 The pelvic fins are much smaller, and bear claspers in males; in "G. murinus" and "G. nipponensis", the pelvic fin inner margins are partially fused to form an "apron" over the base of the claspers.The anal fin is elongated and much larger than the pelvic and dorsal fins; its position relative to the pelvic and caudal fins varies from very close to well-spaced.The caudal peduncle can be nearly cylindrical to laterally compressed, depending on species.