Enypniastes

Lore & Background

The Enypniastes have developed webbed swimming fin-like structures at the front and back of their bodies, enabling them to swim up off the seafloor and journey as much as 1,000 m into the water column. This is thought to help them move to new feeding grounds and avoid predators. The sea cucumber ranges in size from 11 to 25 centimeters. Its most distinct feature is its coloring, which is dictated by size: small Enypniastes are bright pink, and larger individuals are more reddish-brown. It is also semi-transparent, and its intestine can be seen through its body, especially after feeding. The Enypniastes have a round bulbous body, bifurcated tentacles, and a large anterior sail. They can also be bioluminescent.

They can be found mainly in the benthic zone of the ocean, all over the globe in many different regions. They spend most of their time in the water column, touching down on the seafloor only to eat. The first sighting in the southern ocean waters occurred in October 2018, when a team from Australia's Department of the Environment and Energy caught an image of E. eximia on a camera deployed in seas near East Antarctica.

The Enypniastes feed mostly on benthic sediment, pushing food into their mouths with their tentacles. They feed very quickly, staying on the seafloor for at most sixty four seconds, which is mostly enough time to feed fully, so they feed episodically. They move using a few methods: moving their anterior veil in a rowing motion; when there is a current, using their tentacles to pull themselves down current; and using a pushing motion with their tentacles.

Reader's Guide

The Enypniastes genus is notable for its single species, Enypniastes eximia, which has attracted attention due to its unusual appearance and behaviors. Its common names—headless chicken fish, headless chicken monster, Spanish dancer, swimming sea cucumber, and pink see-through fantasia—reflect its striking look. The species is significant for its ability to swim up to 1,000 meters above the seafloor using webbed fin-like structures, a rare adaptation among sea cucumbers that aids in feeding and predator avoidance. Its size-dependent coloration, from bright pink to reddish-brown, and semi-transparent body that reveals the intestine after feeding, are distinctive features. The first recorded sighting in the southern ocean in October 2018 expanded its known range. Its feeding strategy is also remarkable: it feeds episodically on benthic sediment, spending at most 64 seconds on the seafloor per feeding event. The species' bioluminescence adds to its uniqueness. Overall, Enypniastes represents a deep-sea organism with specialized locomotion, feeding, and appearance that distinguish it within its habitat.

Did You Know?

• Enypniastes is monotypic, represented only by the species Enypniastes eximia.
• Its color changes with size: small individuals are bright pink, larger ones reddish-brown.
• The first sighting in the southern ocean was in October 2018 near East Antarctica.