10. Chironomus species NZ10Likely to be conspecific with C. 'thermarum'Currently in Bold Bin BOLD AAJ0168 with C. 'thermarum' and C. novaezelandiae, but see comments below. Adult:
The adult of this species is amongst specimens that D.J. Forsyth called C. 'spilleri' (specimens now in the care of Ian Boothroyd). These males were similar to those of C. species NZ12 in having bands across the anterior two thirds of abdominal segments II to VI and on four fifths of segments VII and VIII.
A pupa with a pharate male (see right) is available, from which the following characters could be determined:Tergite IX with 5 setae in individual pale areas. Anal point (a, right) narrow at base, but appears turned down at the end which is broader
Superior volsella (b, right) with just a small hook at the tip (D(e)-type of Strenzke 1959).
Inferior volsella (a, right) extending to about middle of gonostylus with setae simple (c, right).
Gonostylus (a, right) moderately broad but narrowing only slightly at distal end, about 4+1 setae at tip. Pupa: about 6.9mm (1 male) - 8.3 mm (1 female) long; inner margin of wing case about 1.44-1.66 mm. Cephalic tubercle about 85-114 µm long. Basal ring about 115-145 µm long and 57-65 µm wide, HR 1.77-2.56. Thorax and muscle scars yellow-brown, otherwise pale.
Shagreen on posterior half of segment II, increasing to whole of segments IV-VI, little on segments VII & VIII. Hook row with 70-92 hooks, occupying about 0.6-0.8 of segment width. Pedes spurii B on segs II and III; pedes spurii A of sement IV large (202-218 µm long, 101-145 µm wide) and about 0.26-0.28 length of segment.
Caudolateral spurs of segment VIII with about 2 or 3 spines, at least 1 small. 68-93 taeniae on each side of anal lobe, mostly in a single row, but some double at posterior end.
Fourth instar larva: bathophilus-type larva. Generally smaller due to growing at higher temperature (but larger when reared in the lab at lower temperatures), length about 10-14 mm (fem. 10.3-14.0; male 10.7-11.2 mm). Head capsule usually with pale or slightly darkened frontoclypeus but may be dark; some darkening in posterior region of gula much as on Frontoclypeus, and can be broader than the mentum width. Ventral tubules approximately equal in length, anterior 0.63 (0.44-0.96) mm and posterior 0.64 (0.32-1.01) mm. Anal tubules about equal in size or ventral pair longer and 1.5 to twice as long as wide (abt. 200-265 x 100-165 µm).
Head relatively narrow, mentum width about 0.54-0.60 of ventral head length.
Mentum (Fig. b) with 4th lateral reduced to about level of 5th laterals (type II-III); centre trifid tooth usually with distinct, small c2 teeth (i.e. Type IB or occasionally III).
Ventromentum (Fig. c) about 182-205 µm wide and 3.04-3.86 times wider than deep, and 1.0-1.1 time wider than the mentum, with about 37.9 (33-41) striae; IPD 0.28-0.35; VMR 0.24-0.35. Pecten epipharyngis (Fig. a) with about 11-16 sometimes uneven teeth (type B).
Basal segment of antenna (Fig. d) about 3-4 times longer than wide, RO about 29 (24-33)% up from base; A4 relatively short, only about 20% longer than segment 3; AR about 2.23 (2.00-2.44); proportions (micron) 117 : 27 : 7 : 10 : 7. i.e. A5 about as long as A3 (0.73-1.08 times as long).
Premandible with the usual 2 teeth, inner tooth about 2+-5 times the width of the outer tooth, both coming to a broad, or occasionally a narrow point.
Mandible (Fig. e) about 220-252 µm long (heel to Mdt) with 3rd inner tooth at least partly darkened and somewhat separated (i.e type IIB, to occasionally type IIIC); at least 10-17 furrows on outer surface near the base; 11-13 taeniae in Pecten mandibularis; Mdt-Mat 22-30; MTR 0.30-0.43. Cytology: 4 polytene chromosomes with the pseudothummi cytocomplex arm combination (AE, BF, CD, G).
Arm G without a nucleolus, but with a large subterminal BR, and another may be developed about the middle of the arm. The nucleolus is in arm F.
Arm A has the sequence identical to A4 of oppositus and A1 of C. 'thermarum'.
Arms B, C, D, E, F and G appear identical to B1, C1, E1, F1 and G1 of C. 'thermarum', while D appears similar to that of C. novaezelandiae. C. novae-zelandiae. No polymorphism known. Arm A1: 1a-e, 11 - 10, 2c - 1f, 3e - 2d, 8 - 9, 3f-i, 12c-a, 4 - 7, 13 - 19 ie. as A4 oppositus and A1 of 'thermarum'
Arm B1: Derived from nzlB1 by a long inversion of the distal region. Puff with proximal dark bands (groups 7-8) towards distal end. ie. as 'thermarum'
Arm C1: Appears similar to C1 of tepperi, 'pseudoppositus', nzlC1 - ie. as 'thermarum'
Arm D1: 1 -2, 16 - 11, 4c - 9, 3d-a, 4ba - 3e, 10a-c, 17 - 24 as D3 of novaezelandiae
Arm E1: 1 - 3e, 10b - 3f, 10c - 13 ie. as E1 oppositus, 'thermarum', etc.
Arm F1: 1 - 2a, 10 - 2c, 15c - 11a, 2b, 15d - 23 ie. as oppositus, 'thermarum', etc.as F3 oppositus, & F1 of 'thermarum'
Arm G1: subterminal BR as 'thermarum'? Localities:
North Island:
Lake Ngahewa (38.31°S, 176.37°E), South Auckland (NZ.76.1) (S. Ibarraran) 28-viii-2007.
Lake Rotowhero (38.30°S, 176.40°E), c.24 Km s. Rotorua, South Auckland (NZ.11) (D.J. Forsyth & Jon Martin) 1970-1973; (NZ.11.6) (S. Ibarraran) abt 15-ii-2007.
?Queen Elizabeth Park (37.94°S,175.56°E), South Auckland (NZ.80.1) (S. Ibarraran) abt 15-ii-2007. This species may be confined to thermal lakes. Lake Rotowhero varies in temperature from 29.5 to 38oC during the year. Initially included with C. novaezelandiae, but shows consistent differences in the lighter larval head colour and some unique banding patterns. It is very similar in cytology to C. 'thermarum', differing mainly in the better development of the ventral tubules. Phylogenetic analysis of the mitochondrial COI sequence places it in a cluster along with C. 'thermarum'.See also C. novaezelandiae, C. 'thermarum', and C species NZ12.[ Return to Key| Go to References ] |