First crocodile-tailed lizard (Squamata: Pan-Shinisaurus) from the Paleogene of Europe

ABSTRACT

Crocodile-tailed lizards are represented by a single extant species, Shinisaurus crocodilurus, the Chinese crocodile lizard, which until 2006 was completely unknown in the fossil record. These lizards may play an important role in understanding squamate phylogeny, but their biogeographic history remains murky. A new specimen from the middle Eocene of Messel, Germany, is the first record of the clade in the Paleogene of Europe. The specimen comprises an autotomized tail preserved in complete articulation. It retains a number of plesiomorphies with respect to S. crocodilurus, and it also differs from the coeval species Bahndwivici ammoskius, but comparisons with other shinisaurs are necessarily limited. The present specimen documents for the first time in the fossil record the superficially crocodile-like tail for which the extant species is named, indicating aquatic adaptation already by the middle Eocene. It furthermore raises questions about the identification of isolated ‘necrosaur’ material from the European Paleogene. Finally, it adds to growing evidence of a taxonomically similar squamate fauna in Europe and North America in the early Paleogene.

Citation for this article: SMITH, K. T. 2017. First crocodile-tailed lizard (Squamata: Pan-Shinisaurus) from the Paleogene of Europe. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1313743.

ACKNOWLEDGMENTS

B. Behr (SMF) prepared the specimen, and A. Vogel and S. Tränkner (SMF) took the photographs. I thank J. Conrad for providing high-resolution photographs of Bahndwivici ammoskius, and A. Čerňanský, J. Franzen, S. Schaal, M. Wuttke (all SMF), and M. Zollweg (Dreieich, Germany) for discussion. W. Downs is thanked for the osteology translation of Zhang (1991). Four reviewers (J. Klembara, A. Čerňanský, J. Head, and one anonymous) provided helpful criticism of the manuscript.