Scardinius knezevici, a new species of rudd from Lake Skadar, Montenegro (Teleostei: Cyprinidae)

Scardinius knezevici, new species, is described from Lake Skadar, Montenegro. It also occurs in Lake Ohrid. It differs from Scardinius cf. erythrophthalmus, from Neretva and Krka rivers by having a distinctly more slender body, fewer lateral line scales and fewer branched anal-fin rays. It differs from Danubian populations of S. erythrophthalmus and the S. cf. erythrophthalmus populations of the Padano-Venetian district by having fewer branched rays in the dorsal and anal fins, and fewer lateral line scales. It differs from the Italian S. scardafa by having fewer gill rakers and fewer lateral line scales. Scardinius knezevici differs from the Greek S. acarnanicus and S. graecus by having fewer total gill rakers, fewer lateral line scales and fewer branched anal-fin rays. Scardinius knezevici is still very frequent in Lake Skadar, but introduction of congeneric species might compromise its survival.