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Rauisuchus (Triassic archosaur from Brazil) osteology revised



Ben Creisler
bcreisler@gmail.com

A new online paper:

Stephan Lautenschlager and Oliver W. M. Rauhut (2014)
Osteology of Rauisuchus tiradentes from the Late Triassic (Carnian)
Santa Maria Formation of Brazil, and its implications for rauisuchid
anatomy and phylogeny.
Zoological Journal of the Linnean Society (advance online publication)
DOI: 10.1111/zoj.12196
http://onlinelibrary.wiley.com/doi/10.1111/zoj.12196/abstract



As the eponymous type species for rauisuchians, Rauisuchus tiradentes
von Huene, 1938 represents an important but inadequately known
specimen. The revision of the type material from the Upper Triassic
(Carnian) Santa Maria Formation of Brazil reveals new anatomical data
and previously unrecognised characters, including three new possible
autapomorphies: a knob-like thickening on the base of the posterior
process of the premaxilla; short and ventrally keeled cervicals
lacking postzygodiapophyseal laminae; and mid-caudal vertebrae with an
accessory neural spine and a postspinal lamina. Several elements are
re-identified, including a postorbital (originally identified as
postfrontal) and a pterygoid (originally identified as a prefrontal),
and additional material from a secondary fossil site, originally
assigned to R. tiradentes, including a left ilium, is excluded. Based
on the recovered information and new morphological data, the
systematic position of R. tiradentes is tested in a comparison of two
phylogenetic reanalyses. Both analyses differ in respect to the
phylogenetic position of R. tiradentes, and recover ‘rauisuchians’ as
a paraphyletic assemblage of non-crocodylomoprh archosaurs.