Usia versicolor (Fabricius, 1787)

Gibbs, David, 2011, 2960, Zootaxa 2960, pp. 1-77 : 73-76

Usia versicolor (Fabricius, 1787)

( Figs. 10 & 11, Plate XXII)

Bombylius versicolor Fabricius, 1787: 367 .

Type material of B. versicolor examined. LECTOTYPE here designated: Tunisia, Type / V. versicolor , Tunis Vake / ZMUC 00503995 [♂ in ZMUC, hairy labium form).

Other material examined. Typical form—hairy labium

Algeria, 7 km E of Timgad , 1200m, 4 May 1980 [♂ in PCJD] . Italy, Puglia, Castel del monte, N41º03'45" E16º13'37" 300m, 16 March 1997, leg. J. Dils [♀ in PCJD]; 22 April 1996, leg. J. Dils [3♂ 2♀ in PCJD]; San Giovani, N41º40'32.2" E15º43'42.2" 480m, 18 March 2002, leg. J. Dils & J. Faes [♀ in PCJD]; Foggia , Cagnano varano, 200m, N41º48'33" E15º47'50" 21 April 1996, leg. J. Dils [♀] . Malta, Wied Incira, 28 March 1985 NMW.Z. 1985-032, leg. M.J. Ebejer [2♂ 2♀ in NMWC]; San Anton gardens 13 April 1985 [♀ in NMWC]; Wied il- Qirda 5 April 1985, leg. M.J. Ebejer [♀ in NMWC ); Gozo, Dwejra , 10 April 1993 NMW.Z. 1985-032, leg. M.J. Ebejer [2♀ in PCME, others in NMWC]; Cospicua, 1.iv.1985, leg. Schmid-Egger [2♀ in PCJD]; Wied az Zureiq, 2 April [19]70, leg. D.J. Greathead [♀ in BMNH]; Ghar il-Khibr 8 April 1978, leg. P. Schembri [♀ in BMNH] . Spain, Sevilla, [leg.] Cazurro / M.N.C.N., Madrid [2♂ MNCN] . Tunisia, Kesra, dam, 5km N. Kesra 990m, N35º51'21" E9º23'35.62", 1 May 2005, leg. D.J. Gibbs [2♂ 4♀ in PCDG] .

Intermediate specime n. Morocco, Casablanca 15–19 February 1918, Museum Paris, Maroc, Casablanca, R. Benoist 1919 [♂ in MNHN] .

Atlas form—bare labium. Morocco, Middle Atlas Fas. N of Fesel Bali 8 April 1986, leg. A.H. Kirk-Spriggs [♂]; Azilal, Afourer 800m N31º11'32.8" W6º31'20.4" 8 April 2006, leg. J. Dils & J. Faes [1 pair in cop, 6♂ 14♀ in PCJD]; Khemisset, Oulmes R 701 470m N33º33'23.9" W5º53'10.5" 17 April 2007, leg. J. Dils & J. Faes [6♂ 2♀ in PCJD]; Marrakech, Oukaimeden 2200m N31º14'0.6" W7º49'1.4" 12 April 2006, leg. J. Dils & J. Faes [2♂ in PCJD]; Tizi-n-Test 1450m N30º55'55.9" W8º16'19.7" 30 March 2006, leg. J. Dils & J. Faes [♀ in PCJD]; Taferiate 940m N31º32'35.2" W7º32'7" 6 April 2006, leg. J. Dils & J. Faes [♀ in PCJD] .

Etymology. From the Latin “ versicolor = various colours”.

Diagnosis. Male unmistakable, even in the field, due to dense olive brown dusted mesonotum and abdomen, the latter warm rufous to bright orange on disc. Both sexes readily identified by long, bristly black hairs and patch of small sub-erect black bristles on mid tibia apicoventrally.

Redescription. Measurements. Body length. 2.5–5.4mm Wing length. 2.5–5.5mm.

Typical form—long -haired labium

Male. A very distinctive densely dusted, colourful species, this sex not confusable with any other known species. Head. Frons relatively narrow, about a fifth head width, at narrowest point as wide as labrum viewed dorsally, shining on medial third, laterally grey dusted, in some the dusting coalescing in front of front ocellus. Mouth margin narrow, linear, but quite apparent throughout, entirely shining black-brown. Ocellar tubercle shining black, the ocellar triangle equilateral, lateral ocelli separated from the eye by a little over half their diameter. Longest hairs on ocellar tubercle almost twice as long as width across frons at vertex, black and almost bristle-like. Occiput covered with dense olive-brown dust obscuring ground colour, a little more thinly so on triangular area behind vertex and laterally thinner still such that black ground colour shows through. Black hairs on occiput just a little longer below than above, no hairs longer than hairs on ocellar tubercle. Antennae black, relatively long, third segment elongate, slightly narrowed apically, about twice as long as scape and pedicel combined. Antennae with very short dorsal hairs, a few longer ones usually apparent just before apical sulcus. Proboscis black, relatively short, about as long as mesonotum and scutellum, labrum naked but labium with short, reclinate lateral hairs in apical half and much longer proclinate lateral hairs medially. Palps small, black, clavate with long, strong apical setae. Thorax. Entirely black in ground colour, disc of mesonotum densely olive-brown dusted becoming thinner, the black, shining cuticle, showing through marginally, especially along the paramedian lines anteriorly. Surface of mesonotum smooth, interrupted only by the simple, circular hair insertions. Mesonotum with long, fairly dense, perpendicular black hairs, acrostichals biserial, not noticeably separated by paramedian lines from the generally distributed lateral hairs, the longest about the length of third antennal segment. Scutellum smooth, surface densely olive-brown dusted, base bare, disc with sparse hairs over apical half merging into irregular uniserial row of long marginal hairs as long as scutellum is long medially. Pleura shining black, with thin grey dusting except anepisternum anteriorly and ventrally and katepisternum ventrally. Posterior half of anepisternum with fairly long back hairs. Wing. Clear, suffused PLATE XXII. Usia versicolor (Fabricius, 1787) ; a epiphallic complex ventral, b epiphallic complex lateral, c gonocoxite ventral, d epandrium dorsal, e female genitalia ventral, f female sternite 8 ventral.

yellow basally, the veins yellowish brown. Anal lobe convex, about as wide as anal cell, r-m before or at middle of discal cell. Haltere. Yellowish white knob, stem slightly infuscated basally. Legs. Black, shining, only coxae thinly dusted, femora sparsely haired. A row of very long perpendicular black hairs ventrally, significantly longer than depth of respective femur. Tibia and tarsi with very short, adpressed black hairs, front- and mid-tibia on apical quarter of ventral surface with a patch of strong bristles set at 45º, a character unique to this species. Abdomen. Black ground colour, disc of tergites densely covered with olive-brown dust, medially a patch of rich ochre-orange. Surface sculpture lacking, cuticle smooth other than inconspicuous hair insertions. Disc of tergites covered with relatively long black hairs, shorter, finer and confined to posterior margin on tergite 1, those on tergites 2–6 inclined towards centre. Lateral hairs rather longer, reflexed part of tergites thinly dusted, black cuticle showing through. Sternites black, thinly dusted and sparsely black haired but often difficult to see. Genitalia. Large and rather globular, placed at 90º to axis of abdomen. Epandrium with long apical extensions that fold around the cerci, shining black almost entirely hairless. Viewed caudally gonocoxite deeply hollowed medially, the bifurcate gonostyli often visible. Gonocoxite shining black with long black hairs, especially laterally. Epiphallic complex unlike any other species.

Female. One of the most sexually dichromatic Usia , the female lacking the distinctive colours of the male, much more similar to other Micrusia . Frons a little wider, more divergent in hind half, ocellar triangle more obtuse; mouth margin very slightly broader. Proboscis lacking long hairs, typical of the black-haired Usia . Dusting on occiput, mesonotum and scutellum thinner, brownish grey, the black cuticle not entirely obscured. Tergites vary from shining black to more or less dulled by grey dust, especially apical tergites. Apical sternite with the basal half shining and shallowly transversely ridged, apical part flat, dulled by silvery dust, sometimes with a longitudinal fold medially.

Atlas Mountains form—short -haired labium

Male. Differing from the typical form in being noticeably brighter, where yellow-brown dusted in typical form, the Atlas form is a richer brown to bright ochre on the disc of the mesonotum. The orange dust spot on the abdominal disc is in this form a deep, rich ochre colour, usually more extensive than the paler and less rich patch in the typical form. The most important difference is in the haring of the labium which has lateral and ventral hairs much shorter than in the typical form, no longer than the width of the proboscis. No differences in the genitalia could be found. Female not found to differ from females of the typical form.

Discussion. This very distinct species is not obviously closely related to any other Usia and is perhaps no more closely related to Micrusia than it is to Usia sensu stricto. It shares with Micrusia entirely black hairs which is why it is keyed with and compared to Micrusia but if the subgenus Micrusia is retained, then U. versicolor would seem to deserve equal status.

Distribution. Algeria, Italy (including Sicily), Malta, Morocco, Spain, Tunisia. A spring species, later at higher altitude, often relatively common except in Spain where specimens are very few. Also recorded from France and Portugal (Evenhuis & Greathead 1999) which fits the known distribution. However, records from the Balkans east to Iran are not only unproven but seem unlikely.