Haliday, 1855
Body
Medium sized to large larvae up to 6 mm long. The anterior parapods are partly fused. The two posterior parapods bear rows of claws. Procercus and the anal tubules are absent Clunio marinus anal segm (Wiederholm, 1983; Moller Pillot, 1984b).
Head
Antenna
The antenna consists of five segments. Segment 2 about the same length as segment 1. The blade is shorter than the flagellum. The lauterborn organs are inconspicuous.
Mentum
The mentum has one median tooth and 5 pairs of lateral teeth Clunio marinus mentum. The ventromental plates are weak.
Labrum
The pecten epipharyngis consists of three spines of different length. SI is plumose and the premandible has one basal and one apical tooth (Wiederholm, 1983; Moller Pillot, 1984b).
Mandible
The mandible with an apical tooth and 3 inner teeth. The seta interna has plumose branches (Wiederholm, 1983).
Differential characteristics
Of the marine Orthocladiinae s.l. (Clunio, Halocladius and Telmatogeton) only Clunio has a plumose SI. Of all Orthocladiinae s.l. the combination of one median mentum tooth, 4 pairs of lateral teeth Clunio marinus mentum, no anal tubules Clunio marinus anal segm and antenna with 5 segments is distinctive for Clunio.
European species: 4
Treated species: 0