Deepest Atlantic molluscs: hadal limpets (Mollusca, Gastropoda, Cocculiniformia) from the northern boundary of the Caribbean Plate

Descriptions and scanning electron micrographs of the shell, protoconch, ra dula, and gross external anatomy are provided for four species of cocculini form limpets collected from hadal depths of the Cayman and Puerto Rico tren ches. Of these, one represents a new genus and species, Macleaniella moskal evi (Cocculinidae), endemic to the Puerto Rico Trench. Another, Amphiplica plutonica (Pseudococculinidae), represents a new species from the Cayman Tr ench of a globally distributed abyssal genus. The original descriptions of the remaining two species, Fedikovella caymanensis (Cocculinidae) and Cayma nabyssia spina (Pseudococculinidae), both from the Cayman Trench and type s pecies of their respective genera, contained only poorly reproduced illustr ations of portions of the shells, and line drawings of isolated rows of rad ular teeth. These four species, each apparently endemic to their respective trenches, represent the deepest records of molluscs collected in the Atlan tic Ocean.