Sphenolasioptera Kolesik & Gagné, 2016

Kolesik, Peter & Gagné, Raymond J., 2016, Revision of early taxa of Australian gall midges (Diptera: Cecidomyiidae), Zootaxa 4205 (4), pp. 301-338 : 325-326

Sphenolasioptera Kolesik & Gagné new genus

[Fig. 14]

Type species: Lasioptera vastatrix Skuse 1888: 128 . Monotypic.

Description. Adults. Head. Palpus 3-segmented, palpiger present. Labella acutely tapered in dorsal view. Female antennal flagellomeres 15 (see note in S. vastatrix description below), first and second flagellomeres fused, barrel-shaped in both sexes, circumfila consisting of two transverse and two connecting longitudinal bands. Wing: R4+5 2/3 wing length, straight, closely adjacent to R1 and C, C with break at juncture with R4+5, Cu forked, wingfold visible. Tarsal claws toothed, empodia as long as claws. Male terminalia: gonocoxites cylindrical, gonocoxal apodemes merged basally; gonostylus with comb-like tooth apically, microtrichose basally, carinate beyond, cerci triangular; hypoproct bilobed; mediobasal lobes subdivided, dorsal part short, hemispherical, long-microtrichose, ventral part long-tapered, tightly sheathing aedeagus, apically with short setae, elsewhere with long microtrichia. Ovipositor: eversible part with dense group of numerous hooked bristles on each side, protrusible part fairly long, partially obscured; cerci fused, rigid, pigmented, bilaterally flattened, anteriorly with a dorsal and two lateral apodemes (Fig. 14d), dorsally with single row of large, scooped setae along most of length followed near apex with single row of minute, scooped setae, with scattered, simple, short, lateral and ventral setae; hypoproct not evident.

Pupa. Antennal horns present (“head bifid in front”), dorsal spines absent ( Skuse 1888).

Larva. Spatula with 4 lateral papillae on each side, 2 of them with short setae, the ventral papilla closely approximated to lateral papillae, without seta; terminal segment with three setose papillae on each side.

Etymology. The name combines “sphen”, Greek for wedge, referring to the shape of the fused cerci, and Lasioptera , the type genus of the tribe Lasiopterini . The gender is feminine.

Remarks. The uniquely derived character of Sphenolasioptera within the Lasiopterini is the partially rigid ovipositor. Lasiopterini contain three other genera in Australia: Lasioptera Meigen , Actilasioptera Gagné and Dactylasioptera Kolesik & Veenstra-Quah. Lasioptera and Dactylasioptera have soft ovipositors with cerci bearing scooped setae while Actilasioptera has a rigid ovipositor without scooped setae. Sphenolasioptera differs from these genera by having a partially rigid ovipositor with cerci that bear scooped setae. Sphenolasioptera and Actilasioptera further differ from Lasioptera and Dactylasioptera by the apparent lack of a hypoproct. The ridged fused cerci of Sphenolasioptera are possibly used as a wedge between grass leaves during oviposition. To accommodate the new genus in the key to Cecidomyiinae genera of Australia and Papua New Guinea ( Kolesik 2014) the following addition is made:

35 Ovipositor at least partly rigid, without apparent hypoproct.................................................. 35a – Ovipositor soft, with obvious hypoproct.................................................................. 36 35a Ovipositor with entire protrusible part rigid and glabrous, with only straight setae apically........... Actilasioptera Gagné – Ovipositor with protrusible part mostly flexible, the cerci bilaterally flattened, rigid, microtrichose and bearing scooped setae.

........................................................................ Sphenolasioptera Kolesik & Gagné

Endemic to Australia, 1 sp., S. vastatrix (Skuse) , causing stem swellings on unidentified grass.

FIGFURE 14. Sphenolasioptera vastatrix (Skuse) . a,c: male; b, d–g: female; h–j: larva. (a) terminalia in dorsal view (left lobe of hypoproct missing), (b) mouthparts in ventral view, (c) part of last tarsomere with claw and empodium, (d) postabdomen in lateral view, (e) fused cerci in lateral view, (f) sixth flagellomere, (g) wing, (h) spatula with adjacent papillae, (i) head (left antenna missing), (j) terminal segment in dorsal view.