Tupilakosaur-like vertebrae in Bothriceps australis, an Australian brachyopid stereospondyl

ABSTRACT

A new locality near the Permo-Triassic boundary in Tasmania, Australia, has yielded a number of specimens of the brachyopid stereospondyl, Bothriceps australis, whose provenance was unknown previously. An articulated diplospondylous vertebral column of a morphology typical only of the Tupilakosauridae was found at the same locality. Although the Brachyopidae and Tupilakosauridae have skulls of similar shape, most authors have regarded them as not closely related. Phylogenetic analysis confirms that the Brachyopidae and Tupilakosauridae are both members of the Stereospondyli but are not closely related, despite the remarkable similarity of the Bothriceps and tupilakosaur vertebral columns.

ACKNOWLEDGMENTS

We thank B. and P. Tyson, who discovered the Koonya fossil site and brought it to our attention; A. C. Milner, Natural History Museum, London, for the loan of the holotype of B. australis; R. Jones, Australian Museum, Sydney for AM F125866; I. Percival, Geological Survey of New South Wales, for NSWGS 12572; A. C. and A. R. Milner, D. P. Sengupta, J. Clack, J. Maisey, K. Campbell, and R. Damiani for discussions; H. Gibb for photographic assistance; and TMAG staff. A. Yates originally suggested to A.R. that the centra might be tupilakosaurid. The new material was prepared by A.W. and A. Werner. The manuscript was improved by reviews from M. Ruta and J.-S. Steyer, and by editing by J. Anderson.

Handling editor: Jason Anderson