Acropsilus vorax ( Curran, 1927 ) Curran, 1927

Ya, Igor & Mostovski, Mike B., 2009, Long-legged flies (Diptera: Dolichopodidae) in the collection of the Natal Museum: A review of C. H. Curran’s types, new synonyms, and new combinations, Zootaxa 2194, pp. 37-53 : 38-40

Acropsilus vorax ( Curran, 1927) , comb. nov.

( Figs. 1–2 )

Campsicnemoides vorax Curran, 1927: 184 .

Holotype (examined). Male, [ South Africa:] Barberton, Stentor [25º33'S: 31º24'E], 8.6.[19]25, H.K. Munro / Campsicnemoides Type vorax Curran, No. / Collection Transvaal Museum ( NMSA).

Diagnosis. Having rather long legs, Acropsilus vorax is related to A. errabundus Lamb, 1922 , from Seychelles, differing in having an ornamented hind tarsus that is covered dorsally along entire length with pale silvery shining setulae. A. errabundus has the fore tarsus twice longer than tibia, hind basitarsus 1/4 the length of next segment, while A. vorax has fore tarsus 1.6 times longer than tibia, hind basitarsus 1/3 the length of next segment.

Redescription. Head. Frons shining black-violet. Ocellar tubercle with a pair of strong setae (broken); one strong vertical seta present laterally on frons. Eyes with short hairs; upper and lateral facettes somewhat smaller than other ones. Upper postocular setae short and black, in one row; lower postoculars weak and light. Occiput slightly concave, black, pollinose. Face concave below antennae; clypeus without setae; face blackviolet, grey pollinose, strongly narrowing in middle, slightly widening at clypeus; ratio of its width below antennae to its width in middle to clypeus width to total height of face and clypeus, 13:1:6:25. Palpus black, with dark hairs and with a small bristle; proboscis brown, with dark cilia. Antenna with broken postpedicel; scape and pedicel short, dark brown; pedicel globular, without process, with distal ring of short setulae.

Thorax metallic black, weakly grey-brownish pollinose. Mesonotum convex, with violet reflection. Five dorsocentral setae decreasing in size anteriorly; acrostichals absent; several fine light propleural hairs present; one humeral, one posthumeral, one strong and one fine notopleural setae present. Scutellum with two strong bristles and two microscopic lateral hairs.

Legs mostly yellow, middle and hind coxae brownish at base, apical segments of tarsi darkened. Fore and middle coxae with short yellow hairs, fore coxa with 2 or 3 yellow apical setae, middle and hind coxae with one brown external seta. Fore femur and tibia practically bare. Fore tarsus simple, 1.6 times longer than fore tibia. Length ratio of fore coxa to femur to tibia to tarsus (segments from first to fifth), 40:65:56:38:18:15:10:8. Mid femur bare. Mid tibia simple, with 1 anterodorsal, 2 posterodorsal in basal 1/3, 3 apical setae. Mid tarsus simple. Length ratio of mid coxa to femur to tibia to tarsus (segments from first to fifth), 32:77:114:48:40:26:11:10. Hind femur bare. Hind tibia with one fine short dorsal seta at basal 1/4 and one dorsal seta at apex, 5 very short ventral and 2 short apical setae. Hind tarsus covered dorsally along entire length with pale silvery shining setulae. Hind basitarsus short, with short apicodorsal scale and several ventral setulae nearly as long as diameter of tarsomere. Length ratio of hind coxa to femur to tibia to tarsus (segments from first to fifth), 18:84:116:18:56:30:15:9.

Wing ( Fig. 1 ) slightly darkened in anterior half, veins brown. R2+3 straight. R4+5 and M1+2 almost parallel. R4+5 slightly curved posteriad at apex. M1+2 straight. Ratio of part of costa between R2+3 and R4+5 to this between R4+5 and M1+2, 10: 5. Ratio of m–cu to maximal distance between R4+5 and M1+2 to apical part of CuA1, 5:7:10; m–cu straight. Anal vein foldlike. Anal angle and alula absent. Lower calypter brown, with black cilia. Halter brown.

Abdomen 6-segmented, black, with dark hairs, pressed from lateral sides. Hypopygium ( Fig. 2 ) lightbrown, pedunculate, extending under abdomen; 7th segment thin and long; 8th segment large, covering half of epandrium, covered with short pale hairs in dorsal half, with long ventral inverted “Y” shaped sclerotized process, covered with short pale hairs in its dorsal half. Epandrium distinctly longer than high. Two ventral epandrial setae: the first one short, positioned at base of hypandrium; the second is long and strong, situated at distal third. Hypandrium arising at proximal third of ventral side of epandrium, straight, narrowed at base, nearly as long as height of epandrium, with apical furrow. Aedeagus arising at base of hypandrium, trilobate, with lateral lobi flat, long, thin, weakly widened in third quarter and rounded at apex (lateral view); medial lobe concealed. Apicoventral epandrial lobe long and narrow, slightly curved, with 1 or 2 apical setae of different length. Surstyli bilobate, 1/4 as long as cercus, with small lobi. A large unpaired trilobate postgonite visible between surstyli. Subepandrial sclerite (?proctiger brush) positioned at base of each cercus, each with 1 strong long and 2 fine short setae. Cercus yellow, long and narrow, as long as epandrium, 1.6 times longer than height of epandrium, 5–6 times as long as wide in middle, rounded at apex, densely setose and pubescent; apical and ventral setae often hooked.

Length (mm): body without antenna 1.96, wing 1.93/0.64, postabdomen 0.58.

Remarks. Acropsilus includes now 30 species from Oriental, Palaearctic, Australasian and Afrotropical Regions ( Bickel 1998; Grichanov 1998c; Wang et al. 2007), but many more small-sized species are waiting description. It has not been known previously in the South Africa. The genus has been assigned variously to the Campsicneminae, Sympycninae , Peloropeodinae , Diaphorinae , or left unplaced. Bickel (1998) has noted also some similarity of Acropsilus with Medeterinae . He has also noted strong similarities among Acropsilus and Griphophanes Grootaert & Meuffels , and doubted their placement into Peloropeodinae . At the same time, both genera have many similarities with the genera Urodolichus Lamb , Dactylonotus Parent , and Somillus Brethes (see Grichanov 1998b, d, 2000c; Bickel, 1999), and all may deserve a new tribe or subfamily.

Figures

FIGURE 1. Acropsilus vorax (Curran), wing. Scale bar: 0.5 mm.

FIGURE 2. Acropsilus vorax (Curran), hypopygium, left lateral view. Scale bar: 0.1 mm