Bathymetric Records of Marine Shelled Mollusca from the Northeastern Shelf and Upper Slope of Yucatan, Mexico

Micromolluscs consisting of 185 species of gastropods, 143 species of pelecypods and 11 species of scaphopods from 11 samples ranging from 15 to 260 fm along the northeastern Campeche shelf and upper continental slope of Yucatan are reported, with bathymetry and comparisons of stations of higher similarity (and lower similarity) with depth, horizontal groupings and substrate type.

The greatest number of species were obtained from 15–30 fm, followed by a consecutively smaller number from the 30–65 and 65–260 fathom-zones.

Most of the species seemed to prefer calcarenite sediment, or sediment which is less than 60% clay and silt (62% of the species were in calcarenite only, 15% in calcilutite, or sediment which has more than 60% clay and silt, and 23% were found in both).

Two hundred and sixty-six species were found only on the continental shelf; 48 were found only on the upper slope and 25 were common to both.