Cretaceous palaeogeography of southern Gondwana from the distribution of the marine ostracod Majungaella Grekoff: New data and review

Majungaella is a survivor genus of a long lineage of the family Progonocytheridae, ranging from the Jurassic to the Pliocene. In this paper new species from Argentina and Brazil are described and appropriately illustrated, comprising a systematic review of 16 species, including two new ones. The Jurassic and Early Cretaceous species seem to have inhabited mainly shallow, warm waters, whereas from the mid-Late Cretaceous and especially in the Cenozoic, a retrothermal propensity is observed in the genus. The records of Majungaella are revised and its distribution is used to demonstrate the prior juxtaposition of subsequently separated Gondwana continental blocks and the opening of new seaways. The data have allowed a deeper understanding of the depositional sequences and supplied information on the early geological history and subsequent palaeoceanographic evolution of the South Atlantic Ocean. The affinities of the ostracod faunas from South America and other gondwanan localities are used to analyze the evolution of seaways and oceanic barriers.