Nervijuncta conjuncta ( Freeman) , 1951

Falaschi, Rafaela Lopes & Amorim, Dalton De Souza, 2009, Review of the Neotropical species of Nervijuncta Marshall, 1896 (Diptera, Ditomyiidae), Zootaxa 2219, pp. 18-30 : 25-29

Nervijuncta conjuncta ( Freeman), 1951

( Figs. 8–12 )

Nervijuncta conjuncta ( Freeman), 1951: 7 , figs. (1 3 terminalia), 297 (wing). Type-locality: Argentina, Rio Negro, Lago Correntoso. Distr. – Argentina (Rio Negro), Chile (Llanquihue, Chiloé). Ref.: Papavero 1977: 4 (catalogue). Holotype 3, NHM.

Ditomyia conjuncta Freeman, 1951: 7 , figs. (1 3 terminalia), 297 (wing).

Diagnosis. Two light transverse areas across wing; distal projection of gonocoxites dorsally as long as length of gonocoxite at midline; gonostyli not conspicuously enlarged basally.

Material examined. Ƥ, Chile, Osorno, Pucatrihue 10.ii.1980, Duret, J.P. col.; 3, Argentina, Neuquen, Parque Nacional Lanin, 07.x.1971, Duret, J.P. col. ( MNHN); 3, same data, but 09.xi.1971; 3, same data, but 15.xi.1973 (all specimens of MNHN).

Redescription. Male. Body, 6 mm. Wing, 4 mm. Color. Body mostly dark brown, legs light brown, yellowish bands basally on abdominal segments. Wings maculate, mostly brownish, with two brighter areas across the wing. Head. Brown, darker around the ocelli; face yellowish; palpi brown, remainder of mouthparts yellow or brownish. Clypeus about twice as wide as long, yellowish. Eyes large, eye-bridge hardly extending above eye; fine setulae among ommatidia. Occiput brownish, covered with scattered brownish setae. Antenna twice as long as thorax; pedicel, scape and base of first flagellomere light yellowish, remaining flagellomeres brownish; flagellomeres covered with brownish setae. Maxillary palpus brownish, with three segments, first segment wider. Thorax. Mainly brownish; prothorax yellowish; Scutum yellow, with three longitudinal brown stripes, yellowish laterally, anteriorly to wing base, scattered small setae, some larger setae along the dorsocentral lines; small setae scattered on the scutum; some larger setae along the dorsocentral lines. Scutellum brownish, yellowish laterally, with two strong scutellar bristles. Pleural sclerites brownish, except for the yellowish pronotum and yellowish band along the dorsal half of the katepisternum; katepisternum with three long setae at posterior margin, other sclerites bare. Antepronotum present as a wide stripe anterior to the mesonotum; postpronotum slender, elongate, with a large anterior seta and two small, posterior setae. Proepisternum and proepimeron slender. Primary anapleural suture complete, curved, katepisternum extending dorsally along anterior margin of the anepisternum. Mesepimeron restricted to the dorsal part of the thorax due to the fusion of the katepisternum posteriorly to the laterotergite; laterotergite relatively small, not protruded, mediotergite nearly straight in lateral view. Metepisternum large, but weakly sclerotized, metepimeron scarcely visible. Postnotal phragma short, just ventral to the mediotergite, well sclerotized. Halter light brownish, a yellowish macula on pedicel. Halter entire yellowish. Legs. Legs light brownish, very long and thin. Fore coxa yellowish and with elongate setae distally on anterior face; mid coxa with a group of basal anterior setae and hind coxa with a group of lateral setae. Tibiae covered with dark, dense, scattered setae. Front tibial spur almost twice as long as diameter of tibial apex; mid and hind tibial spurs largely unequal in length, the larger one almost twice length of tibial apex, the smaller very short. Wing ( Fig. 8 ). Wing brownish, two light transverse areas across the wing. Wing more densely covered with macrotrichiae on distal half, with macrotrichiae also on anal lobe; microtrichiae covering entire wing membrane. C extending very shortly beyond apex of R5; Sc incomplete, not reaching level of origin of Rs; Rs originating at basal third of wing; first sector of Rs short, sinuose, well sclerotized; R4 long, originating basally to medial fork, oblique, without clear angle close to origin; r-m absent, base of M1+2 clearly fused to Rs; bM entirely absent; M1+2 long, medial fork originating slightly basal to apex of R1; m-cu long, almost longitudinal; CuA clearly curved close to apex; A1 very faint at apex. All posterior wing veins with macrotrichia except first sector of Rs, basal half of first sector of CuA, M3+4, m-cu, and basal third of A1. M2, M4 and CuA more sclerotized than M1+2, M1, and A1. Abdomen. Brown, apices of segments obscurely pale; Abdomen elongate, segments wider than long; segments brown with a yellowish basal band on segments II to VII. Terminalia ( Fig. 9–11 ). Gonocoxites fused to each other ventrally, forming a syngonocoxite, but also dorsally, distal dorsal projection of gonocoxites about three times the width, no distinctive distal bristle. Gonostyli long and flattened, thinner at apex, but not blunt, inner margin blade-like, with a row of about 100 teeth-like spines, slightly separated from each other, base of gonostylus not expanded inwards ( Fig. 10 ). Tegmen longer than wide; aedeagus with no lateral expansions at base, with an irregular shape at apex ( Fig. 11 ). Tergite 9 small, weakly sclerotized, slightly longer than wide, covering the “opening” left by the dorsal fusion of the gonocoxites; cerci longer than tergite 9 and folded.

Female. Similar to male (including size). Terminalia ( Fig. 12 ). Sternite 8 slightly wider than long, medial distal notch entirely dividing sternite into two separate sclerites, individual digitiform projections distally with either long or short setae. Tergite 8 well developed. Sternite 9 (vaginal furca) extending anteriorly slightly beyond base of sternite 8, parallel sides, very slender. Tergite 10 short, sternite 10 wide, quite membraneous. Basal and distal segments of cerci elongate, longer setae not on digitiform projections.

Comments. The species was originally described in Ditomyia and the first time it appears as a Nervijuncta species was in the catalogue of the family in the Neotropical Region ( Papavero 1977), but without indicating that it was a new combination. For the differences with N. laffooni , see above.

Figures

FIGURE 8. Nervijuncta conjuncta, male wing (Argentina, Neuquén).

FIGURE 9. Nervijuncta conjuncta, male terminalia (Argentina, Neuquén). Dorsal view. Ae, aedeagus; Ce, cercus; Gc, gonocoxite; Gs, gonostylus; S 8, sternite 8; T 8, tergite 8; T 9, tergite 9; Tg, tegmen.

FIGURES 10 – 11. Nervijuncta conjuncta, male (Argentina, Neuquén). 10. Detail of gonostylus. 11. Detail of aedeagus (Ae) and tegmen (Tg), dorsal view.

FIGURE 12. Nervijuncta conjuncta, female terminalia (Chile, Osorno, Pucatrihue). Ventral view. Ce 1, basal segment of cercus; Ce 2, distal segment of cercus; S 8, sternite 8; T 8, tergite 8; T 9, tergite 9; T 10, tergite 10; VF, vaginal furca.