The adults of this species are not known for sure, but slightly larger males than those of C. quinnitukqut, reared from fluviatilis-larvae in the area are similar to those of C. decorus-group species and may belong to this species. Some information is provided:
Frontal tubercles about 38 µm and about twice as long as wide. Palpal proportions (units): 9 : 10: 34 : 31 : 39. P5/P4 1.26; P5/P3 1.15.
Legs dark, and darker tibia, tarsi almost black.
Proportions of anterior leg (units):
Abdomen with dark bands, with darker center-line but pale distal margin. TIX with about 6-11 setae in individual pale areas within larger triangle.
Superior Volsella closest to E(i) type of Strenzke (1959). IVo longer than anal point, which is narrower at the base, and extending to about a third or mid-point of the gonostylus, which is only moderately expanded and narrows gently over posterior half.
The only information available for a possible adult female is a photograph of the female terminalia (below).
Cercus relatively square, but posterior margin shorter, no obvious bulge.
About 14 setae on seg. X, which is about twice as long as its greatest width.
Pupa: not known.
Larva: A small to medium size (fem. abt. 11,7-13.2 mm.)fluviatilus-type. Ventral tubules short, abt equal length (0.52-0.86 mm) or posterior shorter (0.52-0.96 mm). Anal tubules about 320 µm long and twice as long as wide (dorsal) and 340 µm long and 2.4 times longer than wide (ventral). Oesophageal opening about 61 µm wide and 3.5 times wider than deep.
Mouthparts mostly quite worn (see figures). Gula very dark on post 2/3 or almost to the base of the mentum; frontoclypeus pale, but some darkening towards rear of head and at base of antenna.
Mentum (Fig. c.) with 4th lateral only slightly reduced (type I) but may be greater possibly due to wear, 6th lateral at least slightly lower than 5th lateral; c2 teeth often little more than notches on side of c1 tooth (type IB), but sometimes relatively well separate (type IIA). Ventromental plates (Fig. d) about 211 µm wide and about 3.5-3.8 times wider than deep, about 1.03 times the mentum width; separated by about 27-30% of the width of the mentum, with about 41 (38 - 44) striae; VMR about 0.27 (0.25-0.30).
Pecten epipharyngis (Fig. a) with about 20 (16 - 24) usually worn type B teeth, sometimes with multiple small teeth in center. Premandible usually with inner tooth longer (due to wear), and at least 2.3+-4.3 times wider than the outer tooth, which narrows only gently along its length.
Antenna (Fig. b) with basal segment relatively squat, about 2.8-3.2 times as long as wide, but 35-41% of the VHL; RO about a third to almost halfway up from the base; AR about 2.45 2.21-2.74; A2/A1 about 0.20 (0.17-0.22); A5/A3 about 0.95 (0.83-1.0; proportions of the antennal segments (micron) 116.5 : 23 : 6 : 11.5 : 6 ; A5 is normally slightly shorter than A3, although of about equal mean value - A5/A3 about 0.95 (0.83-1.00).
Distance between antennal bases (174 µm )greater than that between S4 setae (155 µm), which are separated by about 84% of the FC width at that point; S5 setae about level or just slightly anterior to the nearby RO.Mandible (Fig. e) about 257 (244-276) µm long, with fourth inner tooth only partially developed and pale (type I-IIA) although this is often unclear as the 4th inner tooth is often broken off; with about 12.2 (10-16) furrows on the outer surface near the base; about 11.8 (10-14) taeniae in the Pecten mandibularis; Mdt-Mat about 30 µm, MTR about 0.36.
Cytology: Four polytene chromosomes with the thummi-arm combination AB, CD, EF, G.
Arm G with a sub-terminal nucleolus, next to a heterochromatic cap; BR immediately distal of nucleolus; homologs either unpaired or paired at the heterochromatic cap. Second nucleolus about 2/3 along arm D. No polymorphism in the specimens examined.
Arm B1: No obvious large puff. Bands 24-28 removed from usual position close to centromere, as in B1 of C. quinnitukqut.
Arm D1: Nucleolus distal of middle of the arm.
Arm E1: appears rearranged compared with C. quinnitukqut
Arm F1: appears to differ by a small median inversion from F1 of C. quinnitukqut.
Found: Massachusetts - East Harbor (Truro), Cape Cod National Seashore, Barnstable Co.
This species has been found in association with C. quinnituqut, for which the larva is very similar. Two characters that seem to help distinguish between them is that sp. ‘Cape Cod’ has a higher number of teeth in the PE (more than 16), the outer tooth of the premandible only narrows gently towards the distal end, and the center teeth of the mentum are usually type IIA, while in C. quinnitukqut the PE has less than 16 teeth, the outer tooth of the premandible narrows sharply, and the center teeth of the mentum are usually type IB. Marine, organic sediments.
Found together with C. quinnitukqut, to which it may be related.
Some larval characters and a photograph of the polytene chromosome complement are given in Martin et al. (2010).