Tanytarsus ejuncidus

Author: (Walker, 1856)

Exuviae 3.9-5.9mm long (n=9).
Cephalothorax: Cephalic tubercles flat mounds. Frontal setae 100µm long (n=2). Antennal sheath bases with a short conical tubercle. Thoracic horn 300-430µm long (n=8), at most minutely toothed; ThR 14.0-18.0 (n=4) (144l.jpg). Posterior thoracic mound absent. Wing sheaths rounded apically, pearl row absent.
Abdomen: Length hook row II 0.18-0.30x width tergite; hooks 57-87 (n=4). Spine bands of tergite III situated further back on the tergite and overlap setae D5, bands curved outwards so that if the line of the spine bases is extended posteriorly it cuts the lateral margin of the segment. Spine bands of tergite IV characteristic: they arise anteriorly as a transverse spinule band which laterally curves sharply posteriorly to form a longitudinal, inwardly diagonal band in which the spines increase markedly in length posteriorly and become more inwardly and transversely orientated; thereafter the length of the spines rapidly diminishes and the band may bend inwards to extend transversely for a short distance (144m.jpg). Armament of tergite V arranged in longitudinal bands. Armament tergite IV strong, 180-240µm long (n=8). ArR III-VI 0.62-0.74 : 1.0 : 0.28-0.36 : 0.16-0.21 (n=8). Postero-lateral comb of segment VIII 47-80µm wide (n=8). Lateral taeniae of segments V-VIII: 0,0,1(0),5.
Note: The very characteristic spine patterns of tergites III and IV preclude confusion with other species.
Anal segment: Anal lobe ratio 1.1-1.4 (n=6). Fringe of anal lobe with 26-41 taeniae (m=33.8, n=10), forming a complete series.
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 485: Tanytarsini 126 Tanytarsus of the Text Key.

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

Ecological notes
Drains and the slower flowing parts of streams and rivers.