A sea anemone symbiotic with gastropods of eight species in the Mariana Islands

Abstract

Fifty-two specimens of the small sea anemone *Neoaiptasia morbilla* Fautin and Goodwill, 2009, were collected attached to shells of gastropods living in shallow subtidal sand on Saipan and Tinian, Mariana Islands, in 1988 and from 2003 through 2007. The anemones were associated with gastropods of eight species belonging to five families. Relative abundance of gastropods in an area where the anemones occurred was the same as the relative abundance of gastropods to which anemones were attached, from which we conclude that the anemones had no preference among the species of gastropods. A gastropod typically carried one or two anemones, but a few with three and four were collected. The anemone was generally located antero-dorsally on cerithiids and terebrids, postero-dorsally on cones, and in an intermediate position on strombids. The position on the shell minimizes the distance between anemone and substrate surface.