Valve sculpturing and aesthete distributions in four species of Australian chitons (Mollusca: Polyplacophora)

Abstract

The shell valve surfaces of the chitons Ischnochiton (Ischnoradsia) australis, Cryptoplax mystica, Liolophura (Liolophura) gaimardi and Onithochiton quercinus are studied by scanning electron microscopy. The distribution of aesthete caps is examined in relation to dorsal sculpturing and the formation of these complexes is compared with the arrangement of holes which penetrate the ventral surface and eave tissue. The presence of Specialized aesthetes (ocelli) on Liolophura (L.) gaimardi and O. quercinus is described. The use of aesthete densities as taxonomic indicators and possible functions in relation to species specific environmental conditions are discussed.