It is a monotypic genus and the only species is Meyenaster gelatinosus which was first described by the Prussian botanist and zoologist Franz Julius Ferdinand Meyen in 1834.

[3] In the kelp forests, M. gelatinosus is one of the dominant predators along with the starfish Stichaster striatus, Luidia magellanica and Heliaster helianthus, the fish Pinguipes chilensis, Semicossyphus darwini and Cheilodactylus variegatus, and the Chilean abalone (Concholepas concholepas), a gastropod mollusc.

[5] In a study in Tongoy Bay in north central Chile, M. gelatinosus was found to be a generalist predator in sand and gravel habitats, but showed a marked preference for the Peruvian scallop (Argopecten purpuratus) in seagrass meadows.

This is an effective response where there is vigorous wave action, as the sea urchin gets swept away by the surging water.

This sea urchin appeared to be able to distinguish between a foraging M. gelatinosus and a non-foraging one, taking evasive action in the first case but not in the second.