Within its genus, Moraria duthiei is a comparatively large and robust species, which is rare in Norway.
Moraria duthiei has a body which is stout. The exopod in the first four legs has three segments, while the endopod is 2-segmented. In the first leg the endopod is as long as the exopod, for legs 1–4 the endopods are considerably shorter than the exopods. All legs have a long setae. The fifth leg is large and also with a long setae. Its rostrum is large and broad. The operculum is smooth and triangular, but not prominent. The caudal ramus is rather large, conical and slightly longer than wide. There is no armour on its inner side. The antennule consists of eight segments.
Female: Length 0.71–0.90 mm
Male: Length 0.70–0.85 mm
Ecology and distribution
All records are from the littoral (often in mosses) of medium sized oligotrophic lakes (0.9–10.7 km2) in East-, West- and North-Norway, situated between 23 and 309 m a.s.l. The species has a Palearctic and Nearctic distribution.