The First Known Mesozoic Mammal in the Democratic People’s Republic of Korea

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.