Abstract—

Based on the study of a representative collection of Berriasian–Barremian oysters from Mangyshlak, their taxonomic composition, stratigraphic and paleobiogeographical distribution are clarified. A new species, Gyrostrea bogdanovae sp. nov., considered to be the most ancient species of the genus Gyrostrea, from the Kugusem Formation (Hauterivian–Barremian), as well as the species Aetostreon subsinuatum (Leymerie, 1842) (with three morphotypes: type, falciforme, and dorsatum) are described from the Mangyshlak Peninsula for the first time.

中文翻译：

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Mangyshlak的早白垩纪牡蛎：分类学组成，地层和古生物地理分布

摘要—

根据对Mangyshlak的Berriasian-Barremian牡蛎的代表性采集进行的研究，弄清了它们的分类学组成，地层和古生物地理分布。一个新种，Gyrostrea bogdanovae sp。11月，被认为是最古老的Gyrostrea属，来自Kugusem组（Hauterivian–Barremian），以及Aetostreon subsinuatum（Leymerie，1842）（具有三种形态型：type，falciforme和dorsatum）是首次从Mangyshlak半岛进行描述。