Planinasus kotrbae, 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 : 23-28

4. Planinasus kotrbae sp. n. Figures 20-29

Description of male.

Moderately small to medium-sized flies, body length 2.50-3.70 mm.

Head: Frons mostly bare of microtomentum, shiny, except for densely microtomentose, velvety-appearing, anterolateral corners, blackish brown; frons much wider than long, frontal ratio averaging 0.48; interfrontal seta long, length subequal to that of lateral vertical seta. Antenna generally blackish brown, basal flagellomere partially yellowish basally; pedicel with ventral projection long, about 1/2 length of basal flagellomere; basal flagellomere long, slightly more than twice basal width; arista bearing 13-14 dorsal rays, 3-4 ventral rays. Face very wide, facial ratio averaging 0.96; face mostly black, black coloration extended to ventral margin of face, lateral margin just ventrad of antennal groove whitish yellow, concolorous with coloration of adjacent parafacial; facial microtomentum sparse or lacking, mostly shiny; midfacies with a conical prominence, shaped like an inverted V; antennal grooves shiny, lacking narrowly triangular, bare area extended medioventrally from ventral margin of antennal groove to oral margin; large facial setae 4-5, not arranged in transverse rows, becoming smaller ventrally; largest seta inserted dorsolaterally, dorsoclinate and slightly convergent; 2nd largest seta inserted medioventrally from largest seta, porrect and parallel; sometimes with a smaller seta inserted just above porrect seta; 2 setae inserted at margin of black and yellowish white color, these oriented ventrally. Clypeus and palpus blackish brown. Gena concolorous with lateral margin of face.

Thorax: Generally dark colored, black to blackish brown, anepimeron paler, brownish, with ventral margin yellowish; mesonotum thinly invested with microtomentum, appearing subshiny, with slightly metallic brown luster medially, becoming more steel blue laterally; postpronotum dark brown; area from postpronotum and extended through notopleuron mostly bare, shiny; anepisternum thinly invested with microtomentum, mostly appearing dull, grayish brown; other pleurites less densely invested. Wing conspicuously and uniformly infumate, brownish, base slightly paler, more hyaline. Coxae yellowish; femora mostly yellowish, only apex blackish (apical 1/3 of forefemur, apical 1/8 of middle and hind femora); forefemur lacking a preapical yellowish annulus; tibiae blackish brown; tarsi, except apical 1-2 dark brown tarsomeres, yellowish. Forefemur with posteroventral surface bearing 1 large seta at apical 1/3.

Abdomen: Uniformly blackish brown to black, mostly shiny, very sparsely invested with microtomentum. Male abdomen: Tergites 1+2-6 well developed, lengths of tergites 3-6 subequal; tergite 7 narrow; sternites 3, 4, 5 generally as rectangular plates, slightly wider than long, lateral margins shallowly arched; sternite 5 slightly wider subposteriorly; no sternites 6, 7, neither segment forming an annulus. Male terminalia (Figs 20-23): Epandrium in lateral view (Fig. 20) higher than wide, anterior margin nearly straight, posterior margin arched, dorsal margin short, length slightly more than width of surstylus, truncate; surstylus almost as long as epandrium, extended from ventroposterior margin of epandrium in nearly oblique alignment with it, in lateral view (Fig. 20) slipper shaped, tapered toward apex, apex curved dorsally, acutely pointed, with a second, dorsal, slender, digitiform process from base, bearing 1 large, basal setula; hypandrium in ventral view (Fig. 21) more or less V-shaped, arms more slender than thickened base, anterior margin rounded; pregonite in ventral view (Fig. 21) approximately triangular, with anterior margin receded and with slightly round corners; postgonite in ventral view (Fig. 21) convoluted, with a lobe about as wide as long, bearing a few apical setulae, lobe in lateral view (Fig. 23) small, bearing two apical setulae; phallus in ventral view (Fig. 21) complex, only partially sclerotized; phallapodeme in lateral and ventral views (Figs 21, 23) elongate, tubular, nearly straight, very shallowly sinuous, bluntly rounded apically; ejaculatory apodeme much reduced, a little longer than half of length of phallapodeme, in lateral view (Fig. 22) expanded apically, lacking fan-like process.

Description of female.

Same as male except as follows: Head: Frontal ratio averaging 0.55; face and antenna mostly blackish brown, lateral margin of face (immediately adjacent to parafacial) whitish yellow; face not as wide, facial ratio averaging 0.42; face projected forward on ventral 1/2, bulbous, evenly arched transversely, shallowly arched vertically, mostly flat.

Abdomen: Internal female reproductive tract (Figs 24-28): Common oviduct opening anterodorsally into vagina. Posterior to this, paired spermathecae and accessory glands opening adjacent to each other into dorsal vaginal wall. Each spermatheca consisting of ovoid dark brown chamber with shallow circular depression apically; its sclerotized wall slightly wrinkled with tiny dimples; no basal introvert present. Spermathecal ducts lined by thick cuticle with more or less distinct annulation, sometimes slightly sclerotized at their base. Accessory glands about as long as spermathecae; their gland reservoirs and ducts lined by membranous cuticle. Ventral receptacle colourless, one-chambered, arising from anteroventral portion of vagina, round with circular apical depression, thus resembling (an inverted toilet plunger or) a shallow double-walled bowl.

Type material.

The holotype male is labeled "ECUADOR. Prt. Or[e]ll[a]na: RioTiputini [Biodiversity Station] (0°38.2'S, 76°8.9'W)[,] 12-26Aug 1999,W.N.Mathis, A. Baptista, M. Kotrba/USNM ENT 00118275 [plastic bar code label]/HOLOTYPE ♂ Planinasus kotrbae Mathis & Rung USNM [red]." The holotype is double mounted (minuten pin in plastic block), is in excellent condition, and is deposited at the USNM. Forty-eight paratypes (30♂, 18♀; USNM, ZSMC) bear the same label data as the holotype. Other paratypes are as follows: PERU. Madre de Dios: Río Manu, Pakitza (11°56.6'S, 71°16.9'W; 250 m), 9-23 Sep 1988, A. Freidberg, W. N. Mathis (14♂, 20♀; USNM); Río Manu, Erika (near Salvación; 12°50.7'S, 71°23.3'W; 550 m), 5-6 Sep 1988, A. Freidberg (3♂, 2♀; USNM). Cuzco: Quincemil (13°13.7'S, 70°45.6'W; 740 m), 13-31 Aug 1962, L. E. Peña (1♂; CNC).

Type locality.

Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2'S, 76°08.9'W).

Other specimens examined.

BOLIVIA. La Paz: Mapiri (5 km west; 15°17.8'S, 68°15.6'W; 750 m), 16 Mar 2001, W. N. Mathis (1♂; USNM).

BRAZIL. Amazonas: Carauari (05°04.5'S, 57°10.2'W), Jul 2005, A. Henriques (1♀; INPA); Manaus, UFAM (03°05.9'S, 59°58.2'W; 50 m), 7 May 2010, D. and W. N. Mathis (3♂; INPA, USNM); Reserva Cuieiras (02°35.2'S, 60°07.2'W; 110 m), 8 May 2010, D. and W. N. Mathis (1♂; USNM); Reserva Florestal Adolpho Ducke (02°55.8'S, 59°58.5'W; 40 m), 5 May 2010, D. and W. N. Mathis (2♂; INPA, USNM); Reserva Florestal Adolpho Ducke, Igarapé Barro Branco (02°58.1'S, 60°0.3'W; 40 m; Malaise trap), A. Henriques (1♂; INPA); Reserva Florestal Adolpho Ducke, Igarapé Tinga (02°55.8'S, 59°58.5'W; suspension trap at 25 m), Mar 2004, A. Henriques (1♀; INPA). Maranhão: São Pedro da Água Branca, Fazenda Santa Rosa (05°07.8'S, 48°15.2'W), 6 Dec 2001, F. L. Oliveira, J. A. Rafael, J. Vidal (1♀; INPA).

COSTA RICA. Puntarenas: San Pedrillo (8°37.2'N, 83°44.1'W), 12-14 Aug 2001, D. and W.N. Mathis (8♀; USNM).

GUYANA. Conservation of Ecological Interactions and Biotic Associations (CEIBA; ca. 40 km S Georgetown; 06°29.9'N, 58°13.1'W), 13-21 Apr-28 Aug 1994, 1995, 1997, W. N. Mathis (47♂, 12♀; USNM). Menzies Landing (05°10.1'N, 59°29.5'W), 23 Aug 1997, W. N. Mathis (3♂, 1♀; USNM). Paramakatoi (04°42'N, 59°42.8'W), 24-25 Aug 1997, W. N. Mathis (1♂, 1♀; USNM).

Distribution

(Fig. 29). Neotropical: Bolivia (La Paz), Brazil (Amazonas, Maranhão), Costa Rica (Puntarenas), Ecuador (Orellana), Guyana, and Peru (Cuzco, Madre de Dios).

Etymology.

The specific epithet, kotrbae, is Latin genitive patronym to honor Dr. Marion Kotrba (ZSMC), who conducted field work with us in Ecuador and allowed us to use her rearing cage for making observations on the mating behavior of this species. Marion directly participated in making these observations.

Mating behavior.

Marion Kotrba and W. N. Mathis observed the mating behavior of Planinasus kotrbae in the field (Ecuador. Orellana: Rio Tiputini Biodiversity Station (0°38.2'S, 76°08.9'W )) and in a rearing cage in the laboratory. In the field, we observed what we called "head butting" on repeated occasions, especially on leaves laying on the substrate. This refers to the specific behavior of males confronting each other head on and then lunging forward, making physical contact with the front of the head. Marion collected several specimens that she released into a rearing cage. Within minutes the specimens were mating and going through sequences of mating behavior. We observed 10 matings with the following durations: 1 × 2s, 2 × 5s, 1 × 10s, 4 × 15s, 2 × 18s. It cannot be decided whether all of these were successful in terms of sperm transfer. Two behavioral elements commonly observed within the context of mating were “kissing” and an "arc dance". Between matings and also at other encounters the flies frequently made contact with the frontally extended proboscis. These “kisses” lasted up to about 4 seconds with sometimes only a brief second between. “Kissing” was observed a few times between specimens of the same gender. When "arc dancing" a male would shuttle back and forth laterally with spread wings while facing the female at a short distance of only a few centimeters. The lateral movements were usually in a short arc pattern of 30-45° but up to 180°. One observed mating sequence consisted of five matings, 24 kisses and four arc dances in total. Another male demonstrated no lateral movements after mating and kissing a female just once.

Having access to a rearing cage facilitated observations in the laboratory as well as temporarily holding specimens that were to be dissected. Keeping females to be dissected in the cage ensured their freshness, which makes dissecting easier, and the preparations that resulted were excellent. The tissue is pliable and extraneous material, such as tracheoles, can easily be removed.

Remarks.

This species is a member of the shannoni group and is distinguished from other congeners of that group by the black antenna in both sexes, the mostly shiny black face except for the whitish yellow, lateral margin immediately adjacent to the parafacial, the conically prominent face of the male, and the mostly yellowish femora (only the apices are dark colored). The presence of a basal projection on the surstylus also distinguishes this species from other members of the same species group.

Antennal bases of males more approximate, distance between slightly more than antennal length; face of males with a subshiny, black area extended obliquely medioventrally from ventral margin of antennal groove nearly to oral margin