Oriental Chironomus: C. nudipes

C. nudipes Kieffer, 1911.

Redescribed by Chaudhuri et al. (1992).

This could be the senior homonym of C. crassiforceps Kieffer 1916.

Adult:

For original Kieffer description see C. nudipes Kieff

(Additional data from Chaudhuri et al., 1992).

For illustrations see C. nudipes drawings from Chaudhuri et al. (1992)

>Male: Body length 3.64 (3.49-3.72) mm; wing 1.54 (1.50-1.61) mm long, 0.50 (0.48-0.57) mm wide; VR abt 0.95 (0.90-1.0). AR 2.06 (2.03-2.09).
Head: Yellowish brown, antennae and palps brown; frontal tubercles well developed; clypeus with 22-24 setae.
Relative lengths of maxillary palp segments: 12 : 11: 38 : 40 : 56; P5/P4 1.40; P5/P3 1.47
Wing (Fig. a) length 1.50-1.61 mm, width 0.48-0.57 mm; VR 0.90-1.00; Scf on brachiolum 2, Squamal fringe with 16 (16-18) setae.
Thorax: Yellow, mesoscutum with 3 yellow to brown vittae. Setae: 12 uniserial Achrostichals, 20 irregularly biserial dorsolaterals, 4 prealars, 1 supra-alar; 18 scutellar.
Legs: proportions and ratios (units not stated).

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	BR
PI	60	52	85	43	37	36	19	1.50-1.63	1.15	No beard
PII	64	63	30	18	15	12	9	0.47	1.02
PIII	54	72	45	25	22	13	9	0.62	0.75

Fore tibial scale (Fig. b) with 2 long setae.
Abdomen brown, tergites VI-VIII with dark brown oval/round median spot (Fig. c). (N.B. these spots are not mentioned in the original descrption). Aparently no setae on TIX.
Hypopygium: (Fig. d) Anal point stout blunt and arrow shaped. Superior volsella bowshaped, Inferior volsella long, curved, expanded at the end with 12-20 incurved setae along the inner margin, almost as long as the gonostylus which has a blunt apex.

Female: Unknown

Pupa (Fig. 14): Body length 6.09 (5.89-6.21) m in male, 5.58 (5.42-5.72) mm in female. Color brown but pale brown in exuvia, cephalothorax and abdomen pale brown. Frontal tubercles 0.11 (0.1-0.13) µm long, 1.1 times longer than wide. Wing sheath 1.31 (1.28-1.34) long. Respiratory organ with an elliptical base, 0.12 (0.10-0.13) µm wide, 2 pairs of precorneal setae.
Abdomen with PSA on segments IV-VI, PSB caudolateral on segment II. Tergite I bare, tergite II with median shagreen and a caudal transverse row of 44-56 hooklets; tergite III-VI with median shagreen, tergite VII with subbasal transverse patches of shagreen, tergite VIII with 2 median patches of shagreen. Caudolateral spur of segment VIII with about 2 equal spines. Anal fin with numerous filamentous setae.

Fourth instar larva (Fig. 13): a small, possibly plumosus-type, length about 6.53-9.38 mm; ventral tubules shown about equal length; Anal tubules about 240-250 µm long, comprised of a single lobe.
Head brown with dark occipital margin. VHL 0.30 (0.29-0.32).
Mentum with 4th laterals reduced (type II), central tooth possibly of type IIA or III.
Ventromentum with striae almost to anterior margin, about 1.6 times longer than deep.PE with 17 teeth (apparently type B). Premandible with two unequal teeth, inner about 3 times the width of the outer, both narrowing to a point.
Antenna with basal segment about 2.8–2.9 times longer than wide, RO just over 1/4 up from base (0.27-0.28); AR about 1.8 (1.6–1.9); segment proportions (units) 88 : 21 : 8 : 11 : 7 .
Mandible aboput 160 µm long, possibly type IIIB, furrows not shown, but 10 taeniae illustrated for Pecten Mandibularis.

Cytology: No information.

Found: India - Purulia (23.33°N, 86.37°E), West Bengal.
Type locality - Calcutta, West Bengal.

This species appears closely related to C. crassiforceps, the most obvious differences being the lack of the abdominal spots on that species, and the relatively short posterior femur (only three quarters of the length of the tibia, but only noted as 'a little shorter' by Kieffer) of C. nudipes.
The synonym listed by Chaudhuri, C. sp. Ikwma(sic) from Ikema Island, Japan, is almost certainly C. crassiforceps.
Pal & Hazra (2107) collected specimens from Berhampur (24.23°N, 88.43°E), West Bengal which they attribute to C. crassiforceps but provide insufficient evidence to prove that it is not C. nudipes, given that it was collected in the same general area as the other specimens of this species.

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