Asselian-Sakmarian Ammonoids of the Early Permian Shakh-Tau Reef (Bashkortostan)
Т. Б. Леонова
Abstract
Ammonoid collections assembled in recent years from the Upper Asselian-Lower Sakmarian limestones of the Sterlitamak Shakh-Tau shikhan enabled a detailed study of this small but very interesting assemblage. Currently, only seven ammonoid genera are known from this locality, including Properrinites sp. from the family Perrinitidae, which is the first record of this family from the Urals. Finds of several well-preserved specimens of Medlicottia subdorbignyi Gerassimov confirmed the occurrence of the earliest known Medlicottia at the top of the Asselian, and not in the upper Sakmarian, as was previously thought. The study of the Asselian-Sakmarian ammonoids of Shakh-Tau allowed the species composition of the genera Medlicottia and Somoholites to be revised.