Also C. species B1 = C. decorus-gr sp.1 of Butler et al. 1995.
In BOLD Bin: BOLD:AAG5453 (Gp. 1)
Adult:The adults and other life stages were described by Wülker et al. (2009). However these descriptions are probably a mixture of specimens of C. bifurcatus and C. 'proulxi', so need to be revised.
Basal dark band at anterior of abdominal tergites, broader at mid-line and becoming more extensive until segs. VI-IX are almost completely dark.Wing length 3.8 for certain–4.1 mm, width 0.9-1.0 mm.
Male terminalia of C. bifurcatus.
Adult from the same egg mass as the Holotype.
Female: - some data from photographs on BOLD
Female BIOUG03114-A06 from BOLD database
Fourth instar larva small to moderate size, length 12.3 (10-15)(33), (fem.11.4-13.8), (male 11.4-11.8) mm; essentially of the bathophilus-type but sometimes a melanotus-type with some development of posterolateral tubules in Canadian samples (0-160 µm). The presence and absence of lateral tubules can be seen even in offspring from a single egg mass, as in the type egg mass larvae, suggesting it is genetic in origin.Ventral tubules essentially the same length although the anterior pair have a slightly higher mean length (ant. 1.41 (0.87–2.28), post. 1.35 (0.87–2.04) mm); those of mid-west larvae are of 'fluviatilis' type (this may be a characteristic of larvae from deeper waters).
Anal tubules with median constriction, dorsal and ventral pair essentially the same size (354-620 µm long, and 2.5-6.2 times longer than wide).
Gular region dark on posterior third to half, frontoclypeus pale or only slightly darkened.
Mentum (Fig. d) with pointed teeth, c2 teeth sometimes only partly separated from the relatively tall c1 tooth (type III); 4th laterals reduced at least halfway to the level of 5th laterals (type I-II).
Ventromentum (Fig. e) about 185-220 µm wide and 3.30-3.69 wider than deep; 0.97-1.19 times the width of the mentum; with about 35.24 (30-49) striae, and separated by a third or more (0.32-0.43) of the mentum width, VMR about 0.22-0.35. Pecten epipharyngis (Fig. a) with about 12.3 (11-15) generally sharp, even teeth (type B). Premandible (Fig. b) with moderately broad inner tooth about 2.5-4 times the width of the outer, which narrows markedly along its length.
Antenna (Fig. c) relatively short, about 30-40% of ventral head length; basal segment about 2.6-4.1 times as long as wide; ring organ a third to almost half way up (0.31-0.47) segment 1; segment proportions (microns) 112 : 29 : 7 : 12 : 6.5 ; AR 2.05 (1.68-2.76); A3 shorter than A4 (A4/A3 about 1.4-2.2), and sub-equal or slightly longer than A5 – 1.06 (0.82-1.37).
Distance between the antennal bases is equally greater or smaller than the distance between the S4 setae, which are separated by about 80-90% of the FC width at that point. S5 setae usually about level with or slightly anterior to the nearby RO.
Mandible (Fig. f) with the third inner tooth partially separated and pale or slightly darkened (type IA-IIB), about 19.1 (18-22) furrows on outer surface near base; Pecten mandibularis with 11.7 (10-13) taeniae; Mdt-Mat 26.7 (20-33), MTR 0.33 (0.27-0.39).
Cytology: 4 polytene chromosomes with thummi arm combination AB, CD, EF, G.
Arm G usually at least partially unpaired with a terminal nucleolus and Balbiani ring. The nucleolar end is always unpaired, giving the forked appearance referred to in the name. The whole arm may be unpaired, and this may be due to the presence of inversion polymorphism. No nucleoli in the long chromosomes. Puff with distal dark bands usually developed near center of arm B. Polymorphic in arms A, B, C, D, E, F and G (at least band polymorphism, but also an inversion). At least three new heterozygous inversions have been identified since the published map of Wülker et al. (2009).
bifA1: 1a-e, 14 - 15, 7b - 4c, 13a-f, 8d - 9, 2d - 3e, 17h-a, 3f-i, 12 - 10, 2c - 1f, 8c - 7c, 4ab, 16a-d, 18 - 19
bifA2: 1a-e, 14 - 15, 7b - 4c, 13a-f, 8d - 9, 2d - 3e, 16d-a, 4ba, 7c - 8c, 1f - 2c, 10 - 12, 3i-f, 17 - 19
bifA3: 1a-e, 14a-g, 3e - 2d, 9 - 8d, 13f-a, 4c - 7b, 15e-a, 14ih, 17h-a 3f-i, 12 - 10, 2c - 1f, 8c - 7c, 4ab, 16a-d, 18 - 19
bifA4: 1a-e, 14a-g, 3e - 2d, 9 - 8d, 13f-a, 4c - 7b, 15e-a, 14ih 4ba, 7c - 8c, 1f - 2c, 10 - 12, 3i-f, 17a-h 16a-d, 18 - 19
bifB1: Large puff (group 7) near the middle of the arm.
bifB2: Puff in more distal position
bifC1: 1 - 6b, 12b - 15, 8 - 11c, 12a - 11d, 6gh, 17a - 16, 7d-a, 6f-c, 17b - 22 as C1 of blaylocki
bifC2: 1 - 4h, 15 - 12c, 6b-4i, 8 - 11c, 12a - 11d, 6gh, 17a - 16, 7d-a, 6f-c, 17b - 22
bifD1: 1 - 3e, 18d - 13d, 7e - 10, 4a-c, 13c - 11, 3gf 18e-g, 7d - 5, 19 - 24
bifD2: 1 - 3e, 10 - 7e, 13d - 18d, 4a-c, 13c - 11, 3gf 18e-g, 7d - 5, 19 - 24
bifD3: approx 1 - 3e, 10 - 9, 16 - 13d, 7e - 8, 17 - 18d, 4a-c, 13c - 11, 3gf 18e-g, 7d - 5, 19 - 24
bifE1: 1 - 3e, 5 - 10b, 4 - 3f, 10c - 13; i.e. as aberratus, sp. 3p.
bifE2: 1 - 3a, 10e-c, 3f - 4, 10b - 5, 3e-b, 11 - 13
bifF1: 1, 9 - 7, 14 - 17, 11e - 13, 11d - 10, 2 - 6, 18 - 23
bifF2: approx. 1, 14 - 17, 19 - 18, 6 - 2, 10 - 11d, 13b - 11e, 17 - 14, 20 - 23
bifF3: approx. 1, 9 - 7, 14 - 17, 11e, 5 - 2, 10 - 11d, 13 - 12, 6, 18 - 23
bifG1: terminal nucleolus and usually a large median BR and a smaller almost terminal one.
bifG2: a small inversion around the median BR (may be C 'proulxi').
Found: Alberta – Elk Island Nat. Pk. (BOLD database)
Nova Scotia – Point Pleasant Park, Halifax (44.623°N, 63.569°W) (from GenBank).
Ontario – Lac Deschêne (45.37°N, 75.85°W) (Type locality); Arboretum (45.40°N, 75.87°W), both Ottawa; Copanspin Farm, Dunrobin
(45.75°N, 75.87°W); 0.5 ml. Dunrobin (45.40°N; 75.87°W); South March (45.40°N, 75.87°W), all Carleton Co.; Costello Creek,
Algonquin Provincial Park, Nipissing Co. (abt. 45.58°N, 78.70°W); Georgian Bay Islands N.P. (44.7418°N, 79.8501°W)(BOLD);
Catholic Central H.S. (42.9869°N, 81.239°W) and Oakridge Secondary School (42.978°N, 81.312°W), both London (BOLD).
Quebec – L. Adéline (48.20°N, 79.17°W); L. D'Allembert (48.38°N, 79.02°W), L. Arnoux (48.25°N, 79.33°W), L. St. Joseph
(46.8°N, 71.63°W), L. Duprat, (48.33°N, 79.12°W) and L. Opasateca (48.17°N, 79.33°W), (Proulx et al.).
Massachusetts – Lake Pleasant (43.56°N, 72.51°W), nr. Montague, Franklin Co.
Minnesota – Turtle Lake, Becker Co. (M.G. Butler).
Localities not clearly identified as C. bifurcatus or C. 'proulxi':
Manitoba – Lake Winnipeg (Sæther 2012)
New Brunswick – Kouchibouguac Natl. Pk. (48.858°N, 64.975°W).
Ontario – Bear Creek, Carlsbad Springs (45.37°N, 75.47°W), Carleton Co.; Algonquin Provincial Park (abt 45.58°N, 78.70°W),
Quebec – Brewery Creek, Hull (45.43°N, 75.73°W), Gatineau.
Kansas – Lone Star Lake (38.83°N, 95.38°W), Douglas Co.
Michigan – Lake Michigan, Epoufette (46.05°N, 85.17°W).
Minnesota– Anderson Lake, Clearwater Co.; Bad Axe Lake, Hubbard Co. (M.G. Butler).
All life stages (except female) and the salivary gland chromosomes described by Wuelker et al. (2009) (but see note above). Some information on arm F given in Fig. 3 of Martin (1979) and a photograph of the chromosomes in Butler et al. (1995) as C. decorus-gr. species 1.
DNA analysis: Sequences for the mitochondrial COI and the nuclear gb2Β genes are available.The data of (Proulx et al. 2013) suggested that the species may comprise two closely related components.
Further data supports this view and is discussed more fully here.
For clarification of which is C. bifurcatus, information on specimens from the same egg mass as the Holotype is provided.