A typical malvinokaffric givetian ostracod fauna from Bolivia

Abstract

A sample from the Iquiri Formation ZSW of Santa-Cruz de la Sierra (Bolivia)], assigned to the Givetian, yielded a small fauna of benthic ostracods including six species of the suborders Palaeocopina, Platycopina and Metacopina. A new species is described: Zudanezina undata. The faunal association is typical of the Malvinokaffric Realm and it includes four species already known from a level assigned to the uppermost Eifelian in the Cape Town Province of South Africa. Palaeobiogeographical and palaeoecological analyses, associated with an analysis of the organic matter content, lead us to propose a new ostracod assemblage: the ‘Neritic Malvinokaffric ecotype’ characterized by thin terrigeneous sediments, devoid of carbonates, which deposited in a shallow marine environment, under normal salinity. Bottom waters were oxygen deficient, and the climate was cool temperate, and markedly seasonal.