The environment, biogeography, and origin of the southern African Recent brachiopod fauna

Abstract

The brachiopod fauna that presently lives in the seas off the coasts of Namibia, South Africa, and southern Moçambique comprises 35 named plus seven unnamed species belonging to 26 genera, making it one of the most diverse in the world. Within the fauna are some species that are confined to the warm waters of the east coast, some that are restricted to the cold west coast waters, and others that enjoy a more widespread distribution. The geographic distribution of species is believed to be controlled by the two major oceanographic systems operating off southern Africa, namely, the Agulhas Current on the east and the Benguela Upwelling System on the west.Among the species that live off the west and south coasts are many that appear to have evolved in situ during times of pronounced environmental stress since the late Miocene. The fauna living off the east coast shows strong similarity with others in the Indian Ocean and it is inferred that many of the species migrated into the South African region by way of the ocean current systems that were established by the mid-Pliocene.Descriptions of Xenobrochus naudei and the previously undescribed Argyrotheca sp. and Amphithyris cf. A. richardsonae are provided.