Mesembrius perforatus (Speiser, 1913)

Jordaens, Kurt, Goergen, Georg, Skevington, Jeffrey H., Kelso, Scott & Meyer, Marc De, 2021, Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data, ZooKeys 1046, pp. 1-141 : 1

publication ID	https://dx.doi.org/10.3897/zookeys.1046.57052
publication LSID	lsid:zoobank.org:pub:66E61C4E-FAFE-45DE-9145-DB38199BDEC3
persistent identifier	https://treatment.plazi.org/id/42E7056D-3668-51C9-86C5-B613BCE4D966
treatment provided by	ZooKeys by Pensoft
scientific name	Mesembrius perforatus (Speiser, 1913)
status

Treatment

Mesembrius perforatus (Speiser, 1913) Figs 16 View Figures 15, 16 , 59 View Figures 58–63 , 96 View Figures 95–100 , 140 View Figures 139–142 , 152 View Figures 151–154 , 163 View Figures 163–165 , 185 View Figures 185–188 , 218 View Figures 217–228

Prionotomyia perforata Speiser, 1913: 129.

Mesembrius perforatus - Smith and Vockeroth (1980): 504.

Differential diagnosis.

Mesembrius perforatus males have a black apical pile brush on the profemur, the protarsi are very broad, orange and the probasitarsus has a tuft of orange pile on the posterior side. The metafemur is long and slender with black pile ventrally which becomes longer towards the distal end. The metatibia has a long and deep posterior depression which is bordered with long black pile. The species resembles other species with a dark apical pile brush on the profemur, but the probasitarsus has a tuft of orange pile as in M. rex from which it differs in the metafemur which is entirely covered in short black pile ventrally (with a row of short spines in M. rex ). Other species with a dense apical pile brush have either no tuft of pile on the probasitarsus ( M. regulus ) or a tuft of black pile (other species). It is the only species which has three depressions on the posterior side of the metatibia. The female is unknown.

Examined material.

Holotype, male: Tanzania • Niussi ; 17 Dec 1905; Chr. Schröder leg. (type not found/studied).

Other material

Benin • 1♂; Calavi ; 11 Nov 1993; G. Goergen leg.; IITA • 1♂; Calavi ; Oct 2001; G. Goergen leg.; IITA . Democratic Republic of the Congo • 1♂; Elisabethville [= Lubumbashi]; Apr 1930; M. Bequaert leg.; KMMA • 1♂; Elisabethville [= Lubumbashi]; Apr 1930; M. Bequaert leg.; RMNH • 1♂; Tshibinda ; 21-27 Aug 1931; W.P. Cockerell leg.; NHMUK . Kenya • 1♂; Kakamega Forest, Isecheno Station ; 24 Jan 1991; Earthwatch Team 2 leg.; NMK . Uganda • 1♂; Entebbe ; 27 May 1912; C.C. Gowdey leg.; NHMUK • 4♂♂; Entebbe ; 7-9 May 1912; C.C. Gowdey leg.; NHMUK • 1♂; Entebbe ; 21 Aug 1911; C.C. Gowdey leg.; NHMUK • 1♂; Entebbe ; 18-20 Nov 1912; C.C. Gowdey leg.; NHMUK • 3♂♂; Entebbe ; 7 Oct 1971; H. Falke leg.; CNC • 1♂; Entebbe ; 23-31 Jan 1973; H. Falke leg.; CNC • 1♂; Entebbe ; 25-27 Mar 1973; H. Falke leg.; CNC .

Re-description male

(Fig. 16 View Figures 15, 16 ). Body length: 14.6-15.7 mm. Wing length: 10.5-11.5 mm.

Head (Fig. 59 View Figures 58–63 ). Eyes bare; slightly dichoptic, distance between the eyes approx. the width of ocellus. Face yellow with dark medial vitta; white pilose; white pollinose. Vertical triangle black; black pilose; yellow pollinose on lower half. Distance between lateral ocellus and eye margin less than 1/2 width of ocellus. Occiput black; yellow pilose with black pile in dorsal area; yellow and white pollinose. Frontal triangle short; black; with some long black pile; white pollinose. Frontal prominence shiny black with orange-brown apex. Antenna, scape and postpedicel black; pedicel dark orange-black; antennal arista reddish-brown.

Thorax. Scutum black with, dorsally, a pair of faint grey pollinose vittae; lateral vitta faint, not well-demarcated; black pilose with long yellow pile on anterolateral part and postpronotum. Scutellum uniformly yellow-brown; with long yellow and black pile.

Legs. Proleg (Figs 152 View Figures 151–154 , 163 View Figures 163–165 ): Femur black; dorsoventrally flattened; with a black apical pile brush; proximoventral section with long, thick black setae; posterior side with long golden pile. Tibia dorsally brown, ventrally orange-brown; with, especially on the ventral side, long black pile. Basitarsus very broad; orange; with a tuft of orange pile on posterior side (Fig. 163 View Figures 163–165 ). Other tarsi very broad; orange; becoming shorter distally; the most distal tarsal segment white; sparsely black pilose dorsally, but with denser short black pile in anterior half, short orange pilose ventrally. Mesoleg: Femur dark brown; with long yellow pile on ventroproximal side, scattered yellow pile posterodorsally, but black at distal end. Tibia dorsally brown, ventrally orange-brown; with a tuft of black curved pile on ventroproximal end. Tarsi orange; sparsely black pilose dorsally, orange pilose ventrally with some thick long black pile. Metaleg (Fig. 185 View Figures 185–188 ): Femur long and slender; dark brown; black pilose ventrally, the pile gradually becomes longer towards distal end; pile otherwise yellow and less dense. Tibia dorsally dark brown, ventrally orange-brown; in anterior view with a strong carina on the ventral side in the middle; with three deep depressions on the posterior side of the proximal half which are bordered with long, black pile, especially dorsally. Tarsi dark brown; sparsely black pilose dorsally, short orange pilose ventrally.

Wing (Fig. 140 View Figures 139–142 ). Entire wing uniformly dense microtrichose.

Abdomen (Fig. 96 View Figures 95–100 ). Tergite II with pair of large, yellow triangular maculae; black marking hourglass-shaped, white pollinose on posterior end; yellow and black pilose, but black pile most conspicuous on posterior black marking of tergite. Tergite III with broad yellow fascia and a triangular black marking on posterior half; black marking strongly white pollinose, covered with short black spines; otherwise yellow pilose. Tergite IV with large triangular posterior black marking, otherwise yellow; strongly white pollinose.

Genitalia (Fig. 218 View Figures 217–228 ). Epandrium: Dorsal lobe of surstylus short, broadly rounded, with short, black spines on almost entire surface. Ventral lobe of surstylus straight; bare.

Female.

Unknown.

Distribution.

Benin, Democratic Republic of the Congo, Kenya, Tanzania and Uganda.

Comments.

We could not find the male holotype in any of the surveyed collections. The male has a set of unambiguous character states mentioned in the original description and cannot be confused with any other species of the genus. The specimens we have studied correspond with the original species description and are therefore considered to be conspecific.