Howickia symmetrica (Richards)

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 : 78

Howickia symmetrica (Richards)

( Figs. 3.17 , 20.1–20.3 )

Leptocera (Biroina) symmetrica Richards, 1973: 335 .

Biroina symmetrica (Richards) , Marshall, 1989: 602; Roháček et al., 2001: 126.

Howickia symmetrica (Richards) , Marshall et al., 2014.

Description. Body length: Male 1.8 mm.

Head: Brown, dark brown around ocelli and behind and extending onto orbital plates, bases of interfrontal bristles dark brown; lower half of frons orange extending upwards along orbital plates; orbital plates microtrichose, microtrichia extending across top of head to surround ocellar triangle; gena reddish-brown; antenna brown. Frontal width 2.2x interfrontal height. Three pairs of large interfrontal bristles, middle pair largest; 2 lateroclinate orbital bristles, anterior bristle 0.5x length of posterior bristle. Gena with very strong upcurved bristle and 2–3 smaller setae, finely and densely striate, shiny, lower half microtrichose; vibrissal angle with 2 subvibrissal setae. Face with a small flattened triangle along ventromedial margin; palpus clavate with 1 large apical and 1 larger preapical seta. Eye height 2.9x genal height.

Thorax: Dark brown; scutum shiny despite brown microtrichia, posterolateral edge thinly lighter and with pale spot on posterior notopleural lobe; katepisternum with lighter posterior spot, anepimeron with lighter ventral spot. One pair of dorsocentral bristles; 7–8 rows of long, fine acrostichal setulae. Prosternum narrow, linear, posteriorly expanded. Scutellum large, microtrichose, subtriangular, its length 0.7x its width; 4 scutellar bristles long, apical pair 1.5x length of basal pair.

Legs: Dark brown, tibiae proximally and distally pale brown; tarsi orange-brown, basal 2 tarsomeres of hind leg dark brown. Male mid tibia with a moderate apicoventral bristle and 2 rows of short apicoventral setae, mid femur with 4 corresponding proximoventral setae. Basal half of mid tibia with 4 dorsal bristles (2 anterodorsal and 2 posterodorsal), distal half with 3 dorsal bristles (2 anterodorsal and 1 posterodorsal).

Wing/halter: Rather weakly infuscate, darkest anteriorly. CS2 0.6x length of CS3. R 2+3 strongly sinuate, curves roughly symmetrical (more angulate than curved), basal curve straight towards costa before bending away slightly, distal curve meeting costa at an angle of 60˚; R 4+5 rather strongly upcurved, meeting costa before wing tip; costa barely extending past R 4+5. Halter pale; knob brown and apically white; stem pale brown.

Male abdomen: Dark brown, microtrichose. T2–5 and S2–4 heavily sclerotized, uniformly long-setose along posterior half with large posterolateral setae. S5 concealed but (according to Richards, 1973) with a posteromedial row of stout, flat teeth. Epandrium (as can be seen from holotype photos) rather large, somewhat flattened, uniformly long-setose. Apex of surstylus apparently tapered and curved. Further details of postabdomen unavailable.

Female abdomen: Female unknown.

Type material. Holotype: AUSTRALIA: New South Wales: Clyde Mountain , landslip, 22.ii.1965, D.H. Colless (♂, ANIC) . Holotype photos provided by James Lumbers, ANIC .

Material examined: Holotype photos only.

Comments. The above redescription is based entirely on holotype photos, as no specimens were available to us during this study. Richards (1973) noted that H. symmetrica would key to H. hardyina “if the costa was considered to overpass R 4+5 ”, though the costa only very slightly extends beyond R 4+ 5 in H. symmetrica (1–2x costal width) compared to the costa extending well beyond R 4+ 5 in H. hardyina (7x costal width). These two species are indeed superficially similar, both with brown body and extensive orange on the frons, but H. symmetrica can be separated from H. hardyina by the 3 large interfrontal bristles (middle pair longest), shorter apical scutellar bristles (1.5x length of basal pair), 2 posterodorsal bristles on the basal half of the mid tibia, and shorter CS2 (0.6x length of CS3).

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 20.1–20.3. Howickia symmetrica (Richards). 20.1, male habitus, lateral; 20.2, male head, anterolateral; 20.3, left wing. Body and wing scale bars indicate 0.5 mm, head scale bar indicates 0.2 mm. Photo credit: J. Lumbers.