Howickia acicula, 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 : 24-27

Howickia acicula sp. nov.

( Figs. 3.1 , 4.1–4.9 )

Description. Body length: Males 2.7–3.4 mm, females 2.7–3.1 mm.

Head: Black, lower margin of frons orange, frontal vitta and orbital plates reddish; frontal vitta, interfrontal plates and orbital plates with pale microtrichia; gena reddish anteriorly; antenna brown. Frontal width 2.1x interfrontal height. Two pairs of large interfrontal bristles preceded by a smaller pair 0.5x length of posterior pair; 2 lateroclinate orbital bristles, anterior bristle 0.5x length of posterior bristle. Gena with strong upcurved bristle and 5–6 smaller setae, finely and densely striate, shiny, lower third microtrichose; vibrissal angle with 3 subvibrissal setae. Face with a slightly flattened triangle along ventromedial margin; palpus clavate with 1 large apical and 1 large preapical seta. Eye height 2.7x genal height.

Thorax: Dark brown; scutum shiny despite brown microtrichia, posterolateral edge lighter and with pale spots on posterior notopleural lobe; anepimeron with lighter posteroventral spot. Two pairs of dorsocentral bristles (anterior pair 0.5x length of posterior); 4–5 rows of long, fine acrostichal setulae. Prosternum narrow, linear, posteriorly expanded. Katepisternum with several small setulae in addition to large posterior seta. Scutellum microtrichose, subtriangular, length 0.7x width; 4 long scutellar bristles, apical pair 2.0x length of scutellum.

Legs: Brown, tibiae proximally pale brown; tarsi pale brown. Male mid tibia with a stout apicoventral bristle and 2 rows of stout ventral setae along entire length, mid femur with 2 corresponding rows of strong proximoventral setae. Basal half of mid tibia with 3 dorsal bristles (2 anterodorsal and 1 posterodorsal), distal half with 3 dorsal bristles (2 anterodorsal and 1 posterodorsal).

Wing/halter: Strongly infuscate; ventral surface of vein R 1 white, other veins light brown. CS2 subequal to CS3. R 2+3 sinuate, distal curve stronger than basal curve; R 4+5 upcurved, meeting costa well before wing tip; costa extending well past apex of R 4+5 (5x costal width). Halter yellow-white.

Male abdomen: Dark brown, almost black, shiny despite microtrichia. T2–5 and S2–4 slightly desclerotized along edges, otherwise heavily sclerotized, uniformly long-setose along posterior half with large posterolateral setae. S5 ( Fig. 4.3 ) large, shiny, broad but short (width 3.0x length), posteromedially desclerotized and bulging with dense patch of short setae, laterally with much longer setae. Epandrium large, hemispherical, and uniformly long-setose; cercus flattened, rectangular with 2 very long setae. Hypandrium medially strongly sinuate; ventral lobe thin, tapered, slightly sinuate with a thin sheet connecting to medial part; posterodorsal lobe short. Surstylus subtriangular and largely bare, with a short, triangular, laterobasal lobe, apically with an extremely large, thickened ventral thorn-like seta and some smaller lateral setae. Postgonite elongate, sinuate, distal third with anterior edge serrate with numerous minute setulae, apex curved forwards into hook. Phallapodeme sinuate with large anterodorsal fin; basiphallus with short, rectangular arms. Distiphallus divided into two distinct sections: basal half heavily sclerotized with a large saddle-like dorsal sclerite and a flattened ventral sclerite articulating to form a tube; distal half with a V-shaped dorsal sclerite and a thin ventral sclerite fused laterally into a tube supporting a membranous apex with numerous dorsoapical rows of small spicules.

Female abdomen: Dark brown, sometimes desclerotized, shiny despite microtrichia. T2–5 uniformly longsetose in posterior two-thirds with large posterolateral setae, S2–5 uniformly long-setose along entire surface. Preabdomen slightly shorter than length of head + thorax. Postabdomen elongate, narrow, 2.6x length of T5. T6 and T7 reduced to a pair of L-shaped lateral plates, each bearing a posterior row of 4 setae. Epiproct rectangular with a triangular posteromedial point and paired dorsomedial setae. Cercus subtriangular with 4 long sinuate setae (1 apical, 2 lateral and 1 dorsal) and several smaller setulae. S6–7 relatively well-developed, entirely microtrichose, medially desclerotized, bell-shaped plates bearing a posterior row of 10 setae. S8 reduced to an ovoid, microtrichose plate with a preapical pair of setae. Hypoproct largely desclerotized, rounded, microtrichose with a patch of setae. Spermathecae short, stout, conical and entirely lightly grooved; stem subequal in length to spermatheca and cylindrical.

Material examined. Holotype: AUSTRALIA: Tasmania: Cuckoo Falls, 4 km E Scottsdale, along Falls Rd. , along creek, pans/some dung, 14.xii.2003, S.A. Marshall, debu00248893 (♂, TMAG).

Paratypes: AUSTRALIA: Tasmania: Mount Williams National Park, Stumpys Bay Campground, dry heath, pans, 12–13.xii.2003, S.A. Marshall (1 ♂, DEBU) ; same data as holotype (9 ♂, 6 ♀, TMAG, DEBU) ; Waratah , 8 km SW, 41˚29’04”S 145˚27’41”E, rainforest, dung pans, 20–21.xii.2003, S.A. Marshall (2 ♀, TMAG, DEBU) .

Other material examined: AUSTRALIA: Tasmania: same data as holotype (1 ♂, 4 ♀, DEBU); Waratah , 8 km SW, 41˚29’04”S 145˚27’41”E, rainforest, dung pans, 20–21.xii.2003, S.A. Marshall (1 ♀, DEBU) .

Etymology. This name is in reference to the elongate, pin- or needle-like postgonite and surstylar seta (Latin acicula : “a needle-like spine or bristle; a hairpin”).

Comments. Howickia acicula is part of the H. flaviterga species group, which also includes H. biantenna , H. flaviterga , H. grandisterna , and H. percostata . It differs from H. grandisterna and H. percostata in having four rows of acrostichal setulae and vein R 2+3 separated from the costa by 2.5x the costal width, and can be distinguished from H. biantenna by the presence of two pairs of dorsocentral bristles. Howickia acicula is externally very similar to H. flaviterga , though it differs in only having four rows of acrostichal setulae and a slightly longer scutellum. Male genitalia also differ significantly. Howickia acicula is sympatric with H. biantenna and H. grandisterna , which were also collected at the same time in Mount Williams National Park.

Figures

FIGURES 3.1–3.22. Mid tibial chaetotaxy of macropterous Australian species of Howickia. 3.1, H. acicula sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.2, H. biantenna sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.3, H. brevior (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.4, H. capitalis (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.5, H. erythrocephala sp. nov., a) dorsal, male, b) lateral female; 3.6, H. flaviterga (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.7, H. fuscalis (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.8, H. grandisterna sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.9, H. hardyina (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.10, H. kurandensis (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.11, H. myrmecophila (Knab & Malloch), a) dorsal, male, b) lateral male, c) lateral, female; 3.12, H. nitidipleura (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.13, H. percostata (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.14, H. pertusa sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.15, H. pseudovittata sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.16, H. subsinuata (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.17, H. symmetrica (Richards), a) dorsal, male, b) lateral male; 3.18, H. trivittata (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.19, H. vernalis (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.20, H. wamini sp. nov., a) dorsal, male, b) lateral male, c) lateral, female; 3.21, H. wilsoni (Richards), a) dorsal, male, b) lateral male, c) lateral, female; 3.22, H. xanthocephala sp. nov., a) dorsal, male, b) lateral male, c) lateral, female. Scale bars indicate 0.25 mm.

FIGURES 4.1–4.5. Howickia acicula sp. nov. 4.1, male habitus, lateral; 4.2, male head, anterolateral; 4.3, male S5–8, ventral; 4.4, male terminalia, lateral; 4.5, aedeagus and associated structures, lateral. Abbreviations: bas—basiphallus, cer—cercus, dist—distiphallus, epa—epandrium, hyp—hypandrium, phal—phallapodeme, post—postgonite, S—sternite, sur—surstylus. Scale bars indicate 0.5 mm.