New species of encrusting foraminifera from the Carboniferous (Upper Mississippian) of Central Russia

Abstract

New encrusting foraminifera Tolypammina kalugensis sp. nov. is described from the Carboniferous of Central Russia. The test of the new species is large and completely attached to hard substrate, consisting of an ovoid-shaped proloculus followed by an undivided tubular second chamber. The encrusting fauna is primarily composed of a monospecific association of T. kalugensis sp. nov. Additionally, there are only a few occurrences of small, phosphatic encrusting brachiopods. The remarkably low diversity and nearly monospecific encrusting fauna found in the Dashkovka Member of the Gurovo Formation indicate unusual environmental conditions. The scarcity of benthic organisms could be attributed to oxygen deficiency. Furthermore, these black and green clays of the Dashkovka Member likely accumulated in the deepest parts of the basin, situated below the photic zone, which further supports the hypothesis of oxygen-poor conditions.