Tanytarsus debilis

Author: (Meigen, 1830)

Diagnosis (n=2)
Exuviae 4.0, 4.1mm long.
Cephalothorax: Cephalic tubercles short conical. Frontal setae 90, 120µm long. Antennal sheath base with a prominent conical tubercle. Thoracic horn 555, 645µm long, without spinules; ThR 13.9, 18.4. Posterior thoracic mound very weak. Dorsocentral seta 4, though conspicuously thicker than 3, is seta-like, 2.5µm or less in breadth at base usually more or less parallel-sided for the basal half (140c.jpg). Wing sheaths rounded apically, pearl row absent.
Abdomen: Hooks of hook row II 67, 86. Small rounded point patches present on tergite II anteriorly. Point patches of tergites III-VI elongate oval, 3 or 4 points wide, on IV more than three times as long as broad (140b.jpg). Armament tergite IV strong, 75, 85µm long. ArR II-VI 0.41 : 0.82 : 1.0 : 0.88 : 0.82; 0.33 : 0.87 : 1.0 : 1.0 : 0.67. Postero-lateral comb of segment VIII 35µm wide, on a flat extension of the corner of the segment; with 5-7 marginal teeth. Lateral taeniae of segments IV-VIII: 0,1,3,4,4, taeniae well-developed.
Anal segment: Fringe of anal lobe with 26-29 taeniae, forming a complete series. Anal lobe ratio 1.19, 1.31.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 459: Tanytarsini 100 Tanytarsus of the Text Key.

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

Ecological notes