Planinasus nigrifacies, 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 : 59-63

17. Planinasus nigrifacies sp. n. Figures 87-90

Description of male.

Moderately small to medium-sized flies, body length 2.50-3.50 mm.

Head: Head ratio 0.64-0.66; frons generally brownish black to black, mostly very finely and sparsely microtomentose, subshiny to shiny, except for densely microtomentose, velvet-like anterolateral angles and anterior margin; anterolateral angles setulose; frons wider than long, frontal ratio 0.45-0.47; interfrontal seta shallowly curved, elongate, length subequal to length of lateral vertical seta. Antenna black; basal flagellomere variable but usually short, length usually not exceeding height at base, tapered to moderately acute point at apex, both dorsal and ventral margins nearly straight to very shallowly depressed dorsally and arched ventrally; 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, 1 medial seta; arista bearing 13-14 dorsal rays, 3-4 ventral rays. Face comparatively narrow, facial ratio 0.45-0.48; dorsad of transverse carina sparsely microtomentose, subshiny to shiny, mostly brownish black to deeply bluish black; ventrad of transverse carina densely microtomentose, silvery white, sericeous; large facial setae arranged in 2 transverse rows of 6 setae; medial pair of dorsal row widely separate, shallowly dorsoclinate; next 2 setae shallowly ventroclinate; ventral row of facial setae all ventroclinate. Clypeus black with 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 infumate with some areas more hyaline. Coxae generally brown to brownish black with gray to whitish gray microtomentum; midcoxa with medial portion yellowish, lateral portion blackish brown; trochanters yellowish brown; femora and tibiae uniformly brownish black; forefemur lacking 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: Uniformly blackish brown, mostly dull to faintly subshiny, moderately invested with microtomentum. Male abdomen: Tergites 1+2-6 well developed, lengths of 3-6 subequal; tergite 7 well developed but narrow, band-like; sternites 3-5 well developed, rectangular, wider than long, lateral margins shallowly arched; sclerotized posterior margin of sternite 5 shallowly incised medially; sternite 6 apparently lacking; sternite 7 moderately well developed, much wider than long, but not fused with tergite 7 to form an annulus. Male terminalia (Figs 87-89): Epandrium in lateral view (Fig. 87) trapezoidal, higher than wide, narrowed dorsally, anterior margin nearly straight, posterior margin straight on dorsal 2/3 thereafter ventrally forming a robust truncate extension; surstylus almost as long as epandrium, extended from ventral margin of epandrium in nearly oblique alignment with it, in lateral view (Fig. 87) elongate, robustly developed basally, distinctly tapered, apex recurved, anterior margin deeply arched, posterior margin swollen medially, apical 1/4 tapered to moderately acute point, partially recurved, bearing medial, elongate setula from posteromedial extension; hypandrium in ventral view (Fig. 88) moderately robustly U- to V-shaped, posterior margin U-shaped, anterior margin truncate, arms tapered toward attachment with epandrium, anterior portion robustly developed with lateral margins nearly straight; postgonite in ventral view (Fig. 88) convoluted, with relatively short lobe bearing apical setula, in lateral view (Fig. 89) with lobe very shallowly extended, bearing 3 apical, short setulae; phallus in ventral view and lateral views (Figs 88, 89) mostly membranous and difficult to discern; phallapodeme in lateral and ventral views (Figs 88-89) elongate, irregularly parallel sided, truncate apically; ejaculatory apodeme greatly reduced.

Description of female.

As in male except as follows: Head generally narrower, head ratio 0.86-89; frontal ratio 0.54-0.57; facial ratio 0.33-0.36.

Type material.

The holotype male is labeled "BRAZIL. São Paulo: Mogi das Cruzes, Serra do Itapeti, 29 March 1992[,] R. & A. Baptista/USNM ENT 00118280 [plastic bar code label]/HOLOTYPE ♂ Planinasus nigrifacies Mathis & Rung MZUSP [red]." Ten paratypes (7♂, 3♀; MZUSP, USNM) bear the same label data as the holotype. The holotype is double mounted (glued to a paper point), is in very good condition (some cephalic setae misoriented), and is deposited in MZUSP.

Type locality.

Brazil. São Paulo: Mogi das Cruzes, Serra do Itapeti (23°31.5'S, 46°11.2'W).

Other specimens examined.

BRAZIL. Minas Gerais: Lavras (21°14.7'S, 45°W), 20 Jul 1992, A. and R. Baptista (11♂, 8♀; MZUSP, USNM). Rio de Janeiro: Nova Friburgo (22°17.2'S, 42°32'W), 1 May 1995, A. and R. Baptista (3♂; USNM). Rio de Janeiro, Floresta da Tijuca (22°57.6'S, 43°16.4'W), 30 Jul 1991, A. and R. Baptista (1♂; MZUSP); Parque Estadual do Desengano (near Santa Maria Madgalena; 21°53'S, 41°55'W), 19-23 Dec 1991, A. and R. Baptista (1♂; MZUSP); Parque Nacional de Itatiaia, Maromba (22°29.7'S, 44°33.7'W), 13-17 Dec 1991, A. and R. Baptista (2♀; MZUSP). São Paulo: São Paulo, Jaraguá (22°44.1'S, 47°40'W), 9 Dec 1990, A. and R. Baptista (1♂; MZUSP); São Paulo, Jardim Botânico (23°39'S, 46°37'W), 11 Feb 1992, A. and R. Baptista (1♂, 1♀; MZUSP).

Distribution

(Fig. 90). Neotropical: Brazil (Minas Gerais, Rio de Janeiro, São Paulo).

Etymology.

The species epithet, nigrifacies, is derived from Latin and refers to the black face, including the all black antenna.

Remarks.

In the key to species, this species is close to Planinasus mcalpineorum . Besides the distribution and characters given in the key, the unique shape of the surstylus (Fig. 87) can be used to distinguish this species readily from congeners.

The obscuripennis group

Included species. Planinasus obscuripennis sp. n.

Diagnosis. This species group is distinguished by the following combination of characters: Head: Interfrontal seta 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. 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; face of males and females similar in shape and color. Thorax: Anepisternum mostly bare but with 2-3 setulae along posterior margin. Wing generally conspicuously and darkly infumate with base more hyaline. Forefemur with a preapical annulus, bearing 1 seta at apical 1/3 along posteroventral surface. Abdomen: Surstylus in nearly oblique alignment with epandrium, not a posterior process, or lobe; postgonite with a digitiform lobe bearing a few setulae apically; phallus mostly sclerotized; aejaculatory apodeme greatly reduced.

Discussion. This species group currently comprises a single species, Planinasus obscuripennis . It shares, with species of the atriclypeus and shannoni groups, the reduced number of setae on the lobe of the postgonite (2-6), and the ejaculatory apodeme is generally reduced or inconspicuous. In all other species of Planinasus , the lobe of the postgonite, which is generally better developed, bears more than 20 setulae, and the ejaculatory apodeme is large, with a fan-like apical expansion. We recognize this group by the characters noted above but also by the unique structures associated with the male pre- and postabdomen. Among these characters are the apparent fusion of sternites 4+5 and a well-developed sternite 6, which is broadly produced medioposteriorly to form a shallowly bifurcate projection. In addition, the ejaculatory apodeme is short and its apex is not expanded.