The Seorsumuscardinus is a rodent that lived during the Early Miocene. It is known through its fossile dormice which was discovered in Europe. 2 species of Seorsumuscardinus are known through a number of isolated teeth.
These teeth were characterised by its long transverse crests. One of these crests distinguished these two separate species. It is thought that the Seorsumuscardinus is related to the Muscardinus which is the genus of the hazel dormouse which currently does exist. It also appeared at the same time during the Early Miocene.
The fossilised teeth were found in Austria, Greece, Switzerland, and Germany. All of them are from MN 4 except for the one found in Germany. In all of these locations, there is a diverse amount of dormouse fauna. As these areas as temporally distinct, it is thought that these fossils would be useful to determine the age of deposits.