Medetera varvara Grichanov & Vikhrev

Ya, Igor & Vikhrev, Nikita E., 2009, Mediterranean species of the Medetera plumbella species group with description of a new peculiar species from Morocco (Diptera: Dolichopodidae), Zootaxa 2170, pp. 46-52 : 48-51

Medetera varvara Grichanov & Vikhrev sp. nov.

( Figs. 1–6 )

Type material. Holotype 3: Morocco, near Essaouira, 31.563ºN 9.714ºW, sand dune, 29 March 2009, N.Vikhrev (ZMU). Paratypes. 2 ƤƤ with same data as holotype, 28 and 29 March (ZMU).

Diagnosis. Medetera varvara is related to Egyptian M. albescens (Parent) which differs from the former by silvery-white frons and face, hind coxa bearing three outer setae and fore tarsus unmodified. Ornamentation of fore legs is unknown for other species of Palearctic Medetera including M. albescens which was published with a rather detailed description. In the Afrotropics, only M. luteoscutata Parent, 1936 , has a small apicoventral process on tarsomere 1 and 3 of fore leg. Mainly Pantropical Saccopheronta Becker, 1914 , a sister genus ( Grichanov 1997b) or “ aberrans ’ group of Medetera species ( Bickel 1985, 1987) includes species with thickened or widened tarsomeres 2 and 3 of male fore leg. The absolute majority of medeterine species of the world fauna have no remarkable fore leg decoration.

Description. Male ( Fig. 1 ): Length (mm): body 2.0, wing 2.0/0.7, antenna 0.7, hypopygium 0.8.

Head: Frons, face, clypeus, palpus and postcranium greenish, evenly and densely dusted greyish-white, so frontoclypeal suture between face and clypeus not distinct. Postocular setae white, somewhat thickened, strongly increasing in length downward. Ventral postcranium shining greenish, with row of long white thickened setae. Frons with pair of strong vertical setae and pair of ocellar setae slightly stronger than verticals. Postverticals absent. Face relatively wide; ratio of height of face to its maximal width to height of clypeus to height of palpus, 15/8/5 /5. Antennal segments short, with short white hairs; scape and pedicel orange-brownish, grey dusted at apex; postpedicel black, rounded. Stylus subapical, bare, about 2 times as long as ocellar seta. Proboscis short, black, shining, with white hairs.

Thorax: Dark, densely grey dusted; mesonotum with 3 narrow bronze stripes distinct in anterior view. Three pairs of strong black dorsocentral setae, slightly decreasing in size anteriorly. Notopleural setae 2, sutural 1, supraalar 1, all black; 1 white humeral seta. Acrostichals very short, biseriate, white, extending to mesonotal flattening. Several white setulae in front of first dorsocentral and sutural setae. Propleuron with 5 white thickened setae, lower one almost 2 times longer than others. Scutellum with pair of strong black median setae, lateral setae absent.

Legs: Yellow, except fore legs whitish-yellow, hind tibia darkened at apex, tarsomeres 4 and 5 and apical part of 2 and 3 of mid and hind legs brownish; mid and hind coxae mostly dark, grey dusted, yellow at apex. Fore coxa with dense brush of long white flattened setae on anterior surface. Fore femur and tibia without setae. Fore tarsomeres 1 to 5 each with pair of small brown apical postero- and anteroventral setulae; tarsomeres 2 to 5 each with pair of very small brown ventral setulae; tarsomeres 2 to 4 slightly flattened laterally; apical 1/3 of tarsomere 1 and tarsomeres 2 to 4 with comb of white thickened cilia on dorsal surface ( Fig. 3 ). Mid coxa with dense brush of long thickened white setae on anterior surface; mid trochanter with single white seta on anterior position; mid femur without setae. Mid tibia with pair of antero- and posterodorsals at 1/4 and long apicoventral seta, all white. Mid tarsus with four brown apical setae on each segment; basitarsus in apical half with 4–5 short brown setulae, somewhat irregularly placed, but in either antero- or posteroventral positions, tarsomere 2 with 3 such setulae, 3rd with 2–3, 4th and 5th with 2 ones each; all these setulae gradually decreasing in size apically. Hind coxa with single white seta on outer surface; hind femur with row of white dorsal setulae in basal half; hind tibia slightly thickened at apex, with posterodorsal setula at 1/4 and ventral apical one, both white; with very short black posterodorsal apical spur; hind tibia on apical 2/3, basitarsus and tarsomere 2 on basal 2/3 with row of short dense white posteroventral cilia; hind basitarsus short, with 2 apicals: brown anteroventral and white ventral, with small white posteroventral basal tooth and shallow basal excavation; tarsomeres 2 to 5 each with 1–3 brown anteroventral and 2–3 brown apical setulae, these setulae gradually decreasing in size apically. Fore leg length ratio (from coxa to tarsomere 5): 24/40/ 35/20/10 /8/5/5, mid leg: 16/42/ 45/22/10 /8/6/5, hind leg: 14/45/ 51/12/24 / 14/8/6.

Wings: Hyaline, veins yellow in anterobasal quarter of wing, brown in other parts ( Fig. 4 ). Costa without long hairs. R1 short, extending to basal third of wing, R4+5 and M1+2 distinctly convergent at apex. Ratio of part of costa between R2+3 and R4+5 to this between R4+5 and M1+2, 25/5. Ratio of apical to basal part of M1+2, 17/18. Ratio of cross-vein m-cu to maximal distance between R4+5 and M1+2 to distal part of CuA1, 10/11/12. Calypter yellow, with white cilia. Halter yellow.

Abdomen: Covered with short white setulae, olive-grey dusted, with fore margin of tergites 3 to 5 bronze dorsally; posterior margin of tergite 1 with 5–6 white flattened setae on each side. Tergite 6 slightly longer than tergite 5; segment 7 longer than preceding, with short hairs; segment 8 large, left basolateral, shorthaired. Epandrium ( Fig. 5 ) black, elongate-triangular; hypandrium basoventral, slightly swollen at base, then thinned, pointed at apex; phallus simple, pointed; epandrial lobe small, hardly divided, bearing pair of long simple setae; surstylus and cercus ( Fig. 6 ) dark-brown; cercus fused almost to apex, covered with short white hairs.

Female ( Fig. 2 ): Length (mm): body 2.2, wing 2.2; similar to male except lacking male secondary sexual characters. Each hemitergite bearing 1 acanthophorite and 1 simple seta; acanthophorites thin, much longer than cercus; cercus small, with short hairs. Dense brush of thickened white setae on anterior surface of fore and hind coxae, but setae about two times shorter and more equal in length than those of male. Fore tarsi unmodified; tarsomeres 4 and 5 and apical part of 2 and 3 of fore legs brownish, as on mid and hind tarsi. Hind tibia without apical spur; hind basitarsus simple, without basal tooth.

Distribution: Morocco.

Etymology. The species is named for Varvara Vikhreva who kindly helped to collect flies in Morocco.

Habitat: All three specimens of the type series were collected from sandy substrates. This habitat is rather unusual for mainly dendrophilous, sometimes petrophilous species of Medetera , although many species of the Nearctic M. petulca group occur in such habitats (Bickel pers. comm. 2009). Trees on sand dunes were also examined, but all specimens of tree trunk Medetera ( M. flavipes Meigen, 1824 , and M. pallipes (Zetterstedt, 1843)) collected on the Essaouira dunes (between 24 and 29 March) belong to other species groups of the genus. The senior author observed M. pallidior imagos in Southern Tajikistan (the Tigrovaya Balka Nature Reserve) in July 1978, where they populated rodent holes (to 5 cm in diameter) on a rather dry and flat semidesert plot not far from the border with a large area of riparian marshes. Males and females of the species concentrated around holes, and frightened or disturbed flies dropped immediately into the holes.

Figures

FIGURES 1 – 6. Medetera varvara Grichanov et Vikhrev sp. nov. 1. male holotype, habitus. 2. female paratype, habitus. 3. male fore tarsus. 4. wing. 5. hypopygium, left lateral aspect. 6. apex of hypopygium, dorsal aspect. Scale bars: 0.2 mm.