A new species of cricetid rodent, Megacricetodon vandermeuleni, sp. nov., is described from the local zone Db, middle Aragonian, from the Calatayud-Montalbán Basin and the Loranca Basin (Spain). The large-sized Megacricetodon is characterized by the elongated anteroconid and anterolophulid on ml and the robust and swollen cusps. Comparisons with other species of similar size and morphology are discussed. We consider M. bezianensis a valid species, based on the morphological differences with M. gersii. We propose a closely related group of Megacricetodon species that includes M. aff. collongensis, M. bavaricus, M. aff. bavaricus, M. bezianensis, M. lappi, M. aunayi, and M. vandermeuleni, nov. sp. The new species is of importance for Spanish biostratigraphy and the proposed Megacricetodon group is very useful for European faunal correlations and timing of migration events.

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