12. Chironomus. species NZ12

In BOLD Bin no. BOLD ABZ5458.

Adult
The adult of this species is not known for certain, but there is a photo in BOLD of a male in the same Bin as above.

This indicates that the abdominal segments have dark bands on the basal part of segments 2-6, wider in mid-line, as in the specimen described below.  Mid F/T abt 1.08; hind F/T abt 0.93.

As well, a male with associated pupal exuvia, which is not C. analis the other species known from Lake Ngapouri, has the following characters:

Wing length: 4.06 mm, width 0.88 mm; VR 1.02.
AR about 3.35.
Small frontal tubercles, about 13 micron; about 29 clypeal setae.
Relative length of palpal segments (micron): 50 : 72 : 250 : 250 : 350.
Thoracic setae: Acrostichal - 13; Dorsolateral - 19; Prealar - 6; Scutellar in two rows, anterior - 14, posterior - 11.
Anterior tibiae and tarsus bearded, BR about 3.7.
Leg proportions (micron):

 
Fe
Ti
Ta1
Ta2
Ta3
PI
1450
1300
1800
1060
790
PII
1550
1440
880
550
380
PIII
1750
1770
1230
750
515
 
Ta4
Ta5
LR
F/T
BR
PI
660
290
1.38
1.12
3.71
PII
270
175
0.61
1.08
 
PIII
350
205
0.69
0.99
 

Abdominal tergites with brown bands covering the basal 2/3 of segments 2 to 6, wider in midline than at edges, and about 4/5 of segments 7 and 8.
4 setae on 9th tergite.  Superior volsella hooked, E(h)-type of Strenzke (1959); more basal setae of inferior volsella ramose.
Anal point relatively narrow.

Pupa:  Exuvial length about 8.8 - 9.7 mm; length of inner margin of wing case about 1.8 mm; Cephalic tubercles abt 50 micron.    About 95 recurved hooks and about 85 setae in the hair fringe on each side.    Muscle scars on tergites faint.  Caudolateral spur of segment VIII with 5 - 7 spines.

Larval Morphology: A bathophilus-type larva.  Length about 17.2-18 mm (female) and 13.8-14.2 (male).  Anterior ventral tubules about 0.72-1.6 mm; posterior about 0.82-1.46 mm.  Head capsule with pale or slightly darkened frontoclypeus, pale or slightly dark posterior third of gula.
Mentum with 4th laterals reduced (type 1-II), generally to height of 5th laterals; central tooth with c2 teeth relatively well separated (type II).
Ventromental plates separated by about 0.4 of mentum width, with about 25-27 striae.  Pecten epipharyngis with about 11-14 teeth.
Premandible with inner tooth about 2-2.5 times the width of the outer tooth, both teeth about equally long.
Antennal ratio about 1.56(aberrant?) -2.78; Ring Organ about one third to two fifths up from base of segment 1, which is about 3.7-4.8 times longer than wide; AR abt 1.57(abnormal?)-2.78; ratio of antennal segments (micron): 155 : 37 : 9 : 14 : 7.
Mandible with 3rd inner tooth partly darkened and only slightly separated (type IIB); about 13 grooves on the outer surface near the base.

Cytology:  4 polytene chromosomes with the pseudothummi arm combination (AE, BF, CD, G).  Arm G without a nucleolus, but with an obvious subterminal BR.  Nucleolus developed in arm F at about group 19.
Polymorphism in arm B, with B2 apparently the more common sequence.

Arm A1:    1a-e, 11 - 10, 2c - 1f, 3e - 2e, 7 - 4, 12a-c, 3i-f, 9 - 8, 2d, 13 - 19                                                        as nzlA2
Arm B1:    Puff (group 7) with reduced dark bands nearer distal end of arm.                                              as nzl B2
Arm B2:    Distal inversion including the puff (group 7) that returns it to near the middle of the arm.        as nzlB3
Arm C1:    as nzlC3
Arm D1:    1 - 2, 16c-a , 17e-a, 10c-a, 3e - 9, 3d-a, 10d -15, 18 - 24                                                 as nzlD2
Arm E1:    1a-c, 5 - 7c, 10g-c, 3f - 4, 1d - 3e, 10b - 7d, 11 - 13                                                                             as nzlE3
Arm F1:    1a-e, 12 - 15c, 2c - 10, 2a, 11i-a, 2b, 15d - 23                                                                                      as nzlF2
Arm G1:    No nucleolus, but an obvious subterminal BR.                                                                               as nzlG2?

Localities:
North Island:
    Lake Ngapouri, Waiotapu, South Auckland (NZ.9) (D.J. Forsyth, Jon Martin & S. Ibarrarán) 1970-1973, 29-viii-2007.
    Lake Rotoiti, about 16 Km north east of Rotorua, South Auckland (NZ.19) (Jon Martin, D.J. Forsyth & S. Ibarrarán) 7-xii-1973 & 29-viii-2007.
    Kinloch Marina, Lake Taupo, South Auckland (NZ.12.1) (D.J.Forsyth) 18-ix-1972
    Waikato area (37.802°S, 175.334°E) (I. Hogg) 16.vii.2012 and (E.Doyle & N. Binks) 12.xi.2013.

Initially included with C. novae-zelandiae, but shows consistent differences in the lighter larval head colour and some unique banding patterns.  The existence of this species is not well supported by the COI barcoding analyses of Sofia Ibarraran, but there are some differences in the ITS-1 sequence.

See also C. species NZ10,  and C. 'spilleri'.

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Modified: 3 September 2020
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