Usia falcata Gibbs, 2011

Gibbs, David, 2011, 2960, Zootaxa 2960, pp. 1-77 : 43-45

Usia falcata Gibbs sp. nov.

(Palte X)

Material examined. HOLOTYPE: Morocco, Middle Atlas Mts. , Azrou 4400ft, 18 June 1936 / K.H. Chapman, & G.A. Bisset., B.M. 1936-527 [♂ in BMNH] . PARATYPES: Morocco, Middle Atlas Mts. , Azrou 4400ft, 18 June 1936 / K.H. Chapman, & G.A. Bisset., B.M. 1936-527 [3♀ in BMNH]; Museum Paris, Maroc, Moyen Atlas, Azrou, R. Benoist 1928/ Foret/ 15 June 1928 [5♀ in MNHN]; Medio Atlante, Ifrane Mischliffen 2200m, 22 June 2002, P. Rosa legit [♀ in CNBFVR, ♀ in MSNM, ♀ in NMWC] .

Etymology. The name derives from the Latin “ falcatus = sickle-shaped”; referring to the epiphallus which, in lateral view, is decidedly reminiscent of a sickle blade.

PLATE X. Usia falcata Gibbs sp. nov.; a epiphallic complex ventral, b epiphallic complex lateral, c gonocoxite ventral, d gonocoxite lateral, e epandrium dorsal, f epandrium lateral, g female genitalia ventral, h female sternite 8 ventral.

Diagnosis. A medium-sized black Moroccan endemic with relatively short hairs. Only one male seen so degree of variation in this sex unknown. Hind femora with short, adpressed hairs, marginal scutellar hairs short, barely longer than half length of scutellum at mid point and mesonotum matt with shagreened surface sculpture. Male with genitalia folded tightly under abdomen, large and globular with epandrium wider than long, a few apical hairs with wavy tips, epiphallus sickle-shaped, diagnostic. Female only reliably identified by examination of genitalia (Plate X).

Description. Measurements. Body length. 3.0– 5.2mm Wing length. 2.9–5.0mm.

Male. Head. Frons relatively wide, almost a quarter head width, at narrowest point about as wide as length of third antennal segment, eye margins straight diverging evenly towards front. Rather matt, frons surface shagreened, with at most faint white-dusted spots at level of antennae, hardly extending on to anterolateral corners. Mouth margin very narrow, practically absent, broader and grey-dusted level with antennae. Ocellar triangle obtuse, lateral ocelli separated from the eye by their diameter. Longest hairs on ocellar tubercle short, about as long as width between lateral ocelli and appreciably shorter than width of frons at vertex (but these mostly lost in holotype). Occiput covered with grey dust, including area behind vertex which is hardly more shining, and relatively short black hairs, shorter above, longer below. Antennae black, relatively short, third segment long-obovate, about twice as long as scape and pedicel combined, almost bare above. Proboscis black, naked, about as long as mesonotum. Palps very small, black with small apical setae. Thorax. Entirely black, mesonotum subshining and disc decidedly shagreened effacing hair insertions, very lightly pale dusted on pronotum, postpronotal lobe, notopleuron and above wing. Hairs short, on disc of mesonotum shorter than on vertex, acrostichals tri- to quadriserial, bare paramedian lines very indistinct, narrower than acrostichal line, laterally hairs evenly distributed becoming longer on notopleuron. Scutellum subshining, shagreened, with shallow transverse striations, disc a little more sparsely haired than mesonotum, marginal hairs longer but only a few exceed half the length of the scutellum. Pleurae black, predominantly covered in thin pale dust, anepisternum shining in posterodorsal half and a narrow anterior strip, small shining patch in middle of anepimeron, katepisternum ventrally also dust free. Anepisternum with dark hairs similar to those on notopleuron in upper half and posterior margin. Wing. Tinged brownish yellow, veins pale brown. Anal lobe convex, almost as wide as anal cell. Haltere. Yellow-white knob, stem infuscated. Legs. Black, hind coxae thinly dusted, otherwise shining but with rough texture to cuticle, with very short, dark, femoral hairs, adpressed, none exceed width of tibia. Hairs shorter and denser on tibia. Abdomen. Shining black, short with rather broad tergites, rough surface sculpture of short, transverse welts at hair insertions, covered with short dark hairs, longer laterally. Sternites dusted, fairly evenly haired. Genitalia. Large and decidedly globular and retracted under the tip of the abdomen. Epandrium very wide, swollen, with blunt apical lobes furnished with longer hairs with slightly wavy tips, Tip of gonocoxite enclosed by epandrium when dry. Epandrium rather evenly covered with short, dark hairs except tip, gonocoxite with longer hairs.

Female. Very similar to male, even frons not appreciably wider, dust spots a little more conspicuous and extending on to frons along eye margins. Mouth margin noticeably a little broader. Hairs marginally shorter on thorax, bare paramedian lines a little wider, more obvious. Tergites a little longer, less densely haired. Sternite eight squarish, strongly domed basally, very short-haired with distinct, narrow apical notch. Apical processes large. Furca membranous proximally.

Discussion. Part of the U. crispa complex of species, U. falcata is the most differentiated of the four, the apical epandrial hairs not nearly as clearly wavy-tipped as in the other three species.

Distribution. Morocco. Exceedingly local, so far known from one male and 11 females from just three localities in a very small area of the Moyen Atlas at quite high altitude. Given the considerable amount of field work done by J. Dils in Morocco in recent years, if this species was much more widespread it should have been found elsewhere.