Howickia nuda, 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 : 132-134

Howickia nuda sp. nov.

( Figs. 41.1–41.8 )

Description. Body length: Males 1.3–1.9 mm, females 1.5–2.0 mm.

Head: Very dark reddish, frons, face, and lunule lighter; entire head (except antenna) shiny despite microtrichia along orbital plates, interfrontal plates and ocellar triangle; frontal vitta entirely smooth and broad; gena dark reddish; antennae orange. Frontal width 1.8x interfrontal height. Three pairs of fine interfrontal bristles, middle pair longest with tips crossing; 2 lateroclinate orbital bristles, anterior bristle 0.6x posterior bristle, preceded by several minute setulae. Ocelli absent and replaced by very fine setulae. Gena with 2–3 fine setae, very finely rugose, shiny, lower third microtrichose; vibrissal angle with 1 smaller seta. Face normal; palpus clavate with 2 large preapical setae. Eye height 2.9x genal height.

Thorax: Black; scutum shiny and devoid of microtrichia, lateral edges very slightly reddish; thorax laterally entirely black. One pair of dorsocentral bristles; 6–7 rows of long, fine acrostichal setae. Prosternum short, triangular. Scutellum shiny, subrectangular, posterior edge gently curved, almost straight, its length ~0.3x its width; 4 scutellar bristles long, basal pair 1.5x length of apical pair.

Legs: Black, femora apically orange, fore and hind tibiae orange, mid tibia reddish-brown and apically orange; tarsi orange-brown, apical 3 tarsomeres of fore leg paler. Male mid tibia with a large apicoventral bristle. Basal half of mid tibia with 2 dorsal setae (1 anterodorsal and 1 posterodorsal), distal half with 2 dorsal setae (1 anterodorsal and 1 posterodorsal).

Wing/halter: Forewing a tiny, yellowish, setulose knob. Halter absent.

Male abdomen: Black, heavily sclerotized, shiny, and lacking any microtrichia. T2–5 and S2–4 uniformly longsetose along entire surface. S5 broad but short (width 4.0x length), asymmetrical (right side 1.6x length of left), uniformly long-setose, broadly posteromedially desclerotized with 3 posteromedial rows of stout, apically-rounded setae. Epandrium moderate, uniformly long-setose; cercus small, slightly extended ventrally with numerous long setae. Hypandrium medially sinuate and very well-sclerotized; ventral lobe stout, well-sclerotized, bilobed, and apically rounded; posterodorsal lobe largely reduced. Surstylus stout, subrectangular with 3 anteroventral setae and a rounded, posterolateral lobe with several thickened, ventral, claw-like setae. Postgonite elongate, narrow, gently curved and gradually tapered, apex with a very slight apical notch. Phallapodeme elongate, sinuate; basiphallus slightly elongate, apex curled ventrally in an S-shape. Distiphallus complex, tubular, composed of several sclerites, apex with a membranous flap supported by an M-shaped distal sclerite.

Female abdomen: Black, heavily sclerotized, shiny, and lacking any microtrichia. T2–5 and S2–5 uniformly long-setose along entire surface. Preabdomen subequal in length to head + thorax. Postabdomen short, stout, 2.2x length of T5. T6 and T7 well developed and well-sclerotized with a posterior row of 6 setae. Dorsal sclerite of T8 apparently absent. Epiproct reduced, medially desclerotized with a pair of dorsal setae. Cercus short, rounded, with two long sinuate setae (1 apical, 1 dorsal) and several smaller setulae. S6 and S7 very broad, well-sclerotized, with a posterior row of 10 and 14 setae, respectively. S8 small, trapezoidal, slightly desclerotized, densely setulose with a pair of large medial setae. Hypoproct reduced, U-shaped, densely setulose with a row of 10 short setae. Spermathecae stout, spherical and entirely lightly grooved; stem elongate (1.5–1.6x length of spermatheca) and gently tapered.

Material examined. Holotype: AUSTRALIA: New South Wales: Lord Howe Island, Mount Gower , bottom of ridge north of igloo, 31˚35’06”S 159˚04’34”E, 812 m, Bubbia /Dracophyllum leaf litter, 20.xi.2001, Hutton, Flemons & Reid (♂, AMSA).

Paratypes: AUSTRALIA: New South Wales: Lord Howe Island, Mount Gower , bottom of southernmost gully, 31˚35’17”S 159˚04’23”E, 670 m, pitfall trap, 18–31.i.2002, I. Hutton (1 ♂, AMSA) ; Lord Howe Island, Mount Gower , midway down last gully, 31˚35’13”S 159˚04’19”E, pitfall trap, 18–31.i.2002, I. Hutton (3 ♂, 4 ♀, AMSA) ; same data as holotype (1 ♀, AMSA) .

Etymology. This name refers to the overall lack of microtrichia on the body (Latin ‘nudus’: unclothed, bare, naked, unadorned).

Comments. Howickia nuda is one of three species of Howickia found on Lord Howe Island, and is very easily separated from the other species, H. robustaseta sp. nov. and H. tricolor sp. nov., in having a very dark head and thorax and lacking microtrichia on the body. Howickia nuda externally resembles several dark, wingless, mainland species of Howickia (such as H. auricoma , H. cynthia , or H. holti ), but differ from all of these species in having smaller eyes, no ocelli, and no microtrichia on the body (excluding the head).

Figures

FIGURES 41.1–41.5. Howickia nuda sp. nov. 41.1, male habitus, lateral; 41.2, male head, anterolateral; 41.3, male S5–8, ventral; 41.4, male terminalia, lateral; 41.5, aedeagus and associated structures, lateral. Scale bars indicate 0.5 mm.