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Rio de Janeiro, Brazil

Kellner A.W.A.,Federal University of Rio de Janeiro | Campos D.A.,Museu de Ciencias da Terra | Riff D.,Federal University of Uberlandia | de Andrade M.B.,University of Bristol
Zoological Journal of the Linnean Society | Year: 2011

A new species of a bizarre notosuchian mesoeucrocodylian is reported here. Caryonosuchus pricei gen. et sp. nov. was found in the outcrops of the Adamantina Formation (Campanian-Masstrichtian) in São Paulo State, Brazil, and shows a typical sphagesaurid dentition: strong and short teeth, obliquely implanted with the crown of the upper teeth showing a rounded anteriolabial margin and a strong compressed posteriolingual edge developed into a carina, ornamented by developed ridges and denticles. Amongst the diagnostic features of the new taxon are the presence of horn-like tubercles on the premaxilla and maxilla, never reported in this group before. The occurrence of C. pricei increases the diversity of sphagesaurids and confirms that all members of this clade, only recorded in Late Cretaceous deposits from Brazil so far, share the same dentition. © 2011 The Linnean Society of London.

Machado E.B.,Federal University of Rio de Janeiro | Avilla L.D.S.,Rio de Janeiro State Federal University | Nava W.R.,Museu de Paleontologia de Marilia | Campos D.D.A.,Museu de Ciencias da Terra | Kellner A.W.A.,Federal University of Rio de Janeiro
Zootaxa | Year: 2013

A new titanosaur dinosaur, Brasilotitan nemophagus gen. et sp. nov., is described from the Adamantina Formation (Turo-nian-Santonian, Bauru Basin). The specimen consistsof a dentary, cervical and sacral vertebrae, one ungual and remains of the pelvic region, that were collected near Presidente Prudente city, São Paulo State. It shows a mandible with an 'L' shaped morphology, with the symphyseal region of the dentary slightly twisted medially, a feature never recorded before in a titanosaur. Brasilotitan nemophagus can be further separated from other members of this clade by: (1) the dorsal portion of the dentary symphyseal contact is broader anteroposteriorly than the ventral part;(2) the ventral portion of the cer-vical centrum is arched dorsally; (3) the presence of an anteriorly directed accessory prezygapophyseal articulation surface on the cervical vertebrae; (4) the intraprezygapophyseal laminae of the cervical vertebrae are 'V' shaped in dorsal view; and other features. Although the phylogenetic position of Brasilotitan nemophagus is difficult to establish, the new species is neither a basal nor a derived member of the Titanosauria and, based on the lower jaw morphology, appears to be closely related to Antarctosaurus wichmannianus and Bonitasaura salgadoi. This discoveryenriches the titanosaur diversity of Brazil and further provides new anatomical information on the lower jaws of those herbivorous dinosaurs. Copyright © 2013 Magnolia Press.

Kellner A.W.A.,Federal University of Rio de Janeiro | Pinheiro A.E.P.,Federal University of Rio de Janeiro | Campos D.A.,Museu de Ciencias da Terra
PLoS ONE | Year: 2014

A new crocodyliform, Sahitisuchus fluminensis gen. et sp. nov., is described based on a complete skull, lower jaw and anterior cervical vertebrae collected in the Sao José de Itabora?́ Basin of Rio de Janeiro, Brazil. The specimen is one of the best preserved crocodyliforms from Paleocene deposits recovered so far and represents a sebecosuchian, one of the few clades that survived the Cretaceous-Paleogene biotic crisis. The new taxon is found in the same deposit as an alligatoroid, a group that experienced large diversification in the Paleogene. The sebecosuchian record suggests that after the Cretaceous- Paleogene biotic crisis, the less specialized members of this clade characterized by a higher number of teeth compared to the baurusuchid sebecosuchians survived, some having terrestrial habits while others developed a semi-Aquatic life style (e.g., Lorosuchus). Starting in the Eocene, sebecid sebecosuchians became specialized with a more accentuated oreinirostry as observed in Sebecus and in Langstonia, but not showing the typical reduced dentition developed by the Cretaceous baurusuchid sebecosuchians. The basal position of Barinasuchus arveloi, a high-snouted Miocene sebecid, indicates the occurrence of an independent lineage sometime after the K-Pg biotic crisis that developed accentuated oreinirostry, suggesting a more complex history of the post-K-Pg crocodyliform radiation. Copyright: © 2013 Kellner et al.

Pinheiro A.E.P.,Federal University of Rio de Janeiro | Fortier D.C.,Federal University of Rio Grande do Sul | Fortier D.C.,Federal University of Minas Gerais | Pol D.,CONICET | And 2 more authors.
Historical Biology | Year: 2013

A new small species of Eocaiman is described on the basis of three anterior left mandibular rami and one isolated tooth. The specimens came from the middle-upper Paleocene Itaboraí Basin (Rio de Janeiro State, Brazil; Itaboraian South American Land Mammal Age). The new taxon differs from the other two Eocaiman species, such as its small size, likely participation of the splenial in the mandibular symphysis, a reduced angle between the longitudinal axis of the symphysis and the mandibular ramus, and enlarged ninth and tenth dentary teeth (in addition to the large first and fourth dentary teeth). The participation of the splenial in the mandibular symphysis is a unique character among caimanines (with the only possible exception being Tsoabichi greenriverensis). The new taxon provides new information on the taxonomic and anatomical diversity of the genus Eocaiman, a taxon of prime importance to understand the evolutionary origins of caimans given its position as the basalmost member of Caimaninae. Furthermore, the new taxon has a relatively small body size in comparison with other species of Eocaiman, a case paralleled by other Itaboraian reptilian groups (e.g. snakes), suggesting that this ecosystem provides critical data to test the relationship between reptilian body size and climate. http://zoobank.org/83636F22-D121-4A77-9141-BE68987B6CBF. © 2013 Copyright Taylor and Francis Group, LLC.

Machado E.B.,Federal University of Rio de Janeiro | Campos D.A.,Museu de Ciencias da Terra | Calvo J.O.,National University of Comahue | Kellner A.W.A.,Federal University of Rio de Janeiro
Revista Mexicana de Ciencias Geologicas | Year: 2013

Although important dinosaur specimens have been recently described from Brazil, the theropod record in this county is still rather scarce, particularly from Cretaceous strata. Here we describe a complete right tibia (MCT 1783-R) from the Marília Formation (Maastrichtian, Bauru Basin) near Peirópolis (Uberaba, Minas Gerais). This is the best theropod specimen recovered from this unit after five decades of collecting. MCT 1783-R shows a well developed cnemial crest with a lobular distal end, that projects significantly above the proximal articular surface, features that are characteristic of the Abelisauroidea. It further shows unique characters such as a marked asymmetry of lateral and medial condyles in posterior view, and a very deep triangular articular face for the astragalus, suggesting that it represents a new taxon.

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