The naval shipworm, Teredo navalis, is not a worm at all. It is a highly specialized bivalve mollusc adapted for boring into and living in submerged wood. The genus Teredo is one of several genera of wood-boring bivalve shipworms. Bankia and Lyrodus are two other genera of shipworm that can be found in the U.S. south Atlantic. Though it now exhibits a cosmopolitan distribution, T. navalis is a cryptogenic species in Florida and is believed to be non-native to North America (Carlton and Ruckelshaus 1997).The body of Teredo navalis is long and wormlike and reddish pale in color. Unlike most bivalves that rely on their shell for protection, T. navalis has a small (up to 2 cm long), helmet-like shell that encloses only a small portion of the animal. The shell modified for burrowing into wood. Fine ridges on the tri-lobed valves of the shell are used to rasp away wood. Instead of relying on the shell for protection, T. navalis protects its soft elongate body by residing in a secreted calcareous tube lining the excavated burrow. The tube is capped near the mouth of the burrow by a calcareous septum. An incurrent and excurrent siphon located at the anterior of the animal protrude through a small hole in the septum and into the water to facilitate feeding, respiration and excretion/egestion. The siphons can be rapidly contracted and protected underneath a pair of 0.5 cm long calcareous paddle-shaped pallets (NIMPIS 2002, Did?iulis 2007).
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