Drosophila setifemur

McEvey, Shane F., 2009, Taxonomic Review of the Australian Drosophila setifemur Species Group, a New Name for the D. dispar Species Group (Diptera: Drosophilidae), Records of the Australian Museum 61 (1), pp. 31-38 : 35-36

The Drosophila setifemur species group

Within the Drosophilidae , but not generally in the Diptera , there is an informal and hierarchical classification between the genus level and the species level. For example, the melanogaster “species group” accommodates a large number of species that share morphological characteristics with D. melanogaster (Bock & Wheeler, 1972; Bock, 1980) and are phylogenetically closely related ( Lemeunier et al., 1986). The “species group” is a superspecific aggregation with a rank below subgenus, it is divided into various “subgroups”, subgroups are sometimes divided into “complexes”, and complexes into sibling pairs, cryptic species or other loosely defined groupings of small numbers of species. (Subspecies is a rank seldom used in the Drosophilidae .) Guidelines for the application of these subgeneric and superspecific names are not offered by the ICZN and so it is difficult to affect an objective re-appraisal of the so-called “ dispar species group”, now that the correct name of the typical species is no longer D. dispar . There is also the untidy situation of synonymy with the “ dispar species group” in another drosophilid genus Zygothrica ; this clash would be rectified if the Drosophila dispar species group was renamed.

The logical course of action, and the one adopted here, is to replace the name “ Drosophila dispar species group” with the name “ Drosophila setifemur species group”. This is done in anticipation of confusion that might result were nothing done. In light of the current systematic uncertainties due to the polyphyletic assemblage of species in Drosophila (O’Grady & DeSalle, 2008) it would be premature to consider erecting a new genus or new subgenus to accommodate D. setifemur and D. prodispar although the atypical male terminalia (especially the acuminate extension of the lower cercus and the form of the ventral projections of the epandrium are quite unlike any other in the Drosophila subgenus Sophophora ) offers a suitable starting point for such a consideration. The typical species of the species group is D. setifemur , and D. prodispar is the only other member. Prior to the present investigation, however, it was generally accepted that the “ Drosophila dispar species group” had three species (e.g., Ashburner et al., 2005) viz. D. dispar [= setifemur ], D. prodispar and D. unguicula Okada & Carson, 1983:138 . Okada & Carson (1983) speculated that D. unguicula from Papua New Guinea “seems to belong to the dispar [= setifemur ] species group” but the “cercus [is] with a strong black spur ventrally” and in this respect it is quite unlike D. setifemur which has instead a long acuminate process with subapical trichose hairs. Drosophila unguicula has not been examined in this study but in light of the description and illustrations offered by Okada and Carson and the detailed examination of the D. setifemur and D. prodispar genitalia in the present study, it is concluded that D. unguicula should be excluded from the setifemur species group.

Other species examined. Drosophila prodispar Parsons & Bock , in Bock, 1982: 51, four paratypes as follows: 1, Paradise, Otway Rd., Vic., off fronds, 20.v.1975, P.A. Parsons, AMS K72928 ; 1, Paradise, Otway Rd, Victoria off tree ferns, 21.v.1975, P.A. Parsons, AMS K72929 ; 2, River on Horden Vale Rd., Otway Rd., Vic., dampish habitat, off sedge 12.ix.1975, P.A. Parsons, AMS K232905 and AMS K232906. Drosophila teratos Bock, 1982: 89 .— holotype, [Royal] National Park N.S.W. 3.11.1956, D.K. McAlpine, AMS K73142 ; Lake Eacham NP Qld, swept off fungi, June 1983, P.A. Parsons, AMS K233710 (det Bock, 1983) fore-femur figured ( Fig. 12 ); QLD: 28.212°S 153.141°E, Lamington NP IBISCA Qld, Plot# IQ-500-B 514 m, 21–26 Jul. 2007, rainforest, Lambkin, Starick, Monteith, Malaise trap 23186, QM T155510 (det McEvey, 2008). Drosophila sulfurigaster (Duda) .—numerous specimens examined in the AMS from islands of the Pacific Ocean: Papua New Guinea, New Ireland, Fiji, Samoa, New Caledonia, Loyalty Islands, Vanuatu, Solomon Islands, Marquesas, Moorea and Tahiti; specimens in the AMS from the Oriental Region: Vietnam, Malaysia, Borneo, Luzon, Guam and Christmas Island (Indian Ocean); and specimens in the AMS from Australia (see Figs. 6–8 ): Moa I. (10.2°S), Thursday I., Mt Adolphus I., Heathlands (11.7°S), Iron Range, Claudie Rv., Gordon Ck (12.7°S), Cooktown (15°S), Cape Tribulation (16.2°S), Mossman Gorge, Kuranda, Cairns (16.9°S), Mulgrave Rv. (17.2°S), Palmerston NP, Maple Ck (17.6°S), Paluma (19°S), Townsville (19.3°S), Campaspe Rv (20.4°S). Drosophila (Drosophila) niveifrons Okada & Carson, 1982: 407 .—13, PNG, Wanigela, 9°16'S 149°08'E, 12–28 Feb 2003, S.F. McEvey, McE 20105, AMS 234063; fore-femur figured ( Fig. 13 ). Drosophila (Drosophila) immigrans Sturtevant. — 1♀, NSW Pinegrove HS, 13km SW Ebor, 1130m, 30°29.935'S 152°16.014'E, banana 17–18 January 2000, Barker McEvey Polak Starmer, McE 14225, AMS 234065; fore-femur figured ( Figs. 9–11 ).

Figures

Figures 12–13.Anteroventral setation of fore-femora of Drosophila teratos and D. niveifrons. (12) Drosophila teratos, male, Lake Eacham, Queensland,AMS K233710. (13) Drosophila niveifrons, male, Wanigela, Papua New Guinea, AMS 234063. Scale 0.5 mm (a niveifrons paratype [marked ex stock 14.x.1979 Kitagawa et al.] in BPBM has 8–9 spinescent setulae, McEvey pers. obs. 26.xi.2008).

Figures 1–11. Fore-femora of Drosophila setifemur, D. sulfurigaster and D. immigrans showing sexual dimorphism in D. setifemur and setation on anteroventral and posteroventral surfaces.(1–5) Drosophila setifemur:(1), D.dispar Mather (= D. setifemur Malloch) allotype female, Samford, Queensland,AMS K67820; (2), D. dispar Mather paratype female, Samford, Queensland,AMS K67825; (3), D. dispar holotype male, Samford, Queensland, AMS K67819; (4) and (5) (the latter is a ventral view showing both anterior and posterior setation of fore-femur), D. setifemur female paratype, Sydney, AMS K50090. (6–8) Drosophila sulfurigaster: (6) and (7), female, Malololelei, Samoa, McE 21321; (8), male, AMS K 234064, Maple Creek, near Innisfail, Queensland. (9–11) Drosophila immigrans: (9) and (10), female, near Ebor, New South Wales, AMS K234065; (11), male, Sydney, AMS K234066. Scale 0.5 mm.