12. Chironomus. species NZ12

The Adult and Pupa of this species are not known.

Fourth instar larva: A bathophilus-type larva.  Length about 17.2-18 mm (female) and 13.8-16 (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 (Fig. b) with 4th laterals reduced (type 1-II), generally to height of 5th laterals; central tooth with c2 teeth relatively well separated (type narrow IIA).
Ventromental plates (Fig. c) separated by about 0.4 of mentum width, with about 25-27 striae.  Pecten epipharyngis (Fig. a) with about 11-14 often irregular teeth.
Premandible with inner tooth about 2-2.5 times the width of the outer tooth, both teeth about equally long.
Antenna (Fig. d), AR 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 (Fig. e) about 298-327 µm long, with 3rd inner tooth partly darkened and only slightly separated (type IIB); about 14-18 furrows on the outer surface near the base; 11-13 striae in the Pecten mandibularis.

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.
South Island:
    Lake Rotoiti (41.82°S, 172.84°E), Nelson Lakes National Park, Tasman region (NZ.83.1) (B.V.Timms) 1-x-1968.

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 was partially supported by the initial barcoding analyses of Sofia Ibarraran, and there are some differences in the ITS-1 sequence.  More detailed analysis of the CO1 barcode sequence places it in the C. novaezelandiae complex (see under C. novaezelandiae) but differing at a number of base positions.  The existence of polymorphic sites in C. novaezelandiae may result in some specimens being incorrectly assigned to the C.spNZ12 Bin.