Baurusuchid crocodyliforms as theropod mimics: clues from the skull and appendicular morphology ofStratiotosuchus maxhechti(Upper Cretaceous of Brazil)

Abstract

The Baurusuchidae crocodyliforms are usually interpreted as active terrestrial predators, but only some positive evidence of such habits has been described to date, mainly the relative position of external nares and orbits. Here we describe features that support this view in a complete specimen of the Baurusuchidae Stratiotosuchus maxhechti, and have executed a parsimony analysis to confirm their phylogenetic position. S. maxhechti exhibits theropodomorph features that have been previously recognized in skulls of the Baurusuchidae, as well as postcranial characteristics related to a parasagittal gait, showing that the similarities between the Baurusuchidae and theropods extend beyond the cranial morphology. These include a well‐developed supracetabular crest, a relatively medially offset femoral head and a caudally orientated calcaneal tuber. The orientations of the surfaces for muscular attachments imply that the appendicular movements of S. maxhechti were mainly anteroposterior, with abduction significantly constrained. S. maxhechti presents features that mimic some present in theropods, including a ‘fossa brevis’ on the ilium and tubercles on the ischium and femur similar to the obturator process and accessory trochanter. The relative proportions of the femur, tibia, and longer metatarsal are more similar to those of Postosuchus than to other Crocodylomorpha. In the skull, besides the theropodomorph (ziphodont) dentition concentrated in the anterior half of the rostrum, the baurusuchids are remarkable by the fusion of the nasals, which can be related to a large resistance against feeding forces acting on a high‐profile skull. The appendicular morphology of S. maxhechti strengthens the interpretation that the Baurusuchidae were active land‐dwelling predators in the Upper Cretaceous of south‐eastern Brazil, occuping ecological niches typical of small to medium‐sized theropod dinosaurs. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, S37–S56.

New material of the ziphodont mesoeucrocodylian Iberosuchus from the Eocene of Languedoc, southern France

“…An autapomorphy of the Baurusuchidae is the extreme reduction of the number of premaxillary and maxillary alveoli (e.g., Montefeltro et al, 2010;Riff et al, 2011). In Iberosuchus, the presence of five premaxillary alveoli, more than five alveoli in the maxilla and a premaxillary palatal foramen discard a referral to the Baurusuchidae or to Bretesuchus bonapartei (Gasparini et al, 1993).…”

“…Turner and Sertich (2010, p. 208) coded Iberosuchus macrodon on the basis of the datamatrix of Ortega et al (2000) and found that this genus shares with Peirosauridae the extremely large perinarial fossa (also present in Baurusuchidae, e.g. Riff et al, 2011) and the wedge-like process of the maxilla in lateral view at the premaxillary-maxillary suture. However, comparing Iberosuchus with the best-represented members of the Peirosauridae reveals several differences including: the premaxilla of Iberosuchus is much taller and rostrocaudally shorter than in any known peirosaurid (i.e., Montealtosuchus, Pepesuchus desae, Peirosaurus, Uberabasuchus terrificus or Hamadasuchus rebouli) and the pattern of ornamentation differs with vermiculation versus pitted ornamentation in Peirosauridae.…”

A New Baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the Phylogeny of Baurusuchidae

“…Characters are either new or adapted from previously published studies. Character 1 was adapted from [4] (character 9), [11](character 65), [30] (character 103), [34] (character: 9); character 2 was adapted from [112] (character 257); character 7 was adapted from [4] (character 23), [113] (character 81); character 8 was modified from [4] (character 20); character 9 was adapted from[75] (Character 260); character 11 was adapted from [4] (character 23); character 12 was modified from [79](character247); character 14 was adapted from [115] (character 6), [4] (characters 19), [114] (character 80); character 16 was adapted from [74] (Character 258); character 17 was adapted from [6] (character 157); character 18 was adapted from [4] (characters 35 and 36) and [114] (character 140); character 19 was adapted from [4] (character 36); character 21 was adapted from [55] (character 181); character 22 was adapted from [4] (character 79) and [30] (character 107); character 24 was adapted from [81] (character 144); character 25 was adapted from [81] (character 144); character 26 was adapted from [114] (character 139); character 27 was adapted from [81] (character 133), [6] (character 145), [12] (character 121), [116] (character 46); character 28 was adapted from [4] (character 18); character 33 was adapted from [74]; character 38 was adapted from [30] (character 57); character 50 was adapted from [116] (character 103); character 54 was adapted from [55] (character 179); character 55 was modified from [27] (character 11), [30] (character 114); character 56 was adapted from [117] (character 27), [6] (character 133); character 57 was adapted from [4] (character 78); character 58 was adapted from [4] (character 78); character 59 was adapted from [116] (character 30); character 61 was adapted from [6] (character 90); character 62 ...…”

Revisão da família Baurusuchidae e seu posicionamento filogenético dentro do clado Mesoeucrocodylia

“…Desta forma, quando Benton & Clark (1988) encontraram um clado Eusuchia fortemente posicionado dentro de Mesosuchia, lançaram mão do termo Mesoeucrocodylia. Pode-se dizer que Mesoeucrocodylia foi corroborado por virtualmente todas as análises filogenéticas publicadas depois de Benton & Clark (1988), como Wu et al (1994), , Wu et al (1997), Ortega et al (2000), Wu et al (2001a, b), Sereno et al (2003), Pol (2003), Gasparini et al (2005), Zaher et al (2006), Larsson & Sues (2007), , Sereno & Larsson (2009), O'Connor et al (2010), , Andrade et al (2011), Riff & Kellner (2011), Pol & Powell (2011), Clark (2011), Nascimento & Zaher (2011), Pol et al (2012).…”

“…Todas concordam com o monofiletismo do gênero Baurusuchus (Sereno & Larsson, 2009;Nascimento & Zaher, 2011;Pol & Powell, 2011;Montefeltro et al, 2011Montefeltro et al, , 2013, e muitos trabalhos incluíram apenas Stratiotosuchus além do Gênero-tipo, mas ainda assim, sempre formando um clado monofilético (Fiorelli & Calvo, 2007;Andrade & Bertini, 2008;Riff & Kellner, 2011;Andrade et al, 2011). Nascimento & Zaher (2011) e Pol & Powell (2011 encontraram dois clados internos em Baurusuchidae: um clado formado pelo gênero Baurusuchus, e um outro formado por Stratiotosuchus + Pabwehshi.…”