Chironomus lacunarius

Author: Wülker, 1973

Diagnosis (Typ. biotope specimens, coll. W. Wülker)
Exuviae 9.0-10.3 long (n=4).
Colour: Exuviae brown. Contrast in colour between thorax and abdomen not so strongly marked: specimens dark anteriorly also have the abdomen infuscated; outer margin of the anal lobes coloured except at base.
Cephalothorax: Cephalic tubercles LxB 150x150-193x150µm (n=4); tubercles gradually contracted to apex. Frontal setae 70µm long (n=1). Thoracic horn much branched; basal ring 160x63, 165x75µm (n=2); tracheal patch 93x28-120x30µm (n=3); 11-17 tracheoles across (n=5). Tracheal patch of thoracic horn without an "eye". Tracheoles of tracheal patch 2µm across. Thoracic granulation distinct and extensive, strong anteriorly, elsewhere reduced.
Abdomen: Hook row II entire, length of row 0.59x width tergite (n=1); 80-107 hooks (n=4). Armament of tergites II-VI in the form of an undivided, somewhat reduced patch of strong points, e.g. on tergite III extending laterally at most only as far as the inner edge of the lateral of the anterior adhesion marks and setae D4, the points between the anterior adhesion marks still quite sturdy. The points in each segment increasing in size posteriorly; the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. On tergite IV seta D3 lies above or internal to seta D4 (102c.jpg). Shagreen of sternite II extensive complete posteriorly. Lateral longitudinal shagreen bands of sternite III, and often IV, present. Sternite VI with the anterior shagreen points in distinct rows which are arranged in a reticulate pattern (102d.jpg). Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Pleura IV sparsely spinulate, spinules to 20µm long, hair-like. Conjunctives IV/V and V/VI at most minutely "rough". Comb of segment VIII with 2-7 elongate teeth (n=4), set on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Lateral setae of anterior segments long, e.g. on III over 100µm long. Lateral taeniae of segments V-VIII: 4,4,4,5.
Anal segment: Anal lobes weakly rounded. Each anal lobe with 82-125 fringe taeniae (n=4), and two dorsal taeniae (the anterior may be more setaceous than taeniate).

Species keys out at Page 212: Chironomini 109 Chironomus of the Text Key.

NW+C Europe.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Alpine pastureland ponds; lakes.