Chironomus esai

Author: Wülker, 1997

Diagnosis (n=1, material in coll. Wülker)
Exuviae large, about 15mm long.
Cephalothorax: Cephalic tubercles large, strongly curved. Thoracic horn much branched; basal ring of horn 225x90µm; tracheal patch 175x28µm; 8 tracheoles across, 3-3.5µm diameter. Thorax granulate anteriorly, indistinctly granulate medially, smooth posteriorly.
Abdomen: Hook row II entire, length of row 0.42x width tergite; 107 hooks. Armament of tergites II-VI in the form of an undivided, usually extensive patch of strong points, the points in each segment increasing in size posteriorly. 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. The point patches increase in extent from tergite II to V, but on VI the patch is more or less reduced. Sternites III and IV with shagreen patches. Pleura IV without spinules. Comb of segment VIII with 4/8 teeth; comb with teeth unusual for Chironomus: the teeth narrow rapidly from base to a long thin point; these points hardly converge apically giving the appearance, although the bases of the points are contiguous, that they are separate from each other; the comb is set on a bulbous swelling which flattens out on a slide to give a square-ended appearance (102m.jpg).
Anal segment: Fringe of anal lobe with about 200 taeniae.

Species keys out at Page 152: Chironomini 49 Chironomus of the Text Key.

(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Hirvijärvi, Finland.