7. Chironomus n.sp. NZ7

Adults not known.

Pupa not known.

Larval Morphology: A bathophilus-type larva, although ventral tubules shorter than C. novae-zelandiae (about 0.5 - 1 mm).  Medium size species, length about 14.2 - 19 mm, about size of C. forsythi, C. analis and larger C. novae-zelandiae.
Head capsule relatively broad, width of mentum at least 2/3 of VHL; gular region dark; generally with a darkened frontoclypeus, and sometimes in surrounding regions.
Mentum with 4th laterals slightly reduced, sometimes higher than 5th laterals (i.e between type I & II), c1 tooth relatively broad, c2 teeth usually separated, but occasionally still partially on shoulders of c1 (i.e. usually type III, but sometimes type IIA).
Ventromentum with about 34 - 46 striae; VMR about 0.32-0.47.  Distance between VMs about 0.31-0.46 of mentum width.  Pecten epipharyngis with 11 - 17 teeth, broad, but some reduced in size.
Antennae with basal segment at least 3.5 to 4.4 times as long as wide; AR about 1.7 - 2.3; A2 about 0.28 length of A1; ratio of segments (micron): 168 : 40 : 11 : 16 : 8.
Distance between antennal bases generally smaller than distance between S$ setae, but may be about equal or even greater (1 of 6 larvae).Mandible of type I or IIB, with about 23 - 27 furrows near the base; about 12 - 15 bristles in the pecten mandibularis.

Cytology: 4 polytene chromosomes with unique chromosome arm combination BG, CD, EA, F.
One large nucleolus proximal on arm G.  Balbiani ring towards distal end of arm G.
Arm E as E1 of Australian species such as C. 'tyleri'; arm F as oppositus F3, australis F1, etc.

Arm A1:    (approx) 1a-e, 11 - 10, 2c - 1f, 6 - 4,12a-c, 8 - 9, 2d - 3,17 - 13, 7d-a, 18 - 19
Arm B1:    Puff (group 7) with proximal dark bands (group 8) near middle of arm.
Arm C1:
Arm D1:
Arm E1:    1 - 3e, 10b - 3f, 10c - 13                            ie. as tylE1
Arm F1:    1 - 2a, 10 - 2c, 15c - 11a, 2b, 15d - 23            ie. as nzlF1, oppF3, ausF1
Arm G1:    Nucleolus near attachment to arm B, with BR towards the distal end.

Known Localities:
South Island:
      10+ m in Lake Pearson, near Cass, Canterbury (NZ.59.1, 2, & 3) (B.V.Timms) 1978/79
      Lake Lochie, c.87 km n.w. Te Anau, Fiordland (NZ.45.1) (Jon & H.I.Martin) 6-i-1974

The unique chromosome arm combination was noted by Wülker & Morath (1989)

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Modified: 8 March 2017
Access: Unrestricted
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