Chironomus coaetaneus

Author: Hirvenoja, 1998

Diagnosis (Material in coll. M. Hirvenoja)
Exuviae 15.5, 16.5mm long (n=2).
Colour: Exuviae golden to golden-brown.
Cephalothorax: Cephalic tubercles LxB 120-150x120µm (n=2). Frontal setae 70µm long (n=1). Basal ring of thoracic horn 250x110-140µm. Tracheolar patch of thoracic horn without an "eye", patch 200x50µm; tracheoles 3.5µm in diameter. Thoracic granulation strong and extensive; reaching the suture dorsally at least as far as the anterior edge of the wing sheath.
Abdomen: Hook row II entire, length of row 0.61x width tergite (n=1); hooks 99-105 (n=2). Armament of tergites II-VI not so strongly waisted and with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Median point patches of tergites III-V with at least some marmoration. Shagreen of sternite II reduced, the lateral longitudinal bands only joined to the median patch anteriorly and, sometimes, posteriorly (the lateral bands may be very reduced in extent posteriad). Shagreen of sternites III and IV forming a lateral longitudinal band on each side, which may spread inwards anteriorly. Pleura IV unarmed. Comb of segment VIII with 5-10 narrow apiculate teeth, set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Lateral taeniae of segments V-VIII: 3,4,4,4.
Anal segment: Anal lobe with >100 fringe taeniae.

Species keys out at Page 158: Chironomini 55 Chironomus of the Text Key.

Northern Finland: Lokka Reservoir (Hirvenoja 1998a).
(For more information see module IdentifyIt – file: Chironominae).