Trichopsomyia pilosa, Steenis & Wyatt, 2020

Steenis, Jeroen van & Wyatt, Nigel P., 2020, The first species of Trichopsomyia Williston, 1888 (Diptera: Syrphidae) described from the Oriental region, with a discussion on the character states of the pilosity of the katepisternum, European Journal of Taxonomy 687, pp. 1-12 : 3-6

Trichopsomyia pilosa sp. nov.

urn:lsid:zoobank.org:act:D4A23D4B-FCAC-4BEC-8B81-2583953DA34E

Figs 1–2 , 3C

Diagnosis

Large, predominantly black and long black pilose pipizine; thorax black, extensively black pilose; wing brown infuscated; cell c wide; legs black with long pilose tarsi and metaleg; terga II and III with large rectangular brownish antero-lateral maculae; genitalia ( Fig. 2 ) epandrium elongate; surstylus bilobed with rather long baso-dorsal process and with very long, elongate and slightly sickle-shaped narrow, elongate ventral process; hypoproct (see Downes et al. 2017) mushroom shaped, shaft on ventral surface densely but short pilose; hypandrium narrow, elongate with elongate rectangular process; postgonite (see Downes et al. 2017) dome-shaped in lateral view, with several small tooth in two rows on apicoventral surface.

Etymology

The specific epithet ʻpilosaʼ, the Latin word for ʻhairyʼ, refers to the extensively and long pilose katepisternum, the long pili on the metasternum and especially the long pilose metatibia. The name is to be treated as an adjective.

Type material

Holotype

INDONESIA – Java • ♂; “ Java: // Tjigaeha // i.1938 // coll. E. le Moult ”; “QR-code // NHMUK 010864268 ”; NHM.

Paratypes

INDONESIA – Java • 1 ♂; same collection data as for holotype; “ NHMUK 010864267 ”; JSA • 1 ♂; “ Java: // Gunung Malang // Djampang Wetan // ii.1938 // coll. E. le Moult ”; “QR-code // NHMUK 010864266 ”; NHM .

Description

Male

LENGTH. Body 9.7–11.4 mm, wing 8.2–9.3 mm.

HEAD. Facial shape simple, in lateral view, almost straight, without central knob and without antennal tubercle; oral cavity round, smooth without notch; clypeus horse-shoe shaped; face black, black pilose; frons black, black pilose with two small white pollinose maculae laterally along eye margin ( Fig. 1C ); vertical triangle black, black pilose; eye pilose; postocular orbit dorsally broad; eye-contiguity relatively short, about a quarter as long as length of vertical triangle; antenna ( Fig. 1D ) orange-brown, elongate, basoflagellomere four times longer than broad.

THORAX. Black, extensively pilose; postpronotum pilose; katepisternum almost entirely pilose, only narrowly bare antero-dorsally and medially along posterior margin ( Fig. 3C ); katepimeron pilose; metasternum rather well developed with some pile medio-laterally.

WING. Membrane entirely brownish infuscated ( Fig. 1 A–B) covered with unusually long microtrichia, except bare on basal ¹⁄10 of cell bm; cell c exceptionally wide, clearly wider than cell bm; vein dm-cu ending almost perpendicularly to vein M; vein M 1 ending strongly oblique at vein R 4+5.

LEGS. Black, except apical half of basitarsi, and tarsomeres 2–4 white; pile long and predominantly black, but white parts of tarsi with long white pile; metaleg ( Fig. 1E ) with femur narrow and elongate, but slightly thickened and more densely long pilose apically; metatibia broad, laterally compressed and densely long-haired, hairs on dorsal surface longer than width of tibia.

ABDOMEN. Black and rather long black pilose; terga II and III each with one pair of large rectangular yellowish-brown maculae; pregenital terga black pilose.

GENITALIA ( Fig. 2 ). See under diagnosis and remarks.

Female

Unknown.

Remarks

According to the description and figures in Downes et al. (2017), our species is similar to the Australian Trichopsomyia formiciphila Downes, Skevington & Thompson, 2017 based on the overall appearance of the species and especially the extent of pilosity on the katepisternum, the shape of the metasternum, the colour of the legs and abdomen, the long basoflagellomere and the infuscated wing with wide cell c. Trichopsomyia pilosa sp. nov. differs from T. formiciphila by the long white pile on the tarsi, the very long black pile on the metatibia and several characters in the male genitalia like the surstylus with the apico-medial surface weakly and short pilose (more densely and long pilose in T. formiciphila ); the shape of surstylus in ventral view weakly curved (more strongly curved in T. formiciphila ); and the apico-dorsal gonocersus with weak teeth in two rows (stronger teeth present, not aligned in clear rows in T. formiciphila ).

Figures

Fig. 1. Trichopsomyia pilosa sp. nov. A. Habitus, lateral view, holotype ♂ (NHMUK 010864268). B. Habitus, dorsal view, paratype ♂ (NHMUK 010864266). C. Head, dorsal view, paratype ♂ (NHMUK 010864266). D. Antenna, lateral view, holotype ♂ (NHMUK 010864268). E. Metaleg, frontal view, paratype ♂ (JSA). Scale bars: A–C, E = 1.0 mm; D = 0.5 mm.

Fig. 2. Trichopsomyia pilosa sp. nov., male genitalia, holotype (NHMUK 010864268). A. Lateral view. B. Epandrium, dorsal view. C. Apical part of hypandrium, ventral view. Scale bars = 0.5 mm.

Fig. 3. Pilosity of the katepisternum, ventro-lateral view. A. Scaeva pyrastri (Linnaeus, 1758), ♂ (JSA), Switzerland, with extensive pilosity. B. Psilota atra (Fallén, 1817), ♂ (JSA), the Netherlands, with extensive pilosity. C. Trichopsomyia pilosa sp. nov., paratype ♂ (JSA), with extensive pilosity. D. Trichopsomyia joratensis Goeldlin, 1997, ♀ (JSA), Belgium, with separated dorsal and ventral pile patch. Scale bars = 0.5 mm. a = ventral pile patch; b = antero-dorsal area; c = postero-medial margin; d = dorsal pile patch.