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Brisingida Fisher 1928 is one of the seven currently recognised starfish orders, and one of the least known taxa as being exclusive deep-sea inhabitants. Modern deep-sea expeditions revealed their common occurrences in various deep-sea settings including seamounts, basins and hydrothermal vent peripheral, underlining the necessity of clarifying their global diversity and phylogeny. In this study, we present a comprehensive molecular phylogeny of Brisingida which encompasses the highest taxonomic diversity to date. DNA sequences (COI, 16S, 12S and 28S) were obtained from 225 specimens collected in the global ocean, identified as 58 species spanning 15 of the 17 extant genera. Phylogenetic relationship was inferred using both maximum likelihood and Bayesian inference methods, revealing polyphyletic families and genera and indicating nonnegligible bias in prior morphology-based systematics. Based on the new phylogeny, a novel classification of the order, consisting of 5 families and 17 genera, is proposed. Families Odinellidae, Brisingasteridae and Novodiniidae (sensu Clark and Mah, 2001) were resurrected to encompass the genera Odinella, Brisingaster and Novodinia. Brisingidae and Freyellidae were revised to include 11 and 3 genera, respectively. A new genus and species, two new subgenera and seven new combinations are described and a key to each genus and family is provided. Transformations of morphological traits were evaluated under the present phylogenetic hypothesis. A series of paedomorphic characters were found in many genera and species, which led to a high degree of homoplasy across phylogenetically distant groups. Our results provide new insights in the phylogeny and ontogeny of the order, and highlight the necessity to evaluate character convergence under sound phylogenetic hypothesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Cetacean falls provide a large amount of organic matter to the deep ocean, an otherwise oligotrophic environment. These events are now believed to maintain endemic species and offer intermediate habitats for species in other deep-sea ecosystems. Only about 70 modern whale falls have been reported in the world's oceans to date. We discovered the first known dolphin fall in the South China Sea in March 2020, on the middle slope of the Zhongnan seamount. We set up a camera at the site to observe animals visiting the dolphin carcass for 30 consecutive days from March 29 to April 28, 2020 and made four additional HOV dives to the dolphin carcass. In total, we observed 14 visible megafauna species visiting this dolphin fall, including six fish species, five crustacean species, two echinoderm species, and one mollusk species, of which most were scavengers or predators. This was the first record of many of these taxa in the deep South China Sea. Furthermore, two bone-eating worms were found in a piece of the dolphin bone. The worms are identified as new species in the genus Osedax based on DNA analysis. The findings of this work suggest that cetacean falls occur frequently in the South China Sea and help to fill a knowledge gap regarding the biodiversity of cetacean falls in the West Pacific. • A 1.8-m dolphin fall was found in the South China Sea for the first time. • We observed 14 visible megafauna species visiting this dolphin fall. • Two bone-eating worms were found in a piece of the dolphin bone. [ABSTRACT FROM AUTHOR]