Eunicea sp.

Eunice aphroditois

''Eunice aphroditois'' is a benthic bristle worm of warm marine waters. It lives mainly in the Atlantic Ocean, but can also be found in the Indo-Pacific. It ranges in length from less than 10 cm to 3 m . Its exoskeleton displays a wide range of colors, from black to purple and more. This species is an ambush predator; it hunts by burrowing its whole body in soft sediment on the ocean floor and waiting until its antennae detect prey. It then strikes with its sharp mandibles. It may also be found among coral reefs.

''Eunice aphroditois'' is also known as the bobbit worm or bobbitt worm. The name is believed to be taken from the John and Lorena Bobbitt case; however, another proposed reason is due to its jaw. It is sometimes called the sand striker. Another name associated with them is trap-jaw worm. Traces of their burrows have been noted in 2021 to have been found among fossils near Taiwan dating back twenty million years.
Bobbit Worm  Anilao,Batangas,Eunice aphroditois,Geotagged,Philippines,Winter,bobbit worm,scubadiving,underwater

Appearance

These ambush predators have five antennae on their head that are used to sense prey. The body is covered by a hard exoskeleton. The mandibles can be retracted inside the body and are responsible for striking and stunning prey; they are capable of snapping some prey in half. Typically, ''E. aphroditois'' ranges from deep purple to black, with an iridescent skin. The largest known specimen on record reached 299 centimeters in length, making it the longest known member of the polychaete class. Despite these great lengths, the worms are slim, with the body only about 25.5 millimeters wide.
Bobbit Worm - Eunice aphroditois This was a " Finally!..." encounter. Eunice aphroditois,Fall,Geotagged,Indonesia

Habitat

This species may be found prowling among the prey-rich environment of coral reefs, where its coloration allows it to blend in and its slim body enables it to hunt in tight places. It inhabits a wide range of other habitats, particularly sandy and muddy sediments, as well as around rocks and sponges. It has been recorded at depths of up to 95 meters .
Bobbit Worm - Eunice aphroditois This Bobbit Worm - Eunice aphroditois is quite an impressive animal.
It buries itself in the sand and comes out at night to hunt.  Usually, a small part of around 5-15 cm of their length is exposed or can be seen and they have been reported to grow up to 3 meters in length!
They sense movement around them with their 5 antennae.  When a fish swims within striking distance, it will use its 'claws' to snap at its prey and if it catches the prey, it will quickly withdraw into its hole, dragging the prey with it. Anilao,Batangas,Bobbit Worm,Eunice aphroditois,Geotagged,Philippines,Winter,Worm

Food

''Eunice aphroditois'' senses passing prey with its antennae, seizes the prey with their mandibles, and drags it into its burrow. This species is not only considered to be a carnivore, feeding on a plethora of species of fish, but it can also be considered an herbivore/omnivore, feeding on algae, as well as a decomposer, feeding on dead and decaying matter.

To reduce predation risk, some fish engage in mobbing behavior, during which a group of fish will direct jets of water into the worm's burrow to disorient it.

Ancestral species may have exhibited the same hunting behavior 20 million years ago, according to fossil-records.

Evolution

Fossil burrows from the Miocene of northeastern Taiwan have been likened to ''E. aphroditois''. The burrows, classified in the ichnogenus ''Pennichnus'', have been found preserved in fine-grained sandstone. They are L-shaped and can reach up to 2 metres in length, with a vertical section covered in feather-like collapse structures comprising around 40% of the burrow length, connected by a short intermediate section to a horizontal section amounting for 50% of the length. The burrows are on average 2.5 centimetres wide at the entrance, and taper down to 2 centimetres at the end of the horizontal section.

Cultural

While not commonly kept in aquaculture, individuals of ''E. aphroditois'' are occasionally found in home aquaria, where smaller specimens can evade detection by being transported into the tank in live rocks, where they then grow in size. As ''E. aphroditois'' hunts fish, it cannot be kept as part of a community tank and should be removed when found, as it will deplete the aquarium's stock by direct predation.

''E. aphroditois'' can be difficult to remove from aquariums due to their abilities to split into new individuals when cut in half, dig holes into rocks, and curl up and hide in small rocks, despite their length.

References:

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Taxonomy
KingdomAnimalia
DivisionAnnelida
ClassUnknown Class
OrderEunicida
FamilyEunicidae
GenusEunice
SpeciesE. aphroditois