Year: 2025, Number: 4, Pages: 17-29
New data on the relationships of bitterlings of the genus Rhodeus with species of the family Unionidae Sinanodonta schrenkii and Nodularia douglasiae from the Razdolnaya River basin are discussed. In this basin, bitterling eggs were discovered for the first time in the gills of S. schrenkii from Lake Lotos (Ussuriysk Urban District, Primorsky Krai). The morphological features of different stages of the R. sericeus prelarvae development in mussels N. douglasiae are presented in comparison with published data.