A new species of Mexicope Hooker, 1985 (Crustacea, Isopoda) - the first record of Acanthaspidiidae Menzies, 1962 from the Mediterranean Sea

Background The marine isopod family Acanthaspidiidae Menzies, 1962 (Asellota, Janiroidea) has global distribution from shelf to hadal depth. The majority of species has been recorded from relatively deep waters and the Southern Hemisphere. To date, 36 species have been described in the family belonging to three genera: Ianthopsis Beddard, 1886; Iolanthe Beddard, 1886; and Mexicope Hooker, 1985. New information Here, a new species of Mexicope is described from Maltese waters, adding a fourth species to the genus. It is the first member of the family reported from the Mediterranean Sea. The new species can be recognised by the unique combination of the following characters: cephalothorax with pre -ocular spine large and pointed anterolaterally, rostral projection blunt, eyes reduced; pereonal sternites each with one ventral spine; pereonite two lateral margins with single projection; pleotelson posterior apex long, projecting to approximately half of the length of the uropod protopod; pleopods I distolateral lobes projecting beyond distomedial lobes, apices curved and pointed laterally; uropod exopod length approximately 0.5 endopod length. An identification key to the species of Mexicope is presented and the generic diagnoses of Ianthopsis and Mexicope are compared, discussed and revised.