Meigen, 1818
Body
Large larvae with a length up to 12 mm. Living larvae are greenish. The fringe of swimming hairs is present (Moller Pillot, 1984a).
Head
The head is relatively small compared to the body, has a length of 0.55 - 0.65 mm with a cephalic index of 90 - 100% Tan head (Moller Pillot, 1984a)
Antenna
The antennal segments are all yellow and the antennal ratio is 5 - 6. The ring organ is situated at 0.8 - 0.9 of the height of the first segment. The second segment is normal and lacks a tuning fork (Wiederholm, 1983; Moller Pillot, 1984a).
Mentum
Dorsomentum with 7 - 8 teeth on each side. Both parts are broadly joined in the middle Tan punctipennis mentum (Moller Pillot, 1984a).
Ligula and paraligula
Ligula with 5 equal-sized yellow teeth in a straight line or slightly convex. Paraligula fan-like with with appr. 13 hair-like rays Tan punctipennis ligula.
Mandible
The mandible is very characteristic. The distal part of the inner margin with 2 long flat teeth and 2 small pointed accessory teeth next to each other. The basal tooth is a hump which is folded inwards distally Tan kraatzi mandible.
Maxilla
The maxilla is short with an undivided basal segment.
Anal tubules
6 anal tubules which are longer than wide Tan 6 anal tubules.
Posterior parapods
Some of the smaller claws with proximal spines Tan punctip claw.
Differential characteristics
The yellow ligula with 5 equal teeth Tan punctipennis ligula, the cephalic index (90 - 100%) and the shape of the mandible Tan kraatzi mandible are distinctive for the genus Tanypus. T. punctipennis differs from T vilipennis by having 6 anal tubules (T. vilipennis only 4). T. punctipennis differs from T. kraatzi by the fan-shaped paraligula Tan punctipennis ligula (T. kraatzi with 2 - 3 spines Tan kraatzi paraligula9, dorsomentum with 7 - 9 teeth Tan punctipennis mentum (5 - 6 in T. kraatzi Tan kraatzi dorsomentum and the proximal spines on the smaller anal claws Tan punctip claw (T. kraatzi with distal spines Tan kraatzi claws).