<p>Littoraria angulifera (Lamarck, 1822) - mangrove periwinkle in Florida, USA (January 2016).
</p><p>The gastropods (snails &amp; 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 &amp; sea slugs &amp; pteropods).  Most members of the Gastropoda are marine.  Most marine snails are herbivores (algae grazers) or predators/carnivores.
</p><p>The snail shown above is a living mangrove periwinkle, Littoraria angulifera, on a large piece of driftwood.  The holes in the surrounding wood were drilled by bivalves.  The mangrove periwinkle is a biofilm grazer.
</p><p>Classification: Animalia, Mollusca, Gastropoda, Littorinidae
</p><p>Locality: marine beach at the southern tip of Cayo Costa Island, Gulf of Mexico coast of southwestern Florida, USA (vicinity of 26° 36' 48.74" North latitude, 82° 13' 19.91" West longitude)
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<hr><p>More info. at:
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<a href="https://en.wikipedia.org/wiki/Littoraria_angulifera" class="extiw" title="en:Littoraria angulifera">en.wikipedia.org/wiki/Littoraria_angulifera</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a>
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/jsjgeology/24317573135/">Littoraria angulifera (mangrove periwinkle) (Cayo Costa Island, Florida, USA) 2</a>