Dois novos crocodilos (Crocodyliformes, Mesoeucrocodylia) do Mato Grosso, Bacia dos Parecis : descrição e relações filogenéticas com os "Notossúquios"

São descritos dois novos táxons de Crocodyliformes do Cretáceo do Mato Grosso, que apresentam: crânios curtos; dentição heterodonte composta por dentes com lado labial mais convexo que o lado lingual e serrilhados; dentes anteriores do dentário procumbentes; presença de uma superfície distintamente lisa, acima da margem alveolar, na superfície lateral da maxila, acima da qual ocorrem forames neurovasculares; e vértebras anficélicas. Estes novos materiais foram informalmente chamados Crocodilo I e Crocodilo II. O Crocodilo I apresenta as seguintes características: fenestra pré-orbitária pequena; barra palatina posterolateral em forma de bastão; dente caniniforme hipertrofiado na pré-maxila; 6 dentes maxilares; dentes anteriores do dentário levemente voltados para trás; junta quadrado-articular localizada ventralmente à fileira dentária. O Crocodilo II, por sua vez, apresenta: focinho tubular em seção; amplo palato secundário; espleniais fusionados; 5 dentes maxilares; mandíbula com região sinfiseal alongada e espatulada. Em ambos os casos, a morfologia geral aponta muitas semelhanças com os “notossúquios”: postura elevada, regiões diferenciadas na coluna, dentição heterodonte, palato secundário relativamente amplo e cavidade nasal relativamente ampla. Para testar as relações filogenéticas dos dois táxons, bem como o próprio monofiletismo dos “notossúquios”, foi construída uma matriz de dados com 27 táxons (incluindo, tanto quanto possível, todos aqueles que já foram ou são considerados “notossúquios”) e 60 caracteres. Com base nos mesmos, foi efetuada uma análise de parcimônia utilizando Paup 3.1.1 (“stepwise addition” - “random”, com 100 repetições e “tree-bisection-reconnection”) e Nona 2.0 (algoritmo heurístico, com 10 replicações e TBR - mult*max*) que apontou uma relação dos dois novos táxons como grupos irmão sucessivos de Notosuchus e Mariliasuchus (Crocodilo II (Crocodilo I (Notosuchus, Mariliasuchus))). Em comparação com outros crocodiliformes do Cretáceo da América do Sul, África, Madagascar e China, é possível assumir que ambos são notossúquios (sensu Pol & Apesteguia, 2005). Em nossa análise, os notossúquios formam um grupo, à exceção de A. buitreraensis, mais proximamente relacionado aos Eusuchia. Na análise ordenada, A. buitreraensis, A. patagonicus e Anatosuchus aparecem mais proximamente relacionados a Eusuchia e Lybicosuchus aloca-se junto a Baurusuchus e Sebecus. Paralelamente, são discutidas análises filogenéticas prévias envolvendo notossúquios, nas quais foram introduzidas modificações, levando a diferentes topologias. A partir disso, propõe-se uma discussão acerca da influência das escolhas e procedimentos de cada autor no resultado final de análises filogenéticas.

A new specimen of Stratiotosuchus maxhechti (Baurusuchidae, Crocodyliformes) from the Adamantina Formation (Upper Cretaceous), southeastern Brazil.

This is a report about the second occurrence and description of the third specimen of Stratiotosuchus maxhechti (Baurusuchidae, Crocodyliformes) from the Bauru Basin, Upper Cretaceous of southeastern Brazil. The material was found in the typical reddish, fine-grained sandstone from the Adamantina Formation, Bauru Group, Monte Alto County, São Paulo State. These strata are considered to be Campanian-Maastrichtian in age. It is the second skull of Stratiotosuchus maxhechti recovered where the choanal region and the skull-mandible articulation is preserved. The holotype of this species comes from the Adamantina Formation from southwestern São Paulo State, while this new specimen comes from its northern-central region, making possible biocbronological and paleoccological correlations among different geographically distant stratigraphic horizons within the Bauru Basin. The main osteologic contributions from this new specimen are the surangular taking part in the skull/mandible articulation and the presence of a relatively well-preserved choanal region, which are not seen in the holotype, furthering the knowledge of Stratiotosuchus maxhechti. Based on the features of this new specimen, an emended diagnosis is provided.

An Additional Baurusuchid from the Cretaceous of Brazil with Evidence of Interspecific Predation among Crocodyliformes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversification events and the effects of mass extinctions on Crocodyliformes evolutionary history

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analise cladística - filogenética e paleobiogeográfica dos Mesoeucrocodylia (Crocodylomorpha; Crocodyliformes) do Grupo Bauru (Cretáceo Superior) do Sudeste do Brasil

Pós-graduação em Geociências e Meio Ambiente - IGCE

A species-level supertree of Crocodyliformes

With fossils found worldwide, Crocodyliformes stands as one of the best documented vertebrates over the Mesozoic and Cenozoic. The multiple phylogenetic hypotheses of relationship proposed for the group allow plenty of space for contentious results, partially due to the small overlapping of taxa and disagreeing homology statements among studies. We present two supertrees of Crocodyliformes, based on different protocols of source tree selection, summarising phylogenetic data for the group into a 'synthetic consensus'. The consensus of the most parsimonious trees, containing 184 terminal taxa, has a remarkably well-resolved branching structure, which may serve as a framework for further macroevolutionary studies. In addition, the IterPCR script was for the first time used in the supertree context to build a reduced consensus tree with the pruning of unstable taxa.

The Quaternary vertebrate fauna of the limestone cave Gruta do Ioio, northeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new crocodilian from the Lower Cretaceous Crato Formation of north-eastern Brazil

A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.

The origin of modern crocodyliforms: new evidence from the Cretaceous of Australia

While the crocodyliform. lineage extends back over 200 million years (Myr) to the Late Triassic, modern forms - members of Eusuchia - do not appear until the Cretaceous. Eusuchia includes the crown group Crocodylia, which comprises Crocodyloidea, Alligatoroidea and Gavialoidea. Fossils of non-crocodylian eusuchians are currently rare and, in most instances, fragmentary. Consequently, the transition from Neosuchia to Crocodylia has been one of the most poorly understood areas of crocodyliform evolution. Here we describe a new crocodyliform from the mid-Cretaceous (98-95 Myr ago; Albian-Cenomanian) Winton Formation of Queensland, Australia, as the most primitive member of Eusuchia. The anatomical changes associated with the emergence of this taxon indicate a pivotal shift in the feeding and locomotor behaviour of crocodyliforms - a shift that may be linked to the subsequent rapid diversification of Eusuchia 20 Myr later during the Late Cretaceous and Early Tertiary. While Laurasia (in particular North America) is the most likely ancestral area for Crocodylia, the biogeographic events associated with the origin of Eusuchia are more complex. Although the fossil evidence is limited, it now seems likely that at least part of the early history of Eusuchia transpired in Gondwana.

An unusual pliosaur (Reptilia, Sauropterygia) from the Kimmeridgian (Upper Jurassic) of northeastern Mexico

We here describe the rostrum of a pliosaur from the Kimmeridgian of northeastern Mexico. The specimen comes from the Upper Jurassic La Casita Formation (Kimmeridgian - Tithonian) and represents one of the few Plesiosauria in the area. The internal anatomy of the specimen is partly visible through cross-sections, which reveal a hitherto undescribed rostral prolongation of a paired bone of the interorbital area, probably the parietal or frontal beneath the premaxillae. The specimen also provides new information on the morphology and function of the choanae. In light of these morphological data, the new pliosaur shows similarities both with the European Late Jurassic genus Pliosaurus and the Australian Early Cretaceous Kronosaurus.