This is a new bivalve species from Easter Island (in fact, the largest bivalve in the area). They live buried in sand and small pebbles, and are usually covered by a lot of other organisms.
Called Pinna rapanui this species is the 249th marine molluscan species found in Easter Island waters, and it is, by far, the largest bivalve species living around the island. A Polynesian origin of this species is suggested; however, its definite affinities with Indo-Pacific or South American fauna are still unknown.
Reference: Francisco Araya and Osorio. 2016. Pinna rapanui n. sp. (Bivalvia: Pinnidae): The Largest Bivalve Species from Easter Island, South Pacific Ocean, Chile . BioOne
Photo: Juan Francisco Araya, who discovered the new species