Australian Dusky Rat

discussion

Discussion: Rattus fuscipes species group. Arranged as a subspecies of R. sordidus by Taylor and Horner (1973), but subsequently treated as a separate species (Mahoney and Richardson, 1988; Watts and Aslin, 1981; Williams, 1995). Although diploid counts are very different, Rattus colletti (2 n = 42) is genetically very close to R. villosissimus (2 n = 50); the two hybridize in the laboratory, but the offspring exhibit severely reduced fertility (Baverstock et al., 1983 a, 1986). An undescribed species related to R. colletti and R. villosissimus is known from a small area in C Queensland (Aplin, in litt., 2004). Fertile hybrids have also been obtained between laboratory crosses of R. colletti and R. tunneyi (Baverstock et al., 1983 a).

Order Rodentia - Family Muridae

distribution

Distribution: Australia; known only from the coastal floodplains of the Northern Territory, the most restricted range of all the native Australian Rattus (Watts and Aslin, 1981; Williams, 1995).

Order Rodentia - Family Muridae

materials_examined

Type Locality: Australia, Northern Territory, South Alligator River (see Mahoney and Richardson, 1988).

Order Rodentia - Family Muridae

discussion

COMMENTS: Arranged as a subspecies of R. sordidus by Taylor and Horner (1973), but subsequently treated as a separate species (Mahoney and Richardson, 1988; Watts and Aslin, 1981). Although diploid counts are very different, Rattus colletti (2 N = 42) is genically close to R. villosissimus (2 N = 50); the two hybridize in the laboratory, but the offspring exhibit severely reduced fertility (Baverstock et al., 1983 a, 1986). Fertile hybrids have been obtained between laboratory crosses of R. colletti and R. tunneyi, but the two are sympatric in the wild where no hybrids have been found (Baverstock et al., 1983 a).

Order Rodentia - Family Muridae