Etjosuchus

Etjosuchus; Temporal range: Middle- Late Triassic, Ladinian–Carnian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Loricata
Genus:	† Etjosuchus; Tolchard et al., 2021
Type species
	Etjosuchus recurvidens; Tolchard et al., 2021

Etjosuchus is an extinct genus of " rauisuchian" ( loricatan) archosaur from the Triassic of Namibia. It is known from a single species, Etjosuchus recurvidens, which is based on a partial skeleton from the Ladinian or Carnian-age Omingonde Formation.^[1]

Classification

To evaluate the evolutionary position of Etjosuchus in a modern context, Tolchard et al. (2021) coded it into a phylogenetic matrix derived from the work of Nesbitt (2011). The phylogenetic analysis was run with several levels of implied weighting (from no weighting to k=1, 3, and 6), a strategy to minimize the effects of homoplasy ( convergent evolution). With no weighting, Etjosuchus is resolved as a basal loricatan closer to crocodylomorphs than Luperosuchus, but not as close as a Heptasuchus + Batrachotomus clade. At k=1, its position shifts crownward towards crocodylomorphs, and Etjosuchus may clade with Fasolasuchus and/or Rauisuchus. Increasing the weighting further strengthens a connection with Rauisuchus, crownward of Fasolasuchus. This would indicate that the family Rauisuchidae is a paraphyletic grade rather than a clade: Postosuchus and Polonosuchus, other proposed rauisuchids, were closer to crocodylomorphs than to Rauisuchus in this configuration.^[1]