Lizards and snakes of the Terlingua Local Fauna (late Campanian), Aguja Formation, Texas, with comments on the distribution of paracontemporaneous squamates throughout the Western Interior of North America

ABSTRACT

The late Campanian–aged (= Judithian) squamates from the Terlingua Local Fauna of the Aguja Formation, southern Texas, includes four scincomorphans: a new taxon (Catactegenys solaster, gen. et sp. nov.), referable to Xantusiidae, that has massive teeth and tooth crown morphology similar to that of contogeniid lizards; an indeterminate scincomorphan (Apsgnathus triptodon, gen et sp. nov.) with robust teeth; and two unnamed scincomorphan morphotypes. Anguimorphans in the fauna include Odaxosaurus piger, cf. Parasaniwa wyomingensis, and a likely xenosaur. Ophidian jaw fragments confirm the presence of a snake in the fauna. The Aguja squamate assemblage is one of the most southerly of a series of paracontemporaneous squamate faunas extending from central Alberta to northern Mexico. Comparison of these faunas reveals that, although two taxa are endemic to the Aguja Formation, others show some latitudinal trends. Odaxosaurus and Parasaniwa are present in all well-sampled faunas from Alberta to Texas. The mammal-like Peneteius and snakes are found only in faunas from southern Utah to Mexico. Chamopsiids are only present from Alberta to New Mexico. The sole representatives of Contogeniidae and Xantusiidae are restricted to southern Utah and southern Texas, respectively. These hypotheses of distributional patterns must continue to be tested through ongoing investigations of all of the relevant faunas from the late Campanian of the Western Interior.

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

ACKNOWLEDGMENTS

We thank the many students, staff, and volunteers (too numerous to name, but all worthy of recognition) of both the OMNH and TMM vertebrate paleontology laboratories for their hard work over the past 25 years on the intermittent investigations of the Terlingua Local Fauna. Comments provided by J. Conrad, J. Müller, and an anonymous reviewer helped to improve this manuscript. The specimens reported herein were recovered during joint expeditions of the OMNH and TMM in 1988–1989.

NOTE ADDED AT PROOF

After final acceptance of the paper the missing specimens mentioned in the Introduction were located and will be included in a subsequent publication on the Aguja fauna.

Handling editor: Johannes Müller