Allometopon infernum, Owen Lonsdale, 2016

Owen Lonsdale, 2016, Revision of the genus Allometopon Kertész (Diptera: Clusiidae), Zootaxa 4106 (1), pp. 1-127 : 36

Allometopon infernum spec. nov.

Figs 125–130

Description. General: ( Figs 125, 126 ) Body length 3.0– 3.4mm. Arista sparsely plumose. M1+2 ratio 3.4–4.0. Female unknown.

Chaetotaxy: Three fronto-orbital setae (decreasing in size anteriorly). Ocellar seta well-developed. Postvertical seta as long as ocellar tubercle. Interfrontal seta absent. Anterior dorsocentral seta half length of posterior seta (closely set posteriorly). Acrostichal seta present. Anterior lateral scutellar seta small.

Colour: Setae yellow to brownish, darker on abdomen. Head predominantly yellow; first flagellomere with wide dorsobasal stripe; ocellar tubercle brown; back of head with one pair of stripes radiating from foramen (broadly joined above foramen in one paratype); face light yellow and pilose; gena and postgena white and silvery tomentose. Scutum yellow with anterior and lateral margins brown (narrowest postsuturally and anteromedially, possibly entirely yellow at centre); one short stripe between dorsocentral rows that is only dark laterally, almost appearing as one pair of small narrow stripes blending medially (mostly destroyed / obscured by pin in holotype). Scutellum brown. Metanotum brown lateral to scutellum. Pleuron and legs light yellow. Wing lightly clouded apically, becoming slightly darker anteriorly. Halter white. Abdomen brown with surstylus and cercus yellow.

Male terminalia: ( Figs 127–130 ) Cerci well-defined, pointed and separate, without intervening membrane on distal half. Surstylus nearly as high as epandrium, angled posteriorly, with small, shallow, uneven basal projections on anterior and posterior margins; outer surface mostly bare and with minute setae apically; distal 2/3 with small, tubercle-like setae on inner surface of apical and posterior margins. Hypandrium fused to adjoining annulus laterally and anteromedially, with two pairs of setae on medial lobe. Phallapodeme rod-like, with broad, nearly circular ventral shield below margin of hypandrium. Pregonite membranous, with basal seta. Postgonite welldefined, length more than twice width, with several apical setae. Basiphallus well-developed, with small process confluent with minutely spinulose membrane underneath very long, arched epiphallus. Distiphallus and paraphallus absent.

Etymology: The specific epithet refers to the warm colouration of the type specimens.

Distribution: Australia (QLD).

Holotype: AUSTRALIA. Qsld., 1913, Brunetti, B.M. 1927–184 (1♂, BMNH).

Paratypes: AUSTRALIA. N. Qld. Mossman Gorge, 24.iv.1967, D.H. Colless (2♂, ANIC).

Comments: Allometopon infernum is the likely sister-species to A. striatum ( Figs 258, 259 ), also from Queensland, and the two cannot be confidently differentiated on the basis of external characters. Male genitalic morphology are also highly similar, but A. infernum has a more slender surstylus; the surstylus of A. striatum has a characteristic subtriangular protrusion at about the midpoint of the posterior margin. Both have a very long, arched epiphallus, but that of A. infernum is longer and covering a minutely spinulose membrane. Allometopon infernum also has a weaker pregonite and the distiphallus and paraphallus are missing, without any evidence that these structures were broken off, although verification following the collection of more material is required.

Figures

FIGURES 125 – 130. Allometopon infernum spec. nov., holotype; 125: photo, dorsal; 126: same, lateral; 127: external genitalia, posterior; 128: same, left lateral; 129: internal genitalia, ventral; 130: same, left lateral.

FIGURES 258 – 263. Allometopon striatum McAlpine; 258: darker male, photo, dorsal; 259: female, photo, dorsal; 260: same, lateral; 261: external genitalia, left lateral; 262: same, posterior; 263: internal genitalia, left lateral.