Australachalcus acornis, Pollet, 2005

Pollet, Marc, 2005, Systematic revision of Neotropical Achalcus and a related new genus (Diptera: Dolichopodidae, Achalcinae) with comments on their phylogeny, ecology and zoogeography, Zoological Journal of the Linnean Society 143 (1), pp. 27-73 : 49-51

AUSTRALACHALCUS ACORNIS SP. NOV. ( FIG. 12 )

Male. Rather small, stout species. Head. Face blackish brown, at least 2¥ as wide as ocellus, not reaching lower eye margin. Frons brownish black. Occiput strongly concave, brownish black, shining bronze. Palp circular, very small, 1/13 of eye, dark brown, partly hidden behind inner eye margin. Antenna mainly dark with scape brownish black; pedicel pale brown; first flagellomere dark brown, acute, 2.9¥ as long as deep and 2¥ as long as scape and pedicel combined. No arista present ( Fig. 12C ).

Thorax. Almost entirely blackish brown with slight green metallic reflection, only postalar area of pleura yellowish. Metapleura concolorous with thorax. Eight ac, more than 2¥ as long as distance between rows. One (broken off) sutural bristle present. Several small bristles present between dc 1–3, presutural and sutural bristles.

Abdomen, including genital capsule, blackish brown, slightly shining metallic green. Hypopygium with apicoventrally spined hypandrium; aedeagus dark, very long with lateral extensions before apex; ventral bristle of surstylus with apical flag; VEP and DEP evident; postgonites doubtful; cercus very small, ribbon-shaped ( Fig. 12E ).

Wing. Halter pale, squamal fringe brownish. Wing pale, with R 4+5 and M 1+2 slightly diverging; vein R 4+5 curved. Proximal section of vein CuA 1 1.2¥ as long as apical section; CuAx ratio 2.1. Wing length 2.3 mm ( Fig. 12D ).

Legs including coxae mainly pale yellow. Coxa I with basal 1/4 slightly darkened on outer face, coxa II and III yellow, brown on basal half and 1/3 resp. Femur I with erect ventral bristle at basal 1/5, preceded by two small setae; with two strong pv preapical bristles ( Fig. 12A ). Femur II with one row of short inclined pv

A bristles on whole length, shortest at middle, at base almost half as long as femur is deep; with one ad preapical bristle ( Fig. 12B ). Femur III slightly infuscated on dorsal 1/3 with one small ad, inserted in lower half, and one strong av preapical bristles. Tibia I and II whitish yellow, tibia III pale yellow, infuscated on extreme apex; tibia I without dorsal bristles; tibia II with two moderate ad and one rather weak pd bristles (2 ¥ tibial depth), basal bristles forming ad-pd couple at basal 1/5; tibia III with two weak ad and three weak pd bristles and three slightly erect ventral setae amid dense pubescence. Tarsus I and II whitish yellow, tarsus I with 4th and 5th tarsomeres darker; tarsus II gradually darker towards apex; tarsus III dark brown. First tarsomere of leg III 0.9¥ as long as 2nd tarsomere.

Female. Unknown.

Etymology. Refers to the absence of the arista in this species.

Holotype. 1♂, CHILE: Region de Valparaiso, Prov. Quillota, Palma de Ocoa, Parque Nacional Campanas , hillside draw, 32∞93¢24 S, 71∞07¢81 W, 215 m, 21.xi- 6.xii.1997, MT ( Barria & Irwin) ( INHS; W, antenna, hypopygium, leg I and II mounted).

Figures

Figure 12. Australachalcus acornis sp. nov. (male). A, femur I; B, femur II; C, antenna; D, wing; E, hypopygium.