C. 'jacksoni'

Larva: a medium sized bathophilus-type larva.  Very difficult to distinguish from other members of the C. oppositus-group.  Ventral tubules relatively short, posterior pair longer.  Gula and frontoclypeus dark to very dark, sometimes with darkening of regions beside the frontoclypeus.  Ventral head length (VHL) 263-300 micron, width of mentum about 0.6-0.7 times the VHL
Mentum essentially as in other members of the C. oppositus-group, i.e c2 teeth largely separated from c1 (type III) and 4th laterals reduced to about the level of the 5th laterals (type II).
Ventromentum with about 32-42 striae.  Pecten epipharyngis with about 14-16 teeth.
Premandible with the usual two teeth, inner tooth at least twice as wide as the outer (1.9-3.0).
Antenna generally slightly shorter than in C. pseudoppositus; AR 2.08-2.37; A1 about 2.8 to 3.8 times as long as wide, and about 0.38-0.43 of VHL, ratio of antennal segments (µm) 119 : 27 : 8 : 12 : 7.Width between the antennal bases at least slightly longer than that between the S4 setae.
Mandible length about 220-255 micron from tip to heel; with third inner tooth pigmented and usually partially separated (type IIB); 10-14 bristles in the pecten mandibularis and 11-17 furrows on the outer surface near the base.

Cytology:  Four polytene chromosomes with the pseudothummi-cytocomplex combination: AE, BF, CD, G.  Arm G commonly without a nucleolus, although a small one may be developed near the middle of the arm.   There is an obvious BR (BR2?) near the middle of the arm, the small BR3 is about half way between the large BR and the distal end of the chromosome, and the site of the potential BR4 is at the presumed centromere.
Polymorphism found in arms C, D and E.  One individual from Bellerive, Tasmania was heterozygous for a centric fusion between arm D and arm G, i.e. one homolog was DG, other CD with one acrocentric G and an acrocentric arm C, while an individual from Squeaky Beach, Wilsons Promontory, Victoria was heterozygous for a translocation between the BF and CD chromosomes.
The Male Determining (MD) locus is on chromosome CD, probably near the centromere (Martin & Lee 1984; Martin 2011).
jacA1:    1a-e, 11-10, 2c-1f, 3e-2d, 8-9, 3f-i, 12c-a, 4-7, 13-19                                                                        as oppositus A4
jacB1:    Large puff with distal dark bands (groups 8-7) are towards the distal end of the arm.                  as oppositus B2
jacC1:                                                                                                                                                                as oppositus C5
jacD1:    1-2, 16-14h, 19c-a, 8-3e, 10a-c, 17-18, 12-10d, 3a-d, 9e-a, 13-14g, 19d-24                                  as oppositus D4
jac D2:    approx. 1 - 2, 16 - 14h, 19c-a, 8 - 3e, 10a-c, 17 - 18, 12 - 10d, 3a-d, 9e-c, 14g - 13, 9ab, 19d - 24
jacE1:    1 - 3e, 10b - 3f, 10c - 13                                                                                                                    as oppositus E1, halophilus, etc.
jacE2:    1 - 3e, 10b - 7c, 3f - 7b, 10c - 13
jacF1:    1-2a, 10-2b, 11-23                                                                                                                                    as oppositus F1

The pupa is also typical of the C. oppositus-group, with only one or two spines on the spur.

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Modified: 30 May 2020
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