A New Heterotrophic Cryptomonad: Hemiarma marina n. g., n. sp.

Abstract We report a new heterotrophic cryptomonad Hemiarma marina n. g., n. sp. that was collected from a seaweed sample from the Republic of Palau. In our molecular phylogenetic analyses using the small subunit ribosomal RNA gene, H .  marina formed a clade with two marine environmental sequences, and the clade was placed as a sister lineage of the freshwater cryptomonad environmental clade CRY1. Alternatively, in the concatenated large and small subunit ribosomal RNA gene phylogeny, H .  marina was placed as a sister lineage of Goniomonas . Light and electron microscopic observations showed that H .  marina shares several ultrastructural features with cryptomonads, such as flattened mitochondrial cristae, a periplast cell covering, and ejectisomes that consist of two coiled ribbon structures. On the other hand, H .  marina exhibited unique behaviors, such as attaching to substrates with its posterior flagellum and displaying a jumping motion. H .  marina also had unique periplast arrangement and flagellar transitional region. On the basis of both molecular and morphological information, we concluded that H .  marina should be treated as new genus and species of cryptomonads.