Description of a new species of Haemogamasus (Mesostigmata, Laelapidae, Haemogamasinae) from Chubut, Río Negro and Neuquén Provinces, Argentina

Abstract. A new species of Haemogamasus mites is described from Chubut, Neuquén and Río Negro Provinces, Argentina. It was collected primarily from rodents of the genus Abrothrix (65 of 77 collections): Abrothrix longipilis (63), Abrothrix olivaceus olivaceus (1) and Abrothrix olivaceus xanthorhinus (1). Additional collections were made from Geoxus valdivianus (5) and Loxdomtomys micropus (5). Possibly incidental or contaminate collections were recorded from Oligoryzomys longicaudatus (1) and Dromiciops gliroides (1). Most collections came from Río Negro Province (36), with 22 from Neuquén and 19 from Chubut. An identification key is provided to distinguish ♀s of this new species from ♀s of species from the western hemisphere, based on morphological characters.