirely aquatic environment with a diverse fish fauna. The morphologies of its limbs and those of Devonian stem-t etrapods suggest that dactyly predates the elaboration of the carpus a nd tarsus, and that polydactyly persisted after the evolutionary diver gence of the principal lineages of living tetrapods. The apparent abse nce of a branchial lamina and gill skeleton suggests that Tulerpeton w as primarily air-breathing, whereas contemporary stem-group tetrapods and more recent batrachomorphs retained greater emphasis on gill-breat hing. (C) 1995 Academic Press Limited