Allometopon tenebrae, Owen Lonsdale, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 60-61

Allometopon tenebrae spec. nov.

Figs 269–270

Description. General: ( Figs 269, 270 ) Body length approximately 3.3mm. Arista short plumose. M1+2 ratio 3.3–3.8. First flagellomere ovate, higher than long. Female unknown.

Chaetotaxy: Three fronto-orbital setae, anterior seta ¾ length. Ocellar seta more than twice length of tubercle. Postvertical seta absent. Interfrontal seta minute. Frons minutely setulose. 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 absent. One or two small lateral scutellar setae.

Colour: Setae yellow, brownish dorsally, darker on abdomen. Antenna yellowish-white with brown stripe above process of pedicel that fades anteriorly; basal half of arista white; frons dark brown with yellow anteromedial spot, very thin yellowish margin along eye and yellowish region anterior to base of vertical setae; back of head brown above foramen with yellowish dorsomedial spot; remainder of head yellowish-white; parafacial, gena and postgena silvery tomentose. Notum dark brown. Pleuron and legs yellowish white, with posterodorsal region of anepisternum faintly to distinctly brown, at least along dorsal margin. Halter yellow. Wing slightly clouded, clear posteriorly. Abdominal tergites, sternite 8 and epandrium excluding distal third dark brown.

Male terminalia: ( Figs 271–274 ) Length of sternite 5 half width, sparsely setose anteriorly, with thin postermedial line of weakness. Sternites 6 and 7 weakly sclerotized, reduced. Cerci separate but weakly defined. Surstylus long setose on outer surface with bare anteromedial and apical regions; shape globular and convoluted, with small rounded posterobasal lobe and short, curved inset apical lobe with stout, short setae on inner surface. Sternite 6 weakly fused to hypandrium; hypandrium weakly sclerotized anteriorly; with one seta. Phallapodeme broad and plate-like on distal half with extension fused to pregonite, and with thin transverse carina across domelike apex that is partially fused to hypandrium; strongly bent at midpoint and minutely spinulose ventrobasally. Pregonite ill-defined, flat, with well-developed medial setae. Postgonite slightly elongate with two apical setae. Basiphallus relatively long, partially fused to small, weak epiphallus on suspended plate. Distiphallus short, narrow, with minute tubercules in two narrow bands that join apically. Paraphallus large and well-developed with broad membranous base that tapers apically and with long spinules along dorsal band.

Etymology: The specific epithet is Latin for “shadows”, referring to the dark dorsum and the small brown infuscation on the anepisternum, which aids in differentiating this species from other similar taxa in the species group.

Distribution: Papua New Guinea.

Holotype. PAPUA NEW GUINEA. Central Province: Aroa R., Kanosia Estate, 8.xii.1963, D.K. McAlpine (1♂, AMSA).

Paratypes: PAPUA NEW GUINEA. Central Province: same collection as holotype (1♂, AMSA), Musgrave R. near Pt. Moresby, 950 ft., 8.xii.1963, D.K. McAlpine (2♂, AMSA), East Sepik Province: Imbia, near Maprik, 14.xii.1963, D.K. McAlpine (1♂, AMSA), Morobe Province: Bubia, near Lae, 27.xii.1963, D.K. McAlpine (1♂, CNC).

Comments: Allometopon tenebrae is characteristic within the A. cavernosium species group in being mostly dark dorsally and having at least a minor infuscation dorsally on the anepisternum, with the pleuron being otherwise yellow to white. Also see comments for A. lunatum .

Figures

FIGURES 269 – 274. Allometopon tenebrae spec. nov., holotype; 269: photo, dorsal; 270: same, lateral; 271: external genitalia, left lateral; 272: same, posterior; 273: internal genitalia, left lateral; 274: detail of paraphallus and distiphallus, ventral.