Complete mitochondrial genome sequences and phylogenetic relationship of Elysia ornata (Swainson, 1840) (Mollusca, Gastropoda, Heterobranchia, Sacoglossa)

The sacoglossans are small sea slugs in the Heterobranchia. In this study, mitochondrial genome of a sacoglossan sea slug, Elysia ornata (Swainson, 1840) is analyzed and phylogenetic tree of the species in the Heterobranchia is reconstructed based on amino acid sequences of mitochondrial protein coding genes. The phylogenetic relationship analysis shows that E. ornata belongs to the monophyletic Sacoglossa in the Heterobranchia and the Sacoglossa shows sister group relationship with a lineage including Anaspidea and Siphonarioidea. This is the fourth record for the mitochondrial genome of sacoglossan sea slugs.