Data from: Palaeoecological inferences for the fossil Australian snakes Yurlunggur and Wonambi (Serpentes, Madtsoiidae)

Madtsoiids are among the most basal snakes, with a fossil record dating
back to the Upper Cretaceous (Cenomanian). Most representatives went
extinct by the end of the Eocene, but some survived in Australia until the
late Cenozoic. Yurlunggur and Wonambi are two of these late forms, and
also the best-known madtsoiids to date. A better understanding of the
anatomy and palaeoecology of these taxa may shed light on the evolution
and extinction of this poorly known group of snakes and on early snake
evolution in general. A digital endocast of the inner ear of Yurlunggur
was compared to those of 81 species of snakes and lizards with known
ecological preferences using three-dimensional geometric morphometrics.
The inner ear of Yurlunggur most closely resembles both that of certain
semiaquatic snakes and that of some semifossorial snakes. Other cranial
and postcranial features of this snake support the semifossorial
interpretation. While the digital endocast of the inner ear of Wonambi is
too incomplete to be included in a geometric morphometrics study, its
preserved morphology is very different from Yurlunggur and suggests a more
generalist ecology. Osteology, palaeoclimatic data, and the
palaeobiogeographic distribution of these two snakes are all consistent
with these inferred ecological differences.