The new species, Paroctopus cthulu sp. nov. Leite, Lima, Lima and Haimovici was recorded from shallow coastal waters of south and southeastern Brazil, where most specimens were found sheltered in marine debris. It is a small octopus; adults are less than 35 mm mantle length (ML) and weight around 15 g. It has short- to medium-sized arms, enlarged suckers on the arms of both males and females, a relatively

A new genus and species of Nerillidae, Nipponerilla irabuensis gen. nov., sp. nov., is described from an anchialine cave in Shimoji Island, west of Irabu Island (Miyako Islands, Southwestern Japan). Its morphology was examined with light, scanning electron, and confocal laser scanning microscopy. This new species, along with two putative new cave species from the Turks and Caicos Islands and several

Sagami Bay is among the most surveyed areas in Japan and the northwestern Pacific for marine biodiversity, partly owing to collecting efforts by the Showa Emperor, Hirohito. It was also here that the first chemosynthesis-based community was found in Japan, in the Off Hatsushima hydrocarbon seep site dominated by large vesicomyid clams. Nevertheless, new discoveries continue to be made in the deep.

Rhynchospio glandulosa sp. nov. inhabits silty tubes on muddy sand intertidally and in shallow water in the Yellow Sea, Sea of Japan (East Sea), and the Sea of Okhotsk (Korea, China, and Russia). Adults are up to 9 mm long, 1 mm wide for 62 chaetigers, with characteristic groups of glandular cells in the bases of branchiae from chaetiger 7 to chaetigers 14–23. Individuals with 29–40 chaetigers have

The genus Leptochiton Gray, 1847 is a paraphyletic group of small, pale, and usually deepwater chitons. They lack some of the morphological shell characters that are important in the systematics of Polyplacophora, and species identification within this genus is challenging. One species complex in the North Pacific includes at least 11 species that were historically synonymized or confused with Leptochiton

Increases in local and global stressors have led to major declines in coral populations throughout the western Atlantic. While abundances of other species have declined, however, the relative abundance of the mustard hill coral, Porites astreoides, has increased. Porites astreoides is relatively resilient to some stressors, and because of its mixed reproductive strategies, its populations often recover

A new species of the sea pen genus Scytalium Herklots, 1858, is proposed based on the morphological and molecular study of a colony collected during the Océano Profundo 2018 cruise to the Caribbean Sea (NW Atlantic). The new species, Scytalium herklotsi sp. nov., is characterized by its well-developed and overlapping polyp leaves (up to 68 mm in length and 27 mm in width), the presence of eight spiculated

Anthropogenic perturbations and climate change are severely threatening habitats of the global ocean, especially in the Arctic region, which is affected faster than any other ecosystem. Despite its importance and prevailing threats, knowledge on changes in its micro- and nanoplanktonic diversity is still highly limited. Here, we look back almost two decades (May 1–26, 2002) in order to expand the limited

The Indo-West Pacific emperor shrimp, Zenopontonia rex (Kemp, 1922) from the family Palaemonidae, was hitherto known as a peaceful symbiotic crustacean, feeding on very small organisms or detritus and other organic particles trapped in its varied hosts’ mucus. However, at two occasions in Indonesia, Z. rex was observed capturing and subduing relatively large and agile animals, representing completely

Isometra vivipara and Phrixometra nutrix are two brooding feather stars (order Comatulida) that are widely distributed along the southern tip of South America to the Antarctic. We examined 210 specimens of I. vivipara and 38 specimens of P. nutrix collected during five cruises in the southwestern Atlantic between 91 and 642 m depth. Specimens were analyzed and deposited in the National Invertebrate

Bobtail squids (Cephalopoda: Sepiolidae) are emerging model organisms for a wide range of genetic, anatomical, neurophysiological and behavioural studies. However, the knowledge about their behavioural ecology is scarce and derives mainly from laboratory-based studies, whereas observations from the wild are rare. Here, we use photo and video footage collected through the Cephalopod Citizen Science

Recent sampling efforts and examinations of museum material provided evidence for a complex of species within Acroteriobatus leucospilus (Norman, 1926). The present manuscript contains a redescription of A. leucospilus involving the syntypes and additional material, as well as formal descriptions of two new species of Acroteriobatus Giltay, 1928. All specimens of both new species were found in the

Vast regions of the Central Pacific, inhabited by low-lying Micronesian nations, have been poorly studied for zooplankton. Atolls of the Republic of the Marshall Islands (RMI) have been surveyed before, during, and after the US nuclear weapons tests between 1946 and 1958, and gelatinous taxa were sporadically mentioned. Gelatinous zooplankton (GZ) were photographed during several thousand SCUBA dives

A correction to this paper has been published: https://doi.org/10.1007/s12526-021-01206-8

A new species of lanternshark, Etmopterus brosei sp. nov. (Squaliformes: Etmopteridae), is described from the southeastern Atlantic and southwestern Indian oceans. The new species resembles other members of the Etmopterus lucifer Jordan & Snyder, 1902 clade in having linear rows of dermal denticles, and most closely resembles the conspecific E. sculptus Ebert, Compagno, & De Vries, 2011 from the southeastern

Two new species of Paracalanidae, Giesbrecht, 1893, have been described. Paracalanus brasiliensis sp. nov. and Bestiolina brasiliensis sp. nov. were registered in four estuaries on the central coast of Brazil. Paracalanus brasiliensis sp. nov. females differ from their congeners mainly with regard to body size, the structure of swimming legs 1–4, absence of bristles in the coxopodites, spinules between

Secondary sexual dimorphism in florarctin tardigrades is a well-known phenomenon. Males are usually smaller than females, and primary clavae are relatively longer in the former. A new species Florarctus bellahelenae, collected from subtidal coralline sand just behind the reef fringe of Long Island, Chesterfield Reefs (Pacific Ocean), exhibits extreme secondary dimorphism. Males have developed primary

Carcasses and bones of whales are interesting yet poorly understood habitats for invertebrates and microbial communities. Nevertheless, bryozoans have never before been reported in this particular habitat at the present day. Here, we present the first study on a bryozoan community colonizing a whale bone from the continental shelf off NW Spain at 128 m depth. Thirty-three species of bryozoans were

Eurythenes S.I. Smith in Scudder, 1882 (Crustacea: Amphipoda) are prevalent scavengers of the benthopelagic community from bathyal to hadal depths. While a well-studied genus, molecular systematic studies have uncovered cryptic speciation and multiple undescribed lineages. Here, we apply an integrative taxonomic approach and describe the tenth species, Eurythenes atacamensis sp. nov., based on specimens

Cephalopods are important members of deep-sea communities. However, the preference of many incirrate octopods for rocky substrate makes them largely unavailable with traditional sampling methods such as trawls. Therefore, much remains to be discovered about their diversity. This study focuses on the diversity and distribution of bathyal incirrate species in the western North Atlantic. We used observations

The polychaete Capitella capitata is historically one of the most commonly used indicators of organic enrichment in marine benthic environments. However, this taxon has been used to refer to several cryptic species with distinct environmental tolerances, which may compromise ecological assessment and monitoring programs. In this study, we aimed to (1) assess the overlap and patterns of dominance in

This updated checklist of chondrichthyans from the Gulf of California (GC) with notes on zoogeography, conservation status, and commercial value includes 2 subclasses, 14 orders, 31 families, 55 genera, and 106 species. Euselachii (Batomorphi 44.3% and Selachii 51.8%) is the most diverse subclass (13 orders, 29 families, 53 genera, and 102 species). The order Carcharhiniformes (4 families, 16 genera

A new species of congrid eel, Ariosoma melanospilos sp. nov., is described from two specimens collected as bycatch landings of deep-sea trawlers at Colachel fish landing centre, off Kanyakumari, the southwest coast of India. The new species is distinguishable from all the known congeners in having two spots on both sides of the mid-dorsal temporal region (vs. absent in all congeners) and a wide interbranchial

Despite being crucial for habitat provision and being able to inhabit most oceans and all depths, documentation of threats affecting antipatharian corals (known as black corals) is very limited. We provide the second report of sea anemones in the genus Nemanthus overgrowing antipatharian corals causing the death of either entire colonies or sections of them. Our observations are from shallow and mesophotic

A Correction to this paper has been published: https://doi.org/10.1007/s12526-021-01193-w

A Correction to this paper has been published: https://doi.org/10.1007/s12526-021-01192-x

The species of Mustelus Linck, 1790 occurring in the northern Indian Ocean are revised and a new species, Mustelus andamanensis sp. nov., is formally described. Previously considered to be conspecific with M. mosis Hemprich & Ehrenberg, 1899, the new species is currently only known from the Andaman Sea. The Red Sea and Arabian Sea populations of Mustelus mosis differ in vertebral counts and degree

The genetic structure of selected five finfish populations, namely, almaco jack (Seriola rivoliana), sailfin grouper (Mycteroperca olfax), stalkeye scorpionfish (Pontinus strigatus), wahoo (Acanthocybium solandri) and yellowfin tuna (Thunnus albacares) in the Galapagos Islands, was studied using mitochondrial DNA cytochrome b (797 bp) and D-loop (426 bp). The results of the present study showed that

Although vital in fisheries management, no comprehensive studies on ichthyoplankton have been conducted in Sri Lankan waters in the north central Indian Ocean hitherto. Hence, this study is the first detailed account of diversity and species composition of larval fish based on samples collected during the southwest monsoon in 2018. In total, 80 species belonging to 69 families were identified using

Tellinidae is one of the most diverse families in Brazilian coastal areas, comprising nine subfamilies, one of which is Macominae. These species are known for their morphological similarities, which make their identification difficult. To minimize such difficulties, taxonomists have sought methods or tools, such as the use of geometric morphometric data, to study the continuous characteristics which

Patelloida pygmaea is one of the most abundantly distributed intertidal marine gastropods along the China coast. The mitochondrial (COI) and internal transcribed spacer 1 (ITS1) DNA of P. pygmaea, one hundred and thirty-seven samples collected from 13 localities along its distribution along the China coast, were used to investigate the phylogeographic patterns of P. pygmaea. Phylogeographic analysis

Biodiversity has critical phylogenetic and functional components, yet many prior studies of marine communities focus only on taxonomic diversity. Here, we surveyed intertidal crustacean communities across 11 sites in the Puget Sound (Washington state). We calculated taxonomic diversity (Shannon’s H), functional diversity (functional evenness and Rao’s Q), and phylogenetic diversity to examine how these

A new deep-sea softnose skate, Notoraja hesperindica, is described based on six specimens caught in 1230–1600 m depths off southern Mozambique and northwestern Madagascar in the western Indian Ocean. The new species is a medium-sized species of Notoraja Ishiyama, 1958 reaching a total length of at least 539 mm. It is the only Notoraja species known from the western Indian Ocean and differs from most

As part of a baseline biodiversity study of the marine fauna associated with the Marina of Puerto Velero (PVM) in the Colombian Caribbean, we record the presence of the azooxanthellate coral Phyllangia pequegnatae Cairns, 2000. This new record extends the geographic distribution of this species to the southwestern Caribbean and increases its bathymetric range to the shallow 0.3 m depth as this species

Jellyfish are important components of the marine ecosystem and present a potential resource for different economic domains (e.g. medicine, food and biotechnology). We present an overview of the current state of jellyfish biodiversity in the Macaronesia region, which includes the archipelagos of the Azores, Madeira, the Canary Islands and Cape Verde, and examine possible biogeography patterns among

Invasive species of intertidal algae drew little attention, even though biological invasions have been a concern around the world. The red algal bangiophyte, Phycocalidia tanegashimensis (I. Shinmura) Santiañez in Santiañez & Wynne, 2020 had been reported from the Southwest Atlantic (Brazil) and Northwest Pacific (Philippines and Japan). The appearance of P. tanegashimensis in Brazil was believed to

Four Pseudopolydora Czerniavsky, 1881 species from European and adjacent waters are distinguished and a key to their identification is provided. Pseudopolydora antennata (Claparède, 1868) is redescribed based on material from the type locality, Gulf of Naples, Italy. Pseudopolydora pulchra (Carazzi, 1893) (type locality in the Gulf of Naples) is also redescribed based on material from Italy. Most previous

Nicidion Kinberg, 1865, and Paramarphysa Ehlers, 1887, were previously recognized as abranchiate groups of Eunice Cuvier, 1817, and Marphysa de Quatrefages, 1865, respectively. However, recent studies have demonstrated Nicidion is monophyletic, and the genus was redefined. Likewise, the character presence/absence of peristomial cirri, which traditionally was used to differentiate between Nicidion and

A continuing impediment to the taxonomy of the reticulate whipray Himantura spp. species complex is the absence of a type specimen for H. uarnak (Gmelin [ex Forsskål], 1789). Here, reticulate whipray specimens were sampled from the Jeddah region in the Red Sea, the assumed type locality of H. uarnak, and characterized genetically at the cytochrome-oxidase subunit 1 (CO1) locus. One of these specimens

A small marine monoraphid diatom with a linear-elliptic shape and simple terminal raphe endings was present on Raivavae (South Pacific). Particularly due to its different stria structure on both valves, this taxon is here classified as Cocconeis. The new species was present on the rocky intertidal shore of the coral-reef lagoon, as an epiphyte on a turf. Cocconeis vaiamanuensis sp. nov. can be compared

Didiscus Dendy, 1922 and Myrmekioderma Ehlers, 1870 are closely related genera of axinellid sponges, distinguished mainly by the presence of didiscorhabd microscleres in Didiscus and of trichodragmata in Myrmekioderma. Their family-level classification, however, is highly controversial, in part because their specific and morphological diversities are still poorly known. Here, we redescribed Didiscus

The genus Halacarellus Viets, 1927 holds 50 species, and this number equals 4% of all halacarid species known to date. The genus is spread in all oceans, and a few species are even known from freshwater. The genus includes species which live on and amongst surface structures, algae, colonial organisms, and macrofauna and in interstices and microcaverns. The North Atlantic species, the ones best studied

The Clarion-Clipperton Zone (CCZ), located in the abyssal equatorial Pacific, has been subject to intensive international exploration for polymetallic nodule mining over the last four decades. Many studies have investigated the potential effects of mining on deep-sea ecosystems and highlighted the importance of defining environmental baseline conditions occurring at potential mining sites. However

In the tropics, the marine sponge Dysidea janiae lives in obligatory symbiosis with the red macroalga Jania adhaerens. However, how this symbiosis is achieved, and how it influences the reproduction of the sponge is still unknown. We analysed the influence of environmental variables on the gametogenesis and embryogenesis of the sponge. We also investigated the histology of the reproductive propagules

The pelagic snail Limacina helicina Phipps, 1774 is widely distributed in high-latitude seas and is a sensitive bioindicator of ocean acidification. It is known that the response patterns to ocean acidification differ among populations within or among species. Thus, it is important to understand their genetic population structure and identify the cryptic species. L. helicina displays different shell

It is proposed to name the Atlantic holothuria Psolidium complanatum Cherbonnier, 1969, whose denomination is already occupied by Psolidium complanatum (Semper, 1867) from the Philippines, as Psolidium bathygalego nom. nov. 843 specimens of Psolidium bathygalego nom. nov., collected between 417 and 1191 m deep in the NW and W of Galicia and in the Galicia Bank, were studied. A detailed description

Biology of planktonic stomatopod larvae has long remained poorly understood and often considered “black boxes” in life history studies. From coralline crustose algal (CCA) reefs at Datan, Taoyuan, Taiwan, using light traps recently designed, we collected considerable number of stomatopod larvae and juveniles. Applying DNA barcoding techniques using mitochondrial cytochrome oxidase I (COI) and 16S ribosomal

Nanipora Miyazaki & Reimer, 2015 is a recently discovered genus of aragonite-skeleton producing octocorals closely related to the blue coral genus Heliopora de Blainville, 1830. Since its discovery, Nanipora has been reported from coral reefs in Okinawa, Japan, and Thailand, and from seagrass beds in the northern South China Sea. However, it remains little known and studied. Here, we report on the

The dark-mouth skate, Raja arctowskii Dollo, 1904 from Antarctic waters is an extraordinary case in skate taxonomy. For more than 100 years, this species has been known only from three empty egg capsules and the species as such has remained undescribed due to the lack of specimens that could be assigned to Dollo’s small capsules. Since trawled egg capsules and an egg capsule containing a near-term

The macrofauna of marine invertebrates of two photophilic algal communities on the Maresme coast (Barcelona, NE Spain) were studied. We evaluated how the type of algal substrate (soft or hard thallus algae) affects the distribution patterns of organisms living in them. Quantitative samples were collected in the months of October 2013 and February 2014 at 15-m depth by scraping standard surfaces of

A new Antarctic fish leech with unique external appearance is described and assigned to the bipolar genus Pterobdellina Bennike & Bruun, 1939. The systematic rank of the latter is elevated from a subgenus of the genus Pterobdella Kaburaki, 1921 to a separate generic level. Pterobdellina vernadskyi sp. nov. bears both marginal fin-like structures and prominent dorsal zigzag folds with an unclear function

The present work resolved the long-standing taxonomic problem associated with the enigmatic ?Mastigoteuthis B Clarke, 1980, by demonstrating that these lower beaks correspond to those of the large deep-sea chiroteuthid Asperoteuthis acanthoderma (Lu, 1977). A review of the existing literature listed 22 specimens of A. acanthoderma, but synonymizing ?Mastigoteuthis B with A. acanthoderma increased 14

The subtropical region of the Southeast Pacific exhibits a strong onshore-offshore gradient in hydrographic conditions and biological production from the eutrophic upwelling zone to the ultra-oligotrophic oceanic area in the central South Pacific gyre (SPG). Across this gradient, zooplankton must cope with either gradual or abrupt changes in environmental conditions. Here, the distribution and diversity

The small size (< 5 mm) of marine microfilamentous green algae makes it difficult to identify based on field collections, remaining largely unnoticed. To catalogue the diversity of these diminutive marine algae, a combination of culture-based taxonomic studies and DNA barcoding has proven to be a successful approach. During subtidal surveys in the northeastern Brazil, microfilamentous green algae were

Sexual reproduction of corals is one of the most important processes for the persistence of coral populations. The Coral Triangle is recognised as a global hotspot of marine biodiversity, harbouring 75% of the world coral species. However, coral reproductive studies remain underrepresented in many reefs in the Coral Triangle. This study reports the coral spawning and spawn slicks occurrences from 2012

A new species of deep-sea neolepadid stalked barnacle, Vulcanolepas verenae sp. nov., is described from Hafa Adai hydrothermal vent field in the Mariana back-arc basin, northwest Pacific. Vulcanolepas verenae sp. nov. is differentiated from other described species in the family morphologically by a mandible with a very small first tooth and small, non-protruding peduncular scales. Its gross external morphology

Octocorals (Octocorallia, Alcyonacea) are distributed worldwide and their taxonomy in the Persian Gulf has been a subject of controversy among experts due to their cryptic features. Here, we present a primary review of the Alcyonacea in the Iranian Persian Gulf with molecular documentation to provide insight into the real diversity within this order. Our molecular study was based on two mitochondrial

Two new species of deep-sea sponges from the Weddell Sea are described. Both are new to science: a carnivorous Demospongiae species Abyssocladia antarctica sp. nov. and a Hexactinellida species Caulophacus leonieae sp. nov., the latter characterized by a new type of microscleres. Both were sampled at the former Larsen Ice Shelf region, Antarctic Peninsula, that was covered by ice until recent breakup

The Critically Endangered shorttail nurse shark Pseudoginglymostoma brevicaudatum (Günther, 1866) is a small-bodied Orectolobiform shark found only in the Western Indian Ocean (WIO). We report here on a significant range extension for P. brevicaudatum based on four records of the species in southern Mozambique, recorded during research surveys, including a specimen collected in 1967 and video surveys

DNA-based analyses have become powerful tools for characterizing the metazoan biodiversity of diverse marine ecosystems. Metabarcoding (i.e., large-scale taxonomic identification of complex samples via high-throughput sequencing of a DNA barcode region) frequently uses hypervariable regions of the nuclear eukaryotic 18S ribosomal RNA (rRNA) gene. However, species-level taxonomic identification is hampered