Shell surface adaptations in relation to water management in rock‐dwelling land snails, Albinaria (Pulmonata: Clausiliidae)

Abstract

Land snails display a great diversity of shell structures subject to adaptive explanations. Ribs, which are transverse protrusions on the shell surface, are an example. For the rock‐dwelling snail Albinaria variation of shell sculpture is attributed to water management adaptations. However, detailed experimental tests of these hypotheses are lacking. Various Albinaria species, differing in rib pattern, were examined for trait conservatism and the capacity to adhere and retain water on their shells, and the relation between ribbing and activation time after aestivation. Phylogenetic signal in all traits was random. Differences in shell sculpture affect shell weight and water adhesion but not water loss and activation time. Climatic variables have no influence on rib variation. Therefore, shell sculpture is not sufficient alone to explain the ability of Albinaria to withstand adverse conditions. Thus, additional morphological, behavioural and physiological adaptations must be considered as promising candidate traits for further studies of divergence.

Keywords:

• Pulmonata
• Albinaria
• adaptation
• phylogenetic signal
• shell ribbing
• snails
• water management
• locomotion

Acknowledgments

I thank C. Adamopoulou for her assistance in the experimental observations, two reviewers for their comments and the Academy of Athens for funding part of this work.