(Goetghebuer, 1921)
Body
Medium sized larvae up to 6 mm long. The posterior parapods bear about 15 simpel claws. The L2 on the abdominal segments is simpel. On abdominal segments 1 and 7 the L2 is branched Par tenellulus body setation (Klink, 1983b; Wiederholm, 1983).
Head
The head is pale and S3 is simpel.
Antenna
The antenna stands on a small smooth pedestal and consists of 5 segments. The basal segment is longer than the flagellum. Segment 2 is often brown, while the remainder of the antenna is pale, slightly wedging out at the apex, shorter to much longer than the remaining segments. Segment 4 is notably longer than the 3d segment. The lauterborn organs are large and taper to a conical tip. The blade reaches to the base of the 5th segment Par tenellulus antenna9.
Mentum
The mentum has a simpel to slightly notched median tooth and 5 pairs of lateral teeth. The ventromental plates are close together medially and slightly wider than the mentum.
Labrum
SI is a comb and labral lamellae a single plate with 30 - 34 teeth. The pecten epipharyngis consists of a single smooth plate with 3 rounded teeth distally. The premandible has 2 teeth.
Mandible
The mandible with a dorsal tooth, apical tooth and 3 inner teeth. The pecten mandibularis is present and seta interna with branches.
Differential characteristics
The pecten epipharyngis with a single plate with 3-5 teeth Par austriacus pect epiph is distinctive, although Lithotanytarsus may have a similar pecten epipharyngis. Paratanytarsus lacks the small pairs of median projections on the antennal pedestal however Lithotan emarg antenna.
P. tenellulus can be separated from the other Paratanytarsus by the pecten epipharyngis with 3 teeth, labral lamella with 30 - 34 teeth. branched L2 and 4th antennal segment longer than the 3d.