Margaritifera marocana (Pallary, 1918): a valid species inhabiting Moroccan rivers

Within the Unionoida the family Margaritiferidae is a small but widely distributed group, whose number of genera and species is under discussion. Using molecular and morphological characters, the present paper redescribes several Moroccan specimens of Margaritifera, previously classified as M. auricularia marocana. The shell and anatomical features of the taxon are similar to those observed in European specimens of M. auricularia auricularia. Notwithstanding, the two subspecies can be separated by certain hinge characters. Partial sequences of the mitochondrial genes COI and 16S rRNA support recognition of the Moroccan populations as a different species: Margaritifera marocana. We examined the phylogenetic relationships of the Margaritiferidae. The COI data indicated two monophyletic clades: one including M. margaritifera, M. dahurica, M. falcata and M. laevis, and the second comprising M. auricularia from the Iberian Peninsula and the Moroccan specimens of M. marocana as an independent lineage. Cumberlandia monodonta was recovered as the basal margaritiferid, sister to Margaritifera.