Cassiopidae gastropods, influence of Tethys Sea of the Romualdo Formation (Aptian–Albian), Araripe Basin, Brazil

•Cassiopidae Family gastropods are typical Tethyan Domain fauna.•Marine invertebrates at the top of the Santana Formation indicate a marine transgression.•Cassiopids in the Araripe Basin indicate the adaptive bioevent.

The Cassiopidae family belongs to a group of gastropods of the Tethyan Realm, whose origin and dispersion are related a transgression of the Tethys Sea during the Early Cretaceous. The Romualdo Formation in the Araripe Basin, located in Northeast Brazil, presents fossil assemblages with echinoids, bivalves and cassiopid gastropods, indicating a marine sedimentation at the top of the formation. This research reveals three new species of this fauna: Gymnentome (Craginia) beurleni sp. nov., ‘Pseudomesalia’ (‘Pseudomesalia’) mennessieri sp. nov and ‘Pseudomesalia’ (‘Pseudomesalia’) santanensis sp. nov. We also review two other species: Craginia araripensis Beurlen, 1964 and Gymnentome romualdoi Beurlen, 1964, which we reclassify taxonomically as Paraglauconia (Diglauconia) araripensis and Gymnentome (Gymnentome) romualdoi, respectively; Paraglauconia (Diglauconia) lyrica Maury, 1936 and Gymnentome (Gymnentome) carregozica Maury, 1936 were the first recorded species in the Araripe Basin. The occurrence of these cassiopid gastropod fauna in other basins, such as Sergipe, Potiguar and Parnaíba, indicate the influence of waters coming from the north through the Tethys Sea in the Aptian–Albian and in the marginal continental basins of the Brazilian Northeast.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide