Hypselosyrphus marshalli, Reemer, Menno, 2013

Reemer, Menno, 2013, Taxonomic exploration of Neotropical Microdontinae (Diptera: Syrphidae) mimicking stingless bees, Zootaxa 3697 (1), pp. 1-88 : 28-29

Hypselosyrphus marshalli spec. nov.

Figs 74, 75 .

Studied type specimens. HOLOTYPE. ECUADOR. Female. Label 1: "ECU: Napo, Tiputini / Biodiversity Stn., 0°36’50”S. / 76°9’1”W, May 2011, S.A. / Marshall, debu00339701”; label 2: “Voucher code M. Reemer / MR398”. Coll. PUCE.

Additionally studied specimens. 1 male was photographed by S.A. Marshall at same locality and date as holotype (fig. 75), but not collected.

Description (based on holotype)

Adult female Body size: 9 mm.

Head. Face occupying between 1/5 and 1/4 of head width in frontal view; shining black; entirely white pilose. Gena hardly developed. Oral cavity directly bordering eye margins; with lateral margins not produced. Frons shining black, short white pilose. Vertex strongly produced, shining black; black pilose. Occiput black; narrow; black pilose on dorsal half, white pilose on ventral half; entirely pollinose. Eye entirely with short, pale pile, about as long as ommati diameter. Antennal fossa about as wide as high. Antenna blackish brown; antennal ratio 5:1:6. Arista blackish brown, about as long as basoflagellomere.

Thorax. Black, except postalar callus brownish. Scutum densely black pilose, except for medially interrupted transverse fasciae of long yellowish pile along suture. Postpronotum and postalar callus black pilose. Scutellum apicomedially sulcate, without calcars; directed upward, making an angle with the scutum of about 50°; black pilose, except yellowish pilose ventrally. Anepisternum a little convex, no clear division between anterior and posterior part; anterior part black pilose, posterior part with a few black pile along posterior margin. Anepimeron entirely black pilose. Katepisternum black pilose dorsally; bare ventrally. Katatergum long microtrichose. Anatergum short microtrichose. Other pleurae bare. Calypter blackish, halter pale yellow.

Wing: basal and apical 1/3 somewhat infuscated, middle 1/3 yellowish white; microtrichose, except bare on 1st costal cell, basal 1/20 of cell r1, basal 3/4 of cell br, posterior 1/3 of cell bm, basal 1/6 of cell cup.

Legs: Black, except fore- and middle-tarsi yellow and apical three tarsomeres of hindleg yellow; black pilose, except yellow pilose on apical three tarsomeres. Hind tibia strongly widened, with greatest width at apical 1/3, a little wider than posterior femur at largest width; with strong excavation at cicatrice (lateral view); pilosity about as long as width of tibia. Hind-basitarsus enlarged; about twice as wide as apex of metatibia in dorsal view. Coxae and trochanters black, with black pile.

Abdomen. More or less oval, wider than thorax, with largest width at posterior 1/3 of tergite 2; black, except tergite 4 posteriorly with pair of submedian dark yellowish vittae of half the length of the tergite, and tergite 5 almost entirely dark yellowish (only black along anterior margin). Tergites black bilose, except tergite 2 with pair of narrow yellow pilose transverse fasciae along posterior margin, tergite 4 white pilose posteriorly, tergite 5 white pilose. Sternites black except sternite 5 yellowish; black pilose, except posterior margin of tergite 4 and tergite 5 entirely yellow pilose.

Male (based on photograph). As female, except for usual sexual dimorphism and following differences. Wing largely infuscated, except for yellow pterostigma and yellow patch between pterostigma and vein R4+5.

Etymology. This species is attributed to Stephen A. Marshall, who collected the holotype, after having made excellent photographs of living specimens. A photograph of the living holotype was also included in his book Flies ( Marshall 2012: 428).

Diagnosis. Recognized by the following combination of characters: scutellum sulcate, alula with small bare patch basomedially, thorax and abdomen largely black, basoflagellomere about as long as scape or longer.

Distribution. Only known from Ecuador.

Figures

FIGURES 72 – 75. 72 – 73. Hypselosyrphus helvus female (holotype). 72. head frontal; 73. head lateral. 74 – 75. Hypselosyrphus marshalli (photographs by S. A. Marshall). 74. female (holotype), habitus; 75. male, habitus.