Dinoflagellate

Dinoflagellate

single celled animal with a long thin tail

The relationship between corals and an unusual group of micro-algae called dinoflagellates in the family Symbiodiniaceae forms the basis of coral reef ecosystems. The flagellated stage -- featuring a whip-like structure that enables the organism to swim -- is featured here with the image of a surface of a coral showing polygonal-shaped polyps in the background.

IMAGE: Todd LaJeuness, Hae Jin Jeong/Penn State