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A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania)

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

DeMar, DG 
Conrad, JL 
Head, JJ 
Varricchio, DJ 
Wilson, GP 

Abstract

Iguanomorpha (stem + crown Iguania) is a diverse squamate clade with members that predominate many modern American lizard ecosystems. However, the temporal and palaeobiogeographic origins of its constituent crown clades (e.g. Pleurodonta (basilisks, iguanas, and their relatives)) are poorly constrained, mainly due to a meagre Mesozoic-age fossil record. Here, we report on two nearly complete skeletons from the Late Cretaceous (Campanian) of North America that represent a new and relatively large-bodied and possibly herbivorous iguanomorph that inhabited a semi-arid environment. The new taxon exhibits a mosaic of anatomical features traditionally used in diagnosing Iguania and non-iguanian squamates (i.e. Scleroglossa; e.g. parietal foramen at the frontoparietal suture, astragalocalcaneal notch in the tibia, respectively). Our cladistic analysis of Squamata revealed a phylogenetic link between Campanian-age North American and East Asian stem iguanomorphs (i.e. the new taxon + Temujiniidae). These results and our evaluation of the squamate fossil record suggest that crown pleurodontans were restricted to the low-latitude Neotropics prior to their early Palaeogene first appearances in the mid-latitudes of North America.

Description

Keywords

Cretaceous, Iguanomorpha, Palaeogene, Pleurodonta, palaeobiogeography, palaeoecology

Journal Title

Proceedings of the Royal Society B: Biological Sciences

Conference Name

Journal ISSN

0962-8452
1471-2954

Volume Title

284

Publisher

Royal Society Publishing
Sponsorship
NSF (EAR) grant nos. 0847777 to D.J.V. and 1325674 to G.P.W., D.J.V. and J.L.C. Richard Gilder Graduate School and the American Museum of Natural History Collections Study Grant and the NSF GRFP grant no. DGE-0718124, both to D.G.D.