Benthodytes

Benthodytes is a genus of sea cucumbers belonging to the family Psychropotidae. These creatures were first described by scientists on the H.M.S. Challenger expedition between 1873 and 1876. Théel, who documented the genus, noted that the body is somewhat flattened, with a broad front brim. The mouth is on the underside, set back from the front end, while the anus is on the upper surface near the rear.

Tentacles number between twelve and twenty. Tube feet are arranged in a single row around the body’s brim and in a double row along the odd ambulacrum. The upper surface often bears small, retractile or non-retractile processes, arranged in rows or scattered across the sides. Théel also recorded the species B. typica, B. sanguinolenta, and B. abyssicola.

Within the Psychropotidae family, members of Benthodytes (also known as Benthodites) are distinguished by soft, retractile tentacles, papillae around or behind the mouth, and the lack of a single dorsal appendage.

Several Benthodytes species serve as useful indicators for studying the potential effects of deep-sea mining and have been the focus of numerous research efforts. Because their delicate bodies are often damaged during collection, species identification usually relies on photographs. Genome sequencing is improving understanding of their evolution and classification, starting with B. rosea and B. typica. The mitochondrial genome of B. marianensis has also been sequenced, revealing a novel gene arrangement among holothurians that may help it survive at great depths.

The list of Benthodytes species is subject to change as phylogenetic data clarifies relationships among these hard-to-identify creatures, whose soft appendages frequently break off during sampling. Known species include: B. abyssicola, B. gosarsi, B. incerta, B. lingua, B. manuensis, B. marianensis, B. plana, B. sanguinolenta, B. sibogae, B. superba, B. typica, B. valdiviae, B. violeta, and B. wolffi.