Barnacle

Barnacles are <a href="/facts/Arthropod/JKJLTFzp">arthropods</a> of the <a href="/facts/Subclass_(taxonomy)/a7MrgFu3">subclass</a> Cirripedia in the subphylum <a href="/facts/Crustacean/PBobIVJP">Crustacea</a>. They are related to <a href="/facts/Crab/GvkhXnSK">crabs</a> and <a href="/facts/Lobster/c5eYu72w">lobsters</a>, with similar <a href="/facts/Nauplius_(larva)/Rnj4CHHf">nauplius larvae</a>. Barnacles are exclusively marine <a href="/facts/Invertebrate/3CyqCVnN">invertebrates</a>; many species live in shallow and tidal waters. Some 2,100 <a href="/facts/Species/oDg6b96r">species</a> have been described.
Barnacle adults are <a href="/facts/Sessility_(motility)/f0xV4VV1">sessile</a>; most are <a href="/facts/Filter_feeder/hmVLwWB5">suspension feeders</a> with hard calcareous shells, but the <a href="/facts/Rhizocephala/awqysf4M">Rhizocephala</a> are <a href="/facts/Parasitic_castration/6y2pPww8">specialized parasites</a> of other crustaceans, with reduced bodies. Barnacles have existed since at least the mid-<a href="/facts/Carboniferous/BRKlkYyd">Carboniferous</a>, some 325 million years ago.
In folklore, <a href="/facts/Barnacle_geese/BI8dtzhc">barnacle geese</a> were once held to emerge fully formed from <a href="/facts/Goose_barnacle/rEwd3wL8">goose barnacles</a>. Both goose barnacles and the <a href="/facts/Austromegabalanus_psittacus/lXDwuIox">Chilean giant barnacle</a> are fished and eaten. Barnacles are economically significant as <a href="/facts/Biofouling/LmkrjvN2">biofouling</a> on ships, where they cause hydrodynamic <a href="/facts/Drag_(physics)/vdl4jF7I">drag</a>, reducing efficiency.

Barnacle open-in-new

Barnacle