The eveolutionary history of Late Permian Darwinulocopina Sohn, 1988 (Ostracoda) from the Russian Plate

摘要

Evolutionary trends in Late Permian Darwinulocopina are summarised with reference to extensive collections from eastern European Russia, from the White Sea in the North to the Cis-Caspian in the South. They inhabited large, shallow lakes in which the variety of habitats was favourable for high ostracod diversity. Theree superfamilies are represented:the Darwinuloidea preferred lakes with terrigenous sedimentation and insignificant bicarbonate, the Suchonelloidea inhabited lakes with increased bicarbonate and could also live in low-sulphate waters, and the Darwinuloidoidea inhabited high-bicarbonate water bodies and could also survive in low-magnesium waters. Different evolutionary trends account for the different ages of the crucial stages of development of each super family:the beginning of themid-Taarian for the Darwinuloidea, the late Tatarian for the Suchonelloidea and Darwinuloidoidea.