The present-day Mediterranean brachiopod fauna: diversity, life habits, biogeography and paleobiogeography

Abstract

The present-day brachiopods from the Mediterranean Sea were thoroughly described by nineteenth-century workers, to the extent that Logan´s revision in 1979 listed the same 11 species as Davidson, almost 100 years earlier. Since then recent discoveries, mainly from cave habitats inaccessible to early workers, have increased the number of species to 14. The validity of additional forms, which are either contentious or based on scanty evidence, is evaluated here. Preferred substrates and approximate bio-depth zones of all species are given and their usefulness for paleoecological reconstruction is discussed. A previous dearth of material from the eastern Mediterranean has now been at least partially remedied by new records from the coasts of Cyprus, Israel, Egypt, and, in particular, Lebanon and the southern Aegean Sea. While 11 species (79 % of the whole fauna) have now been recorded from the eastern basin, Terebratulina retusa, Argyrotheca cistellula, Megathiris detruncata and Platidia spp. appear to be less common than in the western basin. Lacazella mediterranea, <I>Tethyrhynchia mediterranea and Gwynia capsula have not yet been recorded from the eastern Mediterranean, but whether this is due to a west-east faunal impoverishment or insufficient collecting is uncertain. L. mediterranea and T. mediterranea may be endemic to the Mediterranean. The Messinian (Late Miocene) salinity crisis caused most species to disappear from the ancestral Mediterranean Sea. T. mediterranea may be a paleoendemic that has survived in marine refuges mostly located on the outer margin of the western basin, while other species either entered or re-entered the Mediterranean from the Atlantic after the Miocene.