This species has been identified from the larva and cytology. There is one presumptive male known, which is very similar to C. bifurcatus, although the phallapodeme is more similar to that of C. atrella.
10 setae in individual pale patches on TIX; Superior volsella of D-type of Strenzke (1959); Inferior volsella reaching beyond the end of the relatively broad anal point and to about the middle of the gonostylus, which narrows relatively gently over posterior third.
Female and Pupa not known.
Fourth instar larva a medium sized plumosus-type (length about 12.2-13.9 mm female, 11.9 mm male). Ventral tubules long, posterior pair usually longer (3.0-3.76 mm, cf. 2.44-2.80 mm). Lateral tubules well developed, about 300-420 micron. Anal tubules with a medial constriction. Gular region dark over posterior third and a pale or slightly darkened frontoclypeus.
Mentum (Fig. c) with rounded teeth, 4th laterals at same height as 3rd and 5th laterals, or perhaps slightly reduced (type I); center tooth moderately broad with well developed c2 teeth (type III).
Ventromentum (Fig. d) with about 36-40 striae and about 4 times longer than deep, VMR about 2.76. Pecten epipharyngis (Fig. a) with about 13 to 16 teeth, the most lateral ones being somewhat narrower (type B).
Premandible (Fig. c) with outer tooth shorter (may be due to wear), inner tooth about 2.5 times wider.
Antenna (Fig. b) with relatively long basal segment, about 3.7 times longer than wide, ring organ about 1/3 to 1/2 up from base; AR about 2.36; segment proportions (microns) 150 : 38 : 10 : 13 : 8 ; A1/VHL about 0.45; A2/A1 about 0.25.
Mandible (Fig. e) with 3 spines on the inner margin; about 15-16 furrows on outer surface near the base; 3rd inner tooth clearly separated but only moderately dark(type II-IIIB), Pecten mandibularis with about 13 taeniae.
Cytology: 4 polytene chromosomes with thummi arm combination AB, CD, EF, G.
Arm G generally paired with a subterminal nucleolus and nearby Balbiani ring (BR); another BR towards the other end of the arm. No nucleoli in the long chromosomes.
Polymorphic in all arms in areas subject to radioactive effluent (Blaylock et al. 1964), but no endemic inversions recorded for arms A, E and G.
blaA1: 1a-e, 8 - 9, 2d - 3e, 15 - 14, 2c - 1f, 16a-d, 7 - 4, 13a-f, 10 - 12, 3i-f, 17 - 19
blaB1: Puff with distal dark bands about the middle of the arm. Possibly as B2 of Sp. b.
blaB2: Formed by overlapping inversions from B1, such that the puff is near the distal end of the arm, with the dark bands proximal to it.
blaC1: 1 - 6b, 12b - 15, 8 - 11c, 12a - 11d, 6gh, 17a - 16, 7d - 6c, 17b - 22
blaC2: as C1 of sp. a (from W. Wülker)
blaD1: 1 - 3g, 11 - 12d, 18 - 19h, 13 - 17, 4 - 7, 10 - 8, 20 - 24
blaD2: 1 - 3g, 19g - 18, 12 - 11, 19h, 13 - 17, 4 - 7, 10 - 8, 20 - 24
blaE1: 1 - 3e, 8i - 5, 9 - 10b, 4 - 3f, 10c - 13; i.e. as maturus, stigmaterus & sp.b
blaF1: 1, 9 - 2, 10 - 23
blaF2: 1, 9 - 5d, 16f - 10, 2 - 5c, 16g - 23
Found: Tennessee - White Oak Creek (Type locality) (36.03°N, 84.27°W), and McCoy Branch, Clinch River, nr. Oak Ridge, Knox Co.; Ten Mile Creek (35.90°N, 84.07°W), Knox Co.
Pools in creeks.
Larva, presumptive adult and the salivary gland chromosomes described by Wuelker et al. (2009). Chromosomes mapped, as C. tentans, by Blaylock et al. (1964).
The identity of this species as a member of the C. decorus group was noted by Wülker et al. (1968). The sequences of arms E and F were given in Wülker et al. (1989a) and of arms C1 and D1 in Kiknadze et al. (2004).
This species is very close to C. sp. b, and they may be subspecies of the same species.