The ANUROFAUNA Of FORMATION CRATO, EOCRETÃCEO Of the BASIN Of the ARARIPE / A ANUROFAUNA DA FORMAÃÃO CRATO, EOCRETÃCEO DA BACIA DO ARARIPE,

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The Crato Formation, Araripe Basin, has yielded one of the most important Early Cretaceous fossil assemblages world-wide, being specially famous for the abundance, taxonomic diversity, and exceptional preservation of its fossils. Its beds contain remains of a continental flora and fauna that have been interpreted to represent a lacustrine environment. The aim of this work is the study of seven anuran specimens recently recovered from the upper limestone beds of the Crato sequence roused in the Museu de Paleontologia da Universidade Regional de Cariri, Cearà State, Brazil. This study is particularly significant because anuran fossil finds are relatively rare owing to the small size and fragility of their bones, and the underrepresented environments in which many of them live. Taphonomic, systematic, and ecological aspects have been considered in order to shed light on abiotic factors of the depositional environment of the Crato Formation, as well as on the evolutionary history of this amphibian group. The anuran remains are mainly characterized by their articulated condition and relative completeness. This type of preservation suggests rapid burial, minimal transport, and lack of post-mortem scavenging. Diphractometric analysis of the bones indicates that substitution of the bony tissue by calcite (calcitization) was the main process of fossilization. The studied specimens represent a pipimorph pipoid and at least two neobatrachian taxa that are the oldest known records of Neobatrachia in the world. This suggests that the early diversification of neobatrachians might have occurred in the southern continents. The biota of the Crato Formation described so far is taxonomically diverse, with 605 species that represent the five kingdoms. The flora is dominated by gymnosperms, which represent 43% of the plant diversity, whereas insects represent 80% of the fauna. The anurans corroborate the presence of freshwater or oligohaline water in the depositional environment. The anurans, with the possible exception of the aquatic pipimorphs, may have inhabited the paludal marginal areas of the Crato lake, some of them being more terrestrial and others living in protected microhabitats, thus occupying diverse ecological niches.

ASSUNTO(S)

geociencias anuro, neobatraquio, pipoidea, eocretÃceo, formaÃÃo crato anura, neobatrachia, pipoidea, early cretaceous, crato formation

ACESSO AO ARTIGO

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