Life habit Pinna species live in coastal and marine waters, as well as in transitional inlets partially influenced by freshwater flow. All members of the genus
Pinna are
sessile, and orient themselves vertically relative to the substrate with the thin, tapered end pointing downwards and the wide end open upwards. In muddy or soft, sandy conditions,
Pinna will bury 50-95% On more solid, rockier substrates, some
Pinna can anchor themselves directly to hard substrates similarly to other
common byssate molluscs.
Pinna are often hosts of
Pontonia shrimp and
pea crabs, as well as of
cardinalfish,
amphipods,
isopods and
sea anemones, which can live inside of their mantle cavities.
Feeding Members of the genus
Pinna are generally
filter feeders, In
Pinna nobilis, the size of the shell, and, as a result, the proportion of the shell that is above the surface of the substrate, are directly related with where nutrients were sourced. The veliger of the genus
Pinna are stubby, triangular in outline, transparent and already contains the heteromyarian, or anisomyarian musculature seen in adult
Pinna, where one adductor muscle is much reduced in size compared to the other. Upon reaching an appropriate substrate, the larva develops quickly, rapidly becoming sessile, and adult characteristics such as the
ctenidium,
mantle, and shell ornament take shape. Interestingly, all shell growth only occurs along the dorsal (pointed), ventral (wedge), and posterior margins, while no growth occurs anteriorly. The veliger shell quickly erodes, and is rarely preserved in adults. == Human uses ==