Diadocidia (Adidocidia) macrosetigera, Jaschhof, Mathias & Jaschhof, Catrin, 2007

Jaschhof, Mathias & Jaschhof, Catrin, 2007, On the genus Diadocidia (Diptera, Sciaroidea, Diadocidiidae) in Australia, Zootaxa 1655, pp. 63-68 : 64-66

Diadocidia (Adidocidia) macrosetigera sp. n.

( Fig. 1 )

Description. Male. Body length 3.0 mm. Head. Antennal flagellum bearing short non-socketed setae intermingled with a few sensory spines; longest setae as long as flagellomere width; first to third flagellomeres bearing dorsally a few short socketed setae. First flagellomere 4.1 times as long as wide. Fourth flagellomere 2.4 times as long as wide. Maxillary palpus 5-segmented; third segment elongate, not swollen, bearing mesially a few short hyaline sensilla apart from ordinary setae elsewhere; fourth and fifth segments elongate cylindrical.

Thorax. Anepisternum bearing about 10 setae in upper portion, other pleura non-setose. Legs. Anteroapical depression of fore tibia with distinct semicircular rim, bearing numerous non-socketed, stiff setae; apical setae arranged in line. Wing. Sc entering C well before level of ta. Sc-r very weak. R1 entering C well beyond level of M-furcation. A1 reaching wing margin. A2 absent.

Terminalia. Fig. 1 A. Tg 9 a little shorter than wide, tapering towards and rounded on apex, bearing setae of various sizes. Gonocoxites ventrally with deep U-shaped emargination partly filled by membrane, or membranous lobe; bearing setae of various sizes except a non-setose portion ventrobasally. Gonostylus rather stout, bearing mesially 6 large, pointed macrosetae (at least 4 discernible in ventral view) and 2 small denticles (situated dorsosubapically and thus hardly discernible in ventral view), otherwise setae of various sizes ( Fig. 1 B). Aedeagus with rod-like apodeme and largely membranous widening apically, the membranous portion two-pointed, bearing numerous short trichia ( Fig. 1 C). Parameres partly fused to form tegmen; tegmen a little shorter than gonocoxites, apical portion sclerotized and medially separate, with two short processes with finely serrate lateral margins; parameral apodemes strong ( Fig. 1 C). Hypoproct weak, bearing 1 large seta on either side ( Fig. 1 A). Cerci bearing setae of various sizes ( Fig. 1 A).

Female. Body length 3.3 mm. Head. First flagellomere 4.2 times as long as wide. Fourth flagellomere 2.6 times as long as wide.

Thorax. Anepisternum bearing 6 setae. Legs. Fore tarsus not enlarged; four distal tarsomeres bearing sole of dense, stiff setae.

Terminalia. Cercus not widened subapically, bearing 4 very small spines dorsosubapically ( Fig. 1 D).

Discussion. This species shows the characters diagnostic of the subgenus Adidocidia , including the long first antennal flagellomere and the setose anepisternum, and is classified accordingly. This affiliation is supported by characters of the male terminalia, like the ninth tergite lacking apical spine-like setae and the large aedeagus. On first glimpse the striking vestiture on the gonostylus seems aberrant, but becomes plausible if the two small subapical denticles present in megasetigera are considered homologous to the large two-pointed tooth present in most other Adidocidia species. Further, in macrosetigera miniaturization of the double-tooth is practically compensated by the opulence of macrosetae, which is a phenomenon that can be observed similarly in various other sciaroids. The tegmen in macrosetigera , with its sclerotized bifurcate apex, is unparalleled among the species of Diadocidia . The female cercus in macrosetigera bears dorsally several small spines that are similarly found in D. (A.) borealis Coquillett and nigripalpis Edwards, but in our species the cercus is subapically not widened as is found in nigripalpis and the Adidocidia species, including borealis , studied by Laštovka and Matile (1972).

Etymology. From Latin, macrosetiger, macroseta-bearing, referring to the abundant macrosetae on gonostylus.

Types. Holotype. Male (on slide). Australia, Queensland, Mt Glorious, Tony Hiller property (27°20’07’’S, 152°45’30’’E), alt. 720 m, in dense tropical rainforest, 19 Jan.–2 Feb. 1996, by Malaise trap, M.E. Irwin & S.D. Gaimari. Paratype. 1 female, same data as the holotype.

Figures

FIGURE 1. Diadocidia (Adidocidia) macrosetigera sp. n. A: Male terminalia, ventral view (holotype). B: Gonostylus, ventral view (holotype). C: Aedeagus and tegmen, ventral view (holotype). D: Apex of ovipositor, lateral view (paratype). Scale = 0.05 mm (B and C) and 0.1 mm (A and D).