Gymnochiromyia megacephala, Ebejer, 2008

Ebejer, M. J., 2008, New species of Gymnochiromyia Hendel, 1933 (Diptera: Schizophora: Chyromyidae) from Southern Africa, African Invertebrates 49 (1), pp. 77-77 : 95-97

Gymnochiromyia megacephala sp. n.

Figs 14–16

Etymology: From Greek mega (large) and cephalos (head); after the characteristically large head.

Diagnosis: A pale yellow species with a remarkably large head, in some specimens almost as large as thorax excluding scut; markedly protruding fr and deeply recessed gena; acrs in 4–6 irregular rows at the level of the transverse suture, rapidly decreasing behind, so that at the level of the hind dc or even before there are often only two rows; no developed prescutellars; 1–2 dc, mtn yellow to brown.

Description:

Male.

Head: All yellow except for black oc triangle; fr broader than half width of head, narrowing anteriorly where at level of antennae it is 0.5 width that at level of anterior oc, and 0.6 width of one eye, viewed from in front; fr protruding above antennae. Gena markedly recessed so that it is much narrower in front than behind; below middle of eye it is about 1.2 height of eye; gena yellow with pale setulae. ocp in profile clearly visible behind eye, with short postocular setulae in one irregular row; isolated lower post-genal seta distinct. Mouthparts small, all yellow; setulae of oral margin relatively short. Face depressed poorly sclerotised except for a narrow median line.Antenna yellow, second segment paler than third, with distinct short dark seta dorsally; third segment round, finely pubescent: hairs a little shorter than diameter of arista at base; arista pale yellow and completely bare. Chaetotaxy: 3 strong orbs, anterior slightly reclinate, middle and posterior orb reclinate, all more or less equidistant from each other and with a few fine setulae on orb plate between them; in addition, about 30 fine white setulae scattered on fr; pvt very short, indistinct; 1 vti and 1 vte; oc as long as hind orb proclinate and lateroclinate.

Thorax: All yellow with pale yellowish brown markings on msn: two broad stripes from anterior margin between dc and ia lines reaching just beyond wing base, and two central stripes between the dc lines reaching half way to scutellem; scutellum, mtn and pleura yellow. Chaetotaxy: 1 hu, 1 psthu, 2 ntpl, 1 sa, 1 pa, 1 dc with a shorter one in front, acrs in 4–6 irregular rows at transverse suture decreasing markedly in number posteriorly; 1 mspl, 1 stpl.

Wing: Hyaline, veins all pale yellow, distance on costal margin between R 2+3 to R 4+5 is 0.8 that between R 4+5 and M 1+2; distance between crossveins about 0.8 length of apical section of Cu. Haltere yellow.

Legs: Not modified except for slightly thicker femora; generally fine setulae scattered on all pairs of legs and longer setae present on fore femur; claws and pulvilli normal.

Abdomen: All tg and st yellow and with pale setae, the longest about half length of tg. Postabdomen: ep a little narrower than usual for genus, cerci relatively large and finely setulose; surs long, pointed, curved and with undulating outline; hyp broad and short; ph apd well sclerotised; ej apd distinct and trapezoidal in shape; prg lobate and bare, psg similar, but appears narrow in profile; distiphallus asymmetrical and enlarged.

Female.

As in male, except for secondary sexual characters. Postabdomen ( Fig. 16 ) with characteristically shaped sclerites of st 8 each having a medially directed flange; st 7 small but strongly setose.

Length: ♂ 1.6 mm, wing 1.6 mm; ♀1.8 mm, wing 2.0 mm.

Variation: Markings on msn vary in intensity of pattern and colour; depth of gena variable but never less than eye depth and always strongly receding; distance between crossveins sometimes equal to apical section of Cu; a third short dc may be present, but this always behind suture; in darker specimens the apical 2/3 of arista may be brown, as may the larger setae on thorax; there may be anything from 0+1 to 1+4 dc, in the case of the latter the first 2 to 3 are always much shorter than the hindmost dc; the usual number of dc is 0+2.

Holotype: ♂ SOUTH AFRICA: Eastern Cape: Jeffrey’s Bay , dune vegetation, 2.xi.1978, R.M. Miller & J. Londt ( NMSA, 1179).

Paratypes: SOUTH AFRICA: Eastern Cape: 9 ♂ 5♀same data; 2 ♂ 2♀same data (MJE); 2 ♂ 2♀same data ( NMC) ; 2 ♂ 2♀same data ( NMNW) ; 2 ♂ 2♀same data ( TAU) ; 2 ♂ same data ( ZSM) ; 1♀Kleinemond , 7.x.1953, B. Stuckenberg ( NMSA) ; 4 ♂ 7♀Port Elizabeth , Zwartkops R. coastal dunes, 29.x.1964, B. & P. Stuckenberg ( NMSA) ; 1 ♂ 11♀11 km SW Alexandria Boknes , 3326DA, coastal dune vegetation, 3.xi.1978, J. Londt & R.M. Miller ( NMSA) ; 2♀same data ( ZSM) ; 1♀Transkei, The Haven , coastal dunes, 24– 28.vi.1979, 3228 Bb, R. Miller & B. Stabbins ( NMSA) . Western Cape: 2 ♂ 2♀Milnerton , i.1926, R.E. Turner (Brit. Mus. 1926-71) (NHML); 1♀Mossel Bay , 13.xii.1938, R.E. Turner (Brit. Mus. 1939-56) ( NHML) ; 1♀2.5 mi. S Elandsbaai , coastal sand dunes, 30 ft, 16.xi.1972, M.E. & B.J. Irwin ( NMSA) ; 1♀Arniston , 10 m, low coastal dunes, 22.viii.1973, M.E. Irwin ( NMSA) . KwaZulu-Natal: 1♀15 km NE Howick, Karkloof falls , 1500 m, 14.ii.1979, R.M. Miller ( NMSA) .

Figures

Figs 14, 15. G. megacephala sp. n.: (14) male hypopygium, lateral view; (15) head, lateral view. Scale bars = 0.2 mm.

Fig. 16. G. megacephala sp. n., female postabdomen, ventral, with sap omitted (a) and lateral (b) views, and (c) spermatheca, enlarged. Scale bars = 0.2 mm.