Kribiodorum Kieffer, 1921

Cranston, Peter S., 2018, Kribiodorum Kieffer (= Stelechomyia Reiss) (Diptera: Chironomidae) extends into the Oriental region: three new species and expanded diagnoses, Zootaxa 4486 (4), pp. 535-547 : 537-538

Kribiodorum Kieffer

Kribiodorum Kieffer, 1921: 270 .

Stelechomyia Reiss, 1982: 294 . Type-species Chironomus perpulcher Mitchell (orig.des.)

Included species: Kribiodorum pulchrum Kieffer, 1921 ; Kribiodorum perpulchrum ( Mitchell, 1908) ; Kribiodorum belalong Cranston sp. n. Brunei, Kribiodorum malicky Cranston sp.n. Thailand and Kribiodorum kunene Cranston and Harrison sp. n. Namibia.

Generic diagnosis. Male as in Reiss (1982) and Cranston et al. (1989) extended and including the following:

Body length 2.6–5.5 mm, wing length 1.35–1.86 mm. Legs dark banded, wing iridescent, brown with variably interrupted transverse translucent patches ( Fig. 1C–D ).

Antenna. With 13 flagellomeres, A.R. 0.7–1.7.

Head. Eye bare with wedge-shaped or quadrate dorsomedial extension. Frontal tubercles absent. Palp 5– segmented, segment 2 almost globular, segment 3 with 0–2 sensilla not in pit.

Thorax. Antepronotal lobes narrowed dorsally and narrowly or more distinctly separated dorsomedially; scutum extended, overreaching antepronotum( Fig. 1A–B ). Without tubercle. Acrostichals present but numbers uncertain (see comments), dorsocentrals uniserial, up to 12 including 1–2 in humeral position, 3–6 prealars, 3–7 scutellars.

Wing ( Fig. 1C–D ) iridescent, brown with pale patches. Membrane finely punctate, without macrosetae. Anal lobe slight. Costa non-extended, ending above M1+2. R1 and R4+5 well separated with R2+3 running between and ending midway between apices of R1 and R4+5. R4+5 terminating slightly proximal to wing apex. V.R. c. 1.2–1.3. Veins R, R1 and R4+5 setose. Squama bare.

All legs with some darker pigmented bands, setae arising from these areas contrastingly darker than from pale cuticle. Fore-femur weakly to strongly dilate in distal 1/3, dark with dense dark setae. Variable patterns of dark and pale bands on all femora and tibiae ( Fig. 1H–L ), with some darkening on distal tarsomeres, perhaps faint or absent on short mid-leg tarsomeres. Fore-tibial apex with shallow rounded scale and long curved spur inserted subapically on scale ( Fig. 1E, F ), mid- and hind-tibial combs narrowly separated; shorter, higher comb with distinct spur, broader shallower comb without spur ( Fig. 1G ). LR1 2.0. Pulvilli slender, short, not extending beyond apex of simple claw.

Abdomen with dense long setae.

Hypopygium ( Figs. 1M , 2A–I ) with strong anal tergite bands, extending near to base of anal point, not meeting, enclosing field of dense long setae. Anal tergite squared off posteriorly, bearing subterminal anal point varying from long slender and tapering to broad and distally curved downward, with lateral flanges. Superior volsella ( Fig. 2E–I ) comprising raised base with few long setae and distal digitus, either a hyaline lobe or narrower and tapering to point. Mediolateral, in ventral plane at base of superior volsella a pad bearing 4–5 long, mediallydirected strong setae, represents a squat median volsella. Inferior volsella elongate, not fused to gonocoxite other than narrow base. Gonocoxite and gonostylus conventional, with microtrichia and long setae.

Female, based on 2 species only; as diagnosis above excepting dimorphism.

Head. Antenna with 6 flagellomeres (division between 1 st and 2nd can be faint) with paired hyaline sensilla located opposite and subapical on flagellomeres 2–6; terminal flagellomere dark ( Fig. 3A ). Palp with very short segment 2, distally of increasing length; segment 3 subapically with short single, perhaps double small sensillum. Clypeals numerous and strong, few linear aligned verticals.

Thorax with small, dorsally fused antepronotal lobes; scutum narrowed anteriorly, extending beyond antepronotum. Acrostichals not visible, few Dc (5–8) with anteriormost in humeral position; few prealars (2–4) and scutellars (2–3).

Wing ( Fig. 2C ) length 1.45–1.8mm, with dark pigment deeper and slightly more extensive than in male.

Legs as male, but the less dilate fore-femur all are depilate, thus length, strength and pigmentation of setae is not discernible. LR1 2.4. Pulvilli slightly shorter than claw.

Genitalia ( Fig. 3B, C, D ). Notum long, thin, with short rami. Gonocoxapodemes gently curved not fused medially, each with apparent weak branch into gonapophysis VIII. Coxosternapodeme strongly sclerotized, weakly curved. Gonapophysis VIII ( Fig. 3C ) with elongate dorsomesal lobe, essentially continuous with inner contour of vagina, microtrichiose, hyaline apico-medially, and distinct ventrolateral lobe of similar size to dorsomesal lobe, lying lateral to, and separate to dorsomesal lobe, microtrichiose with many short simple medio-apically directed setae. Apodeme lobe not visible. Labia well developed, hyaline, without microtrichia. Gonocoxite IX small, not extended laterally. Tergite IX broad, densely setose, undivided. Postgenital plate not visible. Seminal capsule midbrown, ovoid to near spherical, with weak neck; spermathecal duct straight, thick-walled, dilate prior to fusion at apparent common opening. Cerci large, quadrate.

Pupa as in Pinder & Reiss (1986)

Larva as in Pinder & Reiss (1983) and Epler et al. (2013)

Figures

FIGURE 1. Kribiodorum spp., Adults. A, B. Lateral thorax, A, K. perpulchrum; B, K. kunene; C–D. Wings, C. K. pulchrum female, D, K. perpulchrum male; E, Foretibial apex, spur, male K. belalong, F, foretibial apex, female K. pulchrum; G, hind-leg tibial comb, male, K. pulchrum; H–L, Fore- mid- and hind femora and tibia of: H, K. belalong, I, K. malicky, J, K. kunene, K, K. pulchrum, L, K. perpulchrum; M, Hypopygium K. belalong, Left side dorsal, Right side Ventral/internal, stylised.

FIGURE 2. Kribiodorum spp., Male adults. A–D, hypopygium, left side, A. K. kunene, B, K. malicky, C, K. perpulchrum, D, K. pulchrum; E–I, superior Volsella of E. K. belalong, F. K. kunene, G. K. malicky, H. K. perpulchrum, I. K. pulchrum.

FIGURE 3. Kribiodorum spp., Female adult, A–C, K. malicky, D. K. pulchrum. A, Antenna, B, Genitalia, C, Lobes of gonapophysis VIII, D, spermatheca and duct. Pupa, K. belalong. E, Thoracic horn, F, Posterolateral corner ('spur') of VIII. G, Abdomen.