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

Globally, marine sandy beaches face increasing anthropogenic pressures. Long-term maintenance of their functional capacities depends strongly on robust autochthonous biotic community baseline data. However, fine-scale temporal patterns remain poorly understood in human-impacted sites, limiting our knowledge of beach response to stressors. Marine arenicolous fungi represent a neglected group of endopsamon

Goodingia is a crinoid-parasitic genus of the gastropod family Eulimidae, consisting of two named members: G. varicosa (Schepman, 1909) (type species) and G. capillastericola (Minichev, 1970). Due to their rarity, these species have been scarcely compared with each other. In this study, we assessed the taxonomic and phylogenetic relationships of Goodingia plus an undescribed eulimid species, whose

Shallow water reef fishes of Guerrero and Oaxaca (Mexico) were studied through visual censuses as part of exhaustive biological inventories conducted from 2004 to 2019. The systematic checklist comprises 183 species from 55 families. The most representative families were Serranidae (14 species), Carangidae (13), Muraenidae, and Labridae (11 each). The highest representativeness at the zone level was

Ichthyoplankton communities from Saint John Harbour and Passamaquoddy Bay on the New Brunswick shore of the Bay of Fundy, Canada, were sampled seasonally between 2011 and 2014. Saint John Harbour is an industrialised port whereas Passamaquoddy Bay is less developed, with a focus on aquaculture. In total, 32 species of fish eggs and larvae were recorded: 26 species in Saint John Harbour and 25 in Passamaquoddy

Uncertainty surrounding the number and identity of species of genus Limacia O.F. Müller, 1781, in southern African and European coastal waters presents an ongoing conundrum. Limacia clavigera (O.F. Müller, 1776) was previously thought to be the only species of its genus in the eastern Atlantic, with a distribution covering north- to south-eastern Atlantic waters. In the light of more recent molecular

A new nematode species, Latronema dyngi sp. nov., is described from Skagerrak off the west coast of Sweden with the type locality near Dyngö island. Latronema dyngi sp. nov. is characterized by multispiral amphideal fovea with circular outline, 0.2–0.3 corresponding body diameters wide in males and 0.1–0.2 corresponding body diameters wide in females, 12 cuticular longitudinal ridges and 18–27 precloacal

The Asian Pacific spionid polychaete worm Pseudopolydora paucibranchiata (Okuda, 1937) has been repeatedly reported from the Arabian Gulf and the Arabian Sea. Our recent molecular study showed that the Pacific and the Arabian populations of these worms are not conspecific. Here we describe adult, gamete, and larval morphology of worms from the Arabian Gulf, Kuwait, as the new species Pseudopolydora

Environmental variability often results in morphological plasticity, allowing organisms to acclimate and resist changing environmental conditions. Corals exhibit high morphological variability, possibly influenced by factors such as phenotypic plasticity and hybridization. Pseudodiploria Fukami, Budd & Knowlton, 2012 consists of two species, Pseudodiploria strigosa Dana, 1846 and Pseudodiploria clivosa

Chemosynthetic ecosystems have long been acknowledged as key areas of enrichment for deep-sea life, supporting hundreds of endemic species. Echinoderms are among the most common taxa inhabiting the periphery of chemosynthetic environments, and of these, chiridotid holothurians are often the most frequently observed. Yet, published records of chiridotids in these habitats are often noted only as supplemental

The presence of non-indigenous species outside their home range attracts growing attention by the scientific community, as well as policy makers and common citizens. However, dispersal pathways of most non-indigenous species remain poorly understood. The association between non-indigenous and indigenous species may facilitate dispersal in non-native habitats. Identifying such associations is therefore

Deep-sea cephalopods are important in the bathyal ecosystems in terms of both abundance and diversity, but are seriously understudied. One of the most intriguing groups among the deep-sea cephalopods are Cirrata, relatively primitive octopods. Opisthoteuthis is the largest genus among the Cirrata. The least studied species of Opisthoteuthis in the Atlantic, Opisthoteuthis borealis Collins, 2005 was

Sea pen species of the genus Calibelemnon are important components of soft bottom communities. Here, we formally describe Calibelemnon hinoenma sp. nov. from shallow waters in Amami Oshima, Kagoshima in the Ryukyu Islands, via molecular and morphological observations and analyses. This species can be distinguished from its congeners by the presence of paired autozooids, siphonozooids aligned irregularly

Stolephorus acinaces sp. nov. is described from 14 specimens from the northern coast of Borneo, Malaysia. The new species is closely related to Stolephorus andhraensis Babu Rao, 1966, which is redescribed, both species having a long upper jaw with the posterior tip beyond the posterior margin of the preopercle, no predorsal scutes, the posterior preopercular margin indented and concave, the posterior

In the Mediterranean Sea, the symbiosis between the gorgonian Paramuricea clavata (Risso, 1826) and the polychaete Haplosyllis chamaeleon Laubier, 1960 (Annelida, Syllidae, Syllinae) has only been documented from the western basin. Our findings extend its geographic distribution to the north-central basin and represent the first record of H. chamaeleon in Italy and Croatia. Periodic observations from

In this paper, we describe Wataloricus japonicus gen. et sp. nov. (phylum Loricifera), based on specimens collected during surveys of Japanese waters in the Northwest Pacific conducted onboard the TR/Vs TOYOSHIO MARU and SEISUI MARU. This new loriciferan is placed in the family Pliciloricidae based on the morphology of the adult lorica and Higgins larval internal armature, setae, and toes. It is readily

Having a noncoiled, limpet-like shell is a characteristic shared by numerous gastropod molluscs, including many lineages outside the true limpets (Patellogastropoda) where it has evolved convergently. The shell shape of limpet-formed gastropods has often been used as a key taxonomic character, and although studies have shown that it can vary depending on the substrate morphology, these have mostly

Chella Bank (also known as Seco de los Olivos seamount) is a volcanic submarine elevation (76–700 m deep) located ca. 16 km off the southern coast of Spain, within the Alboran Sea, in the Atlantic-Mediterranean transition zone. It represents a biodiversity hotspot for Europe, with more than 600 species listed to date, and contains several habitats included in the EU Habitats Directive. During three

Invasive species have large economic and ecological impacts and are the leading driver of extinction for both plants and animals worldwide. In the USA, coral reefs, which provide $3.4 billion per year in ecosystem services, are impacted by invasive marine species. One such species is Tubastraea coccinea, which was the first scleractinia to invade the western Atlantic and recently has spread to natural

During the last few decades, several studies relating to coral reef fishes in Vietnam have been conducted and published for individual coral reefs along the coast and offshore islands. However, no attempts have been made to compile a list of all known reef fish species from the area or to examine patterns of reef fish biodiversity across Vietnam. To address this issue, we assembled a comprehensive

A new member of the harpacticoid copepod family Tachidiidae Boeck, 1865 was found in sediment samples of meiobenthic harpacticoids taken during a study on the diversity of meiobenthic harpacticoids along the northern coast of the Persian Gulf. The taxonomic analysis of this material revealed that it contained an undescribed species. A new genus is herein proposed to accommodate the new species. The