Two new species of Metharpinia Schellenberg (Amphipoda: Phoxocephalidae) from the south-west Atlantic

Two new species, Metharpinia dentiurosoma and Metharpinia grandirama, belonging to the family Phoxocephalidae are described and illustrated from the Argentine Sea. Both taxa were collected dredging at different depths and the grain size of the sediment was determined for each sampling station. The new species share character states with Metharpinia Schellenberg, 1931 and Microphoxus Barnard, 1960, and their assignation to the first genus is discussed. Metharpinia dentiurosoma and Metharpinia grandirama are distinguished from the other known species of the genus by the dorsal hook on urosomite 3; in addition, the first species is characterized by its epimeron 3 and the second species by its uropod 2.     

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.