Chironomus pe25

new form

Very close to Chironomus longistylus Goetghebuer: possibly an extreme variant.
Exuviae 10.0, 10.2mm long (n=2).
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 120x80, 160x94µm (n=2). Frontal setae 74µm long (n=1). Basal ring of thoracic horn 184x90, 196x96µm; tracheal patch 150x64, 152x56µm (n=2); 14, 17 tracheoles 4µm in diameter. Tracheolar patch of thoracic horn without an "eye". Thorax less distinctly granulate: anteriorly the granules are small and distinct; medially most of the granules are somewhat flattened, producing an irregular reticulate pattern, or evanescent.
Abdomen: Hook row II entire, length of row 0.49x width tergite (n=1); 79, 85 hooks (n=2). 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. Lateral longitudinal bands of sternites III (and usually IV) extensive. Parasternite II obviously shagreened. Pleura of segment IV spinulate. Comb of segment VIII with 3-5 elongate apiculate teeth (n=2), on the end of an elongate ventral cuticular mound which exceeds appreciably the apico-lateral corner of the segment. Segment VIII with 5 lateral taeniae.
Anal segment: Anal lobe with 84, 88 fringe taeniae and 2 dorsal taeniae (n=2).

Form keys out at Page 200: Chironomini 97 Chironomus of the Text Key.

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

Ecological notes
A pond, Swiss Alps.