Australachalcus incisicornis, 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 : 59-61

AUSTRALACHALCUS INCISICORNIS SP. NOV. ( FIG. 20 )

Male. Rather small and slender species. Head. Face dark brown, narrow, not as wide as ocellus. Frons dark brown. Occiput convex with distinct central dorsal concavity, dark brown. Lower postocular bristles distinctly shorter than uppermost ones. Palp minute (1/11 of eye), ovoid, yellowish white; with black pubescence on disc and whitish marginal fringe. Antenna mainly yellow, distinctly infuscated dorsally; first flagellomere triangular, with deep subapical notch, 1.4¥ as long as deep, and 1.9¥ as long as scape and pedicel combined. Arista as long as first three joints of antenna, inserted in subapical notch, with microscopic pubescence ( Fig. 20B ).

Thorax. Mesonotum and scutellum reddish yellow with presutural depression entirely dark and scutellum slightly darkened on disc; with notopleura slightly infuscated and humeri paler. Pleura and postnotum brownish yellow, latter with very small black frontolateral triangle. Metapleura entirely reddish yellow. 7–8 ac, 1.5–2¥ as long as distance between rows. One small sutural bristle present.

Holotype. 1♂, CHILE: Region del Biobio, Prov. Concepción, Concepción (F. & M. Edwards) ( BMNH; D), not examined.

Other material examined. CHILE: Region de los Lagos, Prov. Llanquihue : 1♂, 3♀, 3 km NW Ensenada 41∞11¢S 72∞32¢W, 29.i.1998 ; 1♂, 1♀, 30.i.1998 (Woodley) ( USNM; D); Prov. Osorno : 3♂, Lago Puyehue, 80 km E. of Osorno (secondary forest), 17–18.i.1997, YWT (Bickel) ( POLLET, CNC; W, antenna, leg I and hypopygium of one ♂ mounted) ; 1♂, Rio Coihueco , c. 31 km NW Las Cascades 40∞54¢S 72∞44¢W, 222 m, 6.i.1998 (Woodley) ( USNM; D) ; Region del Biobio, Prov. Nuble : 1♀, vicinity of Cueva Pincheira , 41 km SE Chillán 36∞54¢S 71∞33¢W, 1100 m, 16.ii.1998 (Woodley) ( USNM; D) ; 11♂, 9♀, 40 km E. of San Carlos , 23.xii.1950 ; 1♂, 24.xii.1950 (Ross & Michelbacher) ( CAS; D, wing and antenna of one ♀ mounted) .

Remarks. The male antenna as depicted by Van Duzee (1930: plate II, fig. 58) is not very accurate and most Abdomen, including genital capsule, blackish brown with olive-green shining; tergites with very strong marginal bristles; 6th tergite small, 5th sternite with caudal incision. Hypopygium with apicoventrally spined hypandrium; aedeagus with two free-ended subapical lateral processes; midventral bristle of surstylus simple; VEP evident, postgonites pale, DEP not evident; cercus very small, tapering, with long black apical bristle ( Fig. 20C ).

Wing. Halter distinctly black. Wing slightly darkened, costal cel darker, with R 4+5 curved; R 4+5 and M 1+2 diverging at apex. Proximal section of vein CuA 1 2.5¥ as long as apical section; CuAx ratio 1.5. Wing length 2.5–2.7 mm (n = 3) ( Fig. 20A ).

Legs. Including coxae whitish yellow, largely infuscated. Coxa I with whitish, dense, short pubescence and black, small marginal and large apical bristles. Femur I with erect ventral bristle, less than half as long as femur is deep, basad of row of rather short av bristles along whole length, decreasing in length towards apex; with two strong pv preapical bristles. Femur II with basal 1/3 whitish yellow, then abruptly blackish on apical 2/3; with one strong ad, one av and one pv preapical bristles. Femur III with basal 1/3 whitish yellow and dorsal, ventral and entire apical 2/3 blackish; with one thin but long ad, inserted in lower 1/3, one very strong av and one small preapical pv bristles. Tibia I blackish, except for extreme base, without dorsal bristles; tibia II whitish yellow, infuscated at middle with two strong ad and one strong pd bristles, basal bristles not forming ad-pd couple; tibia III brownish, with three ad and three pd bristles, dense pd pubescence and a few ventral setae. Tarsus I and II brown with 5th tarsomere black; tarsus III entirely black. First tarsomere of leg III 0.7¥ as long as 2nd tarsomere. Body length 1.8–2.1 mm (n = 3).

Etymology. Refers to the distinct subapical notch of the 1st flagellomere in this species.

Holotype. 1♂, CHILE: Region de los Lagos, Prov. Chiloé, Isla Chiloé, Dalcahue , 17–31.i.1962 (L. Peña) ( CNC; D, hypopygium mounted).

Paratypes. CHILE: 2♂, Region Aisen, Prov. Aisén, Puerto Cisnes 44∞45¢S 72∞40¢W, 1–15.ii.1961 (L. Peña) ( CNC; D, antenna, wing and hypopygium of 1♂ mounted) .

Figures

Figure 20. Australachalcus incisicornis sp. nov. (male). A, wing; B, antenna; C, hypopygium.