Cenchritis muricatus (beaded periwinkle snails) Bahamas

Description:

Description: Tectarius muricatus (Linnaeus, 1758) - beaded periwinkle snails on phytokarst. These snails are on a phytokarst surface of aragonitic calcarenite limestones of the Hanna Bay Member (upper Rice Bay Formation, middle to upper Holocene). They are supratidal rocky shore bacteria/algae grazers. The jagged, pitted rock surface is phytokarst, formed by limestone being subjected to slow, partial dissolution by the life activities of bacteria and algae that coat the surfaces (= dark gray films). The snails are feeding on these biofilms by using their radulas to scrape away at the substrate. Phytokarst is one type of epikarst - limestone dissolution features at the top of the vadose zone. Classification: Animalia, Mollusca, Gastropoda, Littorinidae Locality: rocky cliffs along southern shoreline of Graham’s Harbour, just west of Bahamas Field Station, northern margin of San Salvador Island, eastern Bahamas. Date: 19 June 2010, 07:38. Source: Tectarius muricatus (beaded periwinkle snails) on phytokarst (San Salvador Island, Bahamas) 4. Author: James St. John.