Zetterstedt, 1838
Body
Medium sized larvae up to 7 mm long. The posterior parapods bear only simpel claws (Wiederholm, 1983).
Head
S3 is simpel.
Antenna
The antenna stands on a tall smooth pedestal and consists of 5 segments. The basal segment is much longer than the flagellum Tatars antenna. Segment 2 is cylindrical and longer than the remaining segments. The pedestals of the small Lauterborn organs reach far beyond the antennal apex.
Mentum
In C. ambigua group 3 median mental teeth and 1-2 pairs of lateral teeth situated dorsally behind the median teeth Cor ambigua mentum small. In C. oliveri group also 3 median mental teeth, but the 4 pairs of lateral teeth situated lateral from the central teeth. The ventromental plates are close together medially and wider than the mentum.
Labrum
SI is a comb and labral lamellae a single plate with numerous apical teeth. The pecten epipharyngis consists of 3 smooth plates with distal teeth. The premandible has 5 teeth.
Mandible
The mandible of the ambigua group has no teeth Cor ambigua mandible. The oliveri group has 3 dorsal teeth, apical tooth and 3 inner teeth. An additional toothed lobe is present on the dorsal side of the mandible Cor oliveri mandible. The pecten mandibularis is present and seta interna with branches.
Differential characteristics
The mentum is distinctive for the genus in having a central and dorsal or lateral part with only 1-2 or 4 pairs of teeth Cor ambigua mentum small.
Diversity
European species: 2
Treated species:
Corynocera ambigua
Corynocera oliveri