Sinistrofulgur sinistrum Hollister, 1958 - lightning whelk shell in Florida, USA (January 2016).

The gastropods (snails & slugs) are a group of molluscs that occupy marine, freshwater, and terrestrial environments. Most gastropods have a calcareous external shell (the snails). Some lack a shell completely, or have reduced internal shells (the slugs & sea slugs & pteropods). Most members of the Gastropoda are marine. Most marine snails are herbivores (algae grazers) or predators/carnivores.

The snail shell shown above is a lightning whelk, Busycon sinistrum. This is a rare example of snail species that has a left-handed coiled shell. Almost all snail shells have right-handed coiling (dextral coiling). Busycon sinistrum has left-handed coiling (sinistral coiling). The common name "lightning whelk" is in reference to the slightly zig-zag shape of the dark-colored lines running ~apically along the shell's surface.

Classification: Animalia, Mollusca, Gastropoda, Neogastropoda, Busyconidae