Hipponoe depressa (A. Agassiz, 1863) (unaccepted combination)
A study of the phylogeography of the pantropical sea urchin Tripneustes by Lessios et al. (2003) revealed that based on morphology, COI, and bindin data, Tripneustes depressus A. Agassiz, 1863 from the eastern Pacific is in fact the same species as Tripneustes gratilla (Linnaeus, 1758) from the western Pacific .
In Panama this species is very rarely seen in the Gulf of Panama (Lessios 2005 reports finding two specimens off Isla Pacheca), and only occaisionally in the Gulf of Chiriqui (off Uva Island and Jicarita). However, Lessios (2005) found large number of this species at Jaque (7 31 N, 78 10 W) close to the boarder with Colombia.