New occurrence of sirenians in the Pirabas Formation (Miocene), Pará, Brazil

Abstract

This note reports a new occurrence of sirenian fossils in the Pirabas Formation, at the Praia de Fortalezinha site, in the Maracanã municipality, Pará, Brazil. The aim of this preliminary study is to corroborate the palaeobiogeography knowledge of sirenians from the Miocene of Eastern Amazon. Unlike most previous records, which consists mainly of vertebrae and ribs, the material collected from a sedimentary block chacterised as packstone/grainstone contains ribs and cranial parts, including a fragmented rostrum (premaxilla with incisor tooth remains), key elements for an accurate taxonomic identification. This finding broadens the fossil record of Sirenia within the Pirabas Formation. The cranial elements will
enable a more detailed taxonomic identification and provide relevant data on the distribution and evolution of sirenians in South America during the Neogene.