Androlaelaps marmosops, a new species of laelapid mite, is described from the pelage of the mouse opossum, Marmosops incanus (Lund, 1840) (Mammalia: Didelphidae), in two areas of Atlantic Forest of Rio de Janeiro State. Measurements and illustrations are included for females only.
Acari; Laelapidae; Brazil; Atlantic Forest; taxonomy; marsupial