Analyses of tuatua populations — Paphies subtriangulata and P. donacina

Abstract

Populations of tuatua, Paphies subtriangulata and P. donacina, occur in the same beds in sandy beaches in New Zealand. The species may be differentiated on external and internal shell characters; living individuals may also be separated specifically by the colour of the adductor muscles. The invariable presence of algae and hydroids on the posterior shell surfaces of P. subtriangulata indicates a habitat difference (depth of substrate occupied) from P. donacina, on which epibionts are rare or absent. These conclusions, made from association and multivariate analyses, are supported by differences in esterase phenotypes which indicate that the species do not interbreed.

Keywords:

• Bivalvia
• Mesodesmatidae
• Paphies subtriangulata
• Paphies donacina
• distribution
• association analysis
• multivariate analysis
• esterase phenotype
• character discrimination