Toxomerus hauseri Mengual

Mengual, Ximo, 2011, Black-tie dress code: two new species of the genus Toxomerus (Diptera, Syrphidae), ZooKeys 140, pp. 1-26: 1

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Toxomerus hauseri Mengual

sp. n.

Toxomerus hauseri Mengual  ZBK  sp. n. Figures 18, 19, 20


FEMALE. Head: Face with distinct low facial tubercle, which ends at oral margin, yellow with two submedial black vittae that end before the oral margin, brownish lateroventrally, scarcely yellow pilose; gena brown to black; lunule yellow, yellow also between antennal bases; frons yellow laterally with broad medial black vitta that surrounds antennal bases and continues with the two submedial facial vittae, yellow pilose; vertical triangle shiny black, black pilose; antennae on small produced tubercle, antenna orangish, basoflagellomere brown, orange basoventrally; arista brown, bare (Fig. 20); eye bare, lateral triangular eye emargination large, approximately the half of eye width in lateral view; occiput black, grey pollinose, yellow pilose on ventral 2/3 and black pilose on dorsal 1/3.

Thorax: Scutum shiny with a continuous lateral yellow vitta, yellow pilose laterally and anteriorly, black pilose posteriorly; postpronotum yellow, bare; notopleuron yellow with a black vitta on the lateral side narrowing the lateral yellow scutal vitta; supra-alar area and postalar callus yellow; scutellum black with well-defined yellow margin apically and laterally, black pilose with a row of bristle-like black pile in the posterior margin, subscutellar fringe absent (Figs 18, 19). Pleuron mostly black, except posterior anepisternum yellow on posterior third and katepisternum with dorsal broad yellow macula; metasternum bare; calypter yellow; plumula yellow; halter bright yellow; posterior spiracular fringes yellow. Wing: Wing membrane hyaline, stigma brown; extensively microtrichose, except costal cell bare on basal 2/3, cells R1 and R bare basal to furcation of RS, cell BM bare basally and on anterior margin. Alula microtrichose. Legs: Proleg yellow except coxa brown and femur orangish on apical half, yellow pilose; mesoleg yellow except coxa black, mesofemur black on apical half with apical tip yellow, yellow and black pilose; metaleg black except femur yellow on apical tip, tibia yellow on basal tip and on apical 1/6-1/5 (Figs 18, 19).

Abdomen: Slightly oval, distinctively convex, unmargined. Dorsum shiny black, black pilose; terga 2, 3, 4 and 5 with lateral margins yellow forming a continuous lateral yellow vitta, barely interrupted at the posterior margin of tergum 4. Sterna shiny black; sterna 1 and 2 with brownish-yellow fascia on posterior margin (Figs 18, 19).

Differential diagnosis.

Species with yellow face with two sublateral black vittae, and eye with triangular emargination large, approximately the half of eye width in lateral view. Profemur yellow; cell BM bare on basal third and on anterior and posterior margins. Scutum shiny black with lateral yellow vitta and abdomen shiny black, convex, with lateral margins entirely yellow. Very similar to Toxomerus picudus  sp. n. but differs by having costal cell microtrichose on apical third, metafemur entirely black with at most the apical edge yellow, and occiput rounded posteriorly on dorsal section, without any protuberance.


body, 6.6 mm; wing, 5.9 mm.


Species only known from the holotype, collected in Peru.


This species is named after Martin Hauser in recognition of his work on Diptera  and his help during my study of flower flies.

Type locality.

PERU: Pasco Region, Oxapampa Province, Huancabamba District, Yanachaga-Chemillén N. P., Canon of Huancabamba, Biological Station Huampal, 1050 m, 10°11'08.95"S, 75°34'27.12"W, collected using a Malaise trap, D. Takiya, C. Peña and R. Rakitov leg.

Type specimen.

Holotype female, pinned, deposited at Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima, Peru. Original label: "PERU, Pasco 6-9. Oct. 2002 / Yanachaga-Chemillén N. P. / Canon of Huancabamba R. / Biol. Station Huampal, 1050 m / 10,18582°S, 75,57420°W / Malaise trap across river / D. Takiya, C. Peña, R. Rakitov" "HOLOTYPE / Toxomerus / hauseri / Mengual 2011" [red, handwritten except first line] (♀, MUSM).