Isoneuromyia variabilis Evenhuis

Evenhuis, Neal L., 2006, New species of Isoneuromyia Brunetti (Diptera: Keroplatidae) from the Oriental Region, Zootaxa 1140, pp. 1-29 : 20-22

Isoneuromyia variabilis Evenhuis , n. sp.

( Figs. 8 , 28 , 42)

Diagnosis

Similar in appearance to jata but distinguished from it by the brown scutellum (yellow in jata ) and the presence of hairs on the apex of the fore femur (this area bare in jata ).

Description

MALE. Lengths: Body: 11.3–16.5 mm; wing; 7.0– 9.2 mm.

Head. Vertex and occiput immediately behind ocelli black; remainder of occiput orange with yellow tomentum. Ocelli in horizontal line. Frons yellowish orange, bare. Antennae orange. Face yellow with brown mottling laterally, silvery pruinose. Palpi and proboscis orange.

Thorax. Mesonotum predominantly yellow with two to three black stripes, medial stripe extending anteriorly to pronotum but faded, reduced and not reaching pronotum, or absent altogether. Scutellum dark brown. Mesonotum with admixture of small recumbent black hairs and yellow tomentum, patch of thick black setae above wing root, on postalar calli, and posterior margin of scutellum. Prescutellar area tapering to scutellum. Pronotal lobes yellow with black hairs laterally. Pleura (except predominantly yellow laterotergite) and mediotergite dark brown, bare. Halter yellow.

Legs. Coxae yellow with black hairs; fore and hind coxae with spot of dark brown (amount of dark brown varies among specimens). Fore and mid femora yellow, hind femur yellowish with brown dorsoapically, all femora with recumbent black hairs, denser patches of black hairs appearing as brown ground color. Fore tibia with orange tibial pecten apically ( Fig. 8 ). Tibial spurs black. Fore basitarsus 1.2 x length of fore tibia. Mid and hind basitarsi subequal in length to lengths of respective tibiae. Claws minute.

Wing. Brownish yellow hyaline anteriorly along costal margin, subhyaline elsewhere; vein R4 slightly sinuous, ending in C slightly beyond end of R1; veins M2, CuA1, and CuA2 not reaching wing margin.

Abdomen. Thin, tergites IV–VI expanded in lateral view ( Fig. 28 ). Tergites I–III, V black with orange basally, dense recumbent black hairs on black portion of segments, bare on orange portion; tergite IV orange with thin band of black color covered by black tomentum along posterior margin; tergites VI–VII black with dense black recumbent setae; tergite VIII yellow with yellow recumbent hairs. Sternum patterned as on tergites except I–IV with thin black band of recumbent hairs along posterior margin.

Hypopygium (Fig. 42). Gonocoxites and gonostyli reddish orange, densely fine yellowish white pilose, apex with two large dark black teeth and single short squarish peglike tooth in close association with lower tooth (gonostylus needs to be turned slightly to see this peg­like tooth).

FEMALE. As in male except abdominal segments predominantly orange, black posterobasally; cerci enlarged (cf. Fig. 9 ), length subequal to length of abdominal segment VI, with scattered minute brown hairs.

Types

Holotype ♂ (BPBM 16,600) and paratype Ψ from: LAOS: Vientiane Province: Ban Van Eue, 15 May 1966, native collector. Other paratypes: LAOS: Vientiane Province: 1 ♂, Ban Van Eue, 31 May 1965, native collector; 2♂, same data, 30 Jun 1967; 2 ♂ same data, 30 Sep 1966. Holotype in BPBM. Paratypes in BPBM and MNHN.

Remarks

In addition to the variability of the medial mesonotal stripe (see description above), the laterotergite varies from almost all yellow (with brown only ventrally) to (rarely) predominantly dark brown with paler medial area. In most specimens, the laterotergite is predominantly yellow or at least contrastingly paler than surrounding pleural sclerites. The tibial pecten also varies in size, but is always a shining orange in color.

Etymology

The species epithet derives from the Latin variabilis , referring to the variable nature of the medial mesonotal stripe, size of the tibial pecten, and coloration of the laterotergite.

Figures

FIGURES 7 – 10. 7. Isoneuromyia splendida, n. sp., thorax, lateral view, vestiture removed. 8. Isoneuromyia variabilis, n. sp., apex of fore tibia showing tibial pecten in association with tibial spur. 9 – 10. Isoneuromyia female terminal abdominal segments, showing relative lengths of cerci. 9. I brunettii, n. sp. 10. I. yorki, n. sp.

FIGURES 27 – 33. 27 – 30. Isoneuromyia habituses, lateral view showing thoracic and abdominal shapes and patterning, legs beyond coxae removed and wing venation not shown. 27. I. brunettii, n. sp. 28. I. variabilis, n. sp. 29. I. nigerrima, n. sp. 30. I. pallidopsis, n. sp. 31 – 33. Isoneuromyia abdomens, dorsal view showing patterning. 31. I. splendida, n. sp. 32. I. subapicalis, n. sp. 33. I. nigribasis, n. sp.