In a descriptive study of megafauna of several Southeast Atlantic seamounts, multiple video-transects on upper slopes and summits documented the occurrence of benthic invertebrate taxa, primarily corals, regarded as indicators of vulnerable marine ecosystems (VMEs) as defined in international guidelines. At Schmitt-Ott Seamount there was a pronounced dominance of gorgonian corals (seafans, Alcyonacea). In all other study areas the diversity was greater, and more scleractinians (stony corals, Scleractinia) were observed. Scleractinian corals were mainly dead, and much of the coral framework and rubble may have been ancient. In the Valdivia complex and on Ewing Seamount, which are open to fisheries, scleractinians seemed restricted to some slopes of knolls, and on Valdivia Bank and the subarea denoted Valdivia West the summit substrate was mostly bare rock. Pelagic armourhead Pseudopentaceros richardsoni and splendid alfonsino Beryx splendens (two targets of commercial fisheries in the area) were observed at a few sites, but did not appear to be abundant in the main former fishing areas of the Valdivia area. Orange roughy Hoplostethus atlanticus was common in video records around the summit at Ewing Seamount. The deep-sea red crab Chaceon erytheiae was abundant in the Valdivia area and at Ewing Seamount, and crabs were distributed across a more extensive depth range than the fishes. In areas with high densities of live coral, the video records suggested that the benthic communities were intact and not impacted by fishing. Evidence of past fishing activities included observations of lost pots and rope at Vema Seamount and in the Valdivia area.

The false catshark, Pseudotriakis microdon, is a large-bodied, poorly known deepwater shark, with a global distribution, except for the eastern Pacific and South Atlantic oceans. Here we report the first record of the false catshark from the southeastern Atlantic. The specimen, estimated to be approximately 290 cm in total length, was observed via an unmanned submersible 700 m depth off the western slope of Valdivia Seamount (26.2° S, 6.3° E).

Three new species of Chimaera are described from the Southwestern Indian Ocean. Chimaera willwatchi sp. nov. is distinguished by its large body, blocky head with square snout, well-defined suborbital ridges, and a strong dorsal spine exceeding first dorsal apex; body brown-purple in color, slight iridescent sheen, heavily mottled around mouth and ventral surface, posterior edge of pelvic fins and first dorsal fin with prominent white margin, and anterior edge of second dorsal fin with white margin. Chimaera didierae sp. nov. can be distinguished by its light tan body color, slender body, short trunk, long tail, relatively robust spine, very small unpaired fins, and extremely deciduous skin. Chimaera buccanigella sp. nov. is distinguished by its light tan body color, stocky body, short trunk, tapering rapidly into a long tail, long, very straight spine, skin not deciduous. The three Chimaera species were collected from seamounts of Walters Shoal, the Madagascar Ridge, and the Southwestern Indian Ridge in an area within 34o30’S–44o05’E and 39o30’S–58o15’E. This is the first record of the genus in the Southwestern Indian Ocean, and brings the global total to 19 species. The new species presented here are distinguishable from their congeners by a combination of coloration, morphology, meristic, and structure of the mitochondrial NADH2 gene.

The Southern Lanternshark, Etmopterus granulosus, is a large species of Lanternshark that has been a source of long-standing taxonomic confusion. Recent work suggests E. granulosus to be conspecific with the New Zealand Giant Lanternshark, Etmopterus baxteri, suggesting that the species may be widespread throughout the Southern Hemisphere. The taxonomic affinity of populations off South Africa, however, has remained uncertain. Herein we show that South African samples are also conspecific with E. granulosus based on both molecular and morphometric data. These results extend the known distribution range of this species to South Africa and the southern Indian Ocean, strengthening the hypothesis that E. granulosus has a circum-Antarctic distribution. In addition we show that there is a cryptic, granulosus-like species in South African waters that can likely be assigned to Etmopterus compagnoi.

The genus Centrophorus is one of the most taxonomically complex and confusing elasmobranch groups. A revision of this group is currently underway and this first paper sets an important foundation in this process by redescribing the type species of the genus--Centrophorus granulosus. This taxon name has been previously applied to two different morphotypes: a large species > 1.5 m TL and a smaller species -1 m TL. Centrophorus acus and C. niaukang are the most commonly used names applied to the larger morphotype. The original description of C. granulosus was based on a large specimen of -1.5 m TL, but subsequent redescriptions were based on either of the large or small morphotypes. Centrophorus granulosus is herein redescribed as a large species and a neotype is designated. Centrophorus acus and C. niaukang are found to be junior synonyms of C. granulosus. Centrophorus granulosus is distinguishable from its congeners by its large size, dermal denticle shape, colouration and a number of morphological and biological characteristics. Ontogenetic changes in morphology, dentition and denticle shape for this species are described in detail.