Late Cretaceous mosasaurids of northeastern Brazil: a summary of their record and a paleobiogeographical survey

Abstract

The coastal region of northeastern Brazil holds one of the most important records of mosasaurids from the Late Cretaceous of South America. Analysis of these discoveries allowed us to create a picture of the composition of the fauna, as well as the diversity and paleobiogeography of these clades. In the region, the mosasaurid fossils are contained in Cenomanian to Maastrichtian geological units of epicontinental marine origin, in the Cotinguiba (Sergipe-Alagoas Basin), Alcântara (São Luís Basin), Itamaracá (Paraíba Basin), Calumbi (Sergipe-Alagoas Basin), and Gramame (Paraíba Basin) formations. Paleogeographic data corroborate that these deposits represent low-latitude equatorial environments. The Brazilian fauna is represented by fourteen taxa from one family (Mosasauridae), two subfamilies (Mosasaurinae: Prognathodontini, Globidensini and Mosasaurini; Plioplatecarpinae: Plioplatecarpini), and some indeterminate mosasaurid specimens. Mosasaurids from the northeastern region of Brazil resemble Late Cretaceous marine reptiles from western Africa (Angola, Congo, and Morocco), suggesting faunal continuity in the seaway that bridged these areas. The study of this marine fauna is crucial to understanding the evolutionary and paleobiogeographic history of the group during the opening of the South Atlantic Ocean.