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Skates are characterised by conservative body morphology which hampers identification and leads to frequent taxonomic confusion and market mislabelling. Accurate specimen classification is crucial for reliable stock assessments and effective conservation plans, otherwise the risk of extinction could be unnoticed. The misclassification issue is evident for the genus Dipturus, distributed worldwide, from the continental shelf and slope to the deep sea. In this study, barcode cytochrome oxidase I gene (COI) sequences were used along with species delimitation and specimen assignment methods to improve taxonomy and zoogeography of species of conservation interest inhabiting the Atlantic Ocean and Mediterranean Sea. In this study, we provided new evidence of the occurence of D. nidarosiensis in the Central‐Western Mediterranean Sea and the lack of Atlantic‐Mediterranean genetic divergence. The Atlantic endangered species D. laevis and D. batis clustered together under the same molecular operational taxonomic unit (MOTU) with any delimitation methods used, while the assignment approach correctly discriminated specimens into the two species. These results provided evidence that the presence of the barcode gap is not an essential predictor of identification success, but the use of different approaches is crucially needed for specimen classification, especially when threshold‐ or tree‐based methods result less powerful. The analyses also showed how different putative, vulnerable, species dwelling across South‐Western Atlantic and South‐Eastern Pacific are frequently misidentified in public sequence repositories. Our study emphasised the limits associated to public databases, highlighting the urgency to verify and implement the information deposited therein in order to guarantee accurate species identification and thus effective conservation measures for deep‐sea skates. [ABSTRACT FROM AUTHOR]

A new species of spurdog, Squalus formosus n. sp., from the lower continental shelf and upper continental slope off the coast of Taiwan and southern Japan, is described. It belongs to the 'highfin megalops group', the members of which share a short snout, high dorsal fins, robust dorsal spines, tricuspid denticles and a white posterior caudal margin. Squalus formosus is most similar to Squalus albifrons, a recently described species from eastern Australia, but differs in some morphological characters and fin colouration. Squalus formosus is sympatric with three other species of Squalus in Taiwanese waters, i.e. Squalus brevirostris, Squalus japonicus and Squalus mitsukurii, and can be readily distinguished from these in the following combination of characters: tall and upright first dorsal fin, with a tall and robust spine, short and bluntly pointed snout, white caudal-fin posterior margin and first dorsal fin with a white anterior margin parallel with dorsal spine. This new species was considered by some authors to be conspecific with Squalus blainville from the eastern Atlantic Ocean, but the results of this study reveal that it is probably endemic to Taiwan and southern Japan. [ABSTRACT FROM AUTHOR]

new species of chimaeroid, Chimaera opalescens n. sp., was described from 31 type specimens caught in the north-eastern Atlantic Ocean at 950-1400 m depth. This species differed from all its congeners by the combination of the following characters: body uniformly pale brown to bronze, iridescent on fresh specimens; unpaired fins brown to purple, uniformly coloured or with pale or whitish edges; iris black; claspers tripartite and divided for a third of their length, not extending beyond the pelvic fins in adults; dorsal spine equal to or shorter than first dorsal fin; ventral caudal lobe equal to or deeper than dorsal caudal lobe. Comparison of DNA sequences of the CO1 gene with those of related species supported C. opalescens n. sp. as a distinct species. Specimens of C. opalescens n. sp. were previously misidentified as Chimaera monstrosa, a species sharing a similar geographical distribution. Chimaera opalescens n. sp. lives in deeper water and is a larger-bodied species than C. monstrosa. The two species were newly exploited by deep-sea fisheries and confused under a single landing name. [ABSTRACT FROM AUTHOR]

Examination of the internal genital apparatus ofApristurus longicephalus, a small, deep-water bottom-dwelling catshark(Scyliorhinidae) from the western Pacific and Indian Oceans has revealed that it is a hermaphroditic species. It possesses both the developed genital apparatus of one sex and the undeveloped genital apparatus of the opposite sex in the same individual.Apristurus longicephalusis the first case of normal hermaphroditism to be recorded in cartilaginous fishes and this has been further classified as rudimentary hermaphroditism. [ABSTRACT FROM AUTHOR]