Albian roveacrinids from the southern Congo Basin off Angola

Microfacies study of the Albian of the Pinda Formation in Well BAGRE 1 (Block 2, Angola offshore) revealed several echinoderm-rich layers. Contrary to other fossil remains, the echinoderms have not been dolomitized and are therefore potentially useful for stratigraphic purposes. The remains are compared to those found in the Sergipe Basin in Brazil and assigned to the Roveacrinidae, a group of stemless microcrinoids. The following species were identified: Roveacrinus communis Douglas, 1908; Roveacrinus cf. communis Douglas, 1908; Roveacrinus aff. geinitzi Schneider, 1989; Roveacrinus pyramidalis Peck, 1943; Roveacrinus sp. The assemblage provides a relatively precise stratigraphic framework in comparison to previous age determinations. Although some species have a wide stratigraphic range, the occurrence of the genus Roveacrinus and the species R. pyramidalis Peck, 1943 suggests a late Albian age, which makes the Angolan assemblages among the oldest known. The main area of distribution of roveacrinids is the Tethyan realm, so these extremely southern occurrences in Angola appear to support the theory of a seaway through the Gulf of Guinea in the late Albian.