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.