Systenus zurqui 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 : 178

Systenus zurqui Bickel sp. nov.

( Figs 3 c, d)

Type material. HOLOTYPE ♂, COSTA RICA: San José: Zurquí de Moravia. 10.05°N 84.02°W, 1600 m, Malaise trap, 10.VIII.2014, ZADBI-909 ( LACM; LACM Ent 320001). ( LACM Ent 300001); PARATYPE ♂, Puntarenas: Estación La Casona, R.B. Monteverde, A.C. Arenal, 1520 m, XII.1993, 253250 449700, #2605, N.G. Obando, ( INBIO, CR1001 865191).

Description. Male: body length: 2.6 mm; wing 2.5 x 0.7 mm ( Fig. 3 c); similar to S. tenorio except as noted: Head: proboscis yellowish, projecting anteriorly, keel-like; antenna dark brown with yellowish near base of postpedicel on median side; scape and pedicel short; postpedicel elongate, triangular and tapering gradually, covered with short pubescence, about 3 times as long as basal width, and with short apical arista. Thorax: dorsum dark metallic green but covered with thick grey pruinosity; pleura green with dense grey pruinosity; some 12 pairs of short ac. Legs: CI yellow; CII and CIII mostly dark brown, but distal eighth pale yellow; all trochanters, and the remainder of legs I and II yellow; FIII yellow basally but distal quarter mostly dark brown; TIII yellow but infuscated distally; tarsus III mostly yellow but with brown infuscation; CI and CII with white anterior setae and shorter vestiture, CIII with strong white lateral seta at ½; major leg setae black; I: 3.7; 3.6; 2.0/ 0.9/ 0.7/ 0.4/ 0.3; TI with normal short black vestiture; II: 4.3; 4.8; 2.4/ 1.5/ 1.0/ 0.8/ 0.5; TII with strong ad seta at 1/5 and ½, and weaker pd seta at 1/6 and 2/3, and with apical ring of ad, pd, av and ventral seta; III: 4.7; 6.0; 1.1/ 2.1/ 1.2/ 0.8/ 0.4; TIII with normal black vestiture, with ad-pd setal pair at 1/5 and with 4 spaced black dorsal setae, and with apical ring of dorsal, ad and av seta.

Wing: CuAx ratio: 0.7. Abdomen: tergites 1–6 metallic blue- green with only dusting of pruinosity posterior margin of tergite 1 with posterior row of long black setae, tergites otherwise covered with short black vestiture; segment 7 dark brown and forming unusually long peduncle, distinctly longer than length of epandrium, with sternite 7 glabrous and tergite 7 covered with black vestiture; sternite 8 forming cap-like cover over hypopygial foramen on left side of epandrium; hypopygium ( Fig. 3 d) dark brown with yellow surstylus and cercus; ventral epandrium extended ventrally with 2 subapical setae; surstylus forming long curved and tapering arm, bearing curved ventral lobe with apical seta, and with curved dorsal digitiform projection; cercus elongate and clavate, with subapical field of strong pale setae. Female: unknown.

Remarks. Systenus zurqui is known from the Zurqui site (collected in August) and Monteverde (collected in December), Costa Rica. Both sites are above 1200 m in elevation. The Monteverde specimen is distinctly larger (wing length 3.0) than the Zurqui specimen (2.5 mm), but they are otherwise similar. It has the diagnostic set of male characters of black tapering postpedicel, femora yellow except femur III dark brown in the distal quarter, tibia I without ivory colored vestiture, an unusually long hypopygial peduncle, longer than epandrium, and a subapical field of long pale setae on the cercus.

Etymology. The specific epithet “ zurqui ” is a place name and should be considered as a noun in apposition.

Figures

FIGURE 3. Systenus divericatus sp. nov. (holotype): a. male habitus, left lateral; b. hypopygium, left lateral. S. zurqui sp. nov.: c. male habitus, left lateral; d. hypopygium, left lateral.