Morphology and ecology of bivalve molluscs from Admiralty Bay, King George Island, Antarctica

Abstract

Bivalve species were collected from shallow coastal areas of King George Island (Martel, Mackellar and Ezcurra Inlets of Admiralty Bay). Twenty one species belonging to 16 genera and 12 families were identified and their morphometric and morphological shell characteristics were described. Three main characteristics were found to be common to the majority of the bivalve species sampled: 1) thin fragile shells; 2) small size of individuals (76%), and 3) the lack of true cardinal teeth (72%). Comparison of calcium data from a tropical estuary and a subantarctic coastal shallow area suggested that the calcium in the sea water was not a constraint to shell building but shell thickness could be an adaptation to the efficiency of energy partitioning. Small individual size and the lack of true cardinal teeth are discussed in relation to a high deposition environment and widespread mud bottoms.