Bionomics and distribution of species of Hystrichopsylla in Arizona and New Mexico, with a description of Hystrichopsylla dippiei obliqua, n. ssp. (Siphonaptera: Hystrichopsyllidae).

More than 450 specimens of Hystrichopsylla were collected from nests and hosts of species of Microtus, Neotoma, Tamiasciurus, and Peromyscus in Arizona and New Mexico from 1981-2004. A new subspecies, Hystrichopsylla dippiei obliqua, is described and a map illustrating the distribution of the three taxa (Hystrichopsylla dippiei truncata Holland, H. d. obliqua, and H. occidentalis sylvaticus Campos and Stark) occurring in Arizona and New Mexico is provided. Hystrichopsylla. o. sylvaticus is reported in New Mexico for the first time and H. d. truncata is a new record in Rio Aribba County, NM. Relationships of Mexican species are also discussed. These large fleas are seldom collected from the fur of their mammalian hosts (usually singly) but are prevalent in moist nests. The maximum number of the new subspecies collected from a single nest was 54. Dry nests, particularly those that are not subterranean or otherwise protected from desiccation, do not support development of Hystrichopsylla fleas. Minimum elevation at which H. dippiei ssp. is found in Arizona and New Mexico appears to be about 2,100 m.