The present publication reports new discoveries of Oligocene and early Miocene aplodontid rodents from the Taatsiin Gol area (Valley of Lakes) in Mongolia. The fossil aplodontids recovered in this area are mainly composed of dental remains, some fragmentary jaws plus one partially preserved skull. Aplodontid rodents have been found from the early Oligocene (local biozone A) to the early middle Miocene (local biozone D). Altogether, eight taxa belonging to five genera have been identified in the investigated deposits: Ninamys arboraptus, Ninamys kazimierzi, Promeniscomys cf. sinensis, Prosciurus? mongoliensis and Prosciurus? sp. nov. in the early Oligocene; N. arboraptus, Proansomys badamae sp. nov. and Ansomyinae indet. in the late Oligocene; and Ansomys sp.1 in the early Miocene. In addition, although outside of the topic of the present special issue, one additional taxon, Ansomys sp.2, is reported from the ?middle Miocene. The material of aplodontids is usually relatively scarce in Asian localities. For the first time, with a sample size of 81 specimens, the material from Central Mongolia (mainly from the Oligocene) now allows a more accurate description of the morphological and size variability and resolves some systematic problems. The study of these aplodontids reveals that they are more abundant and diverse in the early Oligocene and that the diversity decreases during the late Oligocene and Miocene. One hypothesis, to explain the opposite diversity trend observed previously for sciurids in the same region, is that both Sciuromorpha families might have competed for the same resources from the early Oligocene to the middle Miocene in Central Mongolia.

中文翻译：

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湖泊谷（中部蒙古）的渐新世和中新世的plo龙科（啮齿类，哺乳动物）的记录，并对形态变异性有一些评论。

本出版物报道了来自蒙古Taatsiin Gol地区（湖谷）的渐新世和中新世早期棘齿类啮齿动物的新发现。在该地区发现的化石类古猿主要由牙齿残骸，一些下颚碎片和一个部分保留的头骨组成。从渐新世早期（局部生物区A）到中期中新世（局部生物区D）发现了棘齿类啮齿动物。总之，八个类群属于五个属一直在研究存款鉴定：Ninamys arboraptus，Ninamys kazimierzi，Promeniscomys参见 冬虫夏草，Prosciurus？蒙古和Prosciurus？sp。十一月 在渐新世早期N. arboraptus，Proansomys badamae sp.。十一月 和Ansomyinae indet。渐新世晚期 和中新世早期的Ansomys sp.1。此外，尽管不在本专刊的主题范围之内，但还有一个分类单元Ansomys从中新世中期报道了第二版。在亚洲地区，刺骨的材料通常相对稀少。来自蒙古中部的材料（主要来自渐新世）首次获得了81个样本的样本，现在可以更准确地描述形态和大小变异性，并解决了一些系统性问题。对这些双齿类的研究表明，它们在渐新世早期更为丰富和多样，而在渐新世和中新世晚期则减少了多样性。一种假设解释了先前在同一地区的孢子虫所观察到的相反的变化趋势，即从蒙古中部的渐新世到中新世中期，两个Sciuromorpha家族都可能竞争相同的资源。