THE CRASSIPES SPECIES‐GROUP, GENUS TRICHOSUROLAELAPS WOMERSLEY (ACARI: DERMANYSSIDAE)

Three mite parasites of Australian possums (Marsupialia) are described: Trichosurolaelaps dixoa sp. n. from Trichosurus caninus (Phalangeridae); T. marra sp. n. from Petaurus norfolcensis, P. breviceps , and Gymnobelideus leadbeateri (Petauridae); and T. fallax sp. n. from Schoinobates volans (Petauridae). Supplementary notes are offered on the three known species ( T. crassipes Womersley, T. harrisoni Domrow, and T. striata Domrow). The considerable reduction of the setation on the disc of the dorsal shield of all species is analysed, and incorporated with other morphological characters into a natural key. Host‐specificity parallels morphology, and indicates that the parasites of petaurids are distinct from those of phalangerids, and that the latter are nearer to the one parasite of a non‐possum: Hypsiprymnodon (Macropodidae).