Systenus naranjensis Bickel

Bickel, Daniel J., 2015, The Costa Rican Systenus Loew (Diptera: Dolichopodidae): rich local sympatry in an otherwise rare genus, Zootaxa 4020 (1), pp. 169-182 : 176

Systenus naranjensis Bickel sp. nov.

( Figs 2 c, d, e)

Type material. HOLOTYPE ♂, COSTA RICA: Guanacaste: 3 km SE Rio Naranjo, 1.II.1993, F. Parker ( LACM, ex. EMUS; LACM Ent 329999).

Description. Male: body length: 3.5 mm; wing 3.4 x 1.2 mm. ( Fig. 2 c); similar to S. tenorio except as noted: Head: frons, face, and clypeus dark metallic green with thick grey pruinosity; palpus brown with short black setae and strong apical seta; proboscis brown; antenna ( Fig. 2 e); scape, pedicel and basal third of postpedicel mostly yellow with dark brown dorsobasal area on postpedicel, with distal 2/3 postpedicel dark brown; scape rather long and distally expanded and pedicel short; postpedicel elongate, subrectangular on basal third and tapering triangular distally, covered with short pubescence, about 3 times as long as basal width, and with short apical arista. Thorax: dorsum dark metallic green with bronze reflections and grey pruinosity; pleura green with dense grey pruinosity; metepimeron yellowish along basal half, becoming infuscated dorsally. Legs: all coxae, trochanters, femora and tibiae I & II, and very base of tarsus II yellow, with distal tarsus II brownish; FIII yellow with distal fifth brown; TIII yellow but basal fifth and distal third brown; basitarsus III yellow in basal half, with distal half and remainder of tarsus III brown; CI and CII with white anterior setae and shorter vestiture, CIII with strong white lateral seta at ½; major leg setae black; I: 5.1; 4.9; 2.7/ 1.8/ 1.2/ 0.8/ 0.6; leg I bare of major setation, and entire leg with short ivory colored vestiture, not usual black vestiture (MSSC); II: 5.5; 5.9; 3.4/ 2.5/ 2.0/ 1.3/ 0.8; TII with strong ad seta and weaker pd seta at ¼, and strong ad seta and small pd seta at 2/3, ventral seta at ½ and 2/3, and with apical ring of ad, pd, av and ventral seta; III: 6.0; 7.5; 1.5/ 3.9/ 2.4/ 1.5/ 0.8; TIII with short black, with some 6 black dorsal setae along length, and with apical ring of dorsal, ad and av seta. Wing: hyaline; vein M diverging from R4+5 and with M slightly bowed one third way between dm-cu crossvein and apex, and with M joining costa just behind wing apex; CuAx ratio: 0.7. Abdomen: tergite 1 mostly yellow; tergites 2 and 3 yellow, but black dorsally and anteriorly, and with dusting of grey pruinosity; tergites 4–5 mostly dull metallic green, but black dorsally and anteriorly and with dense grey pruinosity; tergite 6 black with little pruinosity; posterior margin of tergite 1 with posterior row of long black setae, tergites otherwise covered with short black vestiture; segment 7 forming elongate peduncle, with sternite 7 glabrous and tergite 7 covered with same black vestiture as preabdomen; hypopygium ( Fig. 2 d) dark brown with yellow surstylus and cercus; hypandrium as elongate cover; epandrium ventrally extending to narrow curved point; surstylus as elongate curved arm with short curved ventral fork; cercus elongate, swollen basally and distally, and covered with short yellow setae. Female: unknown.

Remarks. Systenus naranjensis is known from a single male taken at the Rio Naranjo site, Costa Rica in the month of February. Male leg I (including femur, tibia and tarsus), is almost entirely covered with short ivory colored vestiture but the cuticle is yellow. The coloration of the antennae ( Fig. 2 e) is diagnostic.

Etymology. This species is named after the place where the holotype was collected, Rio Naranjo.

Figures

FIGURE 2. Systenus emusorum sp. nov. (holotype): a. male habitus, left lateral; b. hypopygium, left lateral. S. naranjensis sp. nov. (holotype): c. male habitus, left lateral; d. hypopygium, left lateral; e. male head, anterior.