Early Permian continental deposits include a large number of localities containing anthracosiid-like non-marine bivalves traditionally assigned to Anthraconaia Trueman and Weir, 1946, Palaeanodonta Amalitzky, 1895, and Palaeomutela Amalitzky, 1892. In most cases, these classifications are only tentative due to insufficient preservation in which the shells are missing their main characteristics: the ligament and the hinge. Non-marine bivalves from the Early Permian Upper Pospelovka Subformation of Russky Island (South Primorye, Far East Russia), described here as Hypoanthraconaia gen. nov., differ morphologically from the above genera by a set of external features including the initial shell, the mode of intersection of the growth lines with the dorsal margin, and the details of the sculpture. Hypoanthraconaia gen. nov. shows the most external similarity with "atypical'' anthracosiid-like morphotypes of Anthraconaia that are widespread in the Late Pennsylvanian and Early Permian of eastern North America, and the Stephanian and Early Permian Lower Rotliegend of northwestern Europe. On this basis, the new genus is conventionally assigned to the family Naiaditidae Scarlato and Starobogatov, 1979.
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机译:早二叠世大陆沉积物包括大量含有炭疽类非海洋双壳类的地方,传统上分配给Anthraconaia Trueman和Weir,1946年,Palaeanodonta Amalitzky,1895年和Palaeomutela Amalitzky,1892年。在大多数情况下,这些分类只是暂时的,因为贝壳缺少其主要特征:韧带和铰链。来自俄罗斯岛(俄罗斯远东滨海边疆区)早二叠世上波斯佩洛夫卡亚地层的非海洋双壳类,这里被描述为Hypoanthraconaia gen. nov.,在形态上与上述属的区别在于一组外部特征,包括最初的壳、生长线与背缘的交叉方式以及雕塑的细节。Hypoanthraconaia gen. nov.与广泛分布于北美东部宾夕法尼亚晚期和早二叠世以及欧洲西北部斯蒂芬纪和早二叠世下罗特利根德的“非典型”炭疽类形态型的外部相似性最大。在此基础上,新属通常被归入Naiaditidae Scarlato和Starobogatov科,1979。
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