Multituberculate mammals from the Middle Jurassic of Western Siberia, Russia, and the origin of Multituberculata
Multituberculate mammals from the Middle Jurassic of Western Siberia, Russia, and the origin of Multituberculata
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DOI：
10.1002/spp2.1317
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发表时间：
2020-04
影响因子：
2.3
通讯作者：
A. Averianov;T. Martin;A. Lopatin;J. Schultz;R. Schellhorn;S. Krasnolutskii;P. Skutschas;S. Ivantsov
中科院分区：
文献类型：
--
作者：
A. Averianov;T. Martin;A. Lopatin;J. Schultz;R. Schellhorn;S. Krasnolutskii;P. Skutschas;S. Ivantsov
Tashtykia primaeva gen.等十一月和 Tagaria 古董 gen。等十一月（Multituberculata incertae sedis）是根据来自俄罗斯西西伯利亚克拉斯诺亚尔斯克边疆区别列佐夫斯克煤矿的中侏罗世（巴通阶）Itat 地层的孤立牙齿进行描述的。 Tashtykia primaeva gen.等十一月其特征是 P5 具有三排牙尖（牙尖公式 2B:4M:6L），高扇形 p4 具有两个三角形裂片、与唇和舌脊相关的五个锯齿以及独特的远端牙尖。 Tagaria 古董 gen.等十一月与所有其他多疣状动物的不同之处在于，P5 非常长，冠部平坦，并且有许多排列成三行的尖头 (4B:6M:7L)。从形态上看，Kermackodon 和 Megaconus 的牙齿是 Euharamiyida 和中侏罗世 Multituberculata 之间的过渡。 Kermackodon 与 Euharamiyida 有一些共同特征，例如臼齿上有由纵向脊连接的尖尖、M2 上的远唇尖尖高于其他尖尖，以及具有远端盆地的单个大扇形前臼齿 (p4)。 Megaconus 的 euharamiyidan 特征是终极上前臼齿，舌侧较短，p4 具有远端盆地，臼齿上的一个尖牙比其他尖牙大。此外，Megaconus 共享一个最终的上前臼齿，具有三排尖牙，臼齿上有水平磨损，臼齿上有锥体尖牙，由带有多疣的横向凹槽分隔开。 Kermackodon 的多疣特征包括臼齿表面的水平磨损而不是盆底磨损以及 p4 上的锯齿。
Tashtykia primaeva gen. et sp. nov. and Tagaria antiqua gen. et sp. nov. (Multituberculata incertae sedis) are described based on isolated teeth from the Middle Jurassic (Bathonian) Itat Formation from the Berezovsk coal mine in Krasnoyarsk Territory, Western Siberia, Russia. Tashtykia primaeva gen. et sp. nov. is characterized by a P5 with three rows of cusps (cusp formula 2B:4M:6L) and a high sectorial p4 with two triangular lobes, five serrations associated with labial and lingual ridges, and a unique distal cusp. Tagaria antiqua gen. et sp. nov. differs from all other multituberculates by a very long P5 with flat crown and many cusps arranged in three rows (4B:6M:7L). Morphologically the teeth of Kermackodon and Megaconus are transitional between Euharamiyida and Middle Jurassic Multituberculata. Kermackodon shares several characteristics with Euharamiyida, such as pointed cusps on the molars connected by longitudinal ridges, a distolabial cusp on the M2 that is higher than the other cusps, and a single large sectorial premolar (p4) with a distal basin. The euharamiyidan characters of Megaconus are an ultimate upper premolar with a shorter lingual side, a p4 with a distal basin, and one cusp on the molars being larger than the other cusps. In addition, Megaconus shares an ultimate upper premolar with three rows of cusps, horizontal wear on the molars, and pyramidal cusps on the molars separated by transverse grooves with multituberculates. The multituberculate characters of Kermackodon include horizontal rather than basined wear on the surface of the molars and serrations on the p4.