Barnacles of the genus Conopea are obligate epibionts of gorgonians and antipatharians. The species Conopea saotomensis Carrison-Stone et al. 2013, previously only known from the islands of São Tomé and Príncipe and the coast of Gabon, is reported from the Bijagós archipelago, Guinea-Bissau, based on morphological examination and DNA barcoding of specimens. The new record extends the known range of the species about 3000 km to the northwest.

Several individuals of the sea anemone Telmatactis cricoides (Duchassaing, 1850) (order Actiniaria) were observed in the Mediterranean continental Spanish coast (Almeria) and the Balearic Islands (Mallorca) showing an expansion of the species, possibly related to rising sea water temperatures. This finding contributes to increase the knowledge on the geographical distribution range of this actiniarian in the Mediterranean basin.

This article broadens the understanding and empirical study of regime complexes by shifting the focus from the negotiation outcome to the processes of negotiating new international agreements. Although they are important to regime-complex formation and delimitation, the sites where states negotiate new agreements are rather neglected. We aim to enhance the methodological toolbox available to scholars studying global governance in two ways: (1) by demonstrating how dynamic relationships between states and international organisations (IOs) unfolding within the social space of international treaty negotiations contribute to regime-complex formation; and (2) how social network analysis (SNA) can help us to detect patterns in these relationships. Combining participant observation and collaborative event ethnography (CEE) with social network analysis, we present new empirical material illustrating how we delimited a regime complex and how IOs interact throughout the negotiation process. We applied our methodology to the case of marine-biodiversity governance and use observational data collected during three intergovernmental conferences (IGCs) (2018–19) on a new treaty for the conservation and sustainable use of marine biodiversity beyond national jurisdiction (BBNJ) for our analysis. We discuss the results in relation to our approach’s strengths and weaknesses and implications for future research on regime complexity.

Currently, 14 of the 50 species of Lysmata are known to possess a long accessory branch with more than two articles. Historically, Lysmata intermedia and Lysmata moorei were the only two ‘long-branch’ species inhabiting the southwestern Atlantic. Here we describe, based on morphological, molecular and colour pattern data, a new species of Lysmata possessing a long accessory branch from Pernambuco, northeastern Brazil. Our maximum-likelihood analysis recovered Lysmata elisa sp. n. as a sister species to Lysmata jundalini. Both species are closely related to Lysmata holthuisi and L. intermedia. The four aforementioned species comprise the L. intermedia species complex. The new species may be morphologically distinguished from the other closely related species by different sets of characters, which include details of the dorsolateral antennular flagellum, armature of ischium of the second pair of pereiopods, intraorbital process shape and relative proportions of pereiopods. Our results reinforce the importance of refining biodiversity data through the application of integrative taxonomic approaches to expand the knowledge of local and global biodiversity. The biodiversity of Lysmata deserves special attention, as they are intensively exploited in the aquarium trade.

Turtles are important barometers of human impact on marine biodiversity. Very little, however, is known about the deep history of human-turtle interactions and whether this is reflected in the present-day vulnerability of Mediterranean turtle populations. Here, the authors critically assess the zooarchaeological evidence for the nature and intensity of past human interactions with green, loggerhead turtles and Nile soft-shell turtles in the Eastern Mediterranean. Species and sex identifications, estimates of relative abundance, and size reconstructions at five coastal archaeological sites demonstrate the variety in interactions, from turtle capture to processing, and allow informative comparisons with present-day distributions of these species across the region.

This article discusses the current negotiations for an Implementing Agreement under the United Nations Convention on the Law of Sea on the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction. It discusses, in particular, the issue of the relationship of the new agreement with existing and future relevant regional instruments and bodies and the need for cooperation and coordination amongst them, the guiding principles of the new agreement, and the question of implementation and enforcement of the new agreement. These issues and the choices that delegations will make respectively highlight the controversy on the underpinning tenet of the agreement, ie between the ‘freedom of the high seas’ and the common heritage of mankind. The article concludes with a pessimistic prognosis that, in general, the agreement will fall short of the expectations that many States and international community have had at the early days of the negotiation.

Recent studies have improved our understanding of nearshore marine ecosystems surrounding Ascension Island (central Atlantic Ocean), but little is known about Ascension's benthic environment beyond its shallow coastal waters. Here, we report the first detailed physical and biological examination of the seabed surrounding Ascension Island at 100–1000 m depth. Multibeam swath data were used to map fine scale bathymetry and derive seabed slope and rugosity indices for the entire area. Water temperature and salinity profiles were obtained from five Conductivity, Temperature, Depth (CTD) deployments, revealing a spatially consistent thermocline at 80 m depth. A camera lander (Shelf Underwater Camera System; SUCS) provided nearly 400 images from 21 sites (100 m transects) at depths of 110–1020 m, showing high variability in the structure of benthic habitats and biological communities. These surveys revealed a total of 95 faunal morphotypes (mean richness >14 per site), complemented by 213 voucher specimens constituting 60 morphotypes collected from seven targeted Agassiz trawl (AGT) deployments. While total faunal density (maximum >300 m−2 at 480 m depth) increased with rugosity, characteristic shifts in multivariate assemblage structure were driven by depth and substratum type. Shallow assemblages (~100 m) were dominated by black coral (Antipatharia sp.) on rocky substrata, cup corals (Caryophyllia sp.) and sea urchins (Cidaris sp.) were abundant on fine sediment at intermediate depths (250–500 m), and shrimps (Nematocarcinus spp.) were common at greater depths (>500 m). Other ubiquitous taxa included serpulid and sabellid polychaetes and brittle stars (Ophiocantha sp.). Cold-water corals (Lophelia cf. pertusa), indicative of Vulnerable Marine Ecosystems (VMEs) and representing substantial benthic carbon accumulation, occurred in particularly dense aggregations at <350 m but were encountered as deep as 1020 m. In addition to enhancing marine biodiversity records at this locality, this study provides critical baseline data to support the future management of Ascension's marine environment.

Gelatinous zooplankton are an abundant and diverse group of animals in the pelagic environment. However, knowledge of species diversity and spatial distributions, as well as their ecological role, is scarce. We present information of epi- and mesopelagic gelatinous zooplankton recorded by the ‘DeepSee’ submersible between 2006 and 2012 at Isla del Coco (Cocos Island), Costa Rica, an oceanic island in the Eastern Tropical Pacific. Two species of scyphomedusae, three species of hydromedusae, two genera of siphonophores, and two species of ctenophores were observed in the videos, at depths between 50 and 400 m. None of these species had been previously recorded in the waters around the island. Furthermore, except for the jellyfish Pelagia noctiluca and a siphonophore in the genus Praya, all are new records for Costa Rican waters. This study also includes the first record of the cnidarians Modeeria rotunda, Solmissus sp., Halitrephes maasi and Apolemia spp., and the ctenophore Thalassocalyce inconstans in the Eastern Tropical Pacific. We show that surveys in regions with little information about gelatinous zooplankton may broaden our knowledge of their natural history and may result in new records of gelatinous species.

Sowerby's beaked whale (Mesoplodon bidens) was previously known in the Mediterranean Sea from a single live stranding of two individuals in the French Riviera. We report here on two live sightings in the western Mediterranean, central-western Tyrrhenian Sea off eastern Corsica (Montecristo Trough) and off eastern Sardinia (Caprera Canyon) in 2010 and 2012, respectively. In both cases single individuals, possibly the same individual, occurred within groups of Cuvier's beaked whales (Ziphius cavirostris) suggesting inter-specific interactions. Based on our close observations of mixed-species groups of Sowerby's and Cuvier's beaked whales, we hypothesize that some previous long-distance sightings of beaked whales in the Mediterranean may not be reliably attributed to Z. cavirostris. The present sightings and previous live stranding indicate that the western Mediterranean Sea is the easternmost marginal area of M. bidens within the North Atlantic geographic range. Notes on behaviour are also provided.

The degree of development and operability of the indicators for the Marine Strategy Framework Directive (MSFD) using Descriptor 1 (D1) Biological Diversity was assessed. To this end, an overview of the relevance and degree of operability of the underlying parameters across 20 European countries was compiled by analysing national directives, legislation, regulations, and publicly available reports. Marked differences were found between countries in the degree of ecological relevance as well as in the degree of implementation and operability of the parameters chosen to indicate biological diversity. The best scoring EU countries were France, Germany, Greece and Spain, while the worst scoring countries were Italy and Slovenia. No country achieved maximum scores for the implementation of MSFD D1. The non-EU countries Norway and Turkey score as highly as the top-scoring EU countries. On the positive side, the chosen parameters for D1 indicators were generally identified as being an ecologically relevant reflection of Biological Diversity. On the negative side however, less than half of the chosen parameters are currently operational. It appears that at a pan-European level, no consistent and harmonized approach currently exists for the description and assessment of marine biological diversity. The implementation of the MSFD Descriptor 1 for Europe as a whole can therefore at best be marked as moderately successful.

The evolution of symbiotic relationships involving reef corals has had much impact on tropical marine biodiversity. Because of their endosymbiotic algae (zooxanthellae) corals can grow fast in tropical shallow seas where they form reefs that supply food, substrate and shelter for other organisms. Many coral symbionts are host-specific, depending on particular coral species for their existence. Some of these animals have become popular objects for underwater photographers and aquarists, whereas others are hardly noticed or considered pests. Loss of a single coral host species also leads to the disappearance of some of its associated fauna. In the present study we show which mushroom corals (Scleractinia: Fungiidae) are known to act as hosts for other organisms, such as acoel flatworms, copepods, barnacles, gall crabs, pontoniine shrimps, mytilid bivalves, epitoniid snails, coralliophilid snails, fish and certain types of zooxanthellae. Several of these associated organisms appear to be host-specific whereas other species are generalists and not even necessarily restricted to fungiid hosts. Heliofungia actiniformis is one of the most hospitable coral species known with a recorded associated fauna consisting of at least 23 species. The availability of a phylogeny reconstruction of the Fungiidae enables comparisons of closely related species of mushroom corals regarding their associated fauna. Application of a phylogenetic ecological analysis indicates that the presence or absence of associated organisms is evolutionarily derived or habitat-induced. Some associations appear to be restricted to certain evolutionary lineages within the Fungiidae, whereas the absence of associated species may be determined by ecomorphological traits of the host corals, such as coral dimensions (coral diameter and thickness) and polyp shape (tentacle size).

Potential host species were searched for decapod crustaceans along the coasts of Espírito Santo State, Brazil. On five species of sea anemones checked, nine species of decapods were encountered. On three species of black coral checked, two decapod species were encountered. On six species of gorgonians checked, three species of decapods were encountered. In nine species of bivalves and one species of gastropod checked, one decapod species was encountered. On three sea urchin species checked, three decapod species were encountered. A further seven potential host species investigated did not have macroscopically visible symbiotic decapods. Four of these 18 symbiotic decapod species represent new records for the State of Espírito Santo, five species represent new records for Brazil, and at least one species (probably three) were new for science. The sea anemone Condylactis gigantea harboured the largest number of symbionts (eight species) and the shrimp Neopontonides sp. occurred on the largest number of hosts (four different species of gorgonians).

The morphology and taxonomy of a new species of otoplanid (Plathelminthes: Rhabditophora: Proseriata) is discussed. Otoplana proxima sp. nov., collected at Marina di Bibbona (Livorno), presents the typical morphological peculiarities of the subfamily Otoplaninae, but clearly differs from the previously described species with regard to the organization of the genital organs. The new flatworm appears more similar to Otoplana intermedia, but differs sharply in its body length and male copulatory organ made up of 23–24 pliable spines (42–70 μm long) characterized by a forked tip and a canaliculated proximal end.

Present day Southern Ocean benthic biodiversity is the result of climatic changes based on the break-up of Gondwana in the Cretaceous and the Cenozoic and the physiological potential of the fauna to cope with the climatic deterioration. Though many taxa survived the thermal drop in ocean bottom temperatures, zoogeographic ranges changed and some faunal elements even became extinct, e.g. benthic decapods and teleost fish, opening up new ecological niches and the potential for enormous adaptive radiations within some taxa, like the amphipods and isopods (peracarid crustaceans) and notothenioid fish. Ice-sheet extensions and retreats might have enhanced speciation processes as well as eurybathy. Biodiversity on the Antarctic shelf is high within the polychaetes, molluscs, and echinoderms, and within the amphipods and isopods possibly due to the Cenozoic extinction of the benthic decapods. Moreover, some shelf areas are characterized by accumulations of large suspension feeders like poriferans, bryozoans, ascidians, gorgonians, and hydroids. Palaeoclimatic changes also caused that many taxa of the modern, present day Southern Ocean benthic organisms are characterized by gigantism, slow metabolism, longevity, and a reduced number of offspring combined with late maturation. However, our biological knowledge is mainly confined to Southern Ocean shelf organism; we do not know much about the composition, biodiversity and zoogeography of the Southern Ocean deep sea animals. On this background the deep sea expeditions ANDEEP were born and the background and first results of these are presented herein.

Parasites are integral components of marine ecosystems, a general observation accepted by parasitologists, but often considered of trifling significance to the broader community of zoologists. Parasites, however, represent elegant tools to explore the origins, distribution and maintenance of biodiversity. Among these diverse assemblages, host and geographic ranges described by various helminths are structured and historically constrained by genealogical and ecological associations that can be revealed and evaluated using phylogenetic methodologies within the context of frameworks and hypotheses for co-evolution and historical biogeography. Despite over 200 years of sporadic investigations of helminth systematics, knowledge of parasite faunal diversity in chondrichthyan and osteichthyan fishes, seabirds and marine mammals remains to be distilled into a coherent and comprehensive picture that can be assessed using phylogenetic approaches. Phylogenetic studies among complex host–parasite assemblages that encompass varying temporal and geographic scales are the critical context for elucidating biodiversity and faunal structure, and for identifying historical and contemporary determinants of ecological organization and biogeographic patterns across the marine biosphere. Insights from phylogenetic inference indicate (1) the great age of marine parasite faunas; (2) a significant role for colonization in diversification across a taxonomic continuum at deep and relatively recent temporal scales; and (3) a primary role for allopatric speciation. Integration of ecological and phylogenetic knowledge from the study of parasites is synergistic, contributing substantial insights into the history and maintenance of marine systems.