Apsectrotanypus trifascipennis

Author: (Zetterstedt, 1838)

Exuviae 6.1-7.3mm long (m=6.8mm, n=10) (011-2.jpg).
Cephalothorax: Thoracic horn 540-670µm long (m=612µm, n=6) (011e.jpg); ThR 1.65-2.07 (m=1.84, n=6). Plastron plate a narrow band across the apex of the thoracic horn; plate length versus thoracic horn length = 0.08-0.13:1 (m=0.11:1, n=6); rim absent. Thorax with well-spaced, regular, transverse grooves from suture. No thorax comb.
Abdomen: Mark on segment I brown or blackish. Conjunctives not shagreened. Anterior lateral taenia of segment VII at 0.20-0.29 segment length (m=0.23, n=6).
Note: Mark on segment I two parallel longitudinal lines widened posteriorly, occasionally only the posterior part obvious and then superficially resembling Derotanypus sibiricus and Psectrotanypus varius.
Anal segment: Anal lobes fringed with hair-like teeth, externally and internally. Anal lobe ratio 2.13-2.9 (m=2.3, n=10). Length of the anal lobe versus length segment VIII = 2.49-2.89:1 (m=2.71:1, n=7) (011f.jpg). Length of the anal lobe versus exuvial length = 0.15-0.21:1 (m=0.17:1, n=10). Width anal segment versus width segment VIII = 0.97-1.1:1 (m=1.03:1, n=6).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 38: Tanypodinae 24 Apsectrotanypus of the Text Key.

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

Ecological notes
Rivers and streams in the south, lakes in the north.