Tanytarsus usmaensis

Author: Pagast, 1931

Exuviae 3.3-4.8mm long (m=4.1mm, n=28).
Cephalothorax: Cephalic tubercles very shallow conical; frontal setae 60, 85µm long (n=3). Antennal sheath bases with a small conical swelling. Thoracic horn 560-900µm long (n=9), without long setulae; ThR 17.1, 21.5 (n=3). Posterior thoracic mound strongly swollen. Wing sheaths rounded apically, pearl row absent.
Abdomen: Length hook row II 0.28-0.32x width tergite (n=4); hooks 82-105 (n=5). Tergite II without anterior point patches; III-VI with paired anterior point patches (139h.jpg). Spine bands of tergite III without an external border of points, any lateral points restricted to the anterior half of the spine band. Tergites IV and V with the armament arranged in longitudinal bands. Armament tergite IV strong (139h.jpg), 60-155µm long (m=100µm, n=22). ArR III-VI 1.4-2.5 : 1.0 : 0.6-1.4 : 0.4-0.8 (n=22). Comb of segment VIII 35-82µm wide (m=50µm, n=15); with 4-13 marginal teeth (m=7.5, n=28). Lateral taeniae of segments V-VIII: 3(2,1),3(2),4,4.
Anal segment: Anal lobe ratio 1.18-1.56 (n=7). Fringe of anal lobe with 22-42 taeniae (m=30, n=29), forming a complete series beginning near the anterior edge of the lobes.
(Linked adult male: Langton and Pinder, 2003a)

Note: The armament of tergite IV is very variable in length and in the number of spines present. Doubtfully separable from Tanytarsus nigricollis Goetghebuer, 1939.

Species keys out at Page 449: Tanytarsini 90 Tanytarsus of the Text Key.

Holarctic species: widespread in Europe.
(For more information see module IdentifyIt – file: Chironominae).

Ecological notes
Stagnant and running water.