Psectrotanypus varius

Author: (Fabricius, 1787)

Diagnosis (Adult male: Langton and Pinder, 2003a)
Exuviae 5.8-8.3mm long (m=7.2mm, n=24) (011-1.jpg).
Note: Very similar to Derotanypus sibiricus (Kruglova and Chernovskij).
Cephalothorax: Thoracic horn 565-770µm long (m=691µm, n=28); ThR 3.6-7.5 (m=5.1, n=22). Plastron plate length versus thoracic horn length = 0.11-0.23:1 (m=0.16:1, n=23); plate as wide as the horn, 0.81-1.0x horn width (n=8), at least half as long as broad; rim absent. Struts across the horn atrium very narrow, showing up in surface view as dots, best seen in side view (011b.jpg). Thorax with well-spaced, regular, transverse grooves from suture. No thorax comb.
Abdomen: Mark on segment I brown or blackish. The minute spinules of tergites and sternites mostly single. Conjunctives not shagreened. Length lateral taeniae of segment VII 0.49-0.68 of length segment VII; anterior lateral taenia at 0.44-0.53 of length segment VII (m=0.48, n=12).
Anal segment: Anal lobes fringed with hair-like teeth externally and internally; lobe length versus length of segment VIII = 1.7-2.1:1 (m=1.97:1, n=12) (011c.jpg). Anal lobe ratio 1.95-2.35 (m=2.2, n=23). Length of the anal lobe versus exuvial length = 0.13-0.15:1 (m=0.14:1, n=23). Width anal segment versus width segment VIII = 0.79-0.86:1 (m=0.83:1, n=7). Insertion of anterior anal taenia at 0.15-0.19 of lobe length (n=9). Length male genital sheaths 0.39-0.45x lobe length (n=6).
(Linked adult male: Langton and Pinder, 2003a)

Species keys out at Page 39: Tanypodinae 25 Derotanypus/Psectrotanypus of the Text Key.

Palaearctic species: widespread in Europe and NW Africa.
(For more information see module IdentifyIt – file: Other subfamilies).

Ecological notes
Ponds, shallow lakes, ditches and streams.