Small larvae, to 4.6 mm long. Head capsule pale brown. Cephalic setation: ventral - S9 anterior to VP, S10 posterior to VP; S7 anterolateral to S8; dorsal S5, DP and S8 in row, slightly posteriorly directed.
Antenna 4 segmented, 4 times longer than mandible, basal segment 13 times longer than basal width; ring organ on elevated tubercle near middle of basal segment. AR about 4.0.
Mandible, slender, basal tooth distinct, mola swollen.
Dorsomentum with 3 teeth on each side, lateral margin weekly notched.
Maxilla with Ring organ in distal half of basal maxillary palp segment. Basal segment of maxillary palp about 4 times longer than wide.
Anal tubules slender, longer than parapods; supraanal setae on small tubercles, stronger and longer than anal setae; claws of posterior parapods simple but with hyaline outer parts on several claws.
Parapentaneura and Pentaneura larvae are the only Pentaneurini larvae with large, dark supraanal setae, which are longer and stronger than the anal setae and mounted on small humps. The two genera differ in the arrangement of dorsal cephalic setae.
Larvae of Parapentaneura have been found along the whole Rio Bento Gomes, an intermittent lowland river which flows into the northern Pantanal, the largest wetland of South America. Average water temperature lies between 24–28°C, and the water flow is highly variable due to wet and dry seasonal periods. Larvae occurred exclusively among floating water plants like Salvinia and Eichhornia, leaf litter and wood debris.
A very similar larva to that of Parapentaneura bentogomensis has been found in a bromeliad in Costa Rica - and it is possible that references to 'Pentaneura' in phytotelms in Central and South America refer instead to this genus.