Drosophila (Sophophora) dominicana Ayala

Schiffer, Michele & Mcevey, Shane F., 2006, Drosophila bunnanda — a new species from northern Australia with notes on other Australian members of the montium subgroup (Diptera: Drosophilidae), Zootaxa 1333, pp. 1-23 : 8

Drosophila (Sophophora) dominicana Ayala

Drosophila dominicana Ayala 1965 , Pac. Insects 7, p. 620. Type locality: Madang, Papua New Guinea.

We dissected a D. dominicana paratype (AMNH, Reg. 21752) to determine its relationship to the species we describe as new in this paper. We found the novasternum to have a distinctive bicornute caudal margin. This notched form resembles the shape in species of the auraria complex, unlike the smooth convexity of the novasternum of the remaining two D. serrata complex species. Ayala’s drawing (1965a, fig. 2) does not show this but it is clear in an unpublished drawing of D. dominicana by I.R. Bock (dated 9 Feb 1987) that we have been able to view. We can confirm, however, that the secondary claspers are indeed noticeably circular in appearance as described and illustrated by Ayala (1965a, b); this is also reminiscent of auraria complex species. Drosophila dominicana has distinct spines along the ventral cercal margin and has three spines of unequal size (two large, one small) arising from the secondary clasper. The latter may be a variable condition because it is evident in Ayala’s (1965b) drawing and in our dissected specimen, but not in Bock’s unpublished sketch.

Three combinations of interspecific crosses involving D. dominicana and either D. serrata or D. birchii resulted in hybrids ( Ayala 1965a). Drosophila serrata Wau female × D. dominicana Madang male and D. dominicana Madang female × D. birchii Port Moresby male both produced offspring with some fertility, D. serrata Mataranka female × D. dominicana Madang male produced sterile offspring. It is possible, that the new montium species, when intercrossed in certain combinations with these latter species, will produce partially fertile hybrids. This would not be unusual among species of the same complex within the melanogaster species group ( Bock 1984a).

The Y chromosome of the D. dominicana metaphase karyotype has been compared to, and found to share similarities with, the Y chromosomes of D. jambulina and D. nikananu (Baimai 1980) . However, comparisons of the entire metaphase karyotypes revealed that D. dominicana , D. serrata , and D. birchii were all “quite distinct” (Baimai 1980).

Drosophila dominicana is known only from a culture derived from a sample collected at Madang, Papua New Guinea ( Ayala 1965b); we can find no evidence that montium subgroup flies have been sampled in that region since that time. However, many pinned drosophilid specimens from Papua New Guinea remain unsorted (specimens at the B.P. Bishop and Australian Museums). Reports of D. dominicana from several locations in Sabah ( Mather 1968) cannot be confirmed by us because of the lack of voucher material.

Distribution ( Fig. 14 ). Madang, Papua New Guinea and possibly Sabah ( Ayala 1965a; Ayala 1965; Baimai 1980; Mather 1968; also see Appendix).

Figures

FIGURES 14 – 20. Distribution maps of Drosophila montium subgroup species in the Australasian Region. (14) Drosophila dominicana. (15) Drosophila montium subgroup species undissected and unclassified. (16) Drosophila kikkawai. (17) Drosophila sp. cf. jambulina. (18) Drosophila bunnanda (19) Drosophila birchii. (20) Drosophila serrata.