New species of Neopilumnoplax Serène in Guinot, 1969 (Decapoda, Brachyura, Mathildellidae) from Northwest Africa with a key to the genus

Neopilumnoplax corallicola n. sp. is described from waters off Mauritania on the basis of two specimens collected during the Spanish-Mauritanian survey “Maurit-0911” from 488 m over a giant cold-water coral reef running from Cape Timiris to the Senegalese border. The new species is readily separated from its congeners by the shape of the front and anterolateral teeth, the low granulation on the dorsal carapace, and the morphology of the cheliped and ambulatory legs. This is the first record of the family from the Northeastern Atlantic and the second record of the genus in West Africa. A diagnosis of the family Mathildellidae with a key to genus level, as well as dichotomous and tabular keys to the world species of the genus Neopilumnoplax, are included.