Laterality of shell formation differs in two sympatric gastropod species: Mulberry shell (Tenguella granulata), and strawberry topshell (Clanculus pharaonius)

Abstract We studied and found that the populations of two gastropod species in the inter-tidal zone of the Red Sea at Eilat demonstrate a predominantly dextral chirality of their shells. We identified lateralization sinistral/dextral shell torsion for 675 live Tenguella granulata (left = 114, 16.9%; right = 561, 83.1%) and 405 Clanculus pharaonius (left = 102, 25.2%; right = 303, 74.8%). In both cases, we found differences between sinistral and dextral shell torsions for Tenguella granulata and Clanculus pharaonius. The ecological and evolutionary consequences of individuals with sinistral chirality are unclear, but there are indications that it is a directional rather than stochastic process.