Scelomyza hirticornis Séguy, 1938

ROHÁýEK, JindĜich, 2014, The identity and family affiliation of Scelomyza hirticornis (Diptera: Opomyzidae, Anthomyzidae), with a new checklist of Afrotropical Anthomyzidae, Acta Entomologica Musei Nationalis Pragae 54 (1), pp. 383-398 : 389-394

Scelomyza hirticornis Séguy, 1938

( Figs 1–19 )

Scelomyza hirticornis Séguy, 1938: 339 ; STUCKENBERG (1980): 635 (catalogue).

Type material. HOLOTYPE: ♀, labelled: “ KENYA, Kitale, UASIN GISHU, 2.100 m ”, “ MUSÉUM DE PARIS, Mission de l’Omo ”, “C. ARAMBOURG, P.-A. CHAPPUIS & B. JEANNEL 1932-33” (blue label), “ TYPE ” (red), “ Scelomyza hirticornis Génotype [handwritten by Séguy], E. SÉGUY det. 1934”, “Prépar. Microsc. n° 3109. aile.”, “ Holotypus ♀, Scelomyza hirticornis Séguy, J. Roháþek det. 2013” (red). Microscope slide (with both wings) labelled: “ Scelomyza hirticornis [handwritten], HOLOTYPE ” (red). All deposited in the Muséum National d’Histoire Naturelle, Paris, France.The specimen is glued on a pinned rectangular card; it is severely damaged, with both wings removed and mounted on slide (one wing broken into two parts), head and thorax with most bristles having been detached, with all legs originally glued to card but some of their parts removed from the glue during the course of this study and preserved together with the detached tip of the abdomen in glycerine in a sealed plastic tube pinned below the specimen.

Redescription. Male. Unknown. Female. Total body length ca. 1.9 mm; bicolourous, dark brown to black (head, abdomen) and largely orange-brown (thorax), mostly shining ( Fig. 1 ), with sparse or absent microtomentum. Head markedly higher than long ( Figs 2 , 5 ), rounded anteriorly in pro¿le, with frons unusually short and occiput high, largely dark brown to black. Occiput broadly concave, almost black and lustrous, only dorsomedially, behind ocellar triangle, somewhat microtomentose. Frons very short, twice as wide as long, with darker, almost black, less microtomentose, more shining and long frontal triangle, and with brown, less shining and grey microtomentose area between orbits and frontal triangle. Orbit poorly delimited, paler brown anteriorly, darkened posteriorly, less microtomentose and more lustrous than adjacent area. Frontal triangle very long but relatively narrow, reaching to anterior margin of frons. Ocellar triangle small, unusually shifted posteriorly, somewhat behind top of vertex ( Fig. 5 ), black and very little elevated; ocelli reduced, minute. Frontal lunule brown, small but rather wide, poorly visible above antennal scapes. Face relatively narrow, medially concavely folded, largely brown, with microtomentum not visible in the damaged holotype. Parafacialia and gena ochreous, distinctly lighter than face but their microtomentum damaged and hence undescribed. Postgena markedly dilated ( Figs 2 , 5 ), brown to blackish brown. Mouthparts reddish or orange brown; palpus paler orange. Cephalic chaetotaxy (reconstructed from basal scars, photos and original illustrations by SÉGUY 1938, see Figs 5, 8 ): pvt present, widely spaced, small and hair-like; oc present, probably rather weak and not very long; both vte and vti present but their length unknown, obviously longer than oc; only 1 long and strong ors, surely the longest of cephalic setae ( Fig. 5 ), and 2 subequal microsetulae in foremost part of orbit (lateral to antennal base); no medial microsetulae observed; postocular setulae (number unknown, 13 visible in SÉGUY 1938: Fig. 16 ; see also Fig. 8 ) in single row; lateroventral corner of occiput and postgena with a few scattered setulae and 2 posteroventral ¿ne setae; 1 distinct strongly inclinate vi (not observed by SÉGUY 1938 but see Figs 2 , 5 ); subvibrissa probably strongly reduced, hair-like, similar to ¿ne peristomal setulae which are rather numerous (about 10) but obviously fewer than SÉGUY (1938: Fig. 16 ; see also Fig. 8 ) described and illustrated. Palpus slender, with a few pale setulae on apex (1 longer). Eye large, irregularly subovoid in lateral view, with longest diameter subvertical, slightly oblique and about 1.25 times as long as shortest diameter. Eye with ommatidia distinctly enlarged in anteroventral part (cf. Fig. 9 ). Gena very short, shortest height only about 0.06 times as long as shortest eye diameter. Antenna strongly geniculate ( Figs 3 , 5 ); scape small, almost black; pedicel brown, distinctly capiform and bearing 2 long setae (thicker dorsal, weaker ventral) and series of marginal setulae ( SÉGUY 1938: Fig. 16 erroneously depicted them on “large” scape, the latter being in fact basal part of pedicel, see Fig. 8 ); 1st flagellomere orange-yellow (see Figs 3 , 5 ), laterally flattened, of distinctive reniform shape with concave anterior margin and projecting apex, having strikingly long pale setae on tip (3 longer, 1 longest – the latter reconstructed from basal remnant visible in Fig. 3 and Séguy’s illustration in Fig. 8 ). Arista about 2.2 times as long as antenna, dark brown, with distinctly thickened basal segment; basal part of arista with short and dense ciliae, distal flagellum with long brownish cilia (particularly dorsally – see Fig. 3 ), thus subpectinate.

Thorax distinctly narrower than head, bicolour, largely orange brown (including pleura and scutellum) but with distinctive dark brown area covering dorsal part of pronotum and anterior part of mesonotum up to suture ( Figs 1, 4 ), distinctly shining (more laterally) despite sparse microtomentum on mesonotum. Mesonotal microsetae reduced in number; macrosetae relatively long. Thoracic chaetotaxy (reconstructed): 1 reduced, hairlike hu; 2 distinct npl (posterior only half length of anterior); no prs; probably 1 small sa; 1 pa (shorter than posterior npl); 2 long and strong postsutural dc (posterior very long, longest of thoracic setae, anterior not preserved but surely shorter and weaker) and at least 3 dc microsetae in front of them; ac microsetae apparently entirely absent; 2 sc, laterobasal small, hair-like and pale, apical of moderate size (according to SÉGUY 1938, setae not preserved); ppl microseta not visible; 2 distinct and relatively long but thin stpl, anterior somewhat shorter and weaker; ventral part of sternopleuron probably with a few setae (not clearly visible). Scutellum rounded triangular, somewhat convex dorsally; subscutellum distinctly developed.

Legs slender, largely yellow, only fore tibia and fore basitarsus (see Fig. 7 ) blackish brown and contrasting with remaining parts of fore leg. f 1 apparently with ctenidial spine ( Fig. 7 , ct) but its length is unknown (broken off on both front legs), and with a number of other, not very long and ¿ne setae (longest posterodorsally and posteroventrally); fore basitarsus with very dense dark setosity ventrally being distinctly prolonged in proximal ¿fth ( Fig. 7 ); f 2 with some thicker and longer setae on both anterior and posterior side, particularly in distal third; t 2 with ventroapical seta short, hardly longer than maximum width of tibia ( Fig. 6 ), otherwise uniformly setulose; also hind leg and remaining parts of fore and mid leg simply setulose.

Wing ( Figs 10, 11 ) narrow and relatively short (about as long as body length), widest in distal third, with ochreous veins and unpatterned, hyaline, light ochreous membrane. C with distinct spinulae between apices of R 1 and R 2+3. Sc apically fused with R 1 and preapical kink on the latter distinctly developed. R 2+3 long, bent parallel to C, with apex hardly upcurved to C; R 4+5 very slightly bent (recurved) and apically subparallel to almost straight M. Discal (dm) cell narrow and relatively long, with r-m situated distinctly in front of the middle of dm cell. Apical portion of CuA 1 slightly longer than dm-cu, and reaching (with its colourless end) wing margin; A 1 very short, ending far from it. Alula small and very narrow; also anal lobe strongly reduced. Wing measurements: length ca. 1.95 mm, width 0.62 mm, Cs3: Cs4 = 1.05, rm\dm-cu: dm-cu = 4.12. Haltere orange, with darker stem.

Abdomen (except for postabdomen) not cleared and therefore described only super¿cially. Preabdominal terga ( T1 – T5 ) blackish brown to black, very sparsely greyish microtomentose and strongly shining ( Fig. 1 ), all with relatively sparse and short setae. T1 and T2 at least partly (dorsally) separate. T3 – T5 large and broad, subequal in length but T5 narrower, all bent onto ventral side of abdomen. Preabdominal sterna S2–S5 poorly visible in the holotype but also relatively broad, well sclerotized, blackish brown, shining ( Fig. 1 ) and sparsely setose like associated terga ; their shape cannot be described.

Postabdomen (partly reconstructed including chaetotaxy, see Figs 12, 14, 15 ) relatively short and wide. T6 very large ( Fig. 12 ), only somewhat smaller than T5 , blackish brown, broad anteriorly and narrowed posteriorly, sparsely setose, with longest setae in front of posterior margin and on posterolateral corners. S6 relatively broad, distinctly transversely trapezoid, brown, with slightly denser setae than on T6 . T7 completely fused with S7 to form annular synsclerite (tergosternum) T7 +S7 without trace of borders of sclerites, with 7th spiracle laterally near anterior margin (see Fig. 15 ). Dorsal part of T7 +S7 somewhat shorter than ventral part, with large semicircular paler brown area ( Fig. 12 ) but laterally and posteriorly blackish brown as is entire ventral part of T7 +S7 ( Fig. 14 ). Tergosternum T7 +S7 much narrower than T6 , somewhat tapered posteriorly, with setae sparser dorsally than laterally and ventrally. T8 not very small, forming simple square pale brown plate with rounded posterior corners ( Fig. 12 ), with a few setae (longest in latter corners) and sparse microtomentum restricted to anterior half. S8 of distinctive form, medially divided and short ( Fig. 14 ), laterally lobately prolonged anteriorly (cf. Fig. 15 ) but with poorly delimited margins. S8 densely micropubescent (as are all membranous parts of 8th segment) and shortly setose, with single long (sublateral) seta. Genital chamber (uterus) with weakly sclerotized internal structures: annular sclerite ( Figs 18, 19 ) very thin, transversely compressed and loop-shaped ; posterior paired sclerites (situated close to genital opening) weakly sclerotized and only ventrally pigmented, of poorly de¿ned shape ( Fig. 18 ). Distal part of genital chamber damaged (torn off) and, consequently, the ventral receptacle and accessory glands could not be examined. Spermatheca (probably 1+1 but only one preserved in postabdomen) small, obviously subspherical, with plain surface and long, well-sclerotized and dark cylindrical collar (reconstructed from damaged/indented spermathecal body and detached duct, cf. Figs 16, 17 and 13 ). T10 small, transverse, saddle-shaped, thus with both sides bent ventrally, pale brown and bare (without micropubescence), only 1 pair of very medial setae (see Figs 12, 15 ). S10 markedly larger than T10 , unusually long, longer than broad and slightly tapered anteriorly, shortly trough-shaped ( Fig. 14 ), with a few ¿ne setulae at posterior margin and micropubescence restricted to two lines in front of the latter. Cercus relatively short (particularly dorsally, Fig. 12 ), with a number of ¿ne setae (mostly broken off in the holotype), the apical and dorsopreapical being probably longest (judging from largest basal scars observed) .

Discussion. Scelomyza hirticornis Séguy, 1938 can be readily distinguished from all other described Afrotropical species (for ¿rst checklist of them see below) by the unusually long setose antenna ( Figs 3 , 5 ), shiny body, orange-brown thorax with anterior blackish brown area ( Fig. 4 ) and lustrous black abdomen combined with unicolour hyaline wings and fore femur armed with ctenidial spine ( Fig. 7 ).

Biology. Unknown. The holotype female was collected at altitude 2,100 m; date of collection not given.

Distribution. Kenya: Uasin Gishu province, SE of Kitale town.

Figures

Figs 1–4. Scelomyza hirticornis Séguy, 1938, female holotype (before dissection). 1 – body in lateral view; 2 – head, laterally; 3 – antenna, laterally; 4 – head and thorax, dorsally. Body length of the specimen = 1.9 mm. Photo by J. W. van Zuijlen.

Figs 5–9. Scelomyza hirticornis Séguy, 1938, female holotype. 5 – head sublaterally, reconstruction; 6 – left mid femur and tibia, posteriorly; 7 – left fore trochanter, femur, tibia and basitarsus, posteriorly, chaetotaxy of femur reconstructed; 8 – original illustration of head by SÉGUY (1938), laterally; 9 – ditto, frontally.All scales = 0.25 mm. For abbreviations see text (p. 385).

Figs 10–11. Scelomyza hirticornis Séguy, 1938, female holotype. 10 – right wing, reconstructed from two parts on Séguy’s original slide; 11 – left wing, from the same slide. Wing length cca 1.95 mm. Photo by J. Roháþek (10) and J. W. van Zuijlen (11).

Figs 12–19.Scelomyza hirticornis Séguy, 1938, female holotype.12 – postabdomen,dorsally; 13 – spermatheca, shape reconstructed; 14 – postabdomen, ventrally; 15 – ditto, laterally (chaetotaxy and shape of sclerites reconstructed); 16 – spermatheca, original condition; 17 – terminal part of spermathecal duct; 18 – internal sclerites of genital chamber, laterally; 19 – annular sclerite in genital chamber, ventrally. Scales = 0.1 mm (Figs 12, 14, 15), 0.03 mm (Figs 13, 16, 17) and 0.05 mm (Figs 18, 19). For abbreviations see text (p. 385).