Supramarginal scute count of alligator snapping turtles (Macrochelys temminckii) in Texas, USA

David Rosenbaum; Connor S. Adams; Daniel Saenz; Christopher Schalk

Treesearch

Supramarginal scute count of alligator snapping turtles (Macrochelys temminckii) in Texas, USA

Formally Refereed

Authors:

David Rosenbaum, Connor S. Adams, Daniel Saenz, Christopher Schalk

Year:

2023

Type:

Scientific Journal

Station:

Southern Research Station

Source:

Herpetological Review

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Abstract

The genus Macrochelys (Alligator Snapping Turtles) is the only extant turtle clade whose members possess supramarginal scutes (Joyce 2016). The extinct genera Proganochelys (Ascarrunz and Sánchez-Villagra 2022), Platychelys (Sullivan and Joyce 2017), and Boremys (Joyce and Lyson 2015) also all possessed supramaginal scutes. However, supramarginals in these four genera do not likely represent homologous structures. Platychelys is a stem-pleurodire (Sullivan and Joyce 2017) unlike the cryptodires Macrochelys and Boremys, whereas Proganochelys is an early testudinatan that may represent a common ancestor to both cryptodires and pleurodires (Gaffney et al. 1987). Pritchard (2006) argued that supramarginals in Macrochelys are an apomorphic trait, which is supported by the absence of the scutes in all its extant relatives.

Keywords

Macrochelys, Alligator Snapping Turtle, supramarginal scutes, anatomy, evolution

Citation

Rosenbaum, David; Adams, Connor S.; Saenz, Daniel; Schalk, Christopher M. 2023. Supramarginal scute count of alligator snapping turtles (Macrochelys temminckii) in Texas, USA. Herpetological Review. 54(2): 181-185.