Chironomus piger

Author: Strenzke, 1959

Diagnosis (n=2, specimens coll. Strenzke in coll. ZSM.)
Exuviae 8.9mm long.
Colour: Exuviae golden-brown to dark 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 conical, LxB 100x80µm. Frontal setae 30, 40µm long. Basal ring of thoracic horn 145x65, 170x70µm; tracheal patch 112x37, 130x30µm; about 12-14 tracheoles across, tracheoles 2-2.5µm in diameter. Tracheal patch of thoracic horn without an "eye". Thoracic granulation strong to dorsocentral seta 1 and beyond.
Abdomen: Hook row II entire; hooks 63, 74. Armament of tergites reduced, 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. Armament of tergites II-VI not strongly waisted and with the posterior transverse band not successively increasing in extent to tergite VI; usually reduced on VI. Shagreen of sternite II continuous from postero-lateral corner to seta V5, the region between containing points of similar size to those on each side. Lateral longitudinal shagreen bands of sternite IV reduced to a small median patch or absent. Parasternite II obviously shagreened; III and IV smooth, or III with a very few scattered points. Pleura of segment IV extensively armed with relatively large spinules: about 20µm long, 1µm broad at base. Comb of segment VIII with 2, 3 stout 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: 4,4,4,5.
Anal segment: Anal lobes weakly rounded. Anal lobe with 130, 151 fringe taeniae.

Note: The close relationship between Chironomus riparius and this species is reflected in the similarity of their pupae.

Species keys out at Page 184: Chironomini 81 Chironomus of the Text Key.

Widespread in Europe, circum-Mediterranean.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes