Howickia pinnula, Kuwahara & Marshall, 2022

Kuwahara, Gregory K. & Marshall, Stephen A., 2022, A revision of the Australian species of Howickia Richards (Diptera: Sphaeroceridae: Limosininae), Zootaxa 5192 (1), pp. 1-152 : 98-101

Howickia pinnula sp. nov.

( Figs. 27.1–27.9 )

Description. Body length: Males 2.2–3.0 mm, females 2.2–3.3 mm.

Head: Dark brown, frontal vitta orange-brown, area between interfrontal plates and orbital plate orange; frontal vitta, bases of interfrontal bristles and orbital plates with pale microtrichia; gena dark brown, lighter along anterior edge; antenna yellow-brown. Frontal width 1.7x interfrontal height, frontal vitta broad and slightly convex. Two pairs of large interfrontal bristles preceded by a smaller pair (0.3x length of posterior pairs); 2 lateroclinate orbital bristles, anterior bristle 0.6x length of posterior bristle. Gena with large upcurved bristle and 3 smaller setae, finely and densely striate, shiny, lower half microtrichose; vibrissal angle with 2 very fine subvibrissal setae. Face shiny with a very small flattened triangle along ventral margin; palpus elongate, clavate with 1 large apical and 1 large preapical seta. Eye height 2.9x genal height.

Thorax: Dark brown; scutum shiny despite microtrichia, posterolateral edges narrowly reddish and with pale spot on posterior notopleural lobe. Two pairs of dorsocentral bristles (anterior pair just behind suture and 0.6x length of posterior pair); 6–7 rows of long, fine acrostichal setulae. Prosternum narrow, linear, posteriorly expanded. Scutellum microtrichose, subtriangular, its length 0.5x its width; 4 scutellar bristles long, apical pair 1.1x length of basal pair.

Legs: Brown, femora distally and tibiae proximally light brown; tarsi brown. Male mid tibia with a large apicoventral bristle. Basal half of mid tibia with 3 dorsal bristles (2 anterodorsal and 1 posterodorsal), distal half with 2 dorsal bristles (1 anterodorsal and 1 posterodorsal).

Wing/halter: Wings significantly reduced, extending to anterior margin of T2; veins significantly reduced: costa, R 1, R 2+3, discal cell and M 1+2 somewhat identifiable. Halter present as minute white scales.

Male abdomen: Dark brown, normally sclerotized, shiny despite microtrichia. T2–5 and S2–4 uniformly but sparsely long-setose along entire surface with large posterolateral setae. S5 broad (width 2.5x length), densely longsetose posterolaterally, posteromedially desclerotized triangle large with many small setae medially and larger setae laterally. Epandrium large, ovoid, and uniformly long-setose; cercus subquadrate, bulging into a knob medially with 1 extremely large sinuate seta and several other large setae all situated on the knob. Hypandrium medially large, dark, sinuate apically; ventral lobe stout, main part bulbous with a smaller triangular projection at an angle of 70˚; posterodorsal lobe extending horizontally from posterior end of main part, sinuate to articulation with phallus. Surstylus subquadrate and stout with a lateral flange, several fine ventral setulae and an extremely large posteroventral thorn-like seta. Postgonite elongate, bent forwards at about half length, proximally with a pair of anterior setulae, apically curved forwards into a slight knob. Phallapodeme gently sinuate, apical half with a large dorsal fin; basiphallus blade-like, tapered apically. Distiphallus divided into two distinct sections, largely sclerotized: basal half heavily sclerotized with a large, triangular, saddle-like dorsal sclerite and a triangular ventral sclerite articulating to form a tube; distal half with a W-shaped, anterodorsal sclerite and a flattened ventral sclerite fused laterally into a tube supporting a membranous apex.

Female abdomen: Dark brown, shiny despite microtrichia. T2–5 and S2–5 uniformly but sparsely long-setose along entire surface with larger posterolateral setae; pleural membrane with small setal patches. Preabdomen subequal to length of head + thorax. Postabdomen elongate, narrow, 5.3x length of T5. T6 reduced to a pair of broad plates, each bearing a posterior row of 3 setae and a preapical mesial seta; T7 reduced to a pair of elongate, L-shaped plates which may be joined posteriorly and each bearing a posterior row of 3 setae. Epiproct elongate, subtriangular, medially desclerotized and bearing a pair of dorsomedial setae. Cercus subtriangular with 3 long sinuate setae (1 apical, 1 lateral and 1 dorsal) and several smaller setulae. S6 and S7 relatively well-developed, present as microtrichose, rectangular plates bearing a posterior row of 8 and 10 setae, respectively. S8 a subtriangular, posteriorly microtrichose plate with a posterior pair of setae. Hypoproct rounded, posteriorly microtrichose with a patch of setae. Spermathecae stout, cylindrical, finely grooved with a large apical invagination and tapered base; stem short (0.6x length of spermatheca) and cylindrical.

Material examined. Holotype: AUSTRALIA: Tasmania: Waratah , 8 km SW, 41˚29’04”S 145˚27’41”E, rainforest, pans, 20–21.xii.2003, S.A. Marshall, debu00248431 (♂, TMAG).

Paratypes: AUSTRALIA: Tasmania: same data as holotype (6 ♂, 7 ♀, TMAG, DEBU) ; Waratah , 8 km SW, 41˚29’04”S 145˚27’41”E, pans in tree fern crowns, 21–22.xii.2003, S.A. Marshall (1 ♀, DEBU) ; Waratah , 8 km SW, 41˚29’04”S 145˚27’41”E, rainforest, dung pans, 20–21.xii.2003, S.A. Marshall (4 ♂, 9 ♀, TMAG, DEBU) .

Etymology. This name is in reference to this species’ reduced wings (Latin ‘pinnula: small wing, plume of feathers)

Comments. Howickia pinnula sp. nov. can be easily distinguished from the other brachypterous species of Howickia by the plain, dark brown head, less sclerotized abdomen similar to most winged species (very strongly sclerotized in H. cruspica and H. sabina ) and the small, white remains of the halter.

Figures

FIGURES 27.1–27.5. Howickia pinnula sp. nov. 27.1, male habitus, lateral; 27.2, male head, anterolateral; 27.3, male S5–8, ventral; 27.4, male terminalia, lateral; 27.5, aedeagus and associated structures, lateral. Scale bars indicate 0.5 mm.