Campsicnemus zigzag Evenhuis

Evenhuis, Neal L., 2008, The Campsicnemus lobatus and zigzag groups in the Society Islands, French Polynesia (Diptera: Dolichopodidae), Zootaxa 1910, pp. 27-44 : 42-43

Campsicnemus zigzag Evenhuis , new species

( Figs. 18 , 23 )

Diagnosis. Easily separated from the other members of the zigzag group by the characteristic zigzag-shaped setae on the ventral surface of the mid femur ( Fig. 18 ) in males (this setae hooked, curlicue, or kinked in the other species of the zigzag group) and the mid tibia slightly bowed with dark sclerotization on the lateral surface and row of strong stiff black setae on the mesal surface (mid tibia shaped not with these characters in the other species in the zigzag group).

Description. Body length: 1.3–1.5 mm. Wing length: 1.2–1.6 mm. Male. Head. Black, face black; oc and vt black, about one-third length of antennal arista; front, occiput, and vertex black with blue highlights; face constricted at middle, almost holoptic, eyes separated below antennae by width of 1–2 ommatidia; palp small, dark brown; proboscis brown, extending slightly below eye in lateral view; antennal segments brown; postpedicel conical, length about 2 x width; arista slightly longer than head height.

Thorax: Mesoscutum and scutellum brown dorsally, with a few metallic greenish highlights laterally; pleura all yellow except dark brown metepimeron; thoracic setae black: 1 + 3 dc; 2 np; 2 ph; 1 pa; 1 + 1 sc; ac absent; halter stem and knob yellowish brown.

Legs: CI white; CII brown; CIII yellow; FI and FII all yellow; FIII yellow with brown on apical onefourth; rest of legs yellowish brown; FII ( Fig. 18 ) with 8–9 stiff black setae ventrally, with one thick black straight seta and one thick black zigzagged seta on apical third of ventral surface (MSSC); TiII ( Fig. 23 ) slightly bowed with dark sclerotization on lateral surface, with row of 9–10 strong black setae along mesal surface setae basomedially and 3 strong black setae on apical one-third (MSSC), smaller black setae and hairs along entire ventral and posterior surfaces. Remainder of leg segments without MSSC.

Wing: Pale smoky throughout; subcostal section straight, not concave; alula extremely reduced; no indentation on M1+2 beyond crossvein dm-cu; crossvein dm-cu perpendicular to M1+2.

Abdomen. Brown with short black hairs dorsally on each tergite, a few longer hairs laterally; tergal interstices whitish; sternites brown. Hypopygium brown with brown cerci, not dissected.

Female. As in male except for lack of MSSC; postpedicel length subequal to width; legs normal, without modifications.

Types. Holotype ɗ (BPBM 16,640) [BPBM 101326] and 2ɗ [BPBM 101327], 2Ψ [BPBM 101328] paratypes from FRENCH POLYNESIA: Society Is: TAHITI NUI: Mt. Mauru, Faatautia, 730 m, 17°37'45"S, 149°21'10"W, riparian habitat above and below lava tube, 19 Jul 2006, N. Evenhuis, P. O’Grady. Other paratypes: FRENCH POLYNESIA: Society Is: TAHITI NUI: 1 ɗ [BPBM 101329], 2Ψ [BPBM 101330], Mt. Mauru, Faatautia, stream at hydro-electric structure, 720 m, 17°37'39"S, 149°31'26"W, sweeping wet rocks and seeps, 19 Jul 2006, N. Evenhuis, P. O’Grady. Holotype in BPBM. Paratypes in BPBM and EMEC.

Non-type material: FRENCH POLYNESIA: Society Is: TAHITI ITI: 3ɗ [ BPBM 101331] (damaged), 3.5 km SE of Tautira, sweeping wet sand and coral rubble along beach, 18 Jul 2006, N. Evenhuis, P. O’Grady.

Remarks. The finding of 3 specimens of this species at the Tahiti Iti beach locality was surprising as the other specimens are all associated with higher elevation freshwater riparian habitats. But also collected at this beach in our coral rubble sweeps were specimens of an as yet undetermined Simulium . The latter specimens have been sent to Doug Craig in hopes he can identify them as he said he never expected that there would be beach simuliids in Tahiti (we found other beach simuliids at other localities so this collection is not an anomaly).

Etymology. The specific epithet derives from the French zigzag = “forked lightning”; referring to the characteristic stiff, zigzag-shaped, black seta on the ventral surface of the male mid femur.

Figures

FIGURES 14 – 18. Campsicnemus zigzag group male mid femur. 14. C. mylloseta; 15. C. ogradyi; 16. C. ostlinx; 17. C. tahaanus; 18. C. zigzag.

FIGURES 19 – 23. Campsicnemus zigzag group male mid tibia. 19. C. mylloseta; 20. C. ogradyi; 21. C. ostlinx; 22. C. tahaanus; 23. C. zigzag.