The Mangrove Periwinkle
As the vernacular ("common") name implies, the Mangrove Periwinkle, Littoraria angulifera (Lamarck, 1822), inhabits the trunks and branches of mangrove trees, in particular those of the Red Mangrove, Rhizophora mangle. The species may reach 30 mm (about 1.2 inch). Periwinkles are marine snails highly adapted at living almsot completely out of sea water, usually high above the intertidal ("between tides") zone. Mangrove Periwinkles feed, using the teeth of their rasping radula, on the thin film of fungi and algae that grow on the bark of mangrove trees. This living periwinkle was collected by Lorin Buckner in December 2017. (Florida FWC License SAL-17-1119-E.) Read more about local mollusks and their shells in our Southwest Florida Shell Guide.