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Dongusuchus (Middle Triassic archosauriform from Russia) osteology and systematics



Ben Creisler
bcreisler@gmail.com

A new online paper:

Grzegorz Niedźwiedzki, Andrey Sennikov & Stephen L. Brusatte (2014)
The osteology and systematic position of Dongusuchus efremovi
Sennikov, 1988 from the Anisian (Middle Triassic) of Russia.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2014.992017
http://www.tandfonline.com/doi/full/10.1080/08912963.2014.992017#.VJGtkF4AOA

European Russia has yielded several fragmentary but potentially
important archosauriform specimens from the Middle Triassic, but these
have been only briefly described in the literature. One of these
puzzling taxa is Dongusuchus efremovi Sennikov, 1988, described from
the Donguz Svita. We present a redescription of Dongusuchus efremovi,
which includes the first photographic atlas and thorough anatomical
description of the holotype and referred specimens. This taxon is
shown to be a gracile, probably fast-running species with elongate and
slender limbs. A phylogenetic analysis recovers Dongusuchus efremovi
as an early-diverging, non-archosaurian archosauriform. Previous work
had suggested that this taxon was a ‘rauisuchid’. The gracile
proportions of the femur and somewhat wedge-shaped head, however, are
unusual for basal archosauriforms and are similar to the plesiomorphic
state in crocodile and avian-line crown archosaurs. Several
Early-Middle Triassic basal archosauriforms and early members of the
crocodile and avian lineages were gracile with elongate, slender
limbs. This suggests that the limb morphology of Dongusuchus efremovi
may be plesiomorphic for Archosauria and proximal clades.