Shell Shape Variation of Tropical Limpet Cellana testudinaria (Class: Gastropoda, Family: Patellidae) Living on the Rocky Shore in Relation to Their Zonal Distribution

An examination of the body dimensions of C. testudinaria indicated that specimens collected from the three different shore levels were significantly different in shell length (L), width (B), height (H), distance from apex to anterior margin (AA), and distance from apex to posterior margin (AP). The overall relationships between body dimensions and shell length were negatively allometric. The relationships of shell length to AA and AP indicated that the apex of limpets living at the low shore level are shifted backward in individuals less than 18 mm in shell length, while it is shifted forward in larger limpets. Morphometric studies on the ratio of shell length to shell width and shell height and the ratio of shell circumference to volume provided similar results as the analyses of the body dimensions, indicating that limpets inhabiting the low shore level were broader and taller and had more acute, backward shifted apex than those living at the high and middle shore levels.