Sineoamphisbaena

Sineoamphisbaena; Temporal range: Late Cretaceous PreꞒ Ꞓ O S D C P T J K Pg N
	Holotype, Paleozoological Museum of China
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Genus:	†Sineoamphisbaena; Wu et al., 1993
Species
	Sineoamphisbaenia hexatabularis, Wu et al., 1993;

Sineoamphisbaena is an extinct genus of squamate of uncertain phylogenetic placement. Its fossils have been found in Late Cretaceous deposits in Inner Mongolia, China.^[1] It contains a single species, Sineoamphisbaenia hexatabularis.^[1]

Taxonomic affiliation

Wu et al.^[1] and Gao^[2] proposed and argued that Sineoamphisbaenia was the oldest known amphisbaenian; this, however, was challenged by other authors, such as Kearney^[3] and Conrad,^[4] who instead assigned Sineoamphisbaena to the group of squamates variously known as Macrocephalosauridae, Polyglyphanodontidae or Polyglyphanodontia.

A large-scale study of fossil and living squamates published by Gauthier et al. in 2012^[5] did not find evidence for a particularly close relationship between amphisbaenians and Sineoamphisbaena; in their primary analysis Sineoamphisbaena was found to be the sister taxon of the clade containing snakes, amphisbaenians, the family Dibamidae and the American legless lizard. The primary analysis of Gauthier et al.^[5] did not support a close relationship between Sineoamphisbaena and polyglyphanodontians either; however, the authors noted that when all snake-like squamates and mosasaurs were removed from the analysis, and burrowing squamates were then added individually to it, Sineoamphisbaena grouped with polyglyphanodontians. Gauthier et al.^[5] considered it possible that Sineoamphisbaena was a burrowing polyglyphanodontian.

Sources

World Encyclopedia of Dinosaurs & Prehistoric Creatures: The Ultimate Visual Reference To 1000 Dinosaurs And Prehistoric Creatures Of Land, Air And Sea ... And Cretaceous Eras (World Encyclopedia) by Dougal Dixon