Elachiptera coniotrigona Duda, 1933

Mlynarek, Julia J. & Wheeler, Terry A., 2008, Revision of the Costa Rican species of Elachiptera (Diptera: Chloropidae), Zootaxa 1754, pp. 41-51 : 43

Elachiptera coniotrigona Duda, 1933

( Figs. 1–5 )

Elachiptera coniotrigona Duda, 1933: 204 .

Description: Total length 2–2.7 mm. Overall colour black; frontal triangle black, shining except for sparse microtomentum posteriorly (see Remarks), frontal triangle 0.55–0.6 times length of frons with slightly convex margins ( Fig. 1 ); ocellar tubercle black, microtomentose; frons yellow, longer than wide; cephalic setae pale, 4 fronto-orbital setae well-developed, middle 2 slightly longer; gena yellow, microtomentose, 0.1 times eye height; postgena wide, black and microtomentose; face yellow with median black spot below antennal margin; scape and pedicel yellow, brown dorsolaterally, first flagellomere reniform, mostly yellow, black at insertion of arista and dorsolaterally, arista black, broad and flat in basal half, tapering sharply beyond this, very narrow in distal third, pubescence about as long as width of arista at base ( Fig. 2 ); palpus yellow, proboscis and clypeus brown.

Scutum black, mostly shining, punctate, microtomentose on notopleuron, supra-alar region and just anterior to scutellum, 1.2 times longer than wide; scutellum black, flat dorsally, triangular, 0.7 times as long as wide, rugose, apical scutellar bristles strong, on small tubercles on dorsal margin of scutellum, lateral scutellar bristles on small tubercles, longer and darker than adjacent setae ( Fig. 3 ); thoracic pleurites mostly shining black; dorsal margin of anepimeron and lateral region of postscutellum microtomentose. Legs yellow, fore tarsus and hind tibia darker; femoral organ 2 rows of 2–4 small tubercles; tibial organ oval, black, 0.3 times length of tibia. Wing hyaline, ratio of costal sectors C1: C2: C3: C4 – 1: 1.5: 1.25: 0.5; halter white.

Abdomen black, sparsely microtomentose, anteromedial portion of syntergite 1+2 pale, desclerotized; syntergite 1+2 slightly longer than tergites 3 and 4 combined.

Male postabdomen ( Figs. 4, 5 ): Epandrium higher than long in lateral view, wider than high in posterior view, with sparse setae; surstylus short, wide, parallel sided with broadly rounded apex, surstylus with sparse short setae; cercus broad, rectangular, ventral projection large and rounded, cercus with sparse setae and one long posteroventral bristle, cerci separated by deep, narrow cleft; distiphallus weakly sclerotized, blunt-ended.

Material examined: COSTA RICA: Llano Grande, above Cartago at 7000ft, 26.i.1982, K.A. Spencer (1ɗ, 1Ψ, USNM); GUATEMALA: Antigua, 1500–1600m, vi.1981, N.L.H. Krauss (1ɗ, 2Ψ, USNM); Antigua, J.M. Aldrich (4ɗ, 7Ψ, USNM).

Remarks: This species was originally described from Guatemala ( Duda 1933) and had not been recorded from any other countries prior to this study ( Sabrosky and Paganelli 1984). Five of the 11 specimens collected by J.M. Aldrich in Antigua, Guatemala (2 males, 3 females) bear “ typus ” labels and determination labels handwritten by O. Duda and are apparently syntypes.

In the two Costa Rican specimens examined the frontal triangle is almost entirely shining, whereas in the Guatemalan specimens the posterior half of the triangle is microtomentose. This may represent intraspecific variation or the Costa Rican specimens may be a distinct species. Examination of additional specimens would be required to resolve this question.

Figures

FIGURES 1 – 5. Elachiptera coniotrigona. 1. head, dorsal. 2. head, lateral. 3. scutellum, dorsal. 4. male genitalia, posterior. 5. male genitalia, lateral. Abbrevations: cer—cercus; epd—epandrium; fr tr—frontal triangle; sur—surstylus. Scale bars = 0.2 mm (Fig. 1); 0.1 mm (Figs. 3, 4).