The Diversity and Ecological Role of Non-scleractinian Corals (Antipatharia and Alcyonacea) on Scleractinian Cold-Water Coral Mounds

Cold-water coral carbonate mounds, created by framework-building scleractinian corals, are also important habitats for non-scleractinian corals, whose ecology and role are understudied in deep-sea environments. This paper describes the diversity, ecology and role of non-scleractinian corals on scleractinian cold-water coral carbonate mounds in the Logachev Mound Province, Rockall Bank, NE Atlantic. In total ten non-scleractinian species were identified, which were mapped out along eight ROV video transects. Eight species were identified as black corals (three belonging to the family Schizopathidae, one each to the Leiopathidae, Cladopathidae, and Antipathidae and two to an unknown family) and two as gorgonians (Isididae and Plexauridae). The most abundant species were Leiopathes sp. and Parantipathes sp. 2. Areas with a high diversity of non-scleractinian corals are interpreted to offer sufficient food, weak inter-species competition and the presence of heterogeneous and hard settlement substrates. A difference in the density and occurrence of small vs. large colonies of Leiopathes sp. was also observed, which is likely related to a difference in the stability of the substrate they choose for settlement. Non-scleractinian corals, especially black corals, are an important habitat for crabs, crinoids, and shrimps in the Logachev Mound Province. The carrier crab Paromola sp. was observed carrying the plexaurid Paramuricea sp. and a black coral species belonging to the genus Parantipathes, a behavior believed to provide the crab with camouflage or potentially a defense mechanism against predators. More information on the ecophysiology of non-scleractinian corals and fine-scale local organic matter supply are needed to understand what drives differences in their spatial distribution and community structure.</p

Assessment of scientific gaps related to the effective environmental management of deep-seabed mining

A comprehensive understanding of the deep-sea environment and mining’s likely impacts is necessary to assess whether and under what conditions deep-seabed mining operations comply with the International Seabed Authority’s obligations to prevent ‘serious harm’ and ensure the ‘effective protection of the marine environment from harmful effects’ in accordance with the United Nations Convention on the Law of the Sea. A synthesis of the peer-reviewed literature and consultations with deep-seabed mining stakeholders revealed that, despite an increase in deep-sea research, there are few categories of publicly available scientific knowledge comprehensive enough to enable evidence-based decision-making regarding environmental management, including whether to proceed with mining in regions where exploration contracts have been granted by the International Seabed Authority. Further information on deep-sea environmental baselines and mining impacts is critical for this emerging industry. Closing the scientific gaps related to deep-seabed mining is a monumental task that is essential to fulfilling the overarching obligation to prevent serious harm and ensure effective protection, and will require clear direction, substantial resources, and robust coordination and collaboration. Based on the information gathered, we propose a potential high-level road map of activities that could stimulate a much-needed discussion on the steps that should be taken to close key scientific gaps before any exploitation is considered. These steps include the definition of environmental goals and objectives, the establishment of an international research agenda to generate new deep-sea environmental, biological, and ecological information, and the synthesis of data that already exist

The Magnitude of Global Marine Species Diversity

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000–72,000 species are collected but not yet described, and that 482,000–741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7–1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century

New species of Hexapathes Kinoshita, 1910 (Anthozoa, Antipatharia, Cladopathidae) from the South-West Pacific

Molodtsova, Tina N. (2006): New species of Hexapathes Kinoshita, 1910 (Anthozoa, Antipatharia, Cladopathidae) from the South-West Pacific. Zoosystema 28 (3): 597-606, DOI: http://doi.org/10.5281/zenodo.539575

A new species of Leiopathes (Anthozoa: Antipatharia) from the Great Meteor seamount (North Atlantic)

Molodtsova, Tina N. (2011): A new species of Leiopathes (Anthozoa: Antipatharia) from the Great Meteor seamount (North Atlantic). Zootaxa 3138: 52-64, DOI: 10.5281/zenodo.20152

Une espèce nouvelle de &lt;i&gt;Saropathes&lt;/i&gt; (Cnidaria, Anthozoa, Antipatharia) de la Ride de Norfolk (Sud-Ouest Pacifique, Nouvelle-Calédonie)

Une nouvelle espèce du genre Saropathes Opresko, 2002 (Antipatharia, Schizopathidae, Schizopathinae), S. margaritae n. sp., est décrite. Elle est proche de S. scoparia (Totton, 1923) mais se distingue par des pinnules primaires plus courtes et incurvées en arrière, un moins grand nombre de ramifications des pinnules (du troisième ordre au maximum), un plus grand nombre de pinnules secondaires (jusqu’à huit) sur chaque pinnule primaire ainsi que par la taille et la disposition des épines. Chez S. margaritae n. sp. les épines latérales soutenant des polypes sont de forme et de taille différentes selon les côtés, la hauteur maximale des épines relevée sur la nouvelle espèce est 0,12 mm. La faune d’antipathaires récoltée sur les monts sous-marins est discutée et une liste des espèces est fournie.A new species of the genus Saropathes Opresko, 2002 (Antipatharia, Schizopathidae, Schizopathinae) is described. Saropathes margaritae n. sp. differs from the closely related S. scoparia (Totton, 1923) in having shorter curved backward primary pinnules, in a lower order (up to three) of subpinnulation, in more (up to eight) secondary pinnules on each primary, as well as in the size and arrangement of spines. The polypar and abpolypar spines in S. margaritae n. sp. differ in form and size, the maximum height of the polypar spines being up to 0.12 mm. The antipatharian fauna reported from seamounts is discussed and a list of species is provided.</p

Nouvelles espèces d’&lt;i&gt;Hexapathes&lt;/i&gt; Kinoshita, 1910 (Anthozoa, Antipatharia, Cladopathidae) du Sud-Ouest Pacifique

Deux nouvelles espèces du genre Hexapathes Kinoshita, 1910 (Antipatharia, Cladopathidae, Hexapathinae), H. hivaensis n. sp. de l’archipel des Marquises et H. alis n. sp. de l’archipel des Fidji, sont décrites. Les deux espèces ont été récoltées sur le talus des îles à une profondeur de 400-430 m. Hexapathes hivaensis n. sp. est proche de H. heterosticha Kinoshita, 1910 mais se distingue par des pinnules latérales plus grosses, plus serrées et très incurvées en arrière, et aussi par des polypes relativement petits. Hexapathes alis n. sp. se distingue de l’espèce apparentée H. australiensis Opresko, 2003 par la forme du polypier et la longueur relative des pinnules latérales. Un tableau comparatif des caractères des différentes espèces du genre Hexapathes est proposé. La possibilité de polypes dimorphes dans le genre Heliopathes Opresko, 2003 est discutée.Two new species of the genus Hexapathes Kinoshita, 1910 (Antipatharia, Cladopathidae, Hexapathinae), H. hivaensis n. sp. from Marquesas Islands and H. alis n. sp. from Fiji, are described. Both species were found on the slope at depths of 400-430 m. Hexapathes hivaensis n. sp. differs from the closely related H. heterosticha Kinoshita, 1910 by thicker, distinctly curved and denser arranged lateral pinnules and smaller polyps. Hexapathes alis n. sp. differs from the related H. australiensis Opresko, 2003 by the form of the colony and relative length of lateral pinnules. A brief review of the genus Hexapathes is given and the possibility of existence of dimorphic polyps in the genus Heliopathes Opresko, 2003 is discussed.</p

FIGURE 1. Alternatipathes mirabilis n in New species of deep-sea Antipatharians from the North Pacific (Cnidaria: Anthozoa: Antipatharia), Part 2

FIGURE 1. Alternatipathes mirabilis n. sp., holotype, USNM 1070972: A. corallum; B. enlarged view of spines; C. polyps; D. sections of pinnules showing spines, scale bars 0.2 mm (B and D from SEM stub 488).Published as part of Opresko, Dennis M. & Molodtsova, Tina N., 2021, New species of deep-sea Antipatharians from the North Pacific (Cnidaria: Anthozoa: Antipatharia), Part 2, pp. 401-422 in Zootaxa 4999 (5) on page 404, DOI: 10.11646/zootaxa.4999.5.1, http://zenodo.org/record/511942

Cnidarians and Their Polychaete Symbionts

Cnidarians, especially skeleton-bearing anthozoans and hydrocorals, are known to host abundant and diverse symbiotic fauna encompassing members of the majority of metazoan taxa, ranging from sponges and fl at worms to fi shes. Members of the class Polychaeta are between the most diverse and perhaps the least studied taxa of coral symbionts. The last revision (Martin and Britayev, Oceanogr Mar Biol 36:217–340, 1998) reckoned about 60 species of symbiotic polychaetes associated with more than 100 species of cnidarian hosts. However, this number is considerably underestimated. Some populations of scleractinians, sea fans and black corals show up to 100 % infestation by symbiotic polychaetes. Close association and inter-relation of highly host-specifi c symbionts and cnidarian hosts often lead to dramatic changes in the host morphology. At the moment, actual mechanisms of most of mutual relations between host and symbiont in such associations are generally unknown. The objective of the present paper is to summarize data on species composition and ecology of polychaetes associated with cnidarians. In our review, we report 281 species of cnidarian hosts involved in 324 relationships with symbiotic polychaetes. Most polychaete- hosting cnidarians belong to skeleton-bearing taxa, particularly Scleractinia (125 species or 44.48 % of the total cnidarian hosts), Alcyonaria (73 species or 25.97 %) and Hydrozoa (60 species or 21.35 %). About 120 species of symbiotic polychaetes of ten families are reported from cnidarian hosts. Polynoidae include the highest number of cnidarianassociated polychaetes (almost one half of the currently known species), followed by Syllidae and Serpulidae. Host symbiont interrelations, host specifi city, location, infestation characteristics and adaptive modifi cations of symbionts, as well as host reaction on symbionts presence, have been considered. Our review highlights that (1) every group of cnidarians seems to have their own assemblage of symbiotic polychaetes, (2) some deep-sea alcyonaceans and black corals have never been reported without their often undetermined polynoid symbionts so that its presence has been considered as a species-specifi c, robust taxonomic character, and (3) we certainly expect the polychaete symbionts associated with deep-sea corals to be a hidden hot-spot of diversity, with many species still waiting to be described.The research was supported by Russian Foundation of Basic Researches (grant No 13-04-01332) for T.N. Molodzova and Russian Science Foundation (grant No 14-14-01179) for T.A. Britayev. This review is also a contribution of D. Martin to the Research Project MARISYMBIOMICS (CTM2013-43287-P), funded by the Spanish State Research Plan, and to the Consolidated Research Group on Marine Benthic Ecology of the Generalitat de Catalunya (2014SGR120).Peer reviewe

Description of a new and widely distributed species of Bathypathes (Cnidaria: Anthozoa: Antipatharia: Schizopathidae) previously misidentified as Bathypathes alternata Brook, 1889

For many years an undescribed species of the genus Bathypathes has been misidentified as Bathypathes alternata Brook, 1889 (a species currently re-assigned to the genus Alternatipathes). This new species is rather common at mid- and lower bathyal depths of the Pacific, Atlantic and Indian oceans, often in areas with high concentrations of commercially valuable cobalt-rich ferromanganese crusts, where it was observed in underwater photo and video transects to occur in high densities. Under the name B. alternata this species is recorded in several inventories and databases. There is an urgent need for a formal description of this misidentified and widely distributed species to avoid further confusion. The new species is superficially similar to A. alternata in having a monopodial corallum and simple, bilateral and alternately arranged pinnules. However, it differs from the former in that it has an upright corallum with a straight pinnulated part (vs. a horizontally bent pinnulated part), pinnules of uniform length and density (vs. decreasing regularly distally), and a constant distal angle formed by the pinnules and the stem along different parts of the corallum (vs. a decreasing distal angle near the top). The new species can therefore be easily distinguished from A. alternata in underwater imagery. We formally describe this new species in the genus Bathypathes and assign it the new name B. pseudoalternata. An extensive synonymy list with previous misidentified records is provided. To evaluate the distributional patterns of the new species we review the geographic distribution of antipatharians reported below 800 m. The majority of the hitherto described lower bathyal and abyssal species have been recorded from one biogeographic province; however, 20 species are known from more than two provinces, and only three species are widely distributed (>5 provinces), including the newly described Bathypathes pseudoalternata. Members of the family Schizopathidae, to which the new species belongs, represent the majority of the lower bathyal (50.54%) and abyssal (82.35%) species