Kribiodorum belalong Cranston, 2018

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 : 538-539

Kribiodorum belalong Cranston sp. n.

( Figs 1E, H, M , 3E–G ) urn:lsid:zoobank.org:act: 61FF4067-CA43-4B83-B5D9-39650A42568B

Material examined. Holotype P Ƌ, BRUNEI DARUSSALAAM, Temburong District, Kuala Belalong Field Study Centre, Sungai Belalong, 04°33'N 115°09'E, -. viii.1995 (Cranston) ( ANIC).

Description. Adult Male (n=1, teneral). Colour of body not available.

B.l. 2.9 mm, unexpanded W.l. 0.8 mm.

Head. Eyes extended dorsally by 5–6 facets, 5 (?) temporals largely obscured by eye pigment; Fl1–12 400–405, Fl13 450, A.R. 1.1. Apical flagellomere rounded with no strong apical seta. 18 densely packed clypeals. Palps (partly contracted) lengths of segments 2–5: 90, 105, 100; 125, with 1 sensillum subapical on segment 3.

Thorax. Antepronotal lobes narrow, tapering, slightly separated medially, over-reached by scutum. Thorax dorsally smoothly curved without any tubercle. Ac few, indeterminate, Dc 5 with anterior 1–2 in humeral position; Pa 4, Scts 3 in visible half (damaged, estimated as 5–6 total).

Wing (pharate, dissected) with 2 narrowly separated transverse bands of brown pigment, neither band reaching radial sector anteriorly and not reaching wing base or apex. Anal lobe near absent. R ending in costa relatively retracted (c 3/4 wing length), R2+3 ending midway between R1 and R4+5,R4+5 ends close to wing apex. Wing with long setae (most c. 50 long) on anterior veins: R with c. 20, R1 with c.12 and R4+5 with 16+. Squama bare.

Legs (faint, teneral, partially unmeasurable)( Fig. 1H ). Darker pigmentation subapical on femur and tibia of P1 and P3, of P2 paler only with slight darkened apex of Ta2. Fore-femur dilate apically and darkened with dense dark setae. Lengths: P1 550, 400, 630, 400, 250, 280, 100; P2 570, 440, 320, 110, 70, 45, 50; P3 600, 610, 320, 240, 220, 190, 110. Ratios: LR1 2.0, LR2 0.76, LR3 0.53; BV1 1.5, BV2 4.75, BV3 2.0; SV1 1.5, SV2 3.16, SV3 3.78. Pulvilli slender, not extending to apex of simple claw.

Abdominal tergites all densely beset with long (> 120 µm) setae.

Hypopygium ( Fig. 1M ). TIX with 15 tightly clustered median setae demarcated by weak anal tergite bands, and with 5–6 shorter setae towards posterior margin of tergite, lateral to anal point. Anal point distorted by compression, elongate (c 65 µm), narrow, 5 µm wide at base tapering slightly to pointed apex. Base of SVo ( Fig. 2E ) elevated bearing 5–7 setae, partly overlying base of curved, apically pointed, bare digitus with dorsal flange and medio-ventral scoop-shaped inner surface. MVo ventral to any part of SVo, pad bearing 5–6 strong, mediallydirected strong setae, with bases more or less aligned. Inferior volsella an elongate microtrichiose lobe, bearing long setae dorsally only, without any differentiated apical seta. Gonocoxite squat, 75 long, microtrichiose laterally, with few long setae. Gonostylus narrow, 125 long, microtrichiose and setose on dorsal and ventral surfaces, distally tapered to rounded apex, apically with single more posteriorly-directed seta.

Pupa (n=1) length 3.2 mm. Exuviae pale yellow with antennal sheaths and apophyses slightly darkener.

Cephalothorax. Cephalic area smooth without tubercles, pale / hyaline frontal setae 100–110. Dorsal margin of base of antennal sheath with pointed dorso-medially directed projection. One dorsal, 1 lateral antepronotal (damaged, not measurable). Thorax weakly tuberculate in mid-scutum. Dorsocentral setae in 2 clusters, one median the other retracted posteriorly, each seta c. 25 long, but broken. Two precorneals 50–60 long. Thoracic horn ( Fig. 3E ) base oval 14 x 12 µm, horn appears 3-branched: anterior and median both c. 120–130 long, posterior branch mostly bare, tapering distally, 330 long; median branch may hide another convoluted branch, indicating 4 branches likely are present. All branches have few short hyaline spines, and many more small (2 µm maximum diameter) patches. Apparently lacking prealar tubercle.

Abdomen ( Fig. 3F ) [Interpretation difficult as setose pharate male remains largely within exuviae, and layout / orientation is suboptimal]. Tergite I bare or with weak antero-lateral fine spinule patches; Tergites II–IV with substantial quadrate blocks of spinules extending laterally to apophyses but not extending to pleurae, broader anteriorly than posteriorly but not separated into anterior stronger bands of larger spinules; pattern less extensive on T V and VII, narrowed in mid-segment; TVII and VIII bare except for small antero-lateral patches of fine spinules on VI. Tergite II with transverse row of 47 hooks extending 80–85% of tergite width. Conjunctives TIII– IV and IV–V with broad transverse band of 35 disorganised rows of anterior-directed spinules, remaining conjunctives bare. Pedes spurii B slight. Weak but distinct vortex on IV, absent on V and VI. Posterolateral ‘comb’ on VIII with 3–4 teeth with one larger than others ( Fig. 3G ). Abdominal setation difficult to interpret. (D and V setae in Fig. 3F derived from K. perpulchra ). Small 'O' setae on tergites and sternites. I without L seta, II–IV with 3 non-taeniate L setae, V–VIII with 4 taeniate L setae (the side of insertion of setae not possible to distinguish, drawn as if ventral as is evident for VIII); without supernumerary L seta. Anal lobe with 26 uniserial setae, 1 dorsal seta. Genital sac of Ƌ extended, tapering.

Adult female and Larva unknown.

Etymology. (Derivato nominis). From 'Belalong', the name of the river ('sungai') and international field research station located thereupon. To be treated as a noun in apposition.

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.