[2][3] Currently, six marine species of Mesodinium have been described and grouped by nutritional mode: plastidic (M. chamaeleon, M. coatsi, M. major, and M. rubrum) or heterotrophic (M. pulex and M. pupula).

[9][10][11] The availability of suitable cryptophyte prey is important for bloom formation of plastidic Mesodinium species.

[13][14][1] M. rubrum photosynthesizes by sequestering the nucleus of its cryptophyte prey, in order to maintain stolen plastids and other organelles.

[15] In this way, the genus Mesodinium plays an important role in linking cryptophycean prey and diverse predators in the aquatic microbial food web.

For example, the dinoflagellates Dinophysis spp., which are a predator of M. rubrum and the source of their cryptophyte-derived plastids, have been frequently observed to precede or to coincide with high densities of M.