Tanytarsus inaequalis

Author: Goetghebuer, 1921

Exuviae 4.2-6.8mm long (m=5.6mm, n=67).
Cephalothorax: Cephalic tubercles minute tubercles, 15µm high. Frontal setae 55-100µm long (m=75µm, n=40). Antennal sheaths with a small conical projection at base. Thoracic horn 675-1000µm long (m=848µm, n=27); ThR 18.4-32 (m=25.2, n=25). The posterior thoracic mound is bulbous. Wing sheaths rounded apically, pearl row absent.
Abdomen: Length hook row II 0.27-0.34x width tergite; hooks 75-146 (m=115, n=16). Spine band of tergite III straight for most of its length or only weakly curved outwards (if the line of the spine bases is continued posteriorly it cuts the posterior margin of the segment) (144k.jpg). Tergites IV and V with the armament arranged in longitudinal bands. Armament tergite IV strong, 138-338µm long (m=271µm, n=52). ArR III-VI 0.80-1.3 : 1.0 : 0.23-0.42 : 0.14-0.34 (m=1.0 : 1.0 : 0.34 : 0.25, n=61). Longest spine III 75-140µm long (m=118µm, n=51); IV 70-138µm long (m=107µm, n=50); longest spine IV : III 0.73-1.33 : 1 (m=0.91 : 1, n=50). Postero-lateral comb of segment VIII 53-93µm wide (m=70.4µm, n=49); with 6-14 marginal teeth (m=9.2, n=49). Lateral taeniae of segments V-VIII: 0,0,2(1),5; usually two lateral taeniae on segment VII, only occasionally one. Ventral taeniate setae of segment VIII long, reaching well beyond the posterior margin of the segment (146b.jpg).
Anal segment: Armament of tergite IX strong, all or most of the points quite separate from each other (146c.jpg). Anal lobe ratio 1.06-1.44 (m=1.22, n=50). Fringe of anal lobe with 40-183 taeniae (m=82, n=71), forming a complete series.
(Linked adult male: Langton and Pinder, 2003a)

Note: A very variable species, but showing in most water bodies a much reduced variation in variable characters. See also comment on Tanytarsus gregarius.

Species keys out at Page 484: Tanytarsini 125 Tanytarsus of the Text Key.

Holarctic species: widespread in Europe (not Mediterranean).
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Lakes, tarns, pools; very rarely streams.