Species 2v. C. athalassicus Cannings

Larva a medium to large (len. 13.3 - 20.8 mm; female - 20.8 mm; male - 17.0 mm) melanotus (reductus)-type, but apparently longer in lower salinity, where the posterior pair of tubules may have a slight coil at the end (saline - about 0.68 - 0.72 mm; fresh water about 1.12 - 1.56 mm).    Lateral projections relatively short; ventral tubules short to moderate length.    Gular region generally darkened in posterior 1/3 to 2/3, frontoclypeus pale, but darker around antennae and mouthparts.    Mentum (Fig. a) with generally rounded teeth; c2 teeth relatively well separated;  4th laterals reduced to about level of 5th laterals (type II).    Ventromentum (Fig. d) with about 45 - 54 striae); plates separated by about one third of the mentum width.    Pecten epipharyngis (Fig c) with 10-17 teeth.    Mandible (Fig. e) with pale third inner tooth almost separated (type II); about 17 to 21 striae near base; and 2 spines, with partial development of a third, on the inner margin.    Antenna (Fig. b) with AR about 2.37 - 2.57; basal segment about 3.8 - 4.1 times as long as wide; antennal segments 179 : 33 : 10 : 16 : 7 micron; ring organ in middle third of basal segment.

Cytology :    4 pairs of relatively short chromosomes with the thummi arm combination AB, CD, EF, G. Centromeres heterochromatic, forming a chromocentre in BC specimens from saline habitats.
Arm G relatively short and closely paired with a nucleolus about in the centre.    Nucleoli also near the centre of arms B and D.    Polymorphism in arms B, D and F.
Tentative banding patterns:
ath A1:    1 - 2c, 10 - 12, 3 - 2d, 9 - 4, 13 - 19                    i.e. as holomelas
ath B1:    Nucleolus one third from centromere, region proximal as in atrella
ath B2:    inversion of about one third of arm near distal end.
ath B3:    small inv. just distal of nucleolus.
ath C1:    1 - 2g, 6b-2h, 11c - 8a, 15 - 11d, 6g-h, 17a - 16, 7d-a, 6f-c, 17b - 22
ath D1:    1 - 3, 11 - 18d, 7 - 4, 10 - 8, 18e - 24        i.e. as in longistylus, atrella
ath E1:    1a - 3e, 5a - 10b, 4 - 3f, 10c - 13                              i.e. as cucini, plumosus, etc.
ath F1:    1    -    23;                                                        i.e. Standard
ath F2:    1a-d, 9 - 8d, 12 - 10, 2 - 3d, 1i-e, 3e - 4b, 13 - 14c, 8c - 4c, 14d - 23

Click here for the polytene chromosomes.

Found: British Columbia – Boitano Creek, Riske Creek, and Lake Boitano, Springhouse.
            North Dakota – Clearwater Lake, Mountrail Co.; Lake Isabel, Kidder Co.

            Saline habitats in B.C., but N.D. sample from less saline situation.

Larva described by Cannings (1975).    This is C. sp. Is Andreeva of Kiknadze et al. (2004).

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