Drosophila (Sophophora) birchii Dobzhansky & Mather

Drosophila serrata birchii Dobzhansky & Mather, 1961, Evolution 15, p. 462. Type locality: Crystal Cascades, northern Australia.

Drosophila birchii (as species): Ayala, 1965a, p. 538.

Drosophila birchii on the Australian mainland has a distribution limited to northeastern Queensland. It has been collected by Bock in 1975 from Bamaga (Bock pers. comm. to McEvey, 1981), at the northern most tip of Australia and as far south as Yeppoon (22.8°S; Schiffer et al. 2004). It has also been collected throughout Papua New Guinea, as far north as Wewak (3.6°S, Baimai 1970a), and as far east as Rabaul, New Britain (Dobzhansky & Mather 1961). Like the following species, D. birchii is restricted to tropical rainforests.

Studies of metaphase karyotype (Baimai 1969) and chromosomal inversions (Baimai 1970b) within D. birchii have revealed extraordinarily high levels of polymorphism. Furthermore, some geographically divergent populations of D. birchii exhibit both partial and complete reproductive isolation (Dobzhansky & Mather 1961; Ayala 1965a; Baimai 1970a). Since there is a possibility that D. birchii consists of a cluster of morphologically similar species, flies collected by Dean, Hallas, Higgie, Mitrovski and Schiffer, and identified here as D. birchii, were checked using the diagnostic molecular marker Dbir 7 (as discussed in Schiffer et al, 2004) to ensure they all belonged to the same species.

Distribution (Fig. 19): Throughout Papua New Guinea, probably also large parts of West Papua (although no records are currently available) and northeastern Australia as far south as Yeppoon; apparently absent in the Northern Territory (Ayala 1965a; Ayala 1965c; Ayala 1966; Baimai 1970a; Bock 1977; Bock & Parsons 1977; Bock & Parsons 1978; Carson & Okada 1983; Dobzhansky & Mather 1961; McEvey & Bock 1982; van Klinken 1996; van Klinken et al. 2002; also see Appendix).