Erpetosuchus - Systematics

Systematics

Erpetosuchus granti was originally assigned to Thecodontia, but that name is no longer considered valid in scientific literature because it is a paraphyletic group of early archosaurs.

A more recent phylogenetic analysis by Olsen et al. (2000) found E. granti to be the sister-taxon to the Crocodylomorpha. These were united in a clade by the following synapomorphies:

• Medial contact of the maxillae (upper jaw bones) to form a secondary bony palate
• Absence of a postfrontal bone at the top of the skull
• Parietal bones fused without a trace of a suture between them

Benton and Walker (2002) found the same sister-group relationship and proposed the name Bathyotica for the clade containing Erpetosuchus and Crocodylomorpha.

Nesbitt and Butler (2012) included Erpetosuchus within a more comprehensive phylogenetic analysis and found it to group with the archosaur Parringtonia from the Middle Triassic of Tanzania. Both were part of the clade Erpetosuchidae. Nesbitt and Butler did not find support for the sister-group relationship between Erpetosuchus and Crocodylomorpha. Instead, erpetosuchids formed a polytomy or unresolved evolutionary relationship at the base of Archosauria along with several other groups. It could take many positions within Archosauria, but none were as a sister taxon of Crocodylomorpha.