Hygrosoma petersii (A. Agassiz, 1880)is aregular deep-sea urchin from the family Echinothuriidaethat has undergone numeroustaxonomic changes throughout history. It is characterized by the presence of tridentate pedicellariae with spoon-shaped valves with a serrated edge. The geographic distribution of Hygrosoma petersii is extended to the Colombian Caribbean, as the southernmost record of the Caribbean Sea. Species description and, for the first time, Scanning Electron Microscopy (SEM) photographs of its pedicellariae and sphaeridia are presented, comparing it with its Caribbean congeners