This is Lepidodesm languilati f. aligera (Heude)

L. anguilati and L. anguilati often live together, and the number of L. anguilati is often much larger than L. anguilati in the same mussel bed. In molecular biology, there is no obvious difference between the two species, so they can merge into one species. In morphology, L. aligera can be treated as a form or variety of L. anguilati.
In terms of distribution, this species can be found in both Huaihe River basin and Yangtze River basin.