Allometopon cheiris, Owen Lonsdale, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 20

Allometopon cheiris spec. nov

Figs 35–39

Description. General: ( Figs 35, 36 ) Body length approximately 3.7mm. Arista short plumose. M1+2 ratio 3.5. First flagellomere slightly enlarged, ovate, higher than long, with dorsal margin more pronounced. Female unknown.

Chaetotaxy: Three fronto-orbital setae, slightly decreasing in length anteriorly. Ocellar seta thin, approximately 1.5 times length of tubercle. Postvertical seta thin, as long as tubercle. Interfrontal seta minute. First flagellomere along distal margin with hairs longer than width of arista base. Anterior dorsocentral half length of posterior dorsocentral; closely set posteriorly. Acrostichal seta present, not much larger than surrounding setulae. Two lateral scutellar setae, anterior seta smaller.

Colour: Setae yellow to brownish. Antenna yellowish-white; basal half of arista white; frons and back of head yellow, with ocellar tubercle brown and venter of back of head paler; parafacial, gena and postgena white and silvery tomentose. Scutum mostly yellow; wide brown spot on anterior margin confluent with strong, complete medial stripe between dorsocentral rows; sublateral stripe paler brown, reaching anteromedial spot, and fading posteriorly to alar base; postpronotum whitish. Scutellum brown, yellowish marginally along base of setae. Metanotum yellow with posterodorsal spot on apepisternum and broad brownish spot dorsally on mediotergite. Pleuron and legs yellowish-white. Abdomen yellow with broad dorsal stripe from tergite 2 to sternite 8.

Male terminalia: ( Figs 37–39 ) Epandrium relatively broad. Cerci separate, projecting. Surstylus nearly as large as epandrium, broadly rounded and with subrectangular posterobasal process; outer surface mostly bare excluding series of long, stout medial and posteromedial setae; inner surface with several rows of short, stout pointed setae along apical and posterior margins. Hypandrium with single seta at base of stout arm; connecting anteromedial bridge weakly sclerotized with large membranous flap covering apex of phallapodeme. Phallapodeme broad and plate-like on distal half, with thin transverse apical carina on shallow dome; laterobasal extension fused to pregonite. Pregonite subovate with several well-developed setae across surface. Postgonite long and narrow with three medial setae on inner surface. Basiphallus relatively large and developed, fused to weakly sclerotized epiphallus. Distiphallus small, narrow, minutely tuberculate. Paraphallus well-developed, slightly tapered at apex and with long spinules across dorsal surface.

Etymology: The specific epithet is Greek for "glove", referring to the shape of the surstylus.

Distribution: Papua New Guinea.

Holotype: PAPUA NEW GUINEA. East Sepik Province: Kuminibus, near Maprik, 17.xii.1963, D.K. McAlpine (1♂, AMSA).

Comments: Allometopon cheiris has a well-defined scutal stripe between the dorsocentral rows and a paler brown sublateral stripe, both of which join in the brown anteromedial region. The species is further diagnosed by two small pairs of lateral scutellars, a glove-shaped surstylus with long, thick, sparsely spaced setae on the outer surface, which is mostly bare otherwise.

Figures

FIGURES 35 – 39. Allometopon cheiris spec. nov., holotype; 35: photo, dorsal; 36: photo, lateral; 37: external genitalia, left lateral; 38: same, posterior; 39: internal genitalia, left lateral.