Swimming through the shadowy waters off Palau, scuba divers watched life on a coral reef after dark. One reddish sea creature with 17 “feather”-like arms caught their attention — and for good reason.

The new species is “an example of ‘hidden diversity’ among feather star crinoids at some of the most highly diverse sites yet studied.” ...

Scuba diving scientists found cryptic sea animals with over 17 arms that only emerge at night and discovered new species: cryptic feather star, study said.

Sure enough, the nocturnal feather stars were subtly but consistently distinct. Researchers realized they’d discovered a new species: Capillaster crypticus, or the cryptic feather star.