Leggadina Thomas 1910

Leggadina Thomas 1910, Ann. Mag. Nat. Hist., ser. 8, 6: 606.

Type Species: Mus forresti Thomas 1906

Species and subspecies: 2 species:

Species Leggadina forresti (Thomas 1906)

Species Leggadina lakedownensis Watts 1976

Discussion: Pseudomys Division. Sometimes included in Pseudomys, but a distinctive genus considered to be an Australian Old Endemic (Musser, 1981 c). Usually included in the Conilurini (Baverstock, 1984), but data from microcomplement fixation of albumin indicated that L. forresti is not closely related to Pseudomys or any of the other Australian Old Endemics (Watts et al., 1992), but clusters with Hydromys (Australia and New Guinea) and the New Guinea endemic Parahydromys (Watts and Baverstock, 1994 a, 1996), an association seemingly supported by spermatozoal morphology (Breed and Aplin, 1994; Breed, 1997). However, a recently completed phylogenetic analysis of multiple mitochondrial and nuclear genes in a wide selection of "conilurines" (in the sense of Baverstock, 1984) shows that Leggadina is much closer to a Pseudomys / Notomys clade than to Hydromys (F. Ford, in litt., 2004). Compared with DNA sequences, especially from a combination of nuclear and mitochondrial genes, the albumin immulogical data, as well as sperm morphology, are apparently unreliable indicators for detecting deep phylogenetic relationships. Leggadina and other members in the Pseudomys Division are part of a larger clade that includes genera in our Hydromys, Xeromys, and Uromys Divisions, an assemblage that Watts and Baverstock (1994 a) defined as Hydromyini (or the "Australasian clade," Watts and Baverstock, 1995 b, 1996) as opposed to a strictly New Guinean Anisomyini (our Pogonomys Division). Some species of Pseudomys, namely P. delicatulus and P. hermannsburgensis, are often included in Leggadina (Lidicker and Brylski, 1987) but only L. forresti and L. lakedownensis belong here (Mahoney and Posamentier, 1975; Mahoney and Richardson, 1988; Watts and Aslin, 1981).

Morphology of male reproductive tract, external anatomy of glans penis, and spermatozoal structure documented in context of comparative study of Australian murines by Breed (1980, 1984, 1986), Morrissey and Breed (1982), and Lidicker and Brylski (1987). Biochemical and chromosomal data discussed by Baverstock et al. (1976 a, 1981, 1983 b). Taxonomic, distributional, and biological references for species catalogued by Mahoney and Richardson (1988). Moro et al. (1998) analysed variation in mtDNA cytochrome b sequences with particular focus on Western Australian populations. Cooper et al. (2003 a) clarified the wider distributions of the two species based on much newly collected material and a combination of allozyme electrophoresis and morphological analysis. Earliest record of Leggadina comes from late Pliocene sediments (Aplin, 2004; Godthelp, 1997).