Dataset Information

A new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the late cretaceous of Brazil and the phylogeny of Baurusuchidae.

ABSTRACT:

Background

Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diagnose the clade and its members.

Methodology/principal findings

Based on a nearly complete skull and a referred partial skull and lower jaw, we describe a new baurusuchid from the Vale do Rio do Peixe Formation (Bauru Group), Late Cretaceous of Brazil. The taxon is diagnosed by a suite of characters that include: four maxillary teeth, supratemporal fenestra with equally developed medial and anterior rims, four laterally visible quadrate fenestrae, lateral Eustachian foramina larger than medial Eustachian foramen, deep depression on the dorsal surface of pterygoid wing. The new taxon was compared to all other baurusuchids and their internal relationships were examined based on the maximum parsimony analysis of a discrete morphological data matrix.

Conclusion

The monophyly of Baurusuchidae is supported by a large number of unique characters implying an equally large morphological gap between the clade and its immediate outgroups. A complex phylogeny of baurusuchids was recovered. The internal branch pattern suggests two main lineages, one with a relatively broad geographical range between Argentina and Brazil (Pissarrachampsinae), which includes the new taxon, and an endemic clade of the Bauru Group in Brazil (Baurusuchinae).

SUBMITTER: Montefeltro FC

PROVIDER: S-EPMC3135595 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the late cretaceous of Brazil and the phylogeny of Baurusuchidae.

Montefeltro Felipe C FC Larsson Hans C E HC Langer Max C MC

PloS one 20110713 7

<h4>Background</h4>Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diag ...[more]

PMID: 21765925

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Project description:BackgroundRhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island.Methodology/principal findingsRhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6-1.8 m in the Hungarian and Austrian species, 2.4-2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5-6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320-333 mm).Conclusions/significanceOur analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre-Santonian divergence between western and eastern rhabdodontid lineages within the western Tethyan archipelago.

Dataset Information

A new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the late cretaceous of Brazil and the phylogeny of Baurusuchidae.

Background

Methodology/principal findings

Conclusion

Publications

A new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the late cretaceous of Brazil and the phylogeny of Baurusuchidae.

Similar Datasets

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