Dioecious marine vertebrate with external fertilisation is

Petromyzon (lamprey) is a marine vertebrate, unisexual (dioecious) with external fertilisation.Nereis (aquatic annelid) is a marine invertebrate, dioecious with external fertilisation.Though Pristis (sawfish) and Chelone (turtle) are marine vertebrates and dioecious, they exhibit internal fertilisation.