Planinasus argentifacies, 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 : 42-44

10. Planinasus argentifacies sp. n. Figures 53-57

Description of male.

Moderately small flies, body length 2.10-2.75 mm.

Head: Head ratio 0.51-0.54; frons generally brownish black to black, mostly moderately microtomentose, dull to faintly subshiny, except for densely microtomentose, velvet-like, anterior margin, including area laterad of antennal bases; frons wider than long, frontal ratio 0.49-0.53; interfrontal seta shallowly curved, elongate, length subequal to length of lateral vertical seta. Antenna mostly yellowish orange, especially medially and ventrally; dorsum of pedicel and basal flagellomere brownish to blackish; basal flagellomere moderately long, length conspicuously greater than width at base, tapered to moderately acute point at apex, dorsal and ventral margins nearly straight, at most very shallowly curved; pedicel with ventral projection short, not extended anteriorly much beyond dorsal margin, bearing moderately long, ventroapical seta (not extended to apex of basal flagellomere); arista bearing 13-14 dorsal rays, 3-4 ventral rays. Face comparatively wide, facial ratio 0.58-0.62; dorsad of transverse carina moderately microtomentose, subshiny, mostly blackish brown, but becoming brownish to yellowish toward antennal grooves; ventrad of transverse carina densely microtomentose, carina and immediately ventrad blackish brown, thereafter ventrally densely silvery white to slightly yellowish along peristomal margin, sericeous; large facial setae arranged in a more-or-less single transverse row of about 8 setae, medial pair approximate, porrect to shallowly ventroclinate, next seta shallowly curved dorsally, lateral 2 setae ventroclinate. Clypeus and palpus brownish black; clypeus variable, all yellow, two-toned, to all black with some silvery white microtomentum.

Thorax: Mesonotum generally brownish black, faintly bluish black to black, somewhat sparsely microtomentose, subshiny; postpronotum, notopleuron, dorsal portion of anepisternum blackish brown; area from postpronotum and through notopleuron mostly bare to finely microtomentose, subshiny to shiny; pleural areas finely microtomentose, mostly dull, blackish brown, becoming more grayish brown ventrally, especially on katepisternum; anepisternum mostly bare but with 3-4 longer setulae along posterior margin; katepisternum generally setulose, bearing 2 setae toward dorsal margin. Wing without pattern, generally infumate, often slightly more so anteriorly, base and posterior margin slightly more hyaline. Coxae and trochanters grayish brown, yellowish brown to yellow; femora and tibiae uniformly brownish black, bases sometimes partially yellow; forefemur lacking a preapical annulus; foretarsus blackish brown dorsally, yellowish ventrally; mid- and hindtarsi mostly yellowish; apical 2-3 tarsomeres of all legs 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 tergites 3-6 subequal; tergite 7 narrow; sternite 3 only slightly wider than long, posterior margin nearly straight; sternite 4 rectangular with width about 1.5X length; sternite 5 rectangular with width about twice length, becoming slighter wider posteriorly, posterior margin of sclerotized portion with moderately broad, shallow V-shaped emargination on medial portion; sternite 6 apparently absent; sternite 7 narrow, band-like, forming an annulus with tergite 7. Male terminalia (Figs 53-56): Epandrium in lateral view (Fig. 53) broadly trapezoidal, about as wide as high, narrowed dorsally, anterior margin shallowly emarginate, posterior margin straight; surstylus length slightly less than half length of epandrium, extended from ventral margin of epandrium in nearly oblique alignment with it, in lateral view (Fig. 53), moderately wide at base, bifurcate apically with posterior lobe pointed and bearing an apical seta, deeply rounded, relatively narrowed emargination with some setulae, length of robustness of anterior lobe of bifurcation greater than posterior lobe, more robustly developed, apex truncate and slightly dilated; hypandrium in ventral view (Fig. 54) angularly U-shaped, arms narrow, anterior margin straight, robustly developed; postgonite in ventral view (Fig. 54) robust, length more than twice width, with densely setulose lobe, lobe in lateral view (Fig. 56) ovate, apex expanded, bearing more than 20 setulae; phallus in ventral view forming complex, convoluted structure with pre- and postgonites, in lateral view (Fig. 56) with narrow, bar-like processes; phallapodeme in lateral and ventral views (Figs 54, 56) elongate, in ventral view (Fig. 54) parallel sided, bluntly rounded apically, in lateral view with basal 2/3 parallel sided, slightly angulate, thereafter apically enlarged with subapical, angulate, shallow projection, apex rounded; ejaculatory apodeme enlarged, length subequal to that of phallapodeme, basal half relatively slender, almost parallel-sided, apical 1/3 greatly expanded, fan-like.

Description of female.

As in male except as follows: Head generally narrower, head ratio 0.65-0.67; frontal ratio 0.55-0.56; facial ratio 0.35-0.45.

Type material.

The holotype male is labeled "PERU.Madre de Dios: Manu, Rio Manu, 250 m[,] Pakitza, 12°7'S, 70°58'W [sic; 11°56.6'S, 71°16.9'W], 9-23 Sep 1988[,] Amnon Freidberg/USNM ENT 00118286 [plastic bar code label]/HOLOTYPE ♂ Planinasus argentifacies Mathis & Rung USNM [red]." The holotype is double mounted (minuten pin in a plastic block), is in excellent condition, and is held in trust at the USNM for eventual deposit in Peru. Four paratypes (3♂, 1♀; USNM) bear the same label data as the holotype. Other paratypes are as follows: PERU. Madre de Dios: Río Manu, Pakitza (5 km E; Aguajal; 11°58.2'S, 71°17'W; 250 m), 19 Sep 1988, A. Freidberg (1♂, 2♀; USNM).

Type locality.

Peru. Madre de Dios: Río Manu, Pakitza (11°56.6'S, 71°16.9'W; 250 m).

Other specimens examined.

BRAZIL. Amazonas: Novo Aripuaná, Reserva Soka (05°15.9'S, 60°07.1'W; Malaise trap), 28 Apr-5 Mar 1999, R. J. Leite, R. A. Rocha, J. Vidal (2♂; INPA); Reserva Cuieiras (02°35.2'S, 60°07.2'W; 110 m), 8 May 2010, D. and W. N. Mathis (4♂, 2♀; INPA, USNM); Reserva Florestal Adolpho Ducke (02°55.8'S, 59°58.5'W; 40 m), 5 May-7 Nov 2008, 2010, D. and W. N. Mathis (3♂, 3♀; INPA, USNM); Reserva Florestal Adolpho Ducke, Igarapé Barro Branco (02°58.1'S, 60°0.3'W; 40 m; Malaise and suspension traps), 11 Apr-16 Dec 2004, A. Henriques (5♂, 2♀; INPA); Reserva Florestal Adolpho Ducke, Igarapé Tinga (02°55.8'S, 59°58.5'W; Malaise trap), 10-20 May 2004, A. Henriques (1♂; INPA); Sítio Vida Tropical (02°51.9'S, 59°55.9'W; 60 m), 5 May 2010, D. and W. N. Mathis (1♂, 2♀; INPA, USNM).

ECUADOR. Orellana: Rio Tiputini Biodiversity Station (0°38.2'S, 76°8.9'W), 12-26 Aug 1999, A. Baptista, M. Kotrba, W. N. Mathis (10♂, 7♀; USNM, ZSMC).

PERU. Loreto: Campamento San Jacinto (02°30.8'S, 75°43.5'W; 175-215 m), 11 Jul 1993, R. Leschen (2♀; DEBU); Teniente Lopez (1.5 km N; 02°28.5'S, 76°08.1'W; 230-305 m), 22 Jul 1993, R. Leschen (1♀; DEBU).

VENEZUELA. Amazonas: Rio Mavaca Camp (02°02'N, 65°06'W; 150 m), 16-27 Mar 1989, D. A. Grimaldi (1♂; AMNH).

Distribution

(Fig. 57). Neotropical: Brazil (Amazonas), Ecuador (Orellana), Peru (Loreto, Madre de Dios), and Venezuela (Amazonas).

Etymology.

The specific epithet, argentifacies, if of Latin derivation and refers to the distinctive, silvery microtomentum on the ventral one-third of the face.

Remarks.

Structures of the male terminalia of this species and those of Planinasus nigritarsus are very similar, and based on these morphological characters alone, we would have suggested that these two species are conspecific. There are external characters (see diagnosis and key) that clearly distinguish between these two species, however, and based on these, we conclude that they represent closely related but separate species.