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Eunice aphroditois is a giant marine worm in the speciose polychaete family Eunicidae (which contains over 300 species names; Zanol et al. 2010; Fauchald 1992).  One of the world’s longest worms, E. aphroditois is a dramatic sight with different accounts measuring individuals 3-6 meters (10-20 feet) long, their bodies up to 25 mm (1 inch) across.  These omnivorous, opportunistic, free-living worms live head-up in burrows just under sand or gravel sediments or in boulders/coral rubble.  Five tentacles around their mouth, characteristic of the genus, extend in the water.  When it detects prey, the worm springs from its lair, everting its proboscis to expose a fierce pair of mandibles, with which it pulls the prey into its hole.  (Video here:

In the 1990s, a giant eunicid worm from the Indo-pacific was photographed and its astonishing feeding behavior documented (as Eunice sp., as even experts could not identify it to species) in an identification manual, Coral Reef Animals of the Indo-Pacific (Gosliner et al. 1996): “...with its 5 pairs of massive, spring loaded jaws, [this species] appears like a frightening apparition from a science fiction movie… This species is a voracious predator.  It was observed to feed on a file fish of more than 150 mm in length.  When the file fish ventured too close to the worm it emerged slightly from its burrow and seized the fish in its jaws with lightning speed.  In an instant, the worm had pulled the fish beneath the sand surface and begun to consume it.”

Originally described from tropical Indo-Pacific waters around Sri Lanka (Pallas 1788), this species is reported around the world, although experts believe this name confounds a multitude of similar-looking giant eunicid worm species.  For example, recent work formally distinguished the giant eunicid worm (and commercially important fishing bait species) that inhabits the Mediterranean and Agean Seas as E. roussaei rather than E. aphroditois (Zanol and Bettoso 2006).  The difficulties of teasing apart the different species morphologically has made taxonomy, systematics and understanding of the distribution and ecology of species within the genus Eunice very complex.  In combination with further study of type material and more collection at type locations, molecular bar coding and molecular phylogenetic characters may prove a helpful tool in the much needed task of defining this and other giant eunicid species more precisely (Schulze 2011; Salazar-Vallejo et al. 2011; Zanol et al 2010).

Gosliner et al. (1996) coined the name Bobbit worm for the Eunice sp. illustrated in their book, associating the worm to the at the time widely-discussed Lorena Bobbit court case.  The name simply refers to the sharpness of the worm’s mandibles slicing its prey under attack and the resemblance of the worm to a phallus when holding itself erect to catch prey, not to imply that this worm castrates its mate - which it doesn’t as these worms are broadcast spawners - however this misinterpretation has circulated especially on the web.  Just as most giant eunicid worms around the world are ascribed to the species name Eunice aphroditois, most of these worms are also referred to as the Bobbit worm, so rather than as a common name for E. aphroditois, “Bobbit worm” would be better applied generally to all giant eunicid worms (Mah 2013), although these giant worms are not necessarily a monophyletic grouping.


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