Calamoncosis unicornis Wheeler & Solecki

Wheeler, Terry A. & Solecki, Anna M., 2013, New species of Calamoncosis Enderlein (Diptera: Chloropidae) from South Africa, Zootaxa 3702 (4), pp. 379-385 : 383-384

Calamoncosis unicornis Wheeler & Solecki sp. n.

( Figs. 8–13 )

Diagnosis: This species may be distinguished from other described Calamoncosis by the modified antenna. The male antenna has an elongate and distinctive first flagellomere, and the arista is reduced to a minute stub. In the female, the first flagellomere is elongate but retains an arista.

Description: Total length: 1.7–2.0 mm (male), 2.3–2.4 mm (female); head + thorax length: 1.3–1.4 (male), 1.4–1.8 (female). Overall colour shining dark brown; head as long as high, frons densely microtomentose, appearing velvety, especially adjacent to frontal triangle, interfrontal and fronto-orbital setulae sparse (sparser than scutal setulae), fine, brown; frontal triangle 0.6–0.7 times length of frons, polished including ocellar tubercle, with setulae slightly longer than interfrontals, in one irregular punctate row just inside margin of triangle; inner vertical setae barely differentiated from interfrontals, outer vertical seta, ocellars and postocellars longer than interfrontals, ocellars reclinate, postocellars slightly convergent; eye with long, sparse ommatrichia, each hair slightly longer than diameter of 2 ommatidia; gena dark brown, vibrissal angle obtuse, not extending beyond anterior margin of eye, genal height 0.15 times eye height; face dark yellow to brown with carina strongly projecting and clearly visible in lateral view, extending entire length of face ( Fig. 8 ); antenna with pedicel dark yellow; first flagellomere rounded and yellow at base, with brown apex; male first flagellomere drawn out apically into a long point, and with long, dense pubescence ( Fig. 9 ); female first flagellomere elongate but less attenuated ( Fig. 10 ); male arista reduced to a minute stub visible only at high magnification, female arista white, thick at base, pubescent; palpus narrow, as long as gena, dark yellow-brown; proboscis brown, elongate, geniculate, each segment equal to head length ( Fig. 8 ).

Scutum shining but densely punctate, evenly covered with long, pale setulae; thoracic setae: 1 anterior and 2 posterior notopleural (some specimens have additional small, weak notopleurals), 1 postalar, 1 postsutural intraalar, 1 dorsocentral stronger and darker than surrounding setulae; scutellum round, wider than long, punctate and rugose dorsally, apical scutellar setae dark, strong, shorter than scutellum, arising from small but distinct tubercles, at least two pairs of black subapical setae, arising from small but distinct tubercles, longer than other scutellar setae, but shorter and weaker than apicals, other scutellar setae as strong as scutal setulae; thoracic pleurites mostly bare, anepisternum microtomentose posterodorsally, katepisternum with sparse, pale setulae. Legs: fore femur yellow with brown shading in middle, other femora and tibiae dark brown with yellow apices, tarsi yellow; male mid-femoral organ a dense patch of 25-30 small tubercles with minute setulae, hind-tibial organ indistinct, tibia swollen in middle but only sparse velvety setulae apparent. Wing faintly brownish, veins pale brown; a pronounced ventral bulge in cu p area; ratio of costal sectors C1: C2: C3: C4–1: 1: 0.6: 0.4; halter dark brown.

Abdomen slightly paler than thorax, shining.

Male genitalia ( Figs. 11–13 ): epandrium higher than long in lateral view, broad in posterior view, with dense setae on posterior two-thirds; surstylus trapezoidal; narrower at base than margin, with 2-3 rows of weak setae on sinuous margin; hypandrium very robust anteriorly, pregonites, postgonites and phallic guide all well-sclerotized; postgonites with weak setulae posteriorly; basiphallus well-sclerotized, distiphallus longer than basiphallus, membranous; cerci fused medially, not projecting ventrally as in many Oscinellinae , indistinctly sclerotized; subepandrial sclerite not well-developed.

Female postabdomen with segments 8–10 laterally compressed and sclerotized, cerci laterally compressed, sclerotized, knifelike.

Type material: Holotype ♂: SOUTH AFRICA: East Transvaal: Guernsey Farm, 15km E Klaserie, 19- 31.xii.1985, P.M. Sanborne, Malaise (LEM). Paratypes: same data as holotype (7♂, 4♂, LEM).

Etymology: The species name refers to the superficial resemblance of males of this species (in lateral view) to the mythical horned horse.

Remarks: The modified antennae make C. unicornis morphologically distinct from other Calamoncosis , and, indeed, other known chloropids.

Based on the structure of the female ovipositor this species would be assigned to the subgenus Rhaphiopyga Nartshuk.

Figures

FIGURES 8 – 13. Calamoncosis unicornis. 8. male head, lateral. 9. male antenna, lateral. 10. female antenna, lateral. 11. male genitalia, lateral. 12. male genitalia, posterior. 13. male genitalia, ventral. Abbreviations: ar—arista, flag—first flagellomere, cer—cerci, epd—epandrium, ses—subepandrial sclerite, sur—surstylus.