Chironomus nippodorsalis Sasa 1979.

Incorrectly placed as a synonym of C. alpestris, to which it is closely related, but M. Yamamoto has noted some differences in the larva, and there is at least one different sequence in the polytene chromosomes and a number of different base pairs in the Barcode sequence (see below).

Adult

From Sasa 1978 (as C. strenzkei)

From Sasa 1978 (as C. strenzkei)

Male: Wing length 3.40-3.60 mm, width, 0.82 mm.  VR 1.08.  AR 2.96-3.1.  BR 2.0
Coloration generally brown to yellow, with dark brown markings on thorax and abdomen. Vittae almost uniformly dark brown; scutellum yellowish brown, postnotum dark brown.
Head: Frontal tubercles small, abt 18-24 µm.  26 clypeal setae.
Palps (microns) (segs II-IV): 90 : 250 : 260 : 390 (Sasa 1978)
Thoracic setae: Acrostichal - at least 9; Dorsocentral - 21-22; Prealar 8; Supra-alar - 1; Scutellar in two rows - anterior 8, posterior 14.
Legs with dark knees, tibia and tarsi; no beard.
Lengths (micron) and proportions:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	BR
PI	1330	1140	1860	900	790	650	280	1.63-1.75	1.17-1.18	2.0-2.6
PII	1410	1285	780	420	300	190	145	0.60-0.61	1.10-1.11
PIII	1570	1570	1050	600	440	280	160	0.67-0.72	1.00-1.03

Abdominal color pattern (see above) noted as key diagnostic character: ground color yellow/greenish-yellow, and each segment has a dark brown band: posterior on tergite I, but anterior on other tergites, produced posteriorly on segments II and III.
About 5 setae on tergite IX.  Anal point slender, expanded distally; Superior volsella is a little 'beak-like' (S(b) type of Strenzke 1959), but beak is quite short; IVo with about 13 simple, recurved setae.  Gonocoxite moderately expanded c.f. Gonostylus, which narrows relatively slowly from about half way.

Female:
Coloration generally as in male, except that the abdominal segments do not have the the conspicuous pale bands.  Thoracic ground color grey, with vittae black or dark brown, scutellum brown, postnotum nearly black.  Leg coloration as in male. Abdominal tergites almost entirely black.
Wing length 3.6 mm, width 1.1 mm.
Antennal proportions (micron): 110 : 110 : 130 : 130 : 240.  AR 0.5; A5/A1 2.18. Frontal tubercles small 15 µm long and 13 µm wide.
Palp proportions (segs 2-5) (micron): 60 : 220 : 240 : 350 .
Leg lengths (micron) and proportions:

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	Ta4/Ti
PI	1830	1440	2760	1420	1320	1270	450	1.92	1.27	0.31
PII	1810	1730	1000	540	390	220	190	0.58	1.05
PIII	2030	2030	1440	810	630	370	210	0.71	1.00

Pupa: Sasa notes only that the spurs of segment VIII have 3-4 spines.

Fourth instar larva:  a medium plumosus type.  Ventral tubules relatively long, anterior with elbows, posterior pair coiled; anterior pair longer.  Head capsule relatively long and narrow, mentum relatively narrow, mentum width/VHL about 0.49-0.52.  Gular region darkened over posterior 2/3, frontoclypeus dark, also darkened outside clypeus.  Clypeal chaetae smooth in outline; clypeal aperture about 3.14-3.75 times longer than wide.
Mentum with 4th laterals reduced to about the level of 5th laterals (type II), 1st laterals tending to curve outwards; central trifid tooth with c2 teeth well separated (type III).
Ventromental plates separated by about 0.40 of the mentum width, with about 35-37 striae.  Pecten epipharyngis with about 12-14 long pointed teeth (type A) when not worn.
Premandible with sharp teeth, the outer tooth longer; inner tooth about 1.5 to 2 times wider than outer tooth.
Antenna with basal segment about 3.2-3.4 times longer than wide, ring organ about half way up from base; AR about 2-2.15, A3 quite short; segment proportions (microns) 110 : 30 : 7: 11 : 6.
Distance between antennal bases may be greater than or about equal to that between the S4 setae, which are separated by 0.75 of the mentum width; dorsal RO very slightly posterior to S5 setae.
Mandible with 3rd inner tooth well developed, but only moderately colored (type IIIB); about 18-20 furrows on the outer surface at the base; 10-12 taeniae in PMa; MTR 0.28-0.36.

Cytology:  Four polytene chromosomes with the pseudothummi-cytocomplex combination BF, CD, AE, G.  Large almost terminal nucleolus in arm G, which is closely paired and has three BRs, the largest about 1/3 from the other end of the arm.  No nucleoli in the long chromosomes.
No polymorphism in 5 specimens examined.  Very similar to C. alpestris but differs by a complex inversion in arm E.

nidA1:   1 - 2c, 4 - 9, 2d - 3, 12- 10, 13 - 19                                                                   as alpestris
nidB1:   Puff (gp.7?) distal of centre of arm with some dark bands distal                     as alpestris?
nidC1:   possibly 1 - 2f, 11c - 10, 16 - 17a, 6 -2g, 11d - 15, 9 - 7, 17b - 22                    as alpestris?
nidD1:   possibly 1a(b), 17d - 19d, 10d - 1c(b), 17c - 10e, 19e - 24g                             as alpestris?
nidE1:   1 - 2c, 8b - 6, 3 - 2d, 8 - 9, 4 - 5, 12a - 10, 12b - 13         i.e. In5-9 and In9-3 from alpestris
nidF1:   possibly 1 - 10, 15 - 11, 16 - 23                                                               as halophilus, alpestris
nidG1:   large nucleolus ans 3 BRs in distal part of arm                                                 as C. alpestris

Found:  Japan - NIES, Ibaraki, Tsukuba, Honshu (type locality)

Molecular:
MtCOI sequence from Chironomus nippodorsalis, C. dorsalis sensu Strenzke 1959 and C. alpestris is in GenBank and the BOLD databases (where all are in the same BIN).  However, the identification of many specimens is dubious.