Allometopon hirsutum, Owen Lonsdale, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 33-34

Allometopon hirsutum spec. nov.

Figs 107–112

Description. General: ( Figs 107, 108 ) Body length approximately 3.1mm. Arista short plumose. M1+2 ratio 6.6. First flagellomere enlarged, with venter and dorsum produced. Female unknown.

Chaetotaxy: Three fronto-orbital setae, anterior seta half length. Ocellar seta thin, approximately as long as tubercle. Postvertical seta very thin, shorter than tubercle. Interfrontal seta minute. Frons minutely setulose. First flagellomere along distal and anterodistal margins with hairs longer than width of base of arista. Anterior dorsocentral thin, half length of posterior dorsocentral; closely set posteriorly. Acrostichal seta absent. One small, thin lateral scutellar seta.

Colour: Setae yellow, lateral scutellar and abdominal setae brown. Antenna whitish with dorsal base of first flagellomere light brown; arista white from base to past midpoint; frons yellow with posterolateral region brownish and orbital plate with thick brown stripe not reaching anterior margin; back of head with one pair of brown stripes radiating from foramen; parafacial, gena and postgena silvery tomentose. Scutum brown with lateral margin widely dirty yellow behind suture; yellow stripe much narrower anterior to suture, with only postpronotum, notopleuron and anterolateral margin of scutum pale. Scutellum brown. Metanotum brownish, mediotergite darker dorsally. Pleuron and legs yellowish-white. Halter yellow. Wing very lightly infuscated. Abdominal tergites except anterior margin of tergite 1 dark brown; sternite 8 and epandrium excluding distal margin dark brown; surstylus and cercus light yellow.

Male terminalia: ( Figs 109–112 ) Sternite 5 with posteromedial patch of very short setae. Sternites 6 and 7 weakly sclerotized. Cerci small, ill-defined and fused. Surstylus approximately 2/3 height of epandrium and with medial longitudinal carina on outer surface; main section subtriangular with anterior margin strongly curved and posterior margin straight; with broad, shallow, shelf-like posterobasal lobe; outer surface mostly bare with several long, slightly thickened setae that continue to extend across base of lobe; lobe supporting dense brush of long, stout setae; inner surface with cluster of setae on lobe and two rows on inner-medial setae that are small and tubercle-like apically. Hypandrium band-like, mostly consisting of well-sclerotized arm; one medial seta. Phallapodeme broad and plate-like with transverse carina on deep apical dome that fuses to inner-medial section of hypandrium. Pregonite elongate with broader apical subrectangular section that has several medial setae on inner surface. Postgonite elongate and subrectangular with several small apical setae and one thickened medial seta on inner surface. Basiphallus relatively short and flat; terminating in long, flat epiphallus. Distiphallus narrow, flat, minutely textured and as long as basiphallus and paraphallus. Paraphallus leaf-like with sclerotized inner margin, tapered apex and shallow anterodorsal spinules.

Etymology: The specific epithet is Latin for "hairy", referring to the long, stout setae on the external male terminalia.

Distribution: Papua New Guinea.

Holotype: PAPUA NEW GUINEA. Morobe Province: Bubia, near Lae, 27.xii.1963, D.K. McAlpine (1♂, AMSA).

Comments: The surstylus of Allometopon hirsutum is highly diagnostic, both in its shape and in the numerous rows of long, stout, densely arranged setae that it bears. Internally, the phallapodeme is characteristic of the A. cavernosium species group, although the apical dome is especially deep and with a well-defined transverse carina; the postgonite is narrow and subrectangular with a very thick spine on the inner surface, the pregonite is broad and apically rectangular, and the distiphallus is nearly vestigial. External colouration is similar to other species with a brown ill-defined medial stripe, but this species can be diagnosed by thick brown stripe on the orbital plate and the metanotum is yellow with a dorsally brown mediotergite.

Figures

FIGURES 107 – 112. Allometopon hirsutum spec. nov., holotype; 107: photo, dorsal; 108: same, lateral; 109: holotype, external genitalia, left lateral; 110: inner surface right surstylus; 111: external genitalia, posterior; 112: internal genitalia, left lateral.