LARGE THEROPOD TEETH FROM THE EOCENOMANIAN OF NORTHEASTERN BRAZIL AND THE OCCURRENCE OF SPINOSAURIDAE

ABSTRACT – Theropoda teeth can show sufficiently distinct features to be, in some cases, considered as confident diagnostic material. In this work, 275 complete or fragmentary teeth, collected at the Laje do Coringa site (Alcântara Formation), have been analyzed. In some of them, the typical spinosaurine morphology is present while in others an intriguing morphology was observed: teeth combining typical features of spinosaurines (smooth carinae with wrinkles on its base) with other characters as absolutely smooth enamel and basal cross section gently compressed labio-lingually. These different forms typify two morphotypes; a number of other teeth present variation that links them by a morphologic gradient. Morphotype 1 records the presence of spinosaurine dinosaurs in the Eocenomanian of northeastern Brazil and morphotype 2 may represent a new species of Theropoda, unknown by skeletal remains, and perhaps closely related to the spinosaurine form recorded. Key words: Dinosaurs, Spinosauridae, Cretaceous, Cenomanian, Alcântara Formation. RESUMO – Dentes de terópodes podem mostrar características suficientemente distintas para serem, em alguns casos, confiáveis como material diagnóstico. Neste trabalho, 275 dentes completos ou fragmentados, coletados no sítio Laje do Coringa (Formação Alcântara), foram analisados. Em alguns, a morfologia típica de espinossaurinos está presente, enquanto em outros uma intrigante morfologia foi observada: dentes combinando característica