Keilbachia oligonema, Hippa, Heikki & Vilkamaa, Pekka, 2007

Hippa, Heikki & Vilkamaa, Pekka, 2007, The flagria group of Keilbachia Mohrig (Diptera, Sciaridae) in a biodiversity hot spot: nine new sympatric species from Kambaiti, Myanmar, Zootaxa 1556, pp. 31-50 : 45-47

Keilbachia oligonema sp. n.

( Figs 1 I, 2B, 3A, 9A–E)

Material studied. Holotype male (in NRMS). N.E. Burma ( Myanmar), Kambaiti, 7000 ft., 23.4.1934, R. Malaise. Additional material (in NRMS). 2 males with same data as holotype but dated 1.6. and 9.6.

Male. Colour. The specimens are strongly faded, almost unicolorous pale yellowish-brown. Head. Eye bridge 3 facets wide in the holotype, 4 facets wide in the other specimens. Face (prefrons) with 10–11 setae. Clypeus non-setose. Maxillary palpus ( Fig. 1 I) with three palpomeres. Palpomere 1 with one lateral seta and many hyaline sensilla widely scattered on dorsal surface, no sensory pit, palpomere 2 with 2–5 setae, and palpomere 3 with 3–7 setae. Antennal flagellomere 4, Fig. 2 B. Thorax. Anterior pronotum with 2–3 setae. Episternum 1 with 4–5 setae. Wing. Apex broken off on both sides in the holotype so that wing length, width/ length and c/w only refer to the additional specimens. Length 1.57 mm. Width/length 0.42. R1/R 0.74–0.88. c/ w 0.79. r-m as long as bM, r-m/bM 1.00, r-m and bM non-setose. Legs. Apex of fore tibia, Fig. 3 A. Length of fore basitarsomere/length of fore tibia 0.52 (only the holotype measured). Length of fore tibia/length of fore femur 1.17–1.27. Length of hind tibia/length of scutum+scutellum 1.62–1.67. Abdomen. Sternite 8 in the holotype non-setose, in the other specimens with 6 setae in a transverse posterior row. Hypopygium. Fig. 9 : Gonocoxites ventrally with a slight indication of an intercoxal lobe in holotype, more distinctly in the other specimens. Gonostylus with 2 rather short curved mesial megasetae arising from a common basal body, without other megasetae, without an apical tooth. In Fig. 9 B there is apparently only one curved megaseta, but in fact there are two, the more dorsal one being completely hidden under the more ventral one. Tegmen rather simple, broadly subtriangular.

Female unknown.

Discussion. The holotype on the one hand and the two other specimens on the other hand differ rather markedly in the width of the eye bridge, in the setosity of sternite 8 and in the character of the ventral intercoxal area of the hypopygium, and may represent two different species. Keilbachia oligonema is not particularly similar to any other described Keilbachia . It differs from all other Keilbachia with more than one long curved mesial megaseta on the gonostylus by lacking the apical tooth. The other Keilbachia with two mesial megasetae arising from the common basal body are K. acamptochaeta , K. bicuspis , K. biflagrispina and K. sp. 2. All these species differ from K. oligonema by having an apical tooth and also by having one or more mesial megasetae on the gonostylus in addition to the two curved ones.

Figures

FIGURE 1. Maxillary palpus. A, Keilbachia acamptochaeta sp. n. (paratype). B, K. flabellata sp. n. (holotype). C, K. gigas sp. n. (holotype). D, K. fasciata sp. n. (holotype). E, K. foveolata sp. n. (holotype). F, K. bicuspis sp. n. (holotype). G, K. rima sp. n. (holotype). H, K. filigera sp. n. (holotype). I, K. oligonema sp. n. (holotype). Scale 0.10 mm.

FIGURE 2. Antennal flagellomeres 3 and 4 (A) and flagellomere 4 (B – E). A, Keilbachia bicuspis sp. n. (holotype). B, K. oligonema sp. n. (holotype). C, K. fasciata sp. n. (holotype). D, K. filigera sp. n. (holotype). E, K. rima sp. n. (holotype). Scale 0.10 mm.

FIGURE 3. Apical part of fore tibia, prolateral view. A, Keilbachia oligonema sp. n. (Burma). B, K. fasciata sp. n. (paratype). C, K. rima sp. n. (holotype). D, K. acamptochaeta sp. n. (paratype). E, K. flabellata sp. n. (holotype). F, K. foveolata sp. n. (holotype). G, K. filigera sp. n. (holotype). H, K. bicuspis sp. n. (holotype). I, K. gigas sp. n. (holotype). Scale 0.10 mm.

FIGURE 9. Keilbachia oligonema sp. n. (A, B holotype, C, D, E the other specimen). A, part of hypopygium, ventral view. B, gonostylus, ventral view. C, basomedial part of hypopygium, ventral view. D, E, mesial megasetae of gonostylus, ventral view. Scale 0.10 mm.