Polyplax guatemalensis sp n. (Phthiraptera : Anoplura), a new sucking louse from Peromyscus grandis, a montane cloud forest rodent from Guatemala

The adult male and female of Polyplax guatemalensis sp, n, are described fr om the sigmodontine murid rodent Peromyscus grandis Goodwin collected in t he Reserva de Biosfera, Sierra de las Minas, Guatemala, at an elevation of 2,200 m. The new species extends the number of known native species of Poly plax in the New World to four with none of them recorded south of Panama. P olyplax guatemalensis is morphologically most closely related to Polyplax a uricularis is which parasitises a cluster of closely related New World sigm odontine rodents from Canada to Panama. These two species can be distinguis hed from all other known species of Polyplax by the presence of partially o verlapping, subtriangular, anterior abdominal plates in both sexes. Polypla x guatemalensis can be separated from P. auricularis by the abundant tergal abdominal setae and longer pseudopenis in males, and by the presence of on e fewer anterior abdominal, subtriangular tergite and sternite in females.