Elachiptera cultrata Wheeler and Forrest, 2002

Wheeler, Terry A. & Forrest, Jessica, 2002, A new species of Elachiptera Macquart from the Galápagos Islands, Ecuador, and the taxonomic status of Ceratobarys Coquillett (Diptera: Chloropidae), Zootaxa 98, pp. 1-9 : 2-5

Elachiptera cultrata Wheeler and Forrest , sp. nov. ( Figs. 1­5 )

Diagnosis.­ This species may be distinguished from other New World species of Elachiptera by the combination of the breadth of the arista, the shining, yellow scutum with black dorsocentral stripes, the primarily black upper half of the occiput, the presence of a short, pale hind­tibial spur and the shape of the male genitalia.

Description.­ Total length 1.8­4.1mm. Frons yellow, palest anteriorly, subshining, longer than broad; frontal triangle shining yellow except for black ocellar tubercle; triangle with slightly convex sides, extending almost to anterior margin of frons; antenna yellow ventrally, darkened dorsally; first flagellomere reniform; arista black, densely haired, flattened, broad basally, evenly tapering; occiput with yellow spot behind frontal triangle, black on remainder of dorsal half; face yellow, shining; eye with short ommatrichia; gena yellow, palest anteriorly, 0.1 times eye height; vibrissal angle not projecting; palpus and proboscis pale yellow; proboscis short, fleshy. Cephalic chaetotaxy: 5­6 fine, reclinate fronto­orbital setae, two only slightly longer than rest; several interfrontal setulae on anterior of frons, median pair relatively strongly developed; single row of setulae along border of frontal triangle; ocellar bristles short, erect, convergent; postocellar bristles long, cruciate; inner vertical bristles not easily distinguished from surrounding setulae; outer vertical bristles long; setulae along occipital and genal margins; vibrissa approximately twice as long as subvibrissal setulae.

Thorax mostly shining, dark yellow with black, posteriorly tapering dorsocentral stripes present in most specimens; ventral margins of notopleuron and anepisternum dark; scutellum and posterior margin of scutum pollinose; scutum slightly longer than broad; scutellum dorsally flattened, trapezoidal, broader than long. Thoracic chaetotaxy: 1 fine postpronotal, 1 anterior and 1 posterior notopleural, 1 dorsocentral, 1 postalar bristle; scutellum with 1 pair of long, strong apical bristles borne on short dark tubercles at outer angles of scutellum and 1 pair of shorter, weaker subapical bristles; postpronotum, scutum, scutellum, and katepisternum setulose. Legs mostly yellow, variably darkened distally, especially on fore leg; hind tibia with pale pre­apical ventral spur, less than 0.5 times maximum diameter of tibia. Wing length 1.8­2.9mm; second costal sector 1.2­1.4 times length of third costal sector. Halter white.

Abdominal tergites brown, rarely paler, setulose, shining, syntergite 1+2 darker laterally, not noticeably elongated; sternites very pale brown, setulose.

Male postabdomen: Epandrium with long, dense setae; surstylus long, straight and narrow, with row of long anterior setae near base ( Fig. 5 ); cercus broad with narrow lobe projecting ventrally and posteriorly ( Fig. 4, 5 ), cercus with one long seta on ventral projection, another dorsal to this, and a few shorter setae; cerci separated by narrow, V­shaped median cleft ( Fig. 4 ); basiphallus sclerotized ( Fig. 4 ); distiphallus sclerotized, strongly curved, tapering distally ( Fig. 5 ).

Type material.­ Holotype M: ECUADOR: Galápagos Islands: Santa Cruz: 4km N Bellavista, Media Luna , 620m, 14.v­13.vii.1985, S. & J. Peck, Miconia zone, FIT ( CNC) . Paratypes: Galápagos Islands: Floreana : 2F, 8km E Black Beach, 360m, 22­28.iii.1989, Scalesia zone, FIT, Peck & Sinclair ( CNC) ; 1F, agriculture zone, 350m, 22.iii.1989, sweeping, B.J. Sinclair ( CNC) ; Isabela : 7M, 1F, agriculture zone, 380m, sweeping, 9.iii.1989, B.J. Sinclair ( CNC) ; 3M, 5F, Sierra Negra , 1000m, 3­11.ii.1989, sweeping pampa, B.J. Sinclair ( CNC) ; 5M, 2F, guava­pampa zone, 600m, 4.iii.1989, B.J. Sinclair ( CNC) ; 1M, Santo Tomás , 300m, 4­15.iii.1989, humid forest, Malaise, Peck & Sinclair ( CNC) ; 11F, 5km NW Santo Tomás, 600m, 3­15.iii.1989, guava forest, FIT, S. Peck ( CNC) ; 2F, pampa zone, 700m, 3­12.iii.1989, yellow pan traps, B.J. Sinclair ( CNC) ; Santa Cruz: 7M, 5F, 4km N Bellavista, Media Luna , 620m, 14.v­13.vii.1985, S. & J. Peck, Miconia zone, FIT ( CNC) ; 1M, 1F, Media Luna, 500m, Miconia zone, 01­29.ii.1989, Malaise, Peck & Sinclair ( CNC) ; 3F, same data except FIT­trough ( CNC) ; 2F, Media Luna, Miconia zone , 600m, 21.i.1989, pools of intermittent stream, B.J. Sinclair ( CNC) ; 1M, 1km S Media Luna, Miconia zone , 2­8.ii.1989, dung trap, 550m, B.J. Sinclair ( CNC) ; 1F, same data except mushroom trap ( CNC) ; 2M, 4F, Puntudo­Media Luna trail, 18.iii.1989, pampa zone, 600m, B.J. Sinclair ( CNC) ; 1M, Puntudo, 650m, Scalesia forest , 1­ 30.iii.1989, Malaise, Peck & Sinclair ( CNC) ; 1F, same data except FIT ( CNC) ; 4F, Puntudo hilltop, 700m, 2.ii.1989, pampa zone, B.J. Sinclair ( CNC) ; 6F, 1km N Puntudo, Scalesia zone, 650m, 1­8.iv.1989, FIT, S. Peck ( CNC) ; 6M, Bellavista , agriculture zone, 160m, 27.ii.1989, B.J. Sinclair ( CNC) ; 1M, Bellavista , agriculture zone, field, 1­9.iv.1989, Peck & Sinclair ( CNC) ; 2M, 4F, Tortoise Reserve , 180m, transition zone, 6.ii.1989, MV lights, B.J. Sinclair ( CNC) ; 5M, 5F, same data except sweeping ( LEM) ; 2M, 1F, Los Gemelos, 600m, Scalesia forest , sweeping, 25.ii.1989, B.J. Sinclair ( CNC) ; 2M, 1F, same data except MV lights, 31.i.1989 ( CNC) ; 2F, Los Gemelos, 610m, Scalesia forest , FIT, 1­ 28.ii.1989, Peck & Sinclair ( CNC) ; 3F, Los Gemelos, 600m, Scalesia forest , FIT, 1­ 9.iv.1989, Peck & Sinclair ( CNC) ; 1M, Los Gemelos, 31km N Santa Rosa, 570m, Scalesia forest , 13.vi­15.vii.1985, FIT and Malaise, S. & J. Peck ( CNC) ; 1M, 2km N Los Gemelos , 300m, transition zone, 9.iv.1989, B.J. Sinclair ( CNC) ; 1F, Charles Darwin Research Station , arid zone, 16.i.1989, MV lights, B.J. Sinclair ( CNC) ; 1F, Sierra Crocker­hill top, 860m, 8.ii.1989, sweeping, B.J. Sinclair ( CNC) ; Seymour : 1M, MV lights, 23.i.1989, B.J. Sinclair ( CNC) .

Etymology.­ The species name is derived from the Latin culter (ploughshare), referring to the shape of the distiphallus.

Comments.­ This is the only species of Elachiptera known from the Galápagos Islands. The type specimens were collected in a wide range of habitats on four islands; however, the species is apparently associated primarily with humid areas. Although so far known only from the archipelago, E. cultrata appears to be closely related to a group of species known from the southeastern Nearctic and northern Neotropical regions (see Discussion).

Figures

FIGURES 1 ­ 5. Elachiptera cultrata. 1. hind tibia, and basal tarsal segments (lateral); 2. scutellum; 3. antenna; 4. male genitalia (posterior); 5. male genitalia (lateral). Abbreviations: basph ­ basiphallus; cer ­ cercus, epd ­ epandrium; hyp ­ hypandrium; phal ­ phallus; spur ­ hind­tibial spur; sur ­ surstylus. Scale bar = 0.1 mm (Figs. 4 ­ 5).