Abstract

A partial skeleton of a Mesozoic mammal has been discovered from the fourth member (tuffaceous sandstone) of the Lower Cretaceous Sinuiju Formation, Paekto-dong, Sinuiju city, North Phyongan Province, Democratic People’s Republic of Korea (DPRK). This specimen exhibits several characters common to all multituberculates. The femoral head is fully spherical and inflected, and sets off from the shaft by a long neck. The tibia has the pronounced, hook-like dorsolateral process in the proximal part and the medial and lateral articulating condyles on the tibia. The astragalus and the calcaneus are in juxtaposition, as preserved. The metatarsal V is offset from the cuboid. Hence this specimen belongs to multituberculate mammals. But this specimen has also the derived characters. The parafibula is not present. The calcaneocuboid facet is transverse with respect to the length of the calcaneus. In these regards, we suggest that the preserved postcranial skeleton of the new specimen has a mosaic of primitive and derived characters. This interpretation must be corroborated by additional mammal specimens from this locality.

中文翻译：

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朝鲜民主主义人民共和国第一种已知的中生代哺乳动物

摘要

朝鲜民主主义人民共和国（朝鲜）平安北道新义州市白头洞下白垩统新义州组第四层（凝灰质砂岩）中发现了中生代哺乳动物的部分骨骼。该标本表现出所有多瘤动物共有的几个特征。股骨头完全呈球形并弯曲，并通过长颈与股骨干分开。胫骨近端有明显的钩状背外侧突，胫骨上有内侧和外侧关节髁。黄芪和跟骨并置，保存完好。跖骨 V 偏离长方体。因此，该标本属于多瘤哺乳动物。但该标本也具有派生特征。腓旁骨不存在。跟骰小面相对于跟骨的长度是横向的。在这些方面，我们认为新标本保存的颅后骨骼具有原始特征和衍生特征的镶嵌。这一解释必须得到来自该地区的其他哺乳动物标本的证实。