Eumerus armatus Ricarte and Rotheray

Ricarte, Antonio, Nedeljković, Zorica, Rotheray, Graham E., Lyszkowski, Richard M., Hancock, Geoffrey, Watt, Kenneth, Hewitt, Stephen M., Horsfield, David & Wilkinson, Geoffrey, 2012, Syrphidae (Diptera) from the Greek island of Lesvos, with description of two new species, Zootaxa 3175, pp. 1-23 : 7

Eumerus armatus Ricarte and Rotheray , sp. nov.

Figs. 1–3

Material examined. Holotype: 1 3, Greece, Lesvos, quarry below Akrasi, 7.vi.2010, leg. G.E. Rotheray [ NMS].

Etymology. The word armatus means ‘armed’ and refers to the serrated expansion on the hypandrium.

Diagnosis. Medium size species (8.1mm); eye with very short scattered hairs; frontal triangle 1.5× longer than the eye contiguity; basoflagellomere axe-shaped, red, with white sparse pollinosity, striae and an apical circular area with densely-grouped pit-like structures on the outer surface (Fig. 1); legs black, except for the reddish ventral surface of the tarsi; tergum I black; terga II and III almost wholly red (Fig. 2); tergum IV extensively black, only narrowly red anteriorly; genitalia with a serrated expansion on the basal part of the hypandrium (Fig. 3).

Description. Male. L = 8.1mm, WL = 5.1mm. Head. Eye nearly bare, only with very short scattered hairs; facets near the eye contiguity larger than those in the posterior part of the eye; vertical triangle and occiput black; in profile, head virtually flat from the posterior ocelli to the posterior edge of the head, gently curved down in the ocellar triangle; long erect white hairs on the area posterior to the ocellar triangle; ocellar triangle isosceles; frontal triangle 1.5× longer than the eye contiguity; frontal triangle and face white pollinose, with white hairs, denser and more adpressed on the frontal triangle than those on the face; scape and pedicel black; basoflagellomere axeshaped, red, with white, sparse pollinosity, striae and an apical circular area with densely-grouped pit-like structures on the outer surface (Fig. 1); antennal arista black, basally thickened. Thorax. Scutum, scutellum, pleuron and legs completely black, except for the reddish ventral surface of the tarsi; scutum and scutellum with short brownish hairs; scutum with two grey-pollinose vittae extending from the front of the thorax to a point behind the transverse suture; metafemur moderately swollen, with longer hairs postero-ventrally than on the rest of the metafemur; metafemur apically with a row of 7–9 robust spinae on the ventral surface; wing extensively microtrichose; calypter white; halter with blackish pedicel and whitish capitulum. Abdomen. Tergum I black; terga II and III almost wholly red (Fig. 2); tergum IV extensively black, only narrowly red anteriorly; sternum I black, sterna II and III red with long white hairs medially, but some brown hairs on the posterior margin of tergum III; sternum IV reddish black with blackish hairs and, posteriorly, brownish hairs. Genitalia (Fig. 3). Basal part of the hypandrium with a serrated expansion; posterior lobe of the surstylus nearly square and with a few long setae posteriorly; anterior lobe of the surstylus hairy, with hairs extending on the interior side towards the posterior lobe.

Notes. The studied specimen keyed out to the Armenian species Eumerus urartorum Stackelberg, 1960 using Stackelberg (1961); this species is separated from E. armatus sp. nov. by the colouration of the joint between femur and tibiae, which are black in E. armatus but red in the E. urartorum . The new species also seems to be closely related to Eumerus rubescens Villeneuve, 1912 because of the similar antennae ( Dussaix 2010) and male genitalia. Gerard Pennards (in lit.) collected two males and three females of Eumerus on the Greek island of Zakynthos; the females keyed out to E. rubescens in Stackelberg (1961) and Sack (1932), and the males were judged to belong to the same species because they came from the same locality as the females and shared morphological characters with them (Clauss Claussen in lit.). If those are the undescribed males of E. rubescens (identification to be confirmed, Martin Hauser in lit.), they differ from our male, for instance, in that the expansion at the base of the hypandrium appears to have none of the obvious teeth possessed by the new species. Males of E. rubescens also have the tergum IV extensively red ( Dussaix 2010), while it is black in E. armatus sp. nov.