Tanytarsus horni

Author: Goetghebuer, 1934

Diagnosis (Material in coll. ZSM)
Exuviae 3.3-4.4mm long (n=5).
Cephalothorax: Cephalic tubercles 55-75µm long (n=3). Frontal setae 75-83µm long (n=4). Thoracic horn 440-610µm long, horn with long setulae, 40, 45µm long (n=3), longer than the width of the horn and restricted to the middle half (142g.jpg); ThR 17.5-24.5 (n=3). Posterior thoracic mound swollen. Wing sheaths nearly parallel-sided or gently swollen medially, apically rounded; nose usually conspicuous, pearl row absent.
Abdomen: Hooks 91, 95 (n=2). Tergite II with the anterior points stronger than the posterior. Tergite III with strong shagreen anteriorly, spine bands short and situated in front of setae D5 (142f.jpg). Tergites IV and V with the armament arranged in longitudinal bands. Tergite VI with point patches. Armament of tergite IV 90-100µm long (n=3). ArR III-VI 0.88-1.22 : 1.0 : 0.7-0.91 : 0.45-0.5 (n=3). Longest spine III 57-68µm long (n=3), IV 20-50µm long (n=3). Postero-lateral comb of segment VIII 60-85µm wide; with 7-12 marginal teeth (n=4). Lateral taeniae of segments V-VIII: 0,0,1,5.
Anal segment: Anal lobe ratio 1.1-1.4 (n=4). Fringe of anal lobe with 43-52 taeniae (n=5), forming a complete series.

Note: Superficially resembles a member of the lestagei aggregate, but the long cephalic tubercles and the long setulae of the thoracic horn, longer than the width of the horn and restricted to the middle half, will easily distinguish it. (In the lestagei aggregate the cephalic tubercles are, at most, short conical and if the thoracic horn bears spinules they are short and extend to the horn tip).

Species keys out at Page 478: Tanytarsini 119 Tanytarsus of the Text Key.

Afrotropical species; circum-Mediterranean, Germany.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Tropical and subtropical standing and slow-flowing waters.