Benthodytes
A genus of deep-sea cucumbers studied for mining impacts.
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*.
Quick Facts
- Taxon
- Benthodytes
Facts from the source article.
Lore & Background
This group of sea cucumbers was first described by scientists aboard the H.M.S. Challenger during its 1873-1876 voyage. Théel described the genus: 'Body more or less depressed, with the anterior part of its brim rather large. Mouth ventral, at a greater distance from the foremost extremity of the body. Anus posterior, dorsal, usually almost terminal. Tentacles (?) twelve to twenty. Pedicels arranged in a single row round the brim of the body and in a double one along the odd ambulacrum. The dorsal surface seldom naked, commonly with a greater or smaller number of retractile or non-retractile, more or less inconsiderable processes, arranged in a single row all along each ambulacrum or in an irregular double row, or scattered over the lateral interambulacrae.' Théel also documented the details of species B. typica, B. sanguinolenta, and B. abyssicola.
Among Psychropotidae, Benthodytes (synonym Benthodites) are characterized by 'soft retractile tentacles, circum-oral or post-oral papillae and the absence of an unpaired dorsal appendage.' Several species included in the genus Benthodytes have been reclassified using different nomenclature. This list is subject to change as phylogenetic data clarifies the relationships among difficult-to-identify creatures whose soft appendages are often lost in the process of sample collection.
Reader's Guide
Several species of Benthodytes are good indicators of the potential impacts of deep-sea mining and have been the subject of multiple studies. Identification of distinct species is most often based on photography, since the delicate anatomy of the sea cucumbers is often damaged in the process of sampling. Genome sequencing technology is paving the way for more accurate accounts of the evolution and taxonomy of Benthodytes species, starting with B. rosea and B. typica. Additionally, the mitochondrial genome of B. marianensis has been sequenced and was found to contain a novel gene arrangement among holothurians that could be an adaptation allowing for survival at great depths. The list of species is subject to change as phylogenetic data clarifies the relationships among difficult-to-identify creatures whose soft appendages are often lost in the process of sample collection.
Did You Know?
- The mitochondrial genome of B. marianensis contains a novel gene arrangement among holothurians.
- Identification of Benthodytes species is most often based on photography due to damage during sampling.
Frequently Asked Questions
What is Benthodytes?
Benthodytes is a genus of deep-sea sea cucumbers placed in the family Psychropotidae. It is occasionally encountered under the synonym Benthodites.
Who first described Benthodytes and when?
The genus was formally documented by the zoologist Théel during the H.M.S. Challenger expedition, which ran from 1873 to 1876.
What does a Benthodytes specimen look like?
These cucumbers have a somewhat flattened body with a broad front brim, a mouth on the underside set back from the leading edge, and an anus on the upper surface toward the rear. They carry between twelve and twenty tentacles, and their tube feet form a single row around the brim and a double row along the odd ambulacrum.
How many species are recognized in the genus Benthodytes?
Fourteen species are currently listed under this genus, all of which are deep-sea holothurians.
Why do researchers pay attention to Benthodytes?
Because these cucumbers live on the deep-sea floor, they serve as indicator organisms when scientists evaluate the ecological consequences of seabed mining operations.
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