Rio de Janeiro, Brazil
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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.


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.


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.


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.


Brum A.S.,Federal University of Rio de Janeiro | Machado E.B.,Federal University of Rio de Janeiro | Machado E.B.,Estácio de Sá University | Campos D.D.A.,Museu de Ciencias da Terra | Kellner A.W.A.,Federal University of Rio de Janeiro
Cretaceous Research | Year: 2016

The knowledge on the Brazilian theropod fauna is hampered by the limited number of specimens unearthed so far. The most potential deposits for the finding of those dinosaurs are the layers of Bauru Group, which comprises several different formations of Late Cretaceous age. Most of those remains are referred to Abelisauroidea, a clade that is particularly well represented in Gondwana. Here we report two new abelisaurid specimens comprising a left ilium (DGM 927-R) and the distal articulation of a right femur (MCT 1857-R) unearthed from the outcrops of Adamantina Formation (Turonian - Maastrichtian) in the locality known as Santo Anastácio, that comprises an abandoned quarry located in the outskirts of the homonymous city in São Paulo State. The ilium has a preacetabular process horizontally oriented and ventrally deflected, as well as an acute angle between this process and the pubic peduncle. The femur shows a well-developed anteromedial crest, but not to the same degree as in noasaurids, and ossified ridges between condyles and tibiofibular crest. Those features allow us to assign both specimens to Abelisauridae. CT-scans of those specimens shows that the ilium has pneumaticities similar to the camellate pattern previously recorded in neosauropods and reveals the diverticula invasion of abdominal air-sacs. The femur presents a developed anisotropic trabecular system, which suggests that the main muscular strain is located at the distal portion of this bone. These features have not been previously reported in Abelisauridae, indicating that the internal organization of the postcranial skeleton in the group is rather complex and quite variable. © 2015 Elsevier Ltd.


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.


Bandeira K.L.N.,Federal University of Rio de Janeiro | Simbras F.M.,Petrobras | Machado E.B.,Federal University of Rio de Janeiro | Machado E.B.,Estácio de Sá University | And 3 more authors.
PLoS ONE | Year: 2016

Titanosaurian dinosaurs include some of the largest land-living animals that ever existed, and most were discovered in Cretaceous deposits of Argentina. Here we describe the first Brazilian gigantic titanosaur, Austroposeidon magnificus gen. et sp. nov., from the Late Cretaceous Presidente Prudente Formation (Bauru Group, ParanáBasin), São Paulo State, southeast Brazil. The size of this animal is estimated around 25 meters. It consists of a partial vertebral column composed by the last two cervical and the first dorsal vertebrae, all fairly complete and incomplete portions of at least one sacral and seven dorsal elements. The new species displays four autapomorphies: robust and tall centropostzygapophyseal laminae (cpol) in the last cervical vertebrae; last cervical vertebra bearing the posterior centrodiapophyseal lamina (pcdl) bifurcated; first dorsal vertebra with the anterior and posterior centrodiapophyseal laminae (acdl/pcdl) curved ventrolaterally, and the diapophysis reaching the dorsal margin of the centrum; posterior dorsal vertebra bearing forked spinoprezygapophyseal laminae (sprl). The phylogenetic analysis presented here reveals that Austroposeidon magnificus is the sister group of the Lognkosauria. CT scans reveal some new osteological internal features in the cervical vertebrae such as the intercalation of dense growth rings with camellae, reported for the first time in sauropods. The new taxon further shows that giant titanosaurs were also present in Brazil during the Late Cretaceous and provides new information about the evolution and internal osteological structures in the vertebrae of the Titanosauria clade. © 2016 Bandeira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Kellner A.W.A.,Museu de Ciencias da Terra | Figueiredo R.G.,Museu de Ciencias da Terra | Azevedo S.A.K.,Museu de Ciencias da Terra | Campos D.A.,Museu de Ciencias da Terra
Zoological Journal of the Linnean Society | Year: 2011

A new species of Notosuchia, Labidiosuchus amicum gen. et sp. nov., is described based on an incomplete lower jaw (DGM 1480-R) from the Upper Cretaceous Marília Formation (Maastrichtian) recovered from a quarry near the Peirópolis municipality, Minas Gerais State, Southeastern Brazil. The mandibular symphysis is long, strong anterodorsally projected and 'Y-shaped'. The bizarre dentition is formed by at least eight teeth placed in a symphyseal tooth battery, some located lateral to each other. The first pair is larger than all others and procumbent. Some teeth are obliquely implanted (anterolabially to posterolingually) and have sub circular to elliptical outline. At least the posterior teeth are single cuspidate with acute apex. Labidiosuchus amicum shows a rather bizarre dentition, increasing the taxonomic diversity and potential feeding strategies of notosuchian crocodylomorphs. © 2011 The Linnean Society of London.


PubMed | Museu de Ciencias da Terra
Type: Journal Article | Journal: Anais da Academia Brasileira de Ciencias | Year: 2011

A new crocodyliform from the Upper Cretaceous (Campanian-Maastrichtian) Presidente Prudente Formation of the Bauru Group is described based on two almost complete skulls and mandibles. The material comes from the Tartaruguito site, situated at an old railroad between the cities of Pirapozinho and Presidente Prudente, state of So Paulo, Brazil. The new species, Pepesuchus deiseae gen. et sp. nov., is classified in the clade Peirosauridae on the basis of three synapomorphies: the presence of five premaxillary teeth, the anterior two premaxillary alveoli nearly confluent, and the oval cross-section of the jugal along the lower temporal bar. The new taxon increases the outstanding crocodyliform diversity of the Bauru Group, particularly of the Peirosauridae, which might turn out to be one of the most representative clades of gondwanan mesoeucrocodylians.

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