Aspects of conchological features of Anadara senilis in relation to the nature of subtratum

Abstract

Some conchological features of the bloody cockle, Anadara senilis occurring in six lagoons in Ghana were investigated in relation to the particle size of the substratum. Shell indices (i.e., shell length/ shell height, shell width/shell height and shell weight/shell height and the number of ribs on the shells of one hundred (100) specimens from each lagoon were analysed. The mean particle size of the substratum for each of the lagoons was determined and classified according to the USDA system. The substrata ranged from fine to very coarse sand. Cockles inhabiting substrates with larger particles size tended to possess slim and lighter shells with fewer number of ribs, while those in substrates with smaller particles had rotund (tumid) and heavier shells with more ribs. These results are interpreted in terms of the roles of the shell in burrowing and maintaining stability in the subtratum.

JOURNAL OF THE GHANA SCIENCE ASSOCIATION Volume 2 No. 3 (2000) pp. 123-128