Asian Chironomus: C. flaviplumus ty B immatures

C. flaviplumus Type B

Fourth instar larva: a small to medium sized plumosus-type larva (length 9.0-14.8; (fem) 12.0-13.5 mm; (male) 9.0-10.5 mm.  Anterior ventral tubules about 1.54 (1.04-2.44) mm; posterior pair about 1.77 (1.32-2.64) mm; much shorter in Japanese larvae.  Anal tubules about 250-480 µm (upper); 520 µm (lower) long and about 2.5-3 times longer than wide.  Salivarium 77.4 (68-88) µm wide and 3.75-5.6 times wider than deep.
Gula region pale in some Japanese populations, slightly dark to dark over posterior 1/3 to 1/2 in others, Frontoclypeus dark to very dark, particularly towards the rear.   Mentum (Fig. c) with with c1 tooth tall, c2 teeth well separated (type III), 4th laterals slightly reduced (type I-II).
Ventromentum (Fig. c) about 194.4 (183-220) µm wide, with smooth anterior edge and about 38 (34-44) striae; IPD 57.5 (45.5-71) µm (0.31-0.40 of mentum width); VMR 0.29 (0.24-0.38).
Pecten epipharyngis (Fig. a) with 15 (11-16) broad sharp teeth (type B).  Premandible with outer tooth coming to a relatively narrow point, inner tooth coming to a broad point and 2.7-6.7x wider (Ty. B2).
Antenna (Fig. b) with basal segment 3.33 (2.5-4.0) times longer than wide; RO about one third to almost halfway up from base; AR about 2.08 (1.87–2.44); segments lengths (µm) 113 : 28.5 : 8.5 : 11 : 6.
Distance between the antennal bases (127-159 µm)generally greater than that between the S4 setae (117-143 µm), although may be about equal; S4 setae separated by about 0.74-0.88 of the fronto-clypeus width at that point.
Mandible (Fig. e) with third inner tooth partly or sometimes almost fully separated, and partly darkened (type II-IIIB), with about 15 (10-24) furrows on the outer surface at the base.  Pecten mandibularis with about 11 (9-13) taeniae; Mdt-Mat 25-30 µm; MTR 0.33-0.39.

Cytology: 4 polytene chromosomes with the pseudothummi arm combination BF, CD, AE, G.
Nucleolus in arm B (at 11B) (as in map of Nath and Godbole 1997) but may be developed in arm F (at 10D - abt. groups 22-23). Nucleolus at least 10 bands subterminal on arm G. Two BRs, about equally distant from each end, are on arm G.
Limited polymorphism present in arms A, C and G.
Some points can be made by comparison to the Keyl (1962) banding patterns for arms A, E and F:
flaA1: 1 - 2c, 10 - 12, 3-2d, 9 - 4, 13 - 19 as circumdatus A2, holomelas, etc.
flaB1: Characteristic bands at 10F; a nucleolus at 11B, as in C circumdatus.
flaC1: Developmentally stage specific puff at 6B.
flaC2: Inversion of about two thirds of the arm,
flaD1:
flaE1: 1a-i, 5 - 10b, 3e - 2, 4 - 3f, 10c - 13 as halophilis, etc.
flaF1: 1 -2a, 10d-3d, 14c - 11, 2b - 3c, 14d - 23 Nucleolus about region 22-23, so distinctive bands not visible.
flaG1: BRs at 18C and 19CflaG2: Inversion of about 1/3 of arm around the central BR.

The polytene chromosomes can be seen here

Other probable descriptions of the cytology are: De & Gupta (1994) as "C. niger"; Chironomus species 1 by Sharma et al. (1990), Chironomus plumosus form B (although it has no relationship whatever to C. plumosus) (rather a plumosus-type larva)and incorrectly placed in the thummi-cytocomplex (Tripathi et al. 2002), and the similarly incorrect form A (Sharma et al. (2004) are very likely also this species.

Pupa: Exuvia grey/brown. Length of male 6.51 (5.99-6.61) mm, of female 7.35 (7.01-7.53).
Cephalic tubercles about 75 µm long, 57 µm wide (male) and 43 x 66 µm in female. Antennal sheath of female about 550 (540-560) µm long. Thorax rugose; inner margin of wing sheath 1.69 (1.42-1.72) mm in length, respiratory base elliptical and about 320 x 150 µm, slightly narrow in middle; HR abt. 2.56. PSA caudolateral on segment IV and brownish (see figure below), about 138 µm long and 88 µm wide, occupying about 0.11 of the segment length; those of segments V and VI comprising spines; PSB basolateral on segment I and caudolateral on segment II. Hook row on segment II comprised of about 46(?)-86 hooklets. Shagreen pattern (see figure below) darker across the middle of segments II-IV, then even on V-VII, only anterior on VIII.Caudolateral spurs of segment VIII with 1, or 1 large and 1 small spine (Sasa 1978).

Chromosome arms A, E and F were described by Wülker et al. (1989) as C. samoensis. However, some sequences of Australian specimens are not the same, although closely related.
Indian specimens described by Chattopadhyuy et al. (1991) also do not appear to be the same species, as the LR is reported as 1.4; the ant. Ta5 is only about 0.25-0.28 length of Ti, and the frontal tubercles are only about 18-25 µm. The Indian material is also cytologically distinct. However the mtCOI sequence is very similar to those of C. nr. samoensis, and a specimen from Bishnah wetlands, Jammu and Kashmir is particularly close.

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