What is Pattersoncypris Bate (Ostracoda: Cyprididae)? A review of the genus and its species

Abstract

Pattersoncypris is a fossil ostracod genus represented by fourteen species recovered in non-marine, transitional and marine Cretaceous deposits from Brazil, Argentina, Liberia, Congo, Gabon, Angola, and Chad, and USA. As it is an abundant and diversified genus of the Early Cretaceous sedimentary basins of Brazil and Africa related to the opening of the South Atlantic Ocean, taxonomic misidentifications, which have been recurrently occurring with Pattersoncypris species, lead to problems regarding biostratigraphic, paleozoogeographic and paleoenvironmental interpretation. Face to this problem, the aim of this work was to study the morphological variations present in Pattersoncypris species, to identify the most robust diagnostic features that will allow reliable identification of the species, as well as to provide data that will facilitate understanding of the evolutionary history of the genus and its paleozoogeographic distribution. The genus was reviewed from morphological and taxonomic aspects. Ten species underwent taxonomic amendments, and a new species Pattersoncypris labiata n. sp. was proposed. Data analysis indicated that Pattersoncypris is an euryhaline genus that originated in the Gondwana continent, in the region that became the African Continent, from an ancestor of the genus Hourcqia, probably in the early Aptian. The adaptive radiation of the genus peaked during the Aptian, with the diversity center located in northeast Brazil. From the Albian onwards, there was a reduction in richness, with fewer species being recorded in Africa. An interval with no recorded species occurred during the early–middle Cenomanian. A single species was recorded in the late Cenomanian in USA, and by the end of this age, the genus was extinct.