Osteology of R auisuchus tiradentes from the L ate T riassic ( C arnian) S anta M aria F ormation of B razil, and its implications for rauisuchid anatomy and phylogeny

As the eponymous type species for rauisuchians, R auisuchus tiradentes von Huene, 1938 represents an important but inadequately known specimen. The revision of the type material from the U pper T riassic ( C arnian) S anta M aria F ormation of B razil 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. © 2014 The Linnean Society of London