Species 2e.  C. (Lobochironomus) ?nr. austini

The adults and rearings of this species are in the James E. Sublette collection, in the Museum of the University of Minnesota.

Male hypopygium (left) and superior volsella (right) of C. (Lobochironomus) ?nr. austini

The caudolateral spurs on segment VIII have one major spine and one or two smaller ones flanking it.

Caudolateral spur of C. (Lobochironomus) ?nr. austini

Larva a small thummi-type (len. fem. 10.1 - 13.5 mm);  posterior pair of ventral tubules usually longer (ant 0.69 - 1.02 mm; post. 0.82 - 1.19 mm).  Anal tubules about 4 times longer than wide, ventral pair thicker.  Gula and frontoclypeus pale.
Mentum (Fig. d) with somewhat rounded teeth; c1 tooth relatively narrow and rounded, c2 teeth well separated and quite tall (type IV); 4th laterals sometimes slightly reduced (type I-II).
Ventromentum (Fig. e) with about 39-41 striae reaching about half way to margin.  Pecten epipharyngis (Fig. b) with 20-23 teeth, including many small teeth.
Premandible (Fig. c) with both teeth equally long, inner tooth about half to as wide again as the outer tooth.
Antenna (Fig. a) with basal segment over 4.0 times wider than long, Ring organ about 40-50% of way up from base; AR about 1.85; 3rd segment longer than 4th or 5th segment; segment proportions (microns): 145 : 37 : 15 : 13 : 9.
Distance between antennal bases greater than that between S4 setae.
Mandible (Fig. f) with third inner tooth to moderately separated and with some coloration (type I-IIA-B); about 16-18 furrows on outer surface at base and 13 setae in pectin mandibularis.

Cytology:  4 polytene chromosomes with the thummi arm combination AB, CD, EF, G.  Keyl pattern difficult to distinguish because of lack of pairing in many areas.
Arm G unpaired with a subterminal nucleolus and a Balbiani ring (BR) near the other end.  No nucleoli in the long chromosomes.
Polymorphism in arms B and F.
Arm A1:
Arm B1:    No obvious puff/BR.
Arm B2:    Small inversion in distal third of arm.
Arm C1:    Band groups 2-4 not readily obvious
Arm D1:
Arm E1:
Arm F1:
Arm F2:    differs from F1 by simple inversion about one third from distal end
Arm F3:    differs from F1 by a complex inversion of distal third of arm

FoundOntario - 2 ml e. Morven.

            Snow melt pool with thick leaves and some algal growth.

The larval characters of this species correspond relatively well with Epler's (2001) description of C. (Lobo.) austini, but the adult has a much more robust superior volsella.

See also C. (Lobo.) austini, C. (Lobo.) dorsalis, C. (Lobo.) storai, C. (Lobo.) pseudomendax and C. (Lobo.) species 4v.

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Modified: 29 March 2017
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