Chironomus anthracinus

Author: Zetterstedt, 1860

Exuviae 10.3-13.7mm long (n=10).
Colour: Strongly contrasted: cephalothorax dark brown, abdomen colourless with restricted brownish or golden markings; outer margin of anal lobe colourless for most of its length (in pale individuals the contrast is not quite so evident, but the distinction still holds; almost colourless specimens are very similar in appearance to Chironomus bernensis but the extensive granulation of the thorax enables recognition).
Cephalothorax: Cephalic tubercles conical, LxB 125x100-200x157µm (n=5). Frontal setae 57-70µm long (n=3). Thoracic horn much branched, basal ring of horn 155x55-207x80µm. Tracheal patch of thoracic horn without an "eye", patch 107x30-160x43µm (n=7); 16, 22 tracheoles across (n=2); 1.5µm in diameter. Thoracic granulation strong and extensive over anterior half.
Abdomen: Hook row II entire, length of row 0.54x width tergite (n=1); hooks 87-131 (n=7). Armament of tergites II-VI in the form of an undivided, moderately extensive 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 point patches increase in extent from tergite II to V, but on VI the patch is more or less reduced. 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. The points in each segment increasing in size posteriorly. Shagreen of sternites III and IV forming an anterior transverse band and a longitudinal band on each side. Parasternite II obviously shagreened; III without shagreen; IV may have a few minute points in posterior half. Pleura IV smooth. Conjunctive V/VI armed with small strong points. Comb of segment VIII with 3-6 narrow teeth (n=10) 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: 4,4,4,5.
Anal segment: Anal lobes weakly rounded. Fringe of anal lobe with 119-159 taeniae (n=10).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 165: Chironomini 62 Chironomus of the Text Key.

Holarctic species: widespread in Europe.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes