Five new species of the genus Eudactylina are described based on specimens recovered from the branchial lamellae of six species of Japanese elasmobranchs. These are E. musteli nov. sp. from Mustelus griseus Pietschmann, 1908 (Triakidae), E. squatini nov. sp. from Squatina japonica Bleeker, 1858 (Squatinidae), E. dasyati nov. sp. from Dasyatis akajei (Müller & Henle, 1841) and Taeniura meyeni Müller & Henle, 1841 (Dasyatidae), E. taeniuri nov. sp. from T. meyeni, and E. gymnuri nov. sp. from Gymnura japonica (Temminck & Schlegel, 1850) (Gymnuridae). The males of four new species and the copepodid stages IV and V of E. gimnuri nov. sp. are described. Segment formation of the abdomen in the late copepodid stages of this genus and a peculiar process of the 1st endopodal segment of the male leg 2 are discussed.