Adult male:
Wing length: 3.6 - 5.3 mm; width 1.1 - 1.3 mm; VR 0.98 - 1.04
AR: 3.6 - 4.4
Palpal segments 2 -5 (micron): 80 : 280 : 260 : 330. Clypeal setae about 28 - 38.
At least 12 - 18 acrostichal setae; 16 - 24 dorsocentrals; 5 - 7 prealars; scutellars in two approximate rows - anterior row about 6 - 23, posterior row about 15 - 18 setae.
Fore leg ratio: 1.52 - 1.56 may be diagnostic. Legs pale, unbanded, with only a short sparse beard.
Leg proportions (micron):
|
|
Fe |
Ti |
Ta1 |
Ta2 |
Ta3 |
|
PI |
1660 |
1510 |
2240 |
1280 |
890 |
|
PII |
1700 |
1620 |
940 |
620 |
430 |
|
PIII |
1980 |
2040 |
1410 |
880 |
620 |
|
|
Ta4 |
Ta5 |
LR |
F/T |
BR |
|
PI |
700 |
330 |
1.52-1.56 |
1.06-1.10 |
1.7-2.9 |
|
PII |
285 |
215 |
0.57-0.59 |
1.05 |
|
|
PIII |
390 |
245 |
0.66-0.73 |
0.96-0.98 |
|
Abdominal tergites 2-5 with dark brown patches across about two thirds of the segment, although sometimes reducing towards the basal margin to a more triangular appearance.
Bristles on inferior volsella forked. 4 - 11 setae at base of anal point.
Adult female:
Wing length: 3.4 - 5.9 mm; wing width: 0.9 - 1.7 mm; VR 1.03 - 1.08
AR: 0 32 - 0.49; flagella length (micron): 190 : 140 : 135 : 130 : 210
Palpal segments 2 - 5 (micron): 70 : 230 : 250 : 385. Clypeal setae about 26 - 56.
About 15 acrostichal setae; 18 - 38 dorsocentrals; 6 - 8 prealars; scutellars in two approximate rows - anterior row about 5 - 23, posterior row about 6 - 30 setae.
LR slightly lower than that of males, about 1.47 - 1.48 (2).
Leg proportions (micron):
|
|
Fe |
Ti |
Ta1 |
Ta2 |
Ta3 |
|
PI |
1550 |
1410 |
1990 |
940 |
785 |
|
PII |
1580 |
1595 |
830 |
470 |
350 |
|
PIII |
1860 |
1940 |
1300 |
780 |
600 |
|
|
Ta4 |
Ta5 |
LR |
F/T |
BR |
|
PI |
650 |
270 |
1.47-1.48 |
1.08-1.11 |
|
|
PII |
245 |
195 |
0.55-0.57 |
0.97-1.00 |
|
|
PIII |
320 |
220 |
0.63-0.72 |
0.96-0.97 |
|
Genitalia typical for Chironomus s.str.
Pupa: Total length 11.3 - 11.8 mm (female), 6.8 - 10.8 mm (male); inner margin of wing case about 2.15 mm. Cephalic tubercle about 110 - 160 micron, with sub-apical seta about 45 - 65 micron; about 76 - 112 recurved hooks on abdominal tergite II; muscle scars on tergites pale or slightly pigmented; spur with only two or three spines, although some South Island specimens tentatively assigned to this species have about 6 - 11 spines (see below). About 135 - 157 (female) and 56 - 131 (male) multiple ranked setae on each side of the anal lobe.
Larval Morphology: salinarius-type larva. Length about 12.0 - 20.5 mm (female), 12.2 - 20.0 (male) (larger specimens may be a further new species). Head capsule with slight darkening of the frontoclypeus, and posterior third of gula dark. Mentum of type II; centre trifid tooth with c1 tooth relatively broad and c2 teeth separated (type II). Ventromental plate with about 35 - 40 striae. Pecten epipharyngis with about 8 - 16 usually relatively broad even teeth. Mandible generally type II, although 3rd inner tooth somewhat variable in pigmentation and degree of separation; about 13 - 23 striae near base. Antenna with a moderately broad basal segment about 2.6 - 3.4 times longer than wide; AR 1.8 - 2.5; antennal proportions (microns) 133 : 29 : 8 : 14 : 7 . Anal tubules elongated and rounded, from 2 - 3 times as long as wide, often with a constriction in the middle.
Cytology: 4 polytene chromosomes, pseudothummi-complex arm combination (BF, DC, EA, G).
Two nucleoli, one proximal in arm F, the other subterminal in arm G close to a BR, this latter nucleolus not always apparent. Arm G closely paired in some populations, but paired only in the middle of others. Arm A of some individuals with sequence oppA4 of Australian species; arm E with one
sequence as oppE1 of Australian species. Some South Island populations polymorphic
in all arms, including at least 3 sequences each in arms A, B, D, and F, while others have limited polymorphism in arms A and B. This may indicate the presence of 2 or more species in these samples.
forA1: 1a-e, 11-10, 2c-1f, 3e-2d, 8-9, 3f-i, 12c-a, 4-7, 13-19 ie. as A4 oppositus, analis
forA2: 1a-e, 2e - 3, 1f - 2c, 10 - 11, 2d, 8 - 9, 3f-i, 12c-a, 4 - 7, 13 - 19 (int. opp A4 & A5)
forA3: 1a-e, 11d - 10, 2c - 1f, 3 - 2e, 11e, 2d, 8 - 9, 3f-i, 12c-a, 4 - 7, 13 - 19 from forA2
forA4: large inversion of forA1?
forB1: Puff (group 7) with proximal dark bands (group 8) about middle of arm
forB2: Inversion of about centre half of arm, reversed puff and dark bands (groups 7 & 8).
forB3: From forB2 by inversion which reverses puff (group 7) again and moves it near the distal end.
forC1: 10A - 11E; ie. as C1 of oppositus,
australis and 'thermarum'
forC2: 10A-10D6, 11B11-10D7, 11B12-11E; ie. as C1 of sp.9
forC3: 10A-10D6, 11B11-11A7, 11D6-11B12, 10D7-11A6, 11D7-11E from C2
forD1: 1 - 2, 16 - 13, 3e - 9, 3d-a, 10d - 12, 10a-c, 17 - 24
forD2: 1 - 2, 16 - 13, 3e -4, 18 - 17, 10c-a, 12 - 10d, 3a-d, 9 - 5, 19 - 24 from forD1
forD3: approx. 1 - 2, 16 - 13, 3e - 5, 19 - 17, 10c-a, 12 - 10d, 3a-d, 9 - 6, 20 - 24 from forD1
forE1: 1 - 3e, 10b - 3f, 10c - 13 ie. as E1 oppositus
forE2: 1a-e, 3f - 10b, 3e - 2a, 10c - 13
forF1: 1 - 2a, 10 - 2c, 15c - 11a, 2b, 15d - 23 ie. as F3 of oppositus, and F1 of australis, analis, novae-zelandiae and sp.9
forF2: (approx.) 1 - 2a, 10 - 9c, 4 - 9b, 3 - 2c, 15c - 11, 2b, 15d - 23 more common in Sth Is.
forF3: (approx.) 1 - 2a, 10 - 7d, 11 - 15c, 2c - 7c, 2b, 15d - 23 in Sth Is only.
forG1:
Click here to see the chromosomes BF & CD or chromosomes EA & G
Morphology and cytology given by Martin (1998), but some details were incorrect. Both arms A and F show a different sequence to that stated, and the limits of some inversions in those arms were incorrect. These have been corrected in the present sequences and figures.
Based on the banding sequence of arm F, there could be three species included under this name, because the three sequences identified usually occur only as homozygotes (see below). If this proves to be true, the type specimen of C. forsythi is associated with sequence F1. Larvae with F2 are most common in the South Island, but a single larva from Lake Ngaroto, Sth Auckland, was heterozygous for F1.2. Larvae with F3 have been found at only three localities in the South Island: Bealey, Ross Creek Dam and Lake Wakitipu, although a single larva from Sullivans Dam was heterozygous F1.3.