Australachalcus longicornis, (VAN DUZEE), 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 : 61-64

AUSTRALACHALCUS LONGICORNIS (VAN DUZEE)

COMB. NOV. ( FIGS 21 , 22 )

Achalcus longicornis Van Duzee, 1930: 22

Male. Rather large, slender species. Head. Face blackish brown, dusted, about as wide as ocellus (undetermined in holotype due to strong shrinkage of head). Frons dark brown. Occiput concave, dark brown, shining. Palp about 1/4 of eye, ovoid circular, brownish yellow, with dark outer margin. Antenna dark brown with ventral half of pedicel whitish yellow on outer face; first flagellomere elongate triangular, rather tapering, 2.3¥ as long as deep and 1.9¥ as long as scape and pedicel combined. Arista 0.7¥ as long as first three joints of antenna, distinctly subapical ( Fig. 21B ).

Thorax including metapleura dark brown with alar and lateral scutellar areas yellowish. Eight ac, 2¥ as long as distance between rows. One rather strong sutural bristle present. Small additional bristles present between ps, sutural and dc 1–2.

Abdomen, including genital capsule, shining brown; tergites with strong marginal bristles, especially on 1st tergite; 6th tergite less than 1/3 as long as 5th. Hypopygium ( Fig. 22B ) with apicoventrally spined hypandrium; aedeagus robust, with asymmetrical enlargement near apex ( Fig. 22A, B ); midventral bristle of surstylus with apical flag; VEP and DEP evident; postgonites large, with dark apex; cercus rather short, narrow, with three flat apical bristles ( Fig. 22C ).

Wing. Halter dark. Wing very slightly infuscated, with R 4+5 gently curved and M 1+2 straight; both veins parallel at wing apex. Proximal section of vein CuA 1 3.4¥ as long as apical section; CuAx ratio 0.9. Wing length 2.6–3.1 mm (n = 2) ( Fig. 21A ).

Legs including coxae mainly pale yellow, with femora and entire leg III largely infuscated. Coxa II and III reddish yellow. Trochanters of legs I and II pale yellow, reddish brown in leg III. Femur I infuscated dorsally along whole length, with one erect ventral bristle at less than basal 1/5, about as long as femur is deep; with one row of small inclined av bristles along whole length; with one strong pv preapical bristle ( Fig. 21C ). Femur II very slightly infuscated dorsally, with 3–4 very strong (longer than femur is deep) erect av bristles at extreme base; with one strong ad preapical bristle inserted rather anteriorly. Femur III brownish yellow, strongly infuscated on dorsal half; with one row of strong av bristles in apical 1/3 (not visible in Fig. 21D ) and one row of perpendicular short but strong pv bristles on basal half; with one rather small ad, inserted in lower 1/3, and one rather weak av preapical bristles ( Fig. 21D ). Tibia I yellow, without dorsal bristles; tibia II whitish yellow with two moderate ad and one moderate pd bristles, basal bristles forming no clear ad-pd couple; tibia III brownish yellow, darkened on apical 1/4, with two small ad and four small pd bristles. Tarsus I yellow with 5th tarsomere dark; tarsus II whitish yellow, gradually darker towards apex with 5th tarsomere dark; tarsus III entirely dark brown. First tarsomere of leg III as long as 2nd tarsomere.

Female. Unknown.

Remarks. During the examination of the holotype, the long ventral bristle on the 3rd tarsomere of leg I, regarded as a diagnostic feature by Van Duzee (1930: fig. 55, plate II), appeared to be an artefact. The bristle was not inserted and only present on one of the legs.

Holotype. 1♂, CHILE: Region de los Lagos, Prov. Llanquihue, Casa Pangue, 4–10.xii.1926 (F. & M. Edwards) ( BMNH; D, hypopygium mounted), examined. Labels: ‘ Casa Pangue’ / ‘ S. Chile: Llanquihue prov. F. & M. Edwards BM 1927–63’/ ‘ Achalcus longicornis HOLOTYPE Van Duzee’.

Other material examined. CHILE: 1♂, Region de los Lagos, Prov. Chiloé, Isla Chiloé, Dalcahue , 17– 22.i.1962 (L. Peña) ( CNC; D, antenna, wing, leg I and II mounted) .

AUSTRALACHALCUS PSEUDOROBUSTUS SP. NOV.

( FIG. 23 )

Male. Small and stout species. Head. Face pale brown, slightly wider than ocellus. Frons dark brown. Occiput convex ventrally and distinctly concave dorsally, dark brown, shining. Uppermost postocular bristles black, lower ones brown. Palp very small (1/10 of eye), ovoid, almost circular, dark brown. Antenna largely dark with scape with pale spot at extreme base and pedicel reddish yellow on ventral half on inner face; first flagellomere dark, paler on extreme base, elongate triangular, about 1.8¥ as long as deep and 2¥ as long as scape and pedicel combined. Arista 0.6¥ as long as first three joints of antenna, distinctly subapical, with microscopic pubescence.

Thorax including metapleura blackish brown with scutellum dark reddish brown. Six ac, 2¥ as long as distance between rows. One fairly strong sutural bristle present. About three small bristles present between ps, sutural and 1st and 2nd dc.

Abdomen blackish brown with olive-green shining, genital capsule dark brown. Tergites with strong marginal bristles. Hypopygium with apicoventrally spined hypandrium; aedeagus with recurrent apical process; midventral bristle of surstylus with apical flag; VEP not evident; DEP and postgonites evident; cercus moderately developed, rectangular with somewhat enlarged apex ( Fig. 23 ).

Wing. Halter pale. Wing slightly infuscated, with R 4+5 hardly curving, R 4+5 and M 1+2 hardly diverging towards wing apex. Proximal section of vein CuA 1 2.0¥ as long as apical section; CuAx ratio 1.6. Wing length 2.1 mm.

Legs pale yellow with mainly dark coxae and dorsally infuscated femora. Coxa I yellow, distinctly infuscated brownish anteriorly; coxa II and III brown. Trochanters whitish yellow; trochanters of leg II with long black bristles. Femur I and II slightly infuscated dorsally, femur III distinctly infuscated on dorsal half; femur I with erect ventral bristle at basal 1/6, 1.5¥ as long as femur is deep, basad of three small erect av bristles till middle of femur followed by small inclined bristles till apex; with one small ad and two moderately strong pv preapical bristles. Femur II with one strong (as long as femur depth) erect av bristle at extreme base, rest of basal half bare; with one row of strong (two basal bristles as long as femur depth) rather erect pv bristles, decreasing in length towards apex; with one strong ad, one av and two pv preapical bristles. Femur III with one row of rather strong inclined av bristles, weakest at middle (basal bristles longer than 0.5¥ femur depth); with one weak ad, inserted in lower 1/3, and one very strong av preapical bristle. Tibia I and II whitish yellow, tibia III dark yellow; tibia I without dorsal bristles; tibia II with one small (1/10 of tibial length) ad and one small pd bristles, basal bristles forming ad-pd couple at basal 1/3; tibia III distinctly swollen, with two ad and two pd bristles; with dense pd and ventral pubescence, without distinct ventral setae. Tarsus I pale yellow with apex of 4th and with 5th tarsomere dark; tarsus II yellow, darker from 2nd tarsomere onwards with 5th tarsomere dark; tarsus III entirely brown. First tarsomere of leg III 0.8¥ as long as 2nd tarsomere. Body length 2.0 mm.

Female. Unknown.

Etymology. Refers to the resemblance of this species to the closely related A. robustus described below.

Holotype. 1♂, CHILE: Region del Maule, Prov. Curicó, Curicó, Estero La Jaula ( Nothofagus ), i.1964 (L. Peña) ( CNC; D, hypopygium mounted).

Figures

Figure 21. Australachalcus longicornis (Van Duzee) (male). A, wing; B, antenna; C, coxa and femur I; D, femur III, posterior view.

Figure 22. Australachalcus longicornis (Van Duzee) (male). A, hypandrium and aedeagus, ventral view; B, hypopygium; C, apex of cercus, dorsal view.

Figure 23. Australachalcus pseudorobustus sp. nov. (male). Hypopygium.