Amerophidia Vidal, Delmas & Hedges, 2007

Szyndlar, Zbigniew & Georgalis, Georgios L., 2023, An illustrated atlas of the vertebral morphology of extant non-caenophidian snakes, with special emphasis on the cloacal and caudal portions of the column, Vertebrate Zoology 73, pp. 717-886 : 717

Amerophidia Vidal, Delmas & Hedges, 2007

General information.

Amerophidia constitute a recently established group based on molecular phylogenies ( Vidal et al. 2007). It consists of Aniliidae and Tropidophiidae and is thought to represent the most basal group of alethinophidians ( Scanlon and Lee 2011). As their name attests, amerophidians are currently distributed in the Americas. Despite the strong molecular evidence supporting its monophyly (e.g., Vidal et al. 2007, 2010; Wiens et al. 2008; Pyron and Burbrink 2012; Streicher and Wiens 2016; Zheng and Wiens 2016; Burbrink et al. 2020; Ortega-Andrade et al. 2022), amerophidian apomorphic morphological characters are mostly lacking, with the exception of a few cranial features shared among aniliids and tropidophiids, primarily in the shape of their palate, but also a soft anatomical apomorphy, an oviduct connecting to the diverticuli of the cloaca, instead of connecting directly to the cloaca ( Maisano and Rieppel 2007; Scanlon and Lee 2011; Siegel et al. 2011; Hsiang et al. 2015). Indeed, morphology-based phylogenies have failed to recover such close relationship among Aniliidae and Tropidophiidae (e.g., Gauthier et al. 2012; Scanferla et al. 2016; Smith and Scanferla 2021). This is also true for their vertebral morphology, which is rather different between aniliids and tropidophiids.