A new species of Phoxocephalidae and some other records of sand-burrowing Amphipoda (Crustacea) from Argentina

A new species from the Argentine Sea, Metharpinia iado (Phoxocephalidae), is described. It is distinguished by many morphological character states from Metharpinia longirostris Schellenberg, 1931, found in South America for Argentina and Chile, primarily, they differ in numbers of spines and setae on mouthparts and appendages, and shape of epimeron plate 3. The new species is recorded in Buenos Aires and Chubut provinces. Two other Phoxocephalidae, Microphoxus cornutus (Schellenberg, 1931) and Fuegiphoxus fuegiensis (Schellenberg, 1931), partially illustrated, are compared in different populations, and some variations in number of spines and setae on mouthparts and appendages are noted. Microphoxus cornutus, known in Chile (Punta Arenas) and Argentina (Ushuaia), extends its geographical distribution towards the north of Argentina, in Buenos Aires and Chubut. Fuegiphoxus fuegiensis, known in the austral part of South America (Punta Arenas and Ushuaia) and in Chubut (Puerto Madryn), expands its geographical distribution in Chubut. The Ipanemidae Ipanema talpa Barnard and Thomas, 1988 is figured in part, both males and females are compared with the male specimen described from Brazil; it constitutes a new record in Argentina. All taxa were collected from sandy substrata in the intertidal and subtidal regions, in Buenos Aires and Chubut provinces.