A review of the genus Melissiodon (Cricetidae, Rodentia) in the Vallés-Penedès Basin (Catalonia)

Abstract

ABSTRACTMelissiodon is a plesiomorphic cricetid genus characterized by its unique molar morphology, defined by many pits surrounded by thin and high ridges. This genus is endemic to Europe and ranges from the early Oligocene to the early Miocene. However, it is generally rare in rodent assemblages, particularly during the Miocene, rich samples only being available from a few German sites. Here we review all the Melissiodon material from the Vallès-Penedès Basin (Catalonia, Spain). This genus is present in several early Miocene sites ranging from biozone MN3 to MN4, but the scarcity of the material has precluded confident taxonomic assignments. Furthermore, the validity of Melissiodon arambourgi, a species based on a single specimen from the Vallès-Penedès site of el Fallol, has been questioned. After recent field campaigns, the available material has increased significantly, which allows for more robust taxonomic conclusions. All the Vallès-Penedès specimens are here referred to Melissiodon dominans, a widely dispersed species in the European early Miocene. After a revision of the holotype of M. arambourgi, we confirm that the original description and figures do not agree with it and conclude that it is a junior subjective synonym of M. dominans. The last occurrence of Melissiodon in the area is in the Sant Mamet site, located just a few meters below middle Miocene marine deposits, and represents one of the youngest records of this long-ranging genus.