A large cup coral. Difficult to say if its actually on a sandy substrate or ifthe sand is a thin veneer and the cup coral is attached to a rock surface.
4/10/2019 1:15:38 PM
Date: 20150429T174826Z
Credit: NOAA OKEANOS EXPLORER Program, Oceano Profundo 2015; Exploring Puerto Rico's Seamounts, Trenches, and Troughs
Location: hiting Seamount approximately 700 meters