Analysis of information sources in references of the Wikipedia article "Donacidae" in Portuguese language version.
Coquinas, also called Wedge Clams and Butterflies, are the smallest and most abundant shells found on the beaches of the southeast. These wedge-shaped, triangular shells with rounded edges grow to be 1/2-3/4 inch in size. Living in the intertidal zone, these shells obtain a variety of colors and patterns, and can be found in dense groups, often numbering up to 1,500 clams in a single square foot. Coquinas live buried in sand less than one inch from the surface where they extend two siphons above the surface of the sand to filter plankton. These small clams are boiled in broth to make chowder. Coquina stone, which is compacted dead shell, is used as building material in some parts of the world.
