Abstract

A new species of the genus Leptoropha (Kotlassiidae, Seymouriamorpha), L. minima sp. nov, is described based on isolated teeth discovered in the Upper Urzhumian beds of the boundary stratotype of the Severodvinian Stage (Republic of Tatarstan, Russia). A sample from the type locality (Monastyrskii Ovrag-D) enabled the tracing of the modification of maxillar and mandibular tooth shape in individuals with skull lengths of 30–60 mm, from the tricuspid pattern to complex polycuspid fan-shaped crowns with a large (up to 14) number of complementary cusps that definitively formed the marginal portions of the protocingulum in the anteriormost jaw teeth. In addition to the type locality, individual teeth attributed to L. minima were identified from the Upper Urzhumian of the Southern Cis-Ural Region (Orenburg Region, Yashkino locality) and the lowermost Severodvinian beds of the Vyatka River basin (Kirov Region, Povoiska locality); findings of teeth of similar morphology at the Sundyr-1 locality (Mari El Republic, Russia) extend the stratigraphic distribution of Leptorophinae to the Upper Severodvinian (Lower Putyatinian) and indicate the presence of the group in the last fauna of the Dinocephalian Tetrapod Superassemblage of Eastern Europe, the Sundyr’ Tetrapod Assemblage.

中文翻译：

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欧洲俄罗斯上乌尔zh米人的一种新的Leptoropha（Kotlassiidae，Seymouriamorpha）种。

摘要

属一新种Leptoropha（Kotlassiidae，Seymouriamorpha），L.最小值SP。nov是根据在Severodvinian阶段（俄罗斯Ta斯坦共和国）边界层型的上Urzhumian层中发现的孤立牙齿描述的。来自局部类型（Monastyrskii Ovrag-D）的样本能够追踪头骨长为30–60 mm的个体的上颌骨和下颌牙齿形状的变化，从三尖瓣样到复杂的多瓣扇形冠状大（最多14个）尖牙的数量，这些尖牙最终形成了最前颚齿中的proculingulum的边缘部分。除类型局部性外，个别牙齿归因于最小乳杆菌从南部顺式乌拉尔地区的上乌尔zh木河地区（亚什基诺州奥伦堡地区）和维亚特卡河流域的最低的Severodvinian层（基沃夫地区，波沃伊斯卡地区）中识别出来；在Sundyr-1地方（俄罗斯马里共和国），发现了类似形态的牙齿，从而将Leptorophinae的地层分布扩展到了上Severodvinian（下Putyatinian），并表明该类存在于Dinocephalian Tetrapod超组合的最后一个动物群中。东欧，Sundyr'Tetrapod组合。