Allometopon machaeroges, Owen Lonsdale, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 41

Allometopon machaeroges spec. nov.

Figs 157–161

Description. General: ( Figs 157, 158 ) Body length 2.9mm. Arista short plumose. M1+2 ratio 2.0. Arista pubescent. First flagellomere enlarged and lobate above angulate extension of pedicel. Female unknown.

Chaetotaxy: Three fronto-orbitals, anterior seta 3/5 length. Ocellar seta nearly twice length of tubercle. Postvertical minute. Interfrontal seta small but well-developed. First flagellomere with longer hairs along margin. Anterior dorsocentral half length of posterior dorsocentral; closely set posteriorly. Acrostichal seta longer than scutellum. One short lateral scutellar positioned in front of apical scutellars.

Colour: Setae yellow, darker dorsally on abdomen. Head yellow with brown stripe on first flagellomere (dorsal ¼ of inner surface, dorsal 1/3 of outer surface), inner margin of parafacial and ventral margin of gena with shiny orange strip, ocellar tubercle brown, distal half of palpus dark brown, clypeus brownish, and back of head with brownish pigment below ocellar tubercle and with one pair of narrow, irregular brownish lines radiating from foramen dorsally; remainder of parafacial, gena and anterior half of postgena silvery tomentose. Thorax and legs yellow with pleuron, coxae and base of femora paler except for large brown spot on anepisternum. Wing clear. Halter white. Abdomen yellow with broad brown dorsal stripe from tergite 2 to sternite 8; epandrium brown; surstylus and cerci yellowish-white.

Male terminalia: ( Figs 159–161 ) Annulus well-developed, segmentation indistinct. Epandrium with anterolateral margin broadly lobate and with small process dorsally. Cercus small, lobate, with small setae. Surstylus large, higher than epandrium, broadly arched and sickle-shaped with broad, blunt apex; outer surface setose posteriorly, apical and posterior margins lined with tubercle-like setae on inner surface, and anterobasal lobe bare externally but with stout pad of long setae internally. Hypandrial lobe reduced to long, stout arm; with two setae on arm and one floating in membrane confluent with pregonite. Phallapodeme rod-like with stout, dome-like ventral shield. Pregonite ill-defined, elongate globose and with three setae. Postgonite, small, lobate, with two small setae. Basiphallus small, separated from keel-like epiphallus. Distiphallus simple, less than half length of phallapodeme, broader at base. Paraphallus well-developed with sclerotized base, broad, minutely spinulose patch dorsomedially, and clear tapered apex.

Etymology: The specific epithet is derived from the Latin for a large curved sword (L. machaera), referring to the shape of the surstylus.

Distribution: Ivory Coast.

Holotype: IVORY COAST. Lamto Res. Sta., 6˚13′N, 5˚02′W, Malaise trap, 4.viii.1988 (1♂, ROME).

Comments: Characteristic of Allometopon machaeroges are a long prescutellar acrostichal seta and pale colouration. This includes a pale thorax, head and setae, excluding some brownish patches on the first flagellomere and the back of the head, as well as a strong brown spot on the anepisternum. The large, broadly arched surstylus is also diagnostic, with a thick, tuberculate apex and large basal lobe with a patch of long, stout setae. The holotype is the only known specimen from continental Africa, located far from A. glochis , A. fuscinum and A. female 5 in Madagascar and A. flavum in Seychelles, suggesting a much more diverse Afrotropical fauna than is presently understood.

Also see comments for Allometopon eotoxon .

Figures

FIGURES 157 – 161. Allometopon machaeroges spec. nov., holotype; 157: photo, dorsal; 158: same, lateral; 159: external genitalia, left lateral; 160: same, posterior; 161: internal genitalia, left lateral.