Gebrukothuria profundus, a new genus and species of laetmogonid holothurian (Elasipodida, Laetmogonidae) from around the Crozet Plateau in the Southern Indian Ocean

A new genus and species of laetmogonid holothurian (Elasipodida, Laetmogonidae), collected from around the Crozet Plateau in the Southern Indian Ocean, is described. It differs from other members of the family in that the body wall lacks the wheel-shaped calcareous deposits completely. Instead only rods are present. The genus is also distinguished by the combination of other morphological characters lacking in other known genera: absence of circum-oral and ventrolateral papillae together with development of midventral tube feet. All other members of the family Laetmogonidae are known to have wheel-shaped deposits, therefore diagnosis of the family is refined

Peniagone crozeti, a new species of elasipodid holothurian from abyssal depths off the Crozet Islands in the Southern Indian Ocean

Material collected from the RRS Discovery Cruise 300 to the Crozet Islands contained a new species of elasipodid holothurian Peniagone crozeti sp. nov. This new species dominated the megafauna at an abyssal site to the east of the islands under an area of high surface productivity, but was found in low abundance at a site located south of the islands under a high nutrient low chlorophyll regime, typical for many areas in the Southern Ocean. Peniagone crozeti differs from other members of the genus by the shape of its calcareous deposits

Swimming deep-sea holothurians (Echinodermata: Holothuroidea) on the northern Mid-Atlantic Ridge

The ability to swim was recorded in 17 of 32 species of deep-sea holothurians during the RRS James CookECOMAR cruise in 2010 to the Mid-Atlantic Ridge. Holothurians were observed, photographed, and video recorded using the ROV Isis at four sites around the Charlie-Gibbs Fracture Zone at approximate depths of 2,200–2,800 m. For eleven species swimming is reported for the first time. A number of swimming species were observed on rocks, cliffs and steep slopes with taluses. These habitats are unusual for deep-sea holothurians, which are traditionally common on flat areas with soft sediment rich in detritus. Three species were found exclusively on cliffs. Swimming may provide an advantage in cliff habitats that are inaccessible to most epibenthic deposit-feeders

Holothuroidea of the Charlie Gibbs Fracture Zone area, northern Mid-Atlantic Ridge

Holothurians are among the most species-rich taxa in the megabenthos on the northern Mid-Atlantic Ridge at depths of 2200–3700 m. Extensive new collections of 32 holothurian species were made in 2007–2010 in the Charlie Gibbs Fracture Zone area as part of the ECOMAR project. New material includes samples taken using a trawl and the ROV Isis. Samples and in situ observations from the ROV were of particular value because the morphological details of a number of holothurian species could be clarified. Many of these species are gelatinous and fragile and were damaged in trawls. Three species of elasipodid holothurians are described as new to science. An annotated check-list of all species of deep-sea holothurians collected in the Charlie Gibbs Fracture Zone area is provided. The checklist includes synonyms, distribution data and morphological descriptions as well as photographs taken in situ and in vivo. Ecological remarks are given for some species

Psychropotid holothurians (Echinodermata: Holothuroidea: Elasipodida) collected at abyssal depths from around the Crozet Plateau in the Southern Indian Ocean

Seven species of holothurians of the family Psychropotidae were collected during the cruise D300 of RRS Discovery to Crozet plateau. Three of them, Benthodytes wolffi, Psycheotrephes discoveryi and Psychropotes xenochromata are described as new to science. One species, Benthodytes abyssicola Théel, regarded recently as incertae sedis, is redescribed with designation of a lectotype. Additional notes are provided to descriptions of Psychropotes scotiae (Vaney) known from two specimens and Psychropotes longicauda Théel, the cosmopolitan highly variable species

Bathyal benthic megafauna from the Mid‐Atlantic Ridge in the region of the Charlie-Gibbs fracture zone based on remotely operated vehicle observations

Mid-ocean ridges are important geological features that cover around 33% of the global ocean floor, increase environmental heterogeneity on a regional scale and influence benthic community ecology. Benthic communities at the Mid-Atlantic Ridge (MAR) were studied at four contrasting sites, located east and west of the ridge, which were further separated into northern (54°N) and southern (48°N) sites by the Charlie-Gibbs Fracture Zone (CGFZ) and the Sub-Polar Front (SPF). The MAR in the CCFZ region area had flat areas surrounded by gentle slopes between rocky cliffs. A total of 32 remotely operated vehicle video transects (32,000 m2 of seafloor) were surveyed on the flat areas and sedimented slopes (10°). In total, 154 distinct taxonomic units were identified (from 9 phyla) across all sites. The sediments of the flat and sloping sites were generally similar, but differences were seen in the community composition and faunal abundance (~ 4 times higher in the flat sites, except at the northwestern site). Significant differences in abundance were observed between sites (highest in the northern sites). The two northern sites had distinct community compositions, while the two southern sites were similar. This suggests that the MAR acts as a stronger barrier between communities north of the CGFZ than it does to the south. There was high heterogeneity between transects and it was not possible to identify general drivers for the benthic megafauna at the MAR. Our results emphasize the limited knowledge of this vast system with its unique benthic megafauna