Planinasus obscuripennis, Mathis, Wayne N., Rung, Alessandra & Kotrba, Marion, 2012

Mathis, Wayne N., Rung, Alessandra & Kotrba, Marion, 2012, A revision of the genus Planinasus Cresson (Diptera, Periscelididae), ZooKeys 225, pp. 1-83 : 64-66

18. Planinasus obscuripennis sp. n. Figures 52, 91-93

Description of male.

Medium-sized flies, body length 3.00-3.15 mm.

Head: Head ratio 0.71; frons generally brownish black to black, mostly very finely and sparsely microtomentose, subshiny, except for densely microtomentose, anterolateral angles and anterior margin; anterolateral angles setulose; frons moderately wider than long, frontal ratio 0.49; interfrontal seta shallowly curved, elongate, length subequal to length of lateral vertical seta. Scape and pedicel black; basal flagellomere pale, mostly yellowish on basal but black apically and faintly so dorsally, elongate, length much greater than height at base, tapered to moderately acute apex, dorsal margin shallow depressed, ventral margin shallowly arched; pedicel with ventral projection short, length of projection conspicuously less than length of pedicel without considering projection, bearing long, ventroapical seta (extended slightly beyond apex of basal flagellomere), 1 dorsal seta, 1 dorsomedial seta; arista bearing 13-14 dorsal rays, 3-4 ventral rays. Face comparatively narrow, facial ratio 0.35; dorsad of transverse, arched carina sparsely microtomentose, subshiny, sericeous, broad medial portion brown to brownish yellow anteriorly; antennal grooves nearly flat, brownish black; ventrad of transverse carina more densely microtomentose, yellow medially, lateral areas blackish brown; large facial setae arranged in 2 transverse rows; dorsal transverse row consisting of 1 pair of separate, well-developed, dorso- to inclinate setae; ventral row arched, comprising 6 ventroclinate setae about equidistant from peristomal margin. Clypeus black with sparse whitish gray microtomentum; palpus brownish black.

Thorax: Mesonotum generally brownish black to deep bluish black, thinly microtomentose, subshiny to shiny; postpronotum brown, some specimens with some yellowish coloration around margin; area from postpronotum and through notopleuron at most finely and thinly microtomentose, subshiny to shiny; pleural areas finely microtomentose, subshiny, blackish brown; anepisternum mostly bare but with 2-3 setulae along posterior margin; katepisternum generally setulose, bearing 2 setae toward dorsal margin. Wing without pattern, generally conspicuously and darkly infumate with base more hyaline. Coxae generally brown to brownish black with gray to whitish gray microtomentum; mid coxa with medial portion yellowish, lateral portion blackish brown; trochanters yellow to yellowish brown; femora and tibiae uniformly brownish black to black; forefemur with a preapical annulus; tarsi mostly yellowish basally, apical 2-3 tarsomeres becoming darker; forefemur bearing 1 seta at apical 1/3 along posteroventral surface.

Abdomen: Male abdomen: Tergites 1+2-6 well developed, lengths of 3-6 subequal; sternite 3 slightly longer than wide, anterior margin shallowly arched; sternites 4+5 apparently fused, slightly longer than wide; sternite 6 well developed, longer than wide, lateral margins bearing longer setulae, posterior margin produced medially to form shallowly bifurcate, broad projection, each apex of shallow bifurcation bearing longer setae; tergite 7 very narrow, almost forming a complete annulus, narrowly separated from subquadrate sternite ventrally. Male terminalia (Figs 91-93): Epandrium in lateral view (Fig. 91) triangular, length of ventral portion subequal to height, anterior margin nearly straight to shallowly emarginate, posterior margin shallowly arched; surstylus as long as epandrium, extended from posteroventral margin of epandrium in nearly oblique alignment with it, in lateral view (Fig. 91) elongate, robust basally, thereafter apically tapered, apex more thinly developed, shallowly curved, bearing 1 large, elongate, posteromedial setula; hypandrium in lateral view (Fig. 91) elongate, narrow, nearly straight and parallel sided, in ventral view (Fig. 92) broadly U-shaped, robustly developed anteriorly, arms tapered, more slender than wide base, anterior margin irregularly rounded; pregonite in ventral view (Fig. 92) approximately triangular with anterior margin receded and slightly round corners; postgonite in ventral view convoluted (Fig. 92), bearing short lobe with apical setulae, in lateral view (Fig. 93) lobe only slightly longer than wide, bearing three apical setulae; phallus in ventral view (Fig. 92) complex, mostly sclerotized, tubular; phallapodeme elongate, slender, in lateral view (Fig. 93) parallel sided, tubular, nearly straight, rounded apically, in ventral view (Fig. 92) tapered, margins shallowly undulous, apex narrowly developed; ejaculatory apodeme much reduced.

Description of female.

As in male except as follows: Head generally narrower, head ratio 0.70; frontal ratio 0.56; facial ratio 0.35.

Type material.

The holotype male is labeled "PERU.Madre de Dios: Manu, Erika (near Salvacion),550m,5-6 Sept1988,AFreidberg/HOLOTYPE ♂ Planinasus obscuripennis Mathis & Rung USNM [red]/USNM ENT 00118132 [plastic bar code label]/Illustrated ♂ [handwritten]." The holotype is double mounted (minuten in a block of plastic elastomer], is in good condition (some encrustation on head, especially eyes), and is deposited in the USNM. A female paratype (USNM) bears the same label data as the holotype.

Type locality.

Peru. Madre de Dios: Río Manu, Erika (near Salvación; 12°50.7'S, 71°23.3'W; 550 m).

Distribution

(Fig. 52). Neotropical: Peru (Madre de Dios).

Etymology.

The specific epithet, obscuripennis, is of Latin derivation and refers to the infumate wing of this species.

Remarks.

The male abdomen of this species is atypical of other congeners in having apparent fusion of some sternites (sternites 4+5) and a well-developed sternite 6 that is broadly produced medioposteriorly to form a shallowly bifurcate projection. We have observed this condition only in this species, and our observation is limited to the single holotype male.

Fossil species