North American Chironomus: C. 'proulxi' (sp. 2b)

Species 2b. C. 'proulxi'

Chironomus bifurcatus Type 2 (Proulx et al. 2013)

Was in BOLD Bin: BOLD:AAW4003
but BOLD operators have amalgamated it with the Bin containing C. bifurcatus: BOLD:AAG5453, probably because of the confusion caused by short sequences, although the distance graph shows two peaks.

Adult

Male:
Description of a potential type male (UWI.5.2 em#8, reared male 3)

Coloration not clear as specimen had been in ethanol for 40 years. Abdomen appears to have a brown band over the anterior 2/3 of segments II-IV, heaviest in the midline, then most of segments V-VIII.
Wing length 3.36 mm, width 0.81 mm, VR 0.98; 4 SCf on brachiolum, about 34 setae on squamal fringe.
Head: AR 3.14; frontal tubercles well developed, but appearance variable: 35-45 µm long and about 2.3.5 times longer than wide; seta not visible. Palp proportions (micron) 95 : 50 : 190 : 230 : abt 300. Clypeus about 0.7 of the width of the antennal pedicel, with 32 setae.
Thoracic setae: Acrostichal 16; dorsolateral 21-25 beginning at anterior end of lateral vittae; prealar 6,7; Supra-alar 1,1; Scutellar 11 in 2 approximate anterior rows, 14, mostly larger, in posterior row.
Legs pale but with knees and anterior tarsi darkened.
Leg lengths and proportions (micron)

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	Ta5/Ti
PI	1245	1200	1785	945	710	635	300	1.48	1.04	0.25
PII	1320	1265	735	420	310	210	150	0.58	1.05	0.12
PIII	1520	1550	1165	670	495	285	190	0.75	0.98	0.12

7 setae probably in single patches in a pale oval on tergite IX. Superior volsella closest to E(g) of Strenzke (1959); Inferior volsella with simple setae, reaching just beyond end of anal point and to about the middle of the gonostylus which tapers sharply over posterior 3/8.

Male hypopygium (left) and Superior volsella (right) of a male from the same egg mass as the holotype

Some additional information can be provided from other males from the same egg mass, and from a male from a photograph in the BOLD database:

C. bifurcatus male from Arizona

Coloration much as C. bifurcatus, but knees and anterior tarsi darkened.
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 3.34 (2.78-3.8) mm, width 0.78 (0.68-0.9) mm, VR 0.98-1.03; 3.6 (3-4) SCf on brachiolum, about 28.5 (19-34) setae on squamal fringe.
Head: AR 3.23 (3.14-3.50); frontal tubercles 38.3 (35-45) µm long and about 2.5 (1.8-3.5) times longer than wide; seta not visible. Palp proportions (micron) 68 : 50 : 173 : 210 : abt 265; P5/P4 abt. 1.25; P5/P3 abt. 1.51. Clypeus about 0.7 (0.5-0.75) of the width of the antennal pedicel, with 31 (28-32) setae.
Thoracic setae: Acrostichal at least 13.8 (9-16); dorsolateral 24.2 (21-28) beginning at anterior end of lateral vittae; prealar 6.9 (6-8); Supra-alar 1; Scutellar 11 (11-12) in 2 approximate anterior rows, 13.3 (12-14), mostly larger, in posterior row (total 24.7 (24-25)).Approximate leg lengths and proportions (micron):

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	Ta5/Ti
PI	1115	1120	1700	880	710	625	290	1.48-1.56	0.85-1.09	0.25-0.29
PII	1265	1175	720	405	280	190	145	0.58-0.66	1.03-1.18
PIII	1405	1445	1110	650	460	280	180	0.75-0.80	0.93-1.00

BR 1.4-2.0

About 7-8 setae, probably in single patches, in a pale oval on TIX. Superior volsella closest to E(g) of Strenzke (1959); anal point (below) broad, narrowing to distal end and with rounded end; Inferior volsella with simple setae, reaching to about the middle of the gonostylus which tapers noticably over posterior third.

Anal point (note taper and rounded end) and Inferior volsella

Female
Coloration essentially as in the male.
Wing length about 3.40 (3.31-3.48) mm, width abt 0.95 (0.91-1.02) mm; VR 1.05 (1.02-1.080; abt 19,3 (15-25) setae on squamal fringe; 3.2 (3-4) SCf on brachiolum.
Antennal proportions (micron) and proportion of neck in brackets: 165 (0.24) : 106 (0.45); 112 (0.55) : 112 (0.58) : 184; AR - 0.4 (0.34-0.46); A5/A1 – 0.40 (0.97-1.40). Frontal tubules about 34.5 (28-40) µm long and about 1.4-2.3 times longer than wide. Clypeus about twice the width of the antennal pedicel, about 35.7 (33-39) clypelal setae.
Palpal proportions (micron) 59 : 51 : 193 : 230 : 300; P5/P4 abt. 1.35; P5/P3 abt. 1.49-1.63).
Thoracic setae: Acrostichal 15-18; Humeral 10-16, usually 7-10 in cluster plus at 4-6 linear; Dorsocentral abt 29.8 (28-35) if Humerals are recognized, otherwise abt. 34.5 (33-37) DL+H; Prealar 6-7; Supraalar 1: Scutellar 16 (15-17) scattered anteriorly, 13 (9-16) in posterior row - total 29.3 (26-33).
Approximate leg proportions (micron):

	Fe	Ti	Ta1	Ta2	Ta3	Ta4	Ta5	LR	F/T	Ta4/Ti
PI	1320	1095	1865	975	750	730	330	1.68-1.76	1.19-1.23	0.64-0.69
PII	1340	1275	760	415	305	200	155	0.58-0.60	1.02-1.07
PIII	1445	1555	1135	645	500	275	180	0.72-0.74	0.91-0.94

BR about 1.82

9.4 (6-15) setae on seg. X which is crescent shaped, about 3-3.8 times longer than the greatest width, and 3-4 setae on GcIX. Cercus 'helmet' shaped; margin curved with a basal bulge on ventral margin (although not seen in one specimen)./dd>

Pupa, Fourth instar larva and Cytology - Go to C. 'proulxi' immatures.

Found: British Columbia – North Pender Island, Gulf Islands N.P. (48.781°N, 123.301°W)(BOLD); Kelowna C.S., Kelowna
(49.863°N, 119.454°W)(BOLD).
New Brunswick – Kouchebouguac National Park (46.50°N, 65.33°W).
Ontario – Bear Creek, 0.5 ml s.e. Carlsbad Springs (45.37oN, -75.47oW); abt 5 km NE Bobcayeon, Kawartha (44.57°N, 78.5°W) (BOLD); Brockville (44.589°N, 75.689°W)(BOLD); A.B.Lucas SS
(43.033°N, 81.248°W) London (BOLD); 4 ml e. Sudbury (46.52°N, 80.90°W); Sudbury area (Proulx et al.);
McFarlane L. (46.42°N, 80.95°W), and Tilton L. (46.35°N, 81.07°W), Peterborough (44.271°N, 78.394°W)(BOLD).
Prince Edward Island – Bubbling Springs Trail PEI Nat. Pk. (46.411°N, 63.093°W)(BOLD).
Quebec – L. St. Joseph (46.88°N, 71.63°W); L.Kinojévis (48.13°N, 78.90°W) (Proulx et al.).
Saskatchewan – Grasslands Nat. Pk. (49.001°N, 106.557°W); Prince Albert Nat. Pk., (53.85°N, 106.078°W)(both BOLD).
Arizona – at 2033 m Kaibab National Forest (35.939°N, 112.121°W)(BOLD).
Oregon – Rolling Riffle Creek, e. Dexter, Lane Co. (43.90°N, 122.8°W).
Tennessee – 10-Mile Creek, nr. Knoxville, Knox Co. (35.90°N, 84.07°W).
Wisconsin – Greene Prairie, Arboretum (43.03°N, 89.42°W) and University Houses (43.07°N, 89.42°W), Madison, Dane Co.

Molecular sequences:
MtCOI: This species can be separated from the closely related C. bifircatus at the molecular level on the basis of consistent differences at 10 base pairs:

				base	no.
1	2	3	3	3	4	4	5	5	6
9	7	3	4	8	7	9	1	6	2
7	1	6	2	1	7	8	6	4	1
T	A/G	A	C	T	A	T	T	A/T	C/T

Pools and creeks.

See also C. bifurcatus, C. sp. b, C. sp. c, C. sp. j, C. sp. z, C. sp. 2a, C. "butleri", C. sp. 2t, C. decorus Joh., C. sp. 3h, C. sp. 3i, C. sp. 3j, C. sp. 3r, C. harpi, C. blaylocki, C. decorus R & F., C. mozleyi, C. winnelli.

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