Discovery of Middle Jurassic mammals from Siberia
Discovery of Middle Jurassic mammals from Siberia
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西伯利亚发现中侏罗世哺乳动物
DOI：
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发表时间：
2005
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通讯作者：
Averianov
中科院分区：
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作者：
A. Averianov;A. Lopatin;P. Skutschas;Nikolai V. Martynovich;S. V. Leshchinskiy;A. S. Rezvyi;S. Krasnolutskii;Alexey V. Fayngertz;Averianov
来自俄罗斯西西伯利亚克拉斯诺亚尔斯克边疆区南部中侏罗世（巴通纪）别列佐夫斯克采石场的哺乳动物遗骸被称为 Docodonta indet。 （两个无牙的碎片齿骨）和哺乳动物 indet。 （单根牙齿）。齿骨体现了仅在Docodonta和Morganucodon中才在干哺乳动物中发现的拟形特征的独特组合：发育良好的Meckel沟，齿后骨槽，具有悬垂的内侧脊和地板上的对角脊，将“内收肌窝”和角面分开，以及发育良好且向后腹侧定向的假角突，具有反射椎板的面有角的。两个标本与Docodonta共享关节前小面，位于角面腹侧并向后延伸至下颌孔。该刻面在 Morganucodon 中不存在，其前关节位于角的内侧。 Morganucodon 的前关节的内侧位置与该属的复合颌关节相关，其中一个基本的关节-方下颌关节位于齿状-鳞状关节的内侧。在 Docodonta indet 中。从别列佐夫斯克采石场、Haldanodon 和 Docodon 的角度来看，关节前腹侧到角的位置与关节复合体腹侧到齿骨髁的位置相关。这种关节复合体不能起到下颌关节的作用，而齿齿象中的后骨仅用于声音传输。来自别列佐夫斯克采石场的一个标本与摩根齿兽类共享一个用于更换牙板的凹槽，这在之前没有关于Docodonta的报道。别列佐夫斯克采石场的哺乳动物遗骸是最古老的Docodonta发现之一，这是西伯利亚侏罗纪哺乳动物的第一个记录，也是整个俄罗斯的第二个此类记录。
Mammal remains from the Middle Jurassic (Bathonian) Berezovsk Quarry on the south of Krasnoyarsk Territory, West Siberia, Russia are referred to Docodonta indet. (two edentulous fragmentary dentaries) and Mammalia indet. (a sin− gle−rooted tooth). The dentaries exemplify a unique combination of plesiomorphic characters found among stem mam− mals only in Docodonta and Morganucodon: well developed Meckel’s groove, trough for postdentary bones with over− hanging medial ridge and a diagonal ridge on the floor separating the “adductor fossa” and angular facet, and well devel− oped and posteroventrally directed pseudangular process with facet for the reflected lamina of angular. Both specimens share with Docodonta the prearticular facet placed ventral to the angular facet and extending posteriorly to the mandibular foramen. This facet is not present in Morganucodon, where the prearticular lies medial to the angular. Medial position of the prearticular in Morganucodon is connected with the compound jaw articulation in this genus, in which a rudimentary articular−quadrate mandibular joint is present medially to the dentary−squamosal joint. In Docodonta indet. from Berezovsk Quarry, Haldanodon and Docodon the position of the prearticular ventral to the angular is connected with the position of the articular complex ventral to the dentary condyle. Such articular complex could not function as a mandibu− lar joint and postdentary bones in Docodonta were used solely for sound transmission. One specimen from Berezovsk Quarry shares with Morganucodon a groove for replacement dental lamina, which was not reported previously for Docodonta. Mammal remains from Berezovsk Quarry are among the oldest occurrences for Docodonta, the first record of Jurassic mammals for Siberia, and only second such record for the whole of Russia.