Species 3m. C. tenuistylus Brundin 1949

European specimens are in BOLD Bin: BOLD:AAW3994
Nearest neighbor BIN in BOLD database is BOLD:AAC0596, which is identified as Chironomus hyperboreus (but not Species x of this listing).

(based on European specimens in Wülker 1991)

Black, with a dark SV.  Fore tarsi without beard.  Anal point may be more slender than that of C. longistylus.  Brundin (1949) showed a slight constriction at the base of the anal point, but this was not seen at other localities.
Wing length 4.58 - 5.5.
AR 3.73 (3.65 - 3.81); anterior LR 1.36 - 1.60; BR 1.55 - 1.8
Frontal tubercle 30 - 40 µm in length.
Setae: achrostichal 18; dorsocentral 26 - 30; prealar 5 - 6; scutellar 22.
5 - 6 setae on anal tergite.

Pupa:  Not known.

Fourth instar larva of the plumosus-type, larger than larva of C. longistylus.    Gular region completely dark, frontoclypeus with dark stripe and antennal pedicel darkened as in C. utahensis, ring organ about 0.4 of the distance from the base of antennal segment 1.

Cytology:4 polytene chromosomes with the thummi arm combination AB, CD, EF, G.
Arm G frequently paired in the constricted region, nucleolus at this end with a large Balbiani ring near the opposite end but separated from it by dark bands.  No nucleoli in other chromosomes.
Although polymorphism in arms A and B is known in Europe, no polymorphism has been recorded in North America.
tstA1:    1-2c, 10-12, 3-2d, 9-4, 13-19;                                        i.e as holomelas, longistylus, etc.
tstC1:    1-6b, 11c-8, 15-11d, 6gh, 17a-16, 7d-a, 6f-c, 17b-22      i.e. as in longistylus, tardus, pilicornis
tstD1:    1-3, 11a-c, 17-12, 18a-f, 7d-4, 10-7e, 18g-24.
tstE1:    1-3e, 5-10b, 4-3f, 10c-13;                                        i.e. as longistylus, etc.
tstF1:    1-10, 17-11, 18-23;                                                    i.e. as in cucini, major & tardus.
tstG1:    Nucleolus near constriction with BR at other end.

Found:    Wisconsin - Crystal Bog (Lake 27-2), Vilas Co.
            Type locality - Lake Grimsgöl, Vontjarn, Southern SWEDEN
            Also Finland and Norway. report from Netherlands needs checking.

Morphology and cytology described by Wülker (1991a).

[ See also C. longistylus| Return to Index| Go to References ]

Modified: 29 April 2021
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