Deepest echinoderm
- Who
- Prototrochus bruuni
- What
- 10730 metre(s)
- Where
- Tonga
- When
- 1977
The deepest-living echinoderm known is the sea cucumber (holothurian) Prototrochus bruuni (formerly Myriotrochus bruuni), a specimen of which was retrieved from 10,730 m (35,203 ft) in the Tonga Trench in the south-west Pacific Ocean. This discovery was made by trawlings in 1977 by the Soviet research vessel Vityaz, with the findings published by the marine invertebrate expert Dr Georgii Mikhailovich Belyaev in 1989.
The deepest starfish, another type of echinoderm, is an unidentified species of Hymenaster sp. (of the Pterasteridae family) recorded at 9,990 m (32,776 ft) in the Philippine Trench.