Aphaniosoma atriceps, Ebejer, 2009

Ebejer, Martin J., 2009, A revision of Afrotropical Chyromyidae (excluding Gymnochiromyia Hendel) (Diptera: Schizophora), with the recognition of two subfamilies and the description of new genera, African Invertebrates 50 (2), pp. 321-321 : 390-391

Aphaniosoma atriceps sp. n.

Fig. 36

Etymology: From Latin ater (dark) and caput (head), and refers to the distinctive (but not unique) dark brown antenna which gives the head a dark appearance.

Diagnosis: Yellow fr and contrasting dark brown antennal segment 3, very narrow gena, dark grey scutum and scut which has setae shorter than its length, tarsomere 5 of all legs brown, abdominal tg brown with narrow, pale yellow hind margins. Male postabdomen with no distinguishing external features, but internally with large dark psg and with pregenital st having ventrally projecting lobes near apex.

Description:

Male.

Head: Yellow, ocp dark grey to black, oc triangle black, fr narrow and converging anteriorly so that at level of antennae it is about 0.75 as wide as at level of anterior oc, face small, depressed and with distinct, narrow but low facial carina, eye narrow, oval, lying oblique, gena yellow, narrow, at middle about 0.3 height of eye and having numerous fine pale yellow setulae, 3 short setae at vibrissal corner, mouthparts yellow except for two small brown spots deep to proboscis an anterior margin of roof of buccal cavity, 8 setulae on fr with no longer setulae in front of oc triangle, 6 short orb, especially anterior 4, becoming progressively shorter from back to front, 1 vti and 1 vte, pvt distinct and convergent, ocellars long, divergent, antennal segment 3 dark brown contrasting with yellow segments 1 and 2, arista dark brown to base.

Thorax: Scutum and scut uniformly dark grey, mtn entirely dark grey, pprn and ntpl yellow, pleura mostly dark grey, but for narrow yellow margins to sutures. Chaetotaxy: 1 pprn, 1 posthu, 1 ihu, 2 ntpl, 0+4 ia, 1+5 acrs, 3+5 dc only the posterior one well-developed, prpl short, 1 pa, 2 pairs of marginal scut, shorter than usual compared to congeners such that subapical setae, usually the longest, are here shorter than length of scut, 1 katepisternal and several setulae on anterior part of sclerite, 1 anepisternal, all setae pale, with shorter ones and setulae inconspicuous.

Wing: Hyaline and uniformly microtrichose, veins brown, distance between R 2+3 to R 4+5 on costal margin about 0.6 that between R 4+5 and M 1+2, distance between crossveins about 1.7× length of posterior crossvein and length of apical section of Cu about 2.5× length of posterior crossvein. Haltere dusky yellow.

Legs: Yellow and fine yellow setulose, tarsomere 5 of all legs brown.

Abdomen: Brown with narrow, pale yellow hind margins to all tg, especially on sides and on apical segments.

Postabdomen: Yellow with no distinctive external features.

Female.

As male, but several specimens have diffusely infuscated femora dorsally over middle third. Postabdomen: tg 7 complete and broader laterally; cerc and hypr more sclerotized than usual among congeners; st 8 with small sclerites apically and just proximal to these, two small membraneous structures with single microtrichium in centre of each; s with short section of duct sclerotized.

Length: ơ body 1.0 mm, wing 0.9 mm; ^body 1.2 mm, wing 1.1 mm.

Holotype: ơ NAMIBIA: Khorixas District , Huab R. at Krone, 721, 20°37'09"S: 13°54'31"E, sweeping grasses and sedges, 23–26.x.1998, A.H. Kirk-Spriggs ( NMNW).

Paratypes: 2ơ 3^same data as holotype ( NMNW); 2^Walvis Bay, alt. 5 m, 22°60'S: 14°28'E, 6.ix.2003, A. Freidberg ( TAUI) .

Figures

Fig.36. Aphaniosoma atriceps sp. n.: (a) ơ hypopygium, lateral, scale bar = 0.15 mm; (b–d) ^postabdomen: (b) posterior, (c) lateral, (d) spermathecae, scale bar = 0.1 mm.