Species 2l. C. pallidivittatus sensu Beermann (1955)

        Was placed in the subgenus Camptochironomus.   Usually stated to be "sensu Edward 1929", but Beermann did not confirm the identity of his material with that of Edwards, and until the identity is confirmed, this synonymy cannot be made with certainty

Adult similar to that of C. dilutus, but paler and usually slightly smaller.

Males can be differentiated from C. dilutus by characters of the hypopygium, viz.  shorter and less tapered dististyle and inferior appendage,  the shorter superior appendage,  narrower anal point,  and the deep W-shaped indentation in tergite IX.

a. whole hypopygium; b. superior appendage, shorter than inferior appendage.

Larva a medium to large plumosus-type (fem. 18.0 - 19.7 mm; male 14.3 - 17.2 mm);  lateral tubules developed (340 - 680 µm);  ventral tubules about equal length (ant.: fem 1.40 - 2.60; male 1.24 - 2.06 mm; post.: fem. 1.64 - 3.08; male 1.28 - 2.36 mm).
Gular region pale to darkened, frontoclypeus darkened, at least slightly, posteriorly.
Mentum (fig. c) with relatively pointed teeth; 4th laterals about in line with other teeth (type I); c1 tooth moderately broad with parallel sides, c2 teeth well developed and sharp pointed (type IIA).
Ventromentum (figs d and f) with deep clefts on inner edge of the marginal region; abt 52-55 striae reaching about ½ way to anterior margin; VMR abt 0.32-0.35.
Premandible (fig. b) with teeth approximately equal in length, inner tooth about twice the width of the outer. Pecten epipharyngis (fig. a) with about 13-14 even sharp teeth.
Antenna (fig. g) with RO about a third up from the base, A1 about 4 times longer than wide and abt 4.7 time longer than A2, AR abt 2.15, A3 about same length as A4 and longer than A5; segment proportions (µm): 167 : 35 : 13 : 13 : 8.
Distance between antennal bases about the same as that between the S4 setae.
Mandible (fig. e) with third inner tooth generally dark and well separated (type IIB-IIIC), about 24-25 furrows on outer surface at base.

Cytology:  4 pairs of chromosomes with the camptochironomus arm combination AB, DE, CF, G.    Arm G closely paired with three Balbiani rings, 2 close together near one end with a constriction between most distal and the end, and the other towards the other end.    Nucleolus in arm B, virtually at centromere, but other smaller ones may be developed distal to this in sequence B2, known only as a heterozygote and apparently confined to males.

pal h'A1:    1ab, 7d-7b, 3i, 2c-1h, 9c-8f, 10-9d, 11-12, 3h-2d, 8e-a, 1c-g, 7a-4, 13-19
pal n'B8:
pal n'B9:
pal h'C2:    1a-e, 15-14d, 4-6b, 8g-a, 2e-3c, 11c-9, 1f-2d, 11d-14c, 19-16, 7-6c, 20-22
pal h'D2:    1a-2b, 15-14, 22-18e, 8-9, 17-18d, 16a-e, 11-13, 3g-2c,7-4, 10e-a, 23-24
pal n'D3:
pal h'E1:    1-2g, 4b-f, 12f-10c, 3f, 8g-10b, 3a-e, 8f-4c, 12g-13
pal h'F1:    1a-d, 9b-12, 3b-2f, 13-14c, 5d-6, 9a-7a, 14d-16, 5c-3c, 1e-2e, 17-23                i.e. as h'F1 of tentans
pal n'G4:
pal n'G5:

Found: ¿Ontario - South March, Carleton Co.
              Saskatchewan - 5ml nw Theodore.
              North Dakota - Cleveland
              South Dakota - Vermillion, Clay Co.; Sioux Falls, Minnehaha Co.; Lake Francis Case, Yankton Co.

            Generally at low frequency in prairie sloughs containing C. dilutus

Hein and Schmulbach (1971) first described this species in North America, noting that it was not the same as C. pallidivittatus Johannsen.  The cytology of North American populations in comparison to that of European populations was described by Kiknadze et al. (1998a).
Kiknadze et al. (1991) noted that larvae of the European populations of C. pallidivittatus could be distinguished from the related C. tentans by the smaller size as reflected in the head width and the length of antennal segment 1.  It is not clear whether this could be applied to separting the North American specimens from those of C. dilutus, particularly in view of the occurrence of hybridization and the existence of different races of the latter species.
C. pallidivittatus and C. dilutus cannot be separated on the basis of the DNA "barcode" sequence of cox1, but can be separated by the sequence of the globin gene gb2β (Martin et al. 2002).

See also C. dilutus and C. tentans

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Modified: 15 Mayy 2017
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