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The sea urchin Pseudechinus magellancus exhibits a covering behaviour through which it captures different items from the environment and arranges them on its aboral surface with the assistance of podia. The items mainly used include detached algae and inorganic items available in the substrate. Spatial (between sites) and vertical (along a coastal depth gradient from intertidal tidepools to upper circalittoral zones) variability was found in the composition of covering items, indicating that coverage is strongly influenced by the availability of the utilised items. Inorganic biogenic items (eg shell remnants) were prevalent in the lower intertidal, while detached algae predominate in subtidal environments. A positive selection of larger items from those available in the environment was found at least in the intertidal tidepools. The species exhibited an equal degree of coverage between juveniles and adults, and also a higher proportion of individuals with high coverage in the intertidal zone compared to the subtidal zone. The degree of coverage between sites with dissimilar sediment input was similar. The covering behaviour in P. magellanicus may not be a response to a single factor but rather an advantageous trait with multiple functions that could have been selected simultaneously. [ABSTRACT FROM AUTHOR]

A distinctive new genus and species of the subphylum Asterozoa, Componaster spurius n. gen., n. sp., is described from the Late Ordovician (early Katian) of Morocco. Construction of the ambulacral column is considered key to delineation of classes of the subphylum Asterozoa: morphology and configuration of the mouth frame, axial (ambulacral series), and adaxial (lateral series) enable class-level assignment of C. spurius n. gen., n. sp. to the Ophiuroidea Gray, 1840. However, overall form and aspects of extraxial skeletal expression from beyond the ambulacral column are strongly reminiscent of expressions of the Asteroidea de Blainville, 1830. The character complex of C. spurius n. gen., n. sp. precludes its alignment with any available ophiuran ordinal concept, and available data do not justify proposal of new ordinal terminology: the species is left incertae sedis at the ordinal level but a new familial taxon, Componasteridae n. fam., is recognized. Although Late Ordovician, the complex morphology of Componaster spurius n. gen., n. sp. suggests either plesiomorphic expressions from asterozoan diversification surviving until the Katian or significant homoplasy during early asterozoan history. [ABSTRACT FROM AUTHOR]

Globally, key predators such as lobsters are thought to control urchins. In southeastern Australia, the role of Sagmariasus verreauxi (eastern rock lobster) as a key predator of the native urchin Centrostephanus rodgersii (long-spined urchin) has been questioned while the sympatric Heliocidaris erythrogramma (short-spined urchin) may be eaten more frequently. To test this, we tethered and filmed 100 urchins (50 C. rodgersii and 50 H. erythrogramma) outside of a lobster den over 25 nights to identify predators and quantify predation rates, time to feeding onset and handling time. Sagmariasus verreauxi exhibited very low predation rates (4%), despite being filmed walking past urchins repeatedly whereas Heterodontus galeatus (crested horn shark) was the main predator (45%). Predation rates by all predators (lobsters and sharks) were influenced primarily by tethering night but not urchin size or species. Predation increased throughout the study and while H. erythrogramma and C. rodgersii were eaten at similar rates, there was a trend for lobsters to eat H. erythrogramma and sharks to eat C. rodgersii. Feeding onset had no significant predictors though large C. rodgersii took longer to handle during feeding for both predators. Importantly, sharks readily consumed 25 C. rodgersii up to 121 mm Test Diameter (TD) while lobsters only ate one C. rodgersii (58 mm TD). These findings, although from only one test location, provide important insights into the species eating urchins and highlight the potential significance of overlooked predators such as H. galeatus. [ABSTRACT FROM AUTHOR]

Stable transgenesis is a transformative tool in model organism biology. Although the sea urchin is one of the oldest animal models in cell and developmental biology, studies in this animal have largely relied on transient manipulation of wild animals, without a strategy for stable transgenesis. Here, we build on recent progress to develop a more genetically tractable sea urchin species, Lytechinus pictus, and establish a robust transgene integration method. Three commonly used transposons (Minos, Tol2 and piggyBac) were tested for nonautonomous transposition, using plasmids containing a polyubiquitin promoter upstream of a H2B-mCerulean nuclear marker. Minos was the only transposable element that resulted in significant expression beyond metamorphosis. F0 animals were raised to sexual maturity, and spawned to determine germline integration and transgene inheritance frequency, and to characterize expression patterns of the transgene in F1 progeny. The results demonstrate transgene transmission through the germline, the first example of a germline transgenic sea urchin and, indeed, of any echinoderm. This milestone paves the way for the generation of diverse transgenic resources that will dramatically enhance the utility, reproducibility and efficiency of sea urchin research. [ABSTRACT FROM AUTHOR]

The Pliensbachian (Lower Jurassic) age-based Lower Marly Limestone Formation of the Moulay Idriss Zerhoun area (Morocco) and the Ain Ouarka Formation of the Ksour Mountains (Algeria) have yielded rare crinoids. Although crinoids have previously been described from the Jurassic of Algeria, their Pliensbachian occurrence is being reported here for the first time. On the other hand, one isocrinid taxa [Terocrinus subsulcatus (Münster in Goldfuss)] was also recorded from the Pliensbachian strata of Morocco. Additionally, now, from both Morocco and Algeria, Seirocrinus subangularis (Miller), belonging to the family Pentacrinitidae, is documented. This is a cosmopolitan and pseudoplaktonic crinoid species that is well-known from Asia, Europe, and North America. The taxonomic evaluation of the genus Seirocrinus is provided. The present records from Algeria and Morocco are the first finds of Seirocrinus from the African continent. Ticinocrinus moroccoensis sp. nov. represented by a cup of a rare cyrtocrinid (Cyrtocrinida) is associated with S. subangularis from Morocco. Globally, this is the second record of the genus; the first Ticinocrinus being described from the Pliensbachian of Switzerland. Thus, the present records from Morocco and Algeria are also the oldest cyrtocrinids from the southern margin of the Tethys. [ABSTRACT FROM AUTHOR]

Background: The superorder Forcipulatacea is a major clade of sea stars with approximately 400 extant species across three orders (Forcipulatida, Brisingida, Zorocallida). Over the past century, the systematics of Forcipulatacea have undergone multiple revisions by various authors, with some considering numerous families such as Asteriidae, Zoroasteridae, Pedicellasteridae, Stichasteridae, Heliasteridae, Labidiasteridae, and Neomorphasteridae, while others recognized only two families (i.e., Asteriidae and Zoroasteridae). Recent molecular analyses have shown the artificial nature of some of these groupings. Notably, four well-supported clades (Zorocallida, Brisingida, Stichasteridae, and Asteriidae) emerged from a synthesis of morphological and molecular evidence. The majority of extinct forcipulatacean species have been placed in modern families. However, many of these fossil species are in need of revision, especially those species placed within the Asteriidae, the largest of all forcipulatacean families. Methods: In light of recent advancements in forcipulatacean systematics, we comprehensively reassess six well-preserved Jurassic forcipulatacean taxa, including the earliest crown-group members from the Hettangian (∼201.4 Ma), and also describe two new Jurassic genera, Forbesasterias gen. nov. and Marbleaster gen. nov. We assembled the largest and most comprehensive phylogenetic matrix for this group, sampling 42 fossil and extant forcipulatacean species for 120 morphological characters. To infer phylogenetic relationships and construct an evolutionary timeline for the diversification of major clades, we conducted a Bayesian tip-dating analysis incorporating the fossilized birth-death process. A total of 13 fossil species were sampled in our analysis, including six taxonomically revaluated herein, two recently reappraised species from the Jurassic, and five additional species from the Cretaceous and Miocene. Results: Contrary to prior assumptions, our results indicate that none of the Jurassic taxa investigated belong to Asteriidae or any other modern families, and instead represent stem-forcipulatids. Furthermore, our phylogenetic results suggest that Asteriidae likely originated during the late Cretaceous. Our findings highlight a greater early diversity within the Forcipulatacea than previously presumed, challenging existing perceptions of the evolutionary history of this significant clade of marine invertebrates. [ABSTRACT FROM AUTHOR]

Climate change is causing increased coastal freshening in Antarctica, leading to reduced salinity. For Antarctica's endemic echinoderms, adapted to the stable polar environment, the impact of rapid reductions in coastal salinity on physiology and behaviour is currently unknown. Six common Antarctic echinoderms (the sea urchin Sterechinus neumayeri; the sea star Odontaster validus; the brittle star Ophionotus victoriae; and three sea cucumbers Cucumaria georgiana, Echinopsolus charcoti and Heterocucumis steineni), were directly transferred from ambient salinity (34.5‰) to a range of salinity dilutions (29–9‰) for 24 h. All species showed reduced activity and the establishment of a temporary osmotic gradient between coelomic fluid and external seawater. Most species exhibited a depression in oxygen consumption across tolerated salinities; however, at very low salinities that later resulted in mortality, oxygen consumption increased to levels comparable to those at ambient. Low salinity tolerance varied substantially between species, with O. victoriae being the least tolerant (24 h LC50 (lethal for 50% of animals) = 19.9‰) while E. charcoti and C. georgiana demonstrated the greatest tolerance (24 h LC50 = 11.5‰). These findings demonstrate the species-specific response of Antarctica's endemic echinoderms to short-term hypoosmotic salinity events, providing valuable insight into this phylum's ability to respond to an underreported impact of climate change. [ABSTRACT FROM AUTHOR]

Sub-Antarctic islands are expected to show a high degree of endemicity due to their remoteness. However, biogeographic affinities in the sub-Antarctic remain poorly understood, especially in the marine realm. Sub-Antarctic islands being at the crossroads between Antarctic and cold temperate regions, biodiversity characterization and biogeographic analyses are a priority for monitoring and rapidly assessing variations associated with environmental changes. One underexplored sub-Antarctic area is Crozet, a protected archipelago located halfway between Antarctica and South Africa. In this study, we investigated the shallow-water Crozet macrofaunal diversity, distribution patterns and biogeographic affinities based on the examination of fieldwork specimens via a thorough morphological identification and a genetic characterisation. The resulting dataset provides an important baseline for further studies and conservation strategies, compiling the first genetic and taxonomic database for the Crozet archipelago. In total, 100 morphotypes were found, belonging to nine different phyla, among which arthropods (32), molluscs (18) and echinoderms (17) were the richest. Forty-seven morphotypes were identified to the species level, among which 20 were reported in Crozet for the first time. This confirms that Crozet is a poorly known region, even compared to other sub-Antarctic areas. A large proportion of species (62%) had circum Southern Ocean or circum subAntarctic distributions. These species were mostly shared with Kerguelen (72%), the Magellan Province (64%), and Prince Edward Islands (64%), confirming the patterns found in macroalgae and specific macrofaunal groups. However, this large-distribution statement needs to be counterbalanced by the detection (genetic data) of more restricted distributions than expected in four study cases (the tanaid Apseudes spectabilis, the nudibranch Doris kerguelenensis, the polychaete Neanthes kerguelensis and the chiton Hemiarthrum setulosum). Considering that most morphotypes had no genetic data available from other regions, the proportion of morphotypes with restricted distribution is likely to increase alongside future investigations. In addition, we also found a few cases of unrecognized diversity that might lead to the descriptions of new species, some likely to be endemic to Crozet (e.g., within the polychaete genus Harmothoe and the bryozoan genus Antarctothoa). Altogether, this stresses the need to maintain conservation efforts in Crozet and pursue integrative investigations in order to highlight and protect its unusual diversity. [ABSTRACT FROM AUTHOR]

Simple Summary: In China, in addition to green tides and red tides, outbreaks of Cnidaria (jellyfish organisms), Annelida (Urechis unicinctus Drasche, 1880), Mollusca (Philine kinglipini S. Tchang, 1934), Arthropoda (Acetes chinensis Hansen, 1919), and Echinodermata (Asteroidea organisms (commonly known as starfish), Ophiuroidea organisms, and Acaudina molpadioides Semper, 1867) not only damage marine resources, tourism, coastal industries, and navigation but also profoundly impact ecosystems near nuclear plants, beaches, and infrastructures, endangering human lives. This article suggests measures to mitigate future disasters, emphasizing enhanced monitoring and integration into China's marine ecological disaster monitoring system. This review is conducive to enhancing researchers' comprehension and reflection regarding biological disasters in marine ecosystems. Owing to global climate change or the ever-more frequent human activities in the offshore areas, it is highly probable that an imbalance in the offshore ecosystem has been induced. However, the importance of maintaining and protecting marine ecosystems' balance cannot be overstated. In recent years, various marine disasters have occurred frequently, such as harmful algal blooms (green tides and red tides), storm surge disasters, wave disasters, sea ice disasters, and tsunami disasters. Additionally, overpopulation of certain marine organisms (particularly marine faunas) has led to marine disasters, threatening both marine ecosystems and human safety. The marine ecological disaster monitoring system in China primarily focuses on monitoring and controlling the outbreak of green tides (mainly caused by outbreaks of some Ulva species) and red tides (mainly caused by outbreaks of some diatom and dinoflagellate species). Currently, there are outbreaks of Cnidaria (Hydrozoa and Scyphozoa organisms; outbreak species are frequently referred to as jellyfish), Annelida (Urechis unicinctus Drasche, 1880), Mollusca (Philine kinglipini S. Tchang, 1934), Arthropoda (Acetes chinensis Hansen, 1919), and Echinodermata (Asteroidea organisms, Ophiuroidea organisms, and Acaudina molpadioides Semper, 1867) in China. They not only cause significant damage to marine fisheries, tourism, coastal industries, and ship navigation but also have profound impacts on marine ecosystems, especially near nuclear power plants, sea bathing beaches, and infrastructures, posing threats to human lives. Therefore, this review provides a detailed introduction to the marine organisms (especially marine fauna species) causing marine biological disasters in China, the current outbreak situations, and the biological backgrounds of these outbreaks. This review also provides an analysis of the causes of these outbreaks. Furthermore, it presents future prospects for marine biological disasters, proposing corresponding measures and advocating for enhanced resource utilization and fundamental research. It is recommended that future efforts focus on improving the monitoring of marine biological disasters and integrating them into the marine ecological disaster monitoring system. The aim of this review is to offer reference information and constructive suggestions for enhancing future monitoring, early warning systems, and prevention efforts related to marine ecological disasters in support of the healthy development and stable operation of marine ecosystems. [ABSTRACT FROM AUTHOR]

A new crinoid fauna is described from the Trogkofel Group of the Southern Karavanke Mountains, Slovenia (lower Permian, Artinskian). This fauna is from a shallow platform or upper slope setting and is comprised primarily of isolated aboral cups. One taxon, Protencrinus baliensis, previously described from the lower Permian of Crete, is the only species known from elsewhere. New taxa from the Trogkofel Group include Karavankecrinus bedici gen. et sp. nov., Moapacrinus dovjensis sp. nov., Parastachyocrinus sloveniaensis sp. nov., and Sinocrinus websteri sp. nov. Several taxa are left in open nomenclature, including Dieuryocrinus? sp., Platycrinitidae indet., Eucladida indet. A, and unidentified Crinoidea. If Dieuryocrinus? sp. belongs to Dieuryocrinus, this would expand the range of this genus, previously known from the Viséan (Mississippian) of the United Kingdom. Other genera are well known as lower Permian taxa. In addition, the species-level systematics of Parastachyocrinus is revised, and one new species from the lower Permian of Timor is described, P. wanneri sp. nov.

The deep-sea remains the biggest challenge to biodiversity exploration, and anthropogenic disturbances extend well into this realm, calling for urgent management strategies. One of the most diverse, productive, and vulnerable ecosystems in the deep sea are sponge grounds. Currently, environmental DNA (eDNA) metabarcoding is revolutionising the field of biodiversity monitoring, yet complex deep-sea benthic ecosystems remain challenging to assess even with these novel technologies. Here, we evaluate the effectiveness of whole-community metabarcoding to characterise metazoan diversity in sponge grounds across the North Atlantic by leveraging the natural eDNA sampling properties of deep-sea sponges themselves. We sampled 97 sponge tissues from four species across four North-Atlantic biogeographic regions in the deep sea and screened them using the universal COI barcode region. We recovered unprecedented levels of taxonomic diversity per unit effort, especially across the phyla Chordata, Cnidaria, Echinodermata and Porifera, with at least 406 metazoan species found in our study area. These assemblages identify strong spatial patterns in relation to both latitude and depth, and detect emblematic species currently employed as indicators for these vulnerable habitats. The remarkable performance of this approach in different species of sponges, in different biogeographic regions and across the whole animal kingdom, illustrates the vast potential of natural samplers as high-resolution biomonitoring solutions for highly diverse and vulnerable deep-sea ecosystems. eDNA collected by sponges recapitulates the composition and structure of metazoan communities of the North Atlantic deep sea and can be used for monitoring of vulnerable marine ecosystems. [ABSTRACT FROM AUTHOR]

Worldwide, lobsters are considered key predators that control urchin populations. It has been widely reported that lobster size plays a significant role in the size of urchins they feed on, as does the size of the urchin. Generally, it is thought that small palinurid "spiny" lobsters measuring less than 120 mm carapace length (CL) are morphologically incapable of eating urchins, while large lobsters are voracious predators. Urchin size is expected to affect predation with larger urchins of greater than 90 mm test diameter (TD) presenting the most difficult prey. These generalities, however, have not been quantitatively tested for the eastern spiny lobster Sagmariasus verreauxi and recently the accepted size paradigm for lobsters eating urchins has come into question. The aim of this study was to assess whether lobster predation on urchins would differ with urchin size or species, or the size of lobster. Our results indicate that S. verreauxi does not fit the common lobster patterns regarding urchin predation. There were generally low rates of predation and a significant negative relationship between feeding and both lobster size and urchin size. We found that small lobsters were capable urchin predators with a higher likelihood of eating urchins than larger lobsters, which were more reluctant predators. While we did find the expected effect of smaller urchins being significantly more vulnerable prey, there was none of the expected size limitations for small lobsters eating large urchins and predation did not differ between urchin species, indicating that this was a general pattern. Overall, we observed low rates of predation, suggesting that either S. verreauxi may not be a key urchin predator like other lobster species elsewhere, or that small lobsters are underestimated as urchin predators in temperate marine ecosystems. [ABSTRACT FROM AUTHOR]

Background: Discoveries of new species often depend on one or a few specimens, leading to delays as researchers wait for additional context, sometimes for decades. There is currently little professional incentive for a single expert to publish a stand-alone species description. Additionally, while many journals accept taxonomic descriptions, even specialist journals expect insights beyond the descriptive work itself. The combination of these factors exacerbates the issue that only a small fraction of marine species are known and new discoveries are described at a slow pace, while they face increasing threats from accelerating global change. To tackle this challenge, this first compilation of Ocean Species Discoveries (OSD) presents a new collaborative framework to accelerate the description and naming of marine invertebrate taxa that can be extended across all phyla. Through a mode of publication that can be speedy, taxonomy-focused and generate higher citation rates, OSD aims to create an attractive home for single species descriptions. This Senckenberg Ocean Species Alliance (SOSA) approach emphasises thorough, but compact species descriptions and diagnoses, with supporting illustrations and with molecular data when available. Even basic species descriptions carry key data for distributions and ecological interactions (e.g., host-parasite relationships) besides universally valid species names; these are essential for downstream uses, such as conservation assessments and communicating biodiversity to the broader public. New information: This paper presents thirteen marine invertebrate taxa, comprising one new genus, eleven new species and one re-description and reinstatement, covering wide taxonomic, geographic, bathymetric and ecological ranges. The taxa addressed herein span three phyla (Mollusca, Arthropoda, Echinodermata), five classes, eight orders and twelve families. Apart from the new genus, an updated generic diagnosis is provided for four other genera. The newly-described species of the phylum Mollusca are Placiphorella methanophila Vončina, sp. nov. (Polyplacophora, Mopaliidae), Lepetodrilus marianae Chen, Watanabe & Tsuda, sp. nov. (Gastropoda, Lepetodrilidae), Shinkailepas gigas Chen, Watanabe & Tsuda, sp. nov. (Gastropoda, Phenacolepadidae) and Lyonsiella illaesa Machado & Sigwart, sp. nov. (Bivalvia, Lyonsiellidae). The new taxa of the phylum Arthropoda are all members of the subphylum Crustacea: Lepechinella naces Lörz & Engel, sp. nov. (Amphipoda, Lepechinellidae), Cuniculomaera grata Tandberg & Jażdżewska, gen. et sp. nov. (Amphipoda, Maeridae), Pseudionella pumulaensis Williams & Landschoff, sp. nov. (Isopoda, Bopyridae), Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. (Isopoda, Haploniscidae), Macrostylis papandreas Jonannsen, Riehl & Brandt, sp. nov. (Isopoda, Macrostylidae), Austroniscus indobathyasellus Kaiser, Kniesz & Kihara, sp. nov. (Isopoda, Nannoniscidae) and Apseudopsis daria Esquete & Tato, sp. nov. (Tanaidacea, Apseudidae). In the phylum Echinodermata, the reinstated species is Psychropotes buglossa E. Perrier, 1886 (Holothuroidea, Psychropotidae). The study areas span the North and Central Atlantic Ocean, the Indian Ocean and the North, East and West Pacific Ocean and depths from 5.2 m to 7081 m. Specimens of eleven free-living and one parasite species were collected from habitats ranging from an estuary to deep-sea trenches. The species were illustrated with photographs, line drawings, micro-computed tomography, confocal laser scanning microscopy and scanning electron microscopy images. Molecular data are included for nine species and four species include a molecular diagnosis in addition to their morphological diagnosis. The five new geographic and bathymetric distribution records comprise Lepechinella naces Lörz & Engel, sp. nov., Cuniculomaera grata Tandberg & Jażdżewska, sp. nov., Pseudionella pumulaensis Williams & Landschoff, sp. nov., Austroniscus indobathyasellus Kaiser, Kniesz & Kihara, sp. nov. and Psychropotes buglossa E. Perrier, 1886, with the novelty spanning from the species to the family level. The new parasite record is Pseudionella pumulaensis Williams & Landschoff, sp. nov., found in association with the hermit crab Pagurus fraserorum Landschoff & Komai, 2018. [ABSTRACT FROM AUTHOR]

High Latitude fjords can serve as sediment trap, bearing different type of proxies, from geochemical to micropaleontological ones, making them exceptional tools for paleoenvironmental reconstruction. However, some unconventional proxies can be present and can be used to depict a comprehensive and exhaustive interpretation of past changes. Here, studying a sediment core in Edisto Inlet (Ross Sea, Antarctica) we used irregular echinoid spines and ophiuroids (Ophionotus victoriae) ossicles to trace environmental changes throughout the last 3.6 kyrs BP. Irregular echinoids can serve as proxy for the organic matter content, while O. victoriae ossicles can be used as proxy for steady sea-ice cycle along with organic deposition events. O. victoriae release a high number of ossicles, making estimation about the population quite challenging; still, presence data, can be easily collected. By applying Generative Additive Models to the stratigraphical distribution of these data, we detected an environmental phase that was previously unnoticed by other traditional proxies: the Ophiuroid Optimum (2–1.5 kyrs BP). In conclusion, here we demonstrate how echinoderm presence can be used as a valuable source of information, while proving the potential of modelling binary data to detect long-term trend in Holocene stratigraphical records. [ABSTRACT FROM AUTHOR]

Extremely rare skeletal remains of brittle stars, originating from Lower Cretaceous deposits in the Štramberk area are described and a preliminary discussion of depositional environments represented by these rocks is added. Several assemblages of dissociated ossicles from the Kopřivnice Formation (upper Valanginian; mostly from the Kotouč and Lower Blücher quarries) comprise only vertebrae. In contrast, an assemblage from the ?Hradiště Formation (Hauterivian and Barremian; Municipal quarry) has yielded taxonomically important lateral arm plates, which have enabled the present study of ophiuroid diversity. A total of five species have been found, including a single new taxon, Ophiotitanos moravica sp. nov. The remaining taxa are left in open nomenclature. Similar to what has been documented from the Cenomanian and Turonian of the Bohemian Cretaceous Basin, representatives of the genus Ophiotitanos predominate in the present assemblages. The presence of Ophiotitanos, euryalids, ophiomusaids and ophiacanthins is reminiscent of some ophiuroid faunas from the Upper Cretaceous of Europe. The assemblage from the Municipal quarry differs markedly from ophiuroid faunas of the Aptian of Cuchía (Spain) and Wizard Way (Texas), but is closely similar to the one from the Barremian of Serre de Bleyton (France). Problems surrounding echinoderm occurrences in the Kopřivnice and ?Hradiště Formations are discussed. [ABSTRACT FROM AUTHOR]

A new crinoid fauna is described from the Trogkofel Group of the Southern Karavanke Mountains, Slovenia (lower Permian, Artinskian). This fauna is from a shallow platform or upper slope setting and is comprised primarily of isolated aboral cups. One taxon, Protencrinus baliensis, previously described from the lower Permian of Crete, is the only species known from elsewhere. New taxa from the Trogkofel Group include Karavankecrinus bedici gen. et sp. nov., Moapacrinus dovjensis sp. nov., Parastachyocrinus sloveniaensis sp. nov., and Sinocrinus websteri sp. nov. Several taxa are left in open nomenclature, including Dieuryocrinus? sp., Platycrinitidae indet., Eucladida indet. A, and unidentified Crinoidea. If Dieuryocrinus? sp. belongs to Dieuryocrinus, this would expand the range of this genus, previously known from the Viséan (Mississippian) of the United Kingdom. Other genera are well known as lower Permian taxa. In addition, the species-level systematics of Parastachyocrinus is revised, and one new species from the lower Permian of Timor is described, P. wanneri sp. nov. [ABSTRACT FROM AUTHOR]

Four Pseudarchasteridae species, including one new species, are described from Japanese waters. Paragonaster hoeimaruae Kobayshi sp. n. resembles two north-west Pacific congeners, P. chinensis and P. obtusus, but differs from these species in having pedicellariae and lateral abactinal series extending to less than one-half of arm length. We also report the first occurrence of Gephyreaster and P. stenostichus from Japanese waters. [ABSTRACT FROM AUTHOR]

The Sox gene family, a collection of transcription factors widely distributed throughout the animal kingdom, plays a crucial role in numerous developmental processes. Echinoderms occupy a pivotal position in many research fields, such as neuroscience, sex determination and differentiation, and embryonic development. However, to date, no comprehensive study has been conducted to characterize and analyze Sox genes in echinoderms. In the present study, the evolution and expression of Sox family genes across 11 echinoderms were analyzed using bioinformatics methods. The results revealed a total of 70 Sox genes, with counts ranging from 5 to 8 across different echinoderms. Phylogenetic analysis revealed that the identified Sox genes could be categorized into seven distinct classes: the SoxB1 class, SoxB2 class, SoxC class, SoxD class, SoxE class, SoxF class and SoxH class. Notably, the SoxB1, SoxB2, and SoxF genes were ubiquitously present in all the echinoderms studied, which suggests that these genes may be conserved in echinoderms. The spatiotemporal expression patterns observed for Sox genes in the three echinoderms indicated that various Sox members perform distinct functional roles. Notably, SoxB1 is likely involved in echinoderm ovary development, while SoxH may play a crucial role in testis development in starfish and sea cucumber. In general, the present investigation provides a molecular foundation for exploring the Sox gene in echinoderms, providing a valuable resource for future phylogenetic and genomic studies. [ABSTRACT FROM AUTHOR]

To the best of our knowledge, this study is the first to track and demonstrate the mortality event in Diadema setosum (Leske, 1778) along the Egyptian Red Sea coasts. The diadematid is a group of echinoid echinodermates that play an important ecological role in marine ecosystems. However, the current global mass mortality events in Diadema setosum have the potential to significantly change the fundamental structure of the ecosystem. This report was based on the 2023-summer observations of a D. setosum die-off during an ecological investigation in the northern Red Sea, Egypt. To determine the entirety of the event, a group from the Red Sea protectorates carried out an extensive survey simultaneously. The current survey covered the coastal regions of the Elba protectorate in the south, the Wadi El Gemal protected area in the middle, and Hurghada in the north. A diverse population of D. setosum was found dead on the bottom during both snorkeling and scuba diving. Representative photographs were taken at each explored site. Several features were noticed in the dead D. setosum, including a frail body, sand-covered body parts, spines distributed on the bottom, and inactive tube feet. The current findings, therefore, recommend crucially the performance of regular monitoring for the status of D. setosum. In addition, biological and ecological investigations are needed as soon as possible to interpret the causative and potential factors responsible for D. setosum loss. [ABSTRACT FROM AUTHOR]

The Avilés Canyon System (ACS) is located in the southern Bay of Biscay (northern Spain, Cantabrian Sea). It has been declared a Site of Community Importance (SCI: C ESZZ12003) within the Natura 2000 Network and recognized as a Vulnerable Marine Ecosystem (VME). This area is included in the North Atlantic Marine Subdivision (NAMD). The present study reviews ophiuroid fauna collected during the INDEMARES–ACS project and compares the new findings with previous studies using the Official Spanish Checklist ("Inventario Español de Especies Marinas") to update our knowledge on the diversity and distribution of these species. During the surveys carried out within the LIFE + INDEMARES–Avilés Canyon System project (2010–2012), a total of 7413 specimens belonging to 45 ophiuroid species were collected from 50 stations in a depth range between 266 and 2291 m. The most frequent species was Ophiactis abyssicola (M. Sars, 1861). Comparing the identified species with public datasets, seven species should be considered as new records for NAMD: Ophiocten centobi Paterson, Tyler & Gage, 1982, Amphiura borealis (G.O. Sars, 1872), Amphiura fragilis Verrill, 1885, Ophiochondrus armatus (Koehler, 1907), Ophiosabine parcita (Koehler, 1906), Ophiophrixus spinosus (Storm, 1881), Ophiotreta valenciennesi (Lyman, 1879). Furthermore, one species has expanded its bathymetric range: Ophiosabine parcita (Koehler, 1906). [ABSTRACT FROM AUTHOR]

Blastoids underwent a revolution in respiration in the Devonian. Emsian blastoid faunas were dominated by fissiculates such as Pentremitidea, giving rise to a transitional spiraculate, Conuloblastus. Hyperoblastus and a mosaic of spiraculates followed; they featured a more advanced respiratory system and were dominant until the Permian. This diversification occurred just prior to or during the Stony Point and Kačák Events, major ecological disruptions of marine ecosystems. Most new spiraculate blastoids were endemic and short lived, but Hyperoblastus survived the major extinction events, lasting into the Famennian. Material from Germany, Spain and North America enables us to trace the diversification of the spiraculates during the Devonian. We erect the new family Conuloblastidae, including Hreggoblastus differentialis gen. et sp. nov.; also Altusoblastus (type species Pentatrematites eifeliensis) with new species A. eremitus, A. palliolatus, A. sp. 1 and A. sp. 2 in the Hyperoblastidae. Pentremitidea roemeri and Hyperoblastus schultzei are assigned to Altusoblastus. Hyperoblastus batheri is declared the type species of Absensoblastus gen. nov.; H. ludwigi sp. nov. is assigned to Hyperoblastus. Pentahedronoblastus gen. nov. (type species P. giesdorfensis sp. nov.) is described. The fissiculate nymphaeoblastid genus Pentremitella (including P. osoleae and ?P. sp. 1) is redescibed. We recognize the eleutherozoic Freisoblastus gen. nov. (type species F. hemisphaericus sp. nov.), Dissimiloblastus gen. nov. (type species D. inequalis sp. nov.) and non‐eleutherozoic Lotusoblastus gen. nov. (type species Pentremitidea medusa) (order and family incertae sedis). We recognize 13 American species of Hyperoblastus. [ABSTRACT FROM AUTHOR]

Studies of morphology and developmental patterning in adult stages of many invertebrates are hindered by opaque structures, such as shells, skeletal elements, and pigment granules that block or refract light and necessitate sectioning for observation of internal features. An inherent challenge in studies relying on surgical approaches is that cutting tissue is semi-destructive, and delicate structures, such as axonal processes within neural networks, are computationally challenging to reconstruct once disrupted. To address this problem, we developed See-Star, a hydrogel-based tissue clearing protocol to render the bodies of opaque and calcified invertebrates optically transparent while preserving their anatomy in an unperturbed state, facilitating molecular labeling and observation of intact organ systems. The resulting protocol can clear large (> 1 cm3) specimens to enable deep-tissue imaging, and is compatible with molecular techniques, such as immunohistochemistry and in situ hybridization to visualize protein and mRNA localization. To test the utility of this method, we performed a whole-mount imaging study of intact nervous systems in juvenile echinoderms and molluscs and demonstrate that See-Star allows for comparative studies to be extended far into development, facilitating insights into the anatomy of juveniles and adults that are usually not amenable to whole-mount imaging. [ABSTRACT FROM AUTHOR]

The present study explores rare but taxonomically and geographically widespread cases of anterior body axial bifurcation in adult sea cucumbers (Echinodermata: Holothuroidea). One individual of Holothuria (Halodeima) grisea, a common intertidal species along the Atlantic coast of Brazil, was studied externally and internally. Individuals of Apostichopus californicus from the northeastern Pacific coast of Washington (USA), H. (Mertensiothuria) leucospilota in the Indian Ocean off La Réunion, H. (Panningothuria) forskali from the Atlantic coast of Spain, and Parastichopus tremulus from the northeastern Atlantic off Norway were also reported to display similar anterior body axial bifurcation. In each of these species, the anterior body presented two mouths with their respective crown of tentacles. In vivo observations of H. (Halodeima) grisea showed that the two tentacle crowns and mouths were independently functional. Micro‐computed tomography (μCT) revealed that the anterior region of the body (up to the pharynx) was duplicated. Internally, two aquapharyngeal bulbs were found, each with their own calcareous ring (one with two plates missing), madreporite, and Polian vesicles. The body presented a normal set of five longitudinal muscle bands, some of which bifurcated orally to support more than one calcareous ring plate. This is the first report of such abnormalities in Holothuroidea and hypotheses that may explain such phenomenon are discussed. [ABSTRACT FROM AUTHOR]

To explore animal diversity, new experimentally tractable organisms must be established. Echinoderms include five groups of marine animals that have been used as developmental models for over a century thanks to their low costs, high fecundity, optically clear larvae and genetic tractability. An additional advantage of echinoderms is that their larval forms display diverse morphologies. This rich diversity enables comparative studies to investigate the evolutionary relationships among cell types, tissues, and organs. However, reproducible protocols to obtain gametes, detailed information on embryogenesis, and genomic tools have been optimized only for selected species of sea urchins and sea stars. To address this gap, we established the abundant Mediterranean sea cucumber Holothuria tubulosa as a new experimental system. Here we describe a method to reliably obtain gametes and make embryonic cultures multiple times from the same animal and characterize unique larval tissues combining immunohistochemistry and high-resolution microscopy. This work represents a step forward in our understanding of holothurian development and establishes H. tubulosa as an emerging experimental system for evo-devo and other biological disciplines. [ABSTRACT FROM AUTHOR]

In this catalogue, 80 species of ophiuroids collected by the IN2021_V04 and IN2022_V08 expeditions to the Australian Christmas Island and Cocos (Keeling) Islands Territories are described and illustrated. [ABSTRACT FROM AUTHOR]

A unifying feature of echinoderm larvae is the development of a left anterior coelom, which consists of an undivided left axocoel and hydrocoel. Although the axocoel is a key deuterostome trait, the presence of this coelom in holothurians has been the subject of debate. Here, we focus on the development of the coelom in a basal holothuroid, the apodid Chiridota gigas (F. Chiridotidae). The dorsal pore and dorsal duct develop first, just after gastrulation, followed by expansion into an axohydrocoel in the auricularia. The left somatocoel was first evident adjacent to the stomach ~30 days post‐fertilization. The axohydrocoel differentiated into two distinct parts: the hydrocoel adjacent to the stomach, and a thin‐walled axocoel that was mid‐dorsal between the hydrocoel and the dorsal pore. This left axocoel extended to both the anterior and posterior but did not cross the larval midline. Out‐folding of the hydrocoel to form the primary tentacles was first observed at 58 days. Transition to a doliolaria with four‐rings was rapid (24 hr) and similar to the transition in other holothurians, with the hydrocoel encircling the esophagus. This transition involved a posterior shift of elements of the auricularia ciliary band and associated nervous system. The ciliary band of the auricularia was rearranged to form transverse bands of the doliolaria larva, and at the same time, the serotonergic cells and fibers that had been at the anterior end moved with the portions of the ciliary band with which they were associated. These serotonergic cells and fibers were still present in the pentactula. The first pentactula was observed at 66 days. Coelom development in C. gigas showed two differences from that in other holothurians, including the development of the left axocoel and the extension of the anterior coelom into the preoral lobe. Description of the full larval development in C. gigas also revealed highly variable morphology in the late auricularia stage, which may aid in identifying apodid holothurians from plankton samples. [ABSTRACT FROM AUTHOR]

Simple Summary: Basement membranes (BMs) are thin sheets of connective tissue that form boundary layers in the organs of most animal bodies. There is increasing interest in how changes in the strength and stiffness of BMs contribute to the normal processes by which fertilized eggs become mature adults and the abnormal processes associated with disease, such as the spread of cancerous tumors. The spread of cancer can be helped by the weakening and disruption of BMs, which is thought to result mainly from BM components being broken down by specific enzymes, although other factors may be involved. Brittlestars are marine invertebrate animals related to starfish and sea urchins. The BMs of their muscles act as tendons that link the muscles to the skeleton. Brittlestars are able to jettison their arms when they are attacked by predators. Such arm loss depends partly on the ability of muscles to detach from the skeleton due to the sudden weakening of their tendons. This contribution provides an overview of current knowledge of the structure and mechanical behavior of BMs in non-echinoderm animals and of brittlestar tendons and discusses the possible usefulness of brittlestar tendons as a model for understanding mechanisms of BM weakening in normal and disease-related processes. Basement membranes (BMs) are thin layers of extracellular matrix that separate epithelia, endothelia, muscle cells, and nerve cells from adjacent interstitial connective tissue. BMs are ubiquitous in almost all multicellular animals, and their composition is highly conserved across the Metazoa. There is increasing interest in the mechanical functioning of BMs, including the involvement of altered BM stiffness in development and pathology, particularly cancer metastasis, which can be facilitated by BM destabilization. Such BM weakening has been assumed to occur primarily through enzymatic degradation by matrix metalloproteinases. However, emerging evidence indicates that non-enzymatic mechanisms may also contribute. In brittlestars (Echinodermata, Ophiuroidea), the tendons linking the musculature to the endoskeleton consist of extensions of muscle cell BMs. During the process of brittlestar autotomy, in which arms are detached for the purpose of self-defense, muscles break away from the endoskeleton as a consequence of the rapid destabilization and rupture of their BM-derived tendons. This contribution provides a broad overview of current knowledge of the structural organization and biomechanics of non-echinoderm BMs, compares this with the equivalent information on brittlestar tendons, and discusses the possible relationship between the weakening phenomena exhibited by BMs and brittlestar tendons, and the potential translational value of the latter as a model system of BM destabilization. [ABSTRACT FROM AUTHOR]

• Sahune (Oxfordian, Late Jurassic) in south-eastern France Basin is newly described. • Carbonate bodies enclosed within Terres Noires Formation formed at cold seeps. • Associated fauna indicate seepage at bathyal depth ca. 1.500 m. • Several seep ostracod families have evolved at seeps since the Oxfordian. • Colonization of bathyal environments occurred earlier than thought. Hydrocarbon seeps represent some of the most extreme marine habitats but are also home to rich communities developed around chemosynthesis rather than photosynthesis. Here we describe the outcrop of Sahune (Drôme department, south-eastern France), that illustrates a new seeping site during the Late Jurassic (middle Oxfordian), as formally demonstrated by geochemical proxies. We report the associated fauna composed of foraminifers, radiolarians, crinoids, echinoids and ostracods that all point to seepage at bathyal depth. The foraminifer assemblage and the occurrence of the irregular echinoid Tithonia oxfordiana together point to a middle Oxfordian age. We provide an in-depth analysis of the ostracod community, which is the oldest so far reported in such environments. The new species Procytherura praecoquum may be cognate to the seepage site and could illustrate the oldest known example of pore clusters, sometimes proposed as representing ectosymbiosis. The Sahune assemblage demonstrates that cold seep ostracod communities were already a mixture of taxa from platform and deep-sea oligotrophic environments. The post-Jurassic diversification of ostracods at cold seeps was related to colonization events and diversification of families that have been inhabitants of such ecosystems at least since the Oxfordian. The Sahune record changes our current conception of the deep-sea colonization by the ostracods Tethysia and Procytherura that occurred earlier than traditionally considered. [ABSTRACT FROM AUTHOR]

The Asteroidea, Ophiuroidea, and Stenuroidea are the derived classes of the subphylum Asterozoa, the class Somasteroidea stemward within the subphylum. The Stenuroidea, originally recognized at the ordinal level and assigned to the Ophiuroidea, was judged unique and therefore cannot be subsumed within the Ophiuroidea and has been separated at the class level. Somasteroidea have multiple adaxial ossicles, and Asteroidea and Ophiuroidea both a single adaxial. The necessary and sufficient condition for assignment to the Stenuroidea is strict presence of either two, or rarely three or four, adaxial ossicles. Aside from ambulacral column configuration, many stenuroid genera are similar to non-stenuroid asterozoans of all ages, natural selection apparently separating overall form from ambulacral column expression. Selective advantage(s) of the 'extra' adaxial might relate to presence of enlarged podia seated in the enlarged podial receptacles, and/or enhanced ambulacral flexibility. Intrageneric uniformity of expression is taken as favoring enduring selective advantage(s) that arose with a monophyletic stenuroid origin. Alternatively, similarities between certain stenuroids and certain asteroids and ophiuroids can be considered indicative of homoplasy, an approach given the current state of knowledge that imposes serious difficulties on phylogenetic interpretation. To place the Stenuroidea in context, the concept of the subphylum Asterozoa is surveyed along with concepts of those early echinoderm groups that have been the preferred subphylum outgroup candidates. Because a phylogenetic analysis failed to yield clear stenuroid clustering between the class and generic levels, intermediate taxonomic categories remain problematic. Eight available familial names are retained and the new families Hystrigasteridae, Stuertzasteridae, Erinaceasteridae, and Ptilonasteridae are recognized. The eighteen known stenuroid genera are reviewed. [ABSTRACT FROM AUTHOR]

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Metabarcoding is revolutionising the analysis of biodiversity in marine ecosystems, especially as it provides a means of detecting and identifying cryptic life stages in field samples. The planktonic larval stage of many species underpins the abundance and distribution of adult populations but is challenging to characterise given the small size of larvae and diffuse distributions in pelagic waters. Yet, planktonic larval dynamics are key to understanding phenomena observed in adult populations, such as the boom-and-bust dynamics exhibited by some echinoderms. Rapid changes in echinoderm population density can have significant effects on local benthic ecosystems. For example, outbreaks of the crown-of-thorns sea star (CoTS) on the Great Barrier Reef (GBR) have led to considerable declines in coral cover. Here, we used a DNA metabarcoding approach to investigate the spatio-temporal distribution and diversity of echinoderm larvae on the GBR, including CoTS. Generalised linear mixed models revealed that echinoderm larval richness, was significantly correlated with temporal variables (i.e. season and year) which is consistent with expected fluctuations in larval output based on adult spawning periodicity. However, neither site-specific differences in echinoderm larval richness, nor correlations between larval composition and environmental, temporal, or spatial variables were found. This study validates the utility of metabarcoding approaches for detecting and characterising echinoderm larvae, including CoTS, which could prove useful to future monitoring efforts. Our findings suggest that metabarcoding can be used to better understand the life history of planktonic larvae, and analyses combining environmental (e.g., temperature, nutrients) and oceanographic (e.g., currents) data could deliver valuable information on the factors influencing their spatio-temporal distributions. [ABSTRACT FROM AUTHOR]

Holothuria atra (Echinodermata: Holothuroidea) is a type of invertebrate animal that lives on the bottom of the rocky coast and has the potential as a nutritious food raw material for humans and pharmaceutical raw materials. The study aims to determine the microplastic types, microplastic functional groups and simulate the distribution pattern of ingested microplastics in the digestive system of H. atra based on hydrodynamic activity. Microplastic separation was conducted by extraction using the flotation method based on predetermined criteria. Functional group test of microplastic polymers ingested in intestines of sea cucumbers using FT‐IR (Frontier Transform Infrared‐Spectroscopy) Analysis. Hydrodynamic modeling analysis used secondary data: bathymetric, currents, wind direction, and tidal prediction data. The results of sampling of H. atra sea cucumbers at four observation locations, where ten individual sea cucumbers were taken from each location, showed that microplastic waste exposed in the intestines of sea cucumbers obtained an average value of 14,166 individuals‐1, with a particle length range of 0.214–3.978 mm. The highest abundance was from the type of fiber, followed by fragments, pellets, and films. FTIR test results indicate the presence of several functional microplastic groups that are digested in the intestine, including polyamide (PA)/nylon‐6, polyethylene (PE), polypropylene (PP), and polystyrene (PS). The movement of currents carrying microplastic waste particles is dominated to the west and south of Karimunjawa Island, potentially endangering the habitats of sea cucumbers and other animals in the waters of the surrounding small islands. It is recommended that stakeholders establish plastic waste protocols, waste facilities and treatment, and strict supervision of tourists entering the Karimunjawa tourism environment. [ABSTRACT FROM AUTHOR]

Background The superorder Forcipulatacea is a major clade of sea stars with approximately 400 extant species across three orders (Forcipulatida, Brisingida, Zorocallida). Over the past century, the systematics of Forcipulatacea have undergone multiple revisions by various authors, with some considering numerous families such as Asteriidae, Zoroasteridae, Pedicellasteridae, Stichasteridae, Heliasteridae, Labidiasteridae, and Neomorphasteridae, while others recognized only two families (i.e., Asteriidae and Zoroasteridae). Recent molecular analyses have shown the artificial nature of some of these groupings. Notably, four well-supported clades (Zorocallida, Brisingida, Stichasteridae, and Asteriidae) emerged from a synthesis of morphological and molecular evidence. The majority of extinct forcipulatacean species have been placed in modern families. However, many of these fossil species are in need of revision, especially those species placed within the Asteriidae, the largest of all forcipulatacean families. Methods In light of recent advancements in forcipulatacean systematics, we comprehensively reassess six well-preserved Jurassic forcipulatacean taxa, including the earliest crown-group members from the Hettangian (∼201.4 Ma), and also describe two new Jurassic genera, Forbesasterias gen. nov. and Marbleaster gen. nov. We assembled the largest and most comprehensive phylogenetic matrix for this group, sampling 42 fossil and extant forcipulatacean species for 120 morphological characters. To infer phylogenetic relationships and construct an evolutionary timeline for the diversification of major clades, we conducted a Bayesian tip-dating analysis incorporating the fossilized birth-death process. A total of 13 fossil species were sampled in our analysis, including six taxonomically revaluated herein, two recently reappraised species from the Jurassic, and five additional species from the Cretaceous and Miocene. Results Contrary to prior assumptions, our results indicate that none of the Jurassic taxa investigated belong to Asteriidae or any other modern families, and instead represent stem-forcipulatids. Furthermore, our phylogenetic results suggest that Asteriidae likely originated during the late Cretaceous. Our findings highlight a greater early diversity within the Forcipulatacea than previously presumed, challenging existing perceptions of the evolutionary history of this significant clade of marine invertebrates.

Globally, key predators such as lobsters are thought to control urchins. In south-eastern Australia, the role of Sagmariasus verreauxi (eastern rock lobster) as a key predator of the native urchin Centrostephanus rodgersii (long-spined urchin) has been questioned while the sympatric Heliocidaris erythrogramma (short-spined urchin) may be eaten more frequently. To test this, we tethered and filmed 100 urchins (50 C. rodgersii and 50 H. erythrogramma) outside of a lobster den over 25 nights to identify predators and quantify predation rates, time to feeding onset and handling time. Sagmariasus verreauxi exhibited very low predation rates (4%), despite being filmed walking past urchins repeatedly whereas Heterodontus galeatus (crested horn shark) was the main predator (45%). Predation rates by all predators (lobsters and sharks) were influenced primarily by tethering night but not urchin size or species. Predation increased throughout the study and while H. erythrogramma and C. rodgersii were eaten at similar rates, there was a trend for lobsters to eat H. erythrogramma and sharks to eat C. rodgersii. Feeding onset had no significant predictors though large C. rodgersii took longer to handle during feeding for both predators. Importantly, sharks readily consumed 25 C. rodgersii up to 121 mm Test Diameter (TD) while lobsters only ate one C. rodgersii (58 mm TD). These findings, although from only one test location, provide important insights into the species eating urchins and highlight the potential significance of overlooked predators such as H. galeatus.

We conducted experiments with various growing conditions, both at sea and indoors, to explore the growth potential of Holothuria (Panningothuria) forskali Delle Chiaje, 1823 juveniles. Sea trials involved co-culture with European abalones (EA) or placement underneath European flat oysters (EO) or Pacific oysters (PO), using juveniles of 6–8 g initial weight. In sea-based conditions around summer (Apr–Sep), sea cucumbers grew best in EO at 0.94% d−1, followed by EA (0.88% d−1), both being in deep water (8–12 m), while sea cucumbers in the foreshore of a mega-tidal environment (PO) had the lowest growth (0.24% d−1). The indoor trial (IM) was performed with smaller individuals (≈0.3 g) and yielded a remarkable growth of 2.76% d−1 during summer (May–Sep). All experiments resulted in high survival rates, exceeding 80%. Additionally, we analysed fatty acid, amino acid, and stable isotope compositions of sea cucumbers' body walls, along with the pigment composition of their stomach contents. These analyses provided evidence that juveniles had distinct diets in each rearing condition, all differing from the diet of adults found in the wild. Our results also demonstrate that sea cucumbers do not compete for food resources in the shellfish production, which is crucial for their integration into multi-trophic aquaculture systems. However, whether sea cucumbers may have benefitted from the organic matter from shellfish faeces and pseudofaeces and/or grew on the biofilm growing on the cage walls remains to be elucidated. [ABSTRACT FROM AUTHOR]

A large and taxonomically diverse collection of Ordovician Asterozoa from France and Morocco enables new insights into the early evolution of the subphylum. Available specimens of both Asteroidea and Stenuroidea are comparatively few, the collection dominated by Ophiuroidea and to a lesser extent, Somasteroidea. Nearly all the asteroid specimens are assigned to Petraster Billings, 1858; P. caidramiensis n. sp. is differentiated based on the complexity of the extraxial skeleton. The genus Petraster is reviewed. Another asteroid fragment, Euaxosida sp. A, is too incomplete to assign below the ordinal level. Among species of Petraster, the extraxial skeleton suggests homoplastic emergence of ossicular series definition whereas evolution of ambulacral axial-adaxial series expressions was conservative. The stemward asteroid axial/adaxial configuration is considered largely a plesiomorphic derivative of the somasteroid condition. Ossicular details of all series, however, differ among Petraster species. Euaxosida sp. A also offers oral-surface expressions suggestive of a transitional status. Differences among ossicular series expressions exemplify concerns surrounding interpretation of early asterozoan phylogeny and taxonomy. [ABSTRACT FROM AUTHOR]

Asexual reproduction by means of splitting, also called fissiparity, is a common feature in some asterozoan groups, especially in ophiactid brittle stars. Most fissiparous brittle stars show six instead of the usual five rays, live as epibionts on host organisms, and use clonal fragmentation to rapidly colonize secluded habitats and effectively expand the margins of their distribution area. While the biology and ecology of clonal fragmentation are comparatively well understood, virtually nothing is known about the evolution and geological history of that phenomenon. Here, we describe an exceptional fossil of an articulated six-armed brittle star from the Late Jurassic of Germany, showing one body half in the process of regeneration, and assign it to the new species Ophiactis hex sp. nov. Phylogenetic inference shows that the fossil represents the oldest member of the extant family Ophiactidae. Because the Ophiactis hex specimen shows an original six-fold symmetry combined with a morphology typically found in epizoic ophiuroids, in line with recent fissiparous ophiactid relatives, we assume that the regenerating body half is an indication for fissiparity. Ophiactis hex thus shows that fissiparity was established as a means of asexual reproduction in asterozoan echinoderms by the Late Jurassic. [ABSTRACT FROM AUTHOR]

The Pacific Porgy (Calamus brachysomus) is a commercially important fish in Baja California Sur, Mexico, where it reproduces year-round. The feeding habits of fishes can change during reproductive stages in response to changes in energetic demand. The objective of this study was to characterize the trophic habits of the Pacific Porgy and how these varied by sex, reproductive stage, and season. Monthly samples were obtained from July 2015 to July 2016 in the central Gulf of California. The stomach contents of 235 specimens (108 males and 127 females) were analyzed. The trophic spectrum comprised 90 prey items, including 58 mollusks, 14 echinoderms, 13 arthropods, 2 chordates, 1 annelid, 1 poriferan, and algal remains. According to the prey-specific index of relative importance (%PSIRI), the most important prey items were the bivalves Transennella spp. (7.24%), Argopecten spp. (6.94%), Anadara spp. (6.25%), Septifer zeteki (6.19%), and Tivela spp. (6.1%). The trophic spectrum varied significantly by season but not by sex or reproductive stage. There were no significant interactions between sex and season or sex and reproductive stage. According to the Levin index, C. brachysomus exhibited a narrow trophic niche (Bi = 0.31). Costello graphs indicated the dominance of a few species, with shifts in the relative abundance of prey species. Based on the trophic analysis, C. brachysomus was classified as a tertiary consumer (3.18). Therefore, C. brachysomus represents an important link between upper and lower trophic levels. Based on these results, we inferred that the Pacific Porgy is an opportunistic predator that feeds actively during all reproductive stages. Thus, the energetic requirements needed for reproduction appear to be covered by the prey that comprise the trophic spectrum of C. brachysomus without this species needing to switch to more energy-rich prey. [ABSTRACT FROM AUTHOR]

In this catalogue, the 17 species of echinoids collected by the IN2021_V04 and IN2022_V08 expeditions to the Australian Christmas Island and Cocos (Keeling) Islands Territories are described and illustrated. Ashley Miskelly. 2024. Catalogue of the Echinoidea (sea urchins, phylum Echinodermata) collected by the IN2021_V04 and IN2022_V08 expeditions to the Australian Christmas Island and Cocos (Keeling) Islands Territories. [ABSTRACT FROM AUTHOR]

Echinoderms are a major group (phylum) of invertebrate animals with a rich fossil record stretching back to the Cambrian period, approximately 518 million years ago. While all modern species are characterized by pentaradial (i.e., fivefold) symmetry, Cambrian echinoderms also include taxa with different types of symmetry (e.g., bilateral symmetry). These distinct forms were present from very early in the phylum's history, demonstrating that the initial diversification of echinoderm body plans was extremely rapid. The phylogenetic relationships of Cambrian echinoderms have long been debated, hindering efforts to reconstruct the evolution of the phylum, but recent analyses have consistently recovered bilaterally symmetrical forms as the earliest-diverging echinoderms. This reveals the sequence of character acquisition in echinoderm evolution, indicating that radial symmetry is a derived character of the group, which evolved after the acquisition of a mineralized skeleton. Cambrian echinoderms were adapted to diverse modes of life, with ecology an important factor shaping their early evolution. However, the reasons why echinoderms evolved their unique pentaradial body plan remain unclear. The Cambrian fossil record provides valuable insights into the origin and early evolution of echinoderms over half a billion years ago. Cambrian echinoderms were morphologically diverse, with several extinct groups exhibiting character combinations that distinguish them from living species. Phylogenetic analyses of bilateral, asymmetrical, triradial, and pentaradial fossils have allowed us to decipher the assembly of the modern echinoderm body plan. Echinoderms became ecologically diverse early in their history, with varied modes of feeding, locomotion, and attachment. [ABSTRACT FROM AUTHOR]

The Salento peninsula in southern Italy (Mediterranean Sea) is a strip of land between the Adriatic and the Ionian Seas, both characterized by local regimes of currents, different geological and physical backgrounds, and quite diversified fauna. In this area, specimens of the sea cucumber Holothuria tubulosa (Brünnich, 1768) (Echinodermata) were collected at four stations in the spring and autumn of 2020 to investigate a possible symbiotic association with the inquiline fish Carapus acus (Brünnich, 1768). Among the collected holothurians, five pearlfish specimens were found in the body cavity of four H. tubulosa collected at 10 m of depth, in autumn, at "Grotta Verde" in Marina di Andrano, Lecce (Ionian Sea). More than half of the sea cucumbers from the latter station hosted the symbiont, suggesting the presence of a shallow population of C. acus inhabiting this coastal area. Furthermore, morphometric analysis carried out on the collected fish helped to shed light on the population dynamics characterizing this neglected species. This is the first report of C. acus from Apulian waters, allowing us to unite previously disjoined areas and providing essential baseline knowledge for planning future in-depth analysis of this difficult-to-study fish in a geographical area that is strategic in terms of the conservation of Mediterranean biodiversity. Furthermore, the range of preferred host species is extended, as C. acus was previously known to prefer other sea cucumber species such as Parastichopus regalis (Cuvier, 1817) instead of H. tubulosa. Finally, the finding of C. acus in a single station and in only one season is not trivial and delivers baseline useful information for future conservation purposes. [ABSTRACT FROM AUTHOR]

Great strides have been made in understanding the phylogeny of the five extant echinoderm classes, however, many Palaeozoic groups have yet to be examined in a rigorous, quantitative framework. The aberrant morphologies of Paracrinoidea, an unusual group of Palaeozoic echinoderms, have hindered their inclusion in large‐scale phylogenetic and morphologic studies. This study uses a combined approach of phylogenetic analysis and morphological disparity to elucidate species relationships within the clade. Findings from this study suggest that Paracrinoidea is a monophyletic group and that respiratory structures, oral plate arrangement, and ambulacral morphologies are important for defining subclades within Paracrinoidea. Examination of paracrinoids in a quantitative framework, facilitates their inclusion in larger projects examining Palaeozoic echinoderm evolution, ecology and biogeography. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) is a growing threat to coastal habitats, and is likely to exacerbate the impacts of other stressors. Kelp forests are dominant habitats on temperate reefs but are declining due to ocean warming and overgrazing. We tested the independent and interactive effects of ALAN (dark versus ALAN) and warming (ambient versus warm) on grazing rates and gonad index of the sea urchin Centrostephanus rodgersii. Within these treatments, urchins were fed either 'fresh' kelp or 'treated' kelp. Treated kelp (Ecklonia radiata) was exposed to the same light and temperature combinations as urchins. We assessed photosynthetic yield, carbon and nitrogen content and C : N ratio of treated kelp to help identify potential drivers behind any effects on urchins. Grazing increased with warming and ALAN for urchins fed fresh kelp, and increased with warming for urchins fed treated kelp. Gonad index was higher in ALAN/ambient and dark/warm treatments compared to dark/ambient treatments for urchins fed fresh kelp. Kelp carbon content was higher in ALAN/ambient treatments than ALAN/warm treatments at one time point. This indicates ocean warming and ALAN may increase urchin grazing pressure on rocky reefs, an important finding for management strategies. [ABSTRACT FROM AUTHOR]

Sea cucumbers are the second most diverse class among echinoderms. They are characterized by an elongated body and dermal ossicles in the body wall. Among the included groups in that class, the order Holothuriida encompasses many species of commercial interest. Faced with the threats of biodiversity loss resulting from the climate crisis and the advancement of cities, this study provides an overview of recent research involving the Holothuriida of the Brazilian Coast. Searches were carried out in the main periodical databases, using appropriate keywords, targeting publications on the subject in the period between 2000 and 2023. In total, 69 publications were found, most of them corresponding to scientific articles in international journals. Most of the studies come from the Northeast region in Brazil (56.52%). Regarding lines of research, those involving taxonomy and molecular analysis were the most prevalent. Over these 20 years, seven species constituted new occurrences. Of note are the studies focused on Holothuria (Halodeima) grisea, which makes up 39.13% of papers. Despite progress, little is known about morphological variations, genetic distance between populations, population densities, and on reproductive biology of species. Brazil has a vast, heterogeneous coastal area, with unique characteristics to which the species are adapted. The findings reinforce the importance to expand studies aiming on knowing the biodiversity, reproductive biology, and population densities of species. Such data are essential for the creation of public policies aimed at the conservation of species of Holothuriida and their habitats. [ABSTRACT FROM AUTHOR]

In this catalogue, 30 species from 25 genera and 11 families, of Asteroidea collected by the IN2021_;V04 and IN2022_;V08 expeditions to the Australian Christmas Island and Cocos (Keeling) Islands Territories are described and illustrated. [ABSTRACT FROM AUTHOR]

We describe a novel foraging technique of the blue bat star Patiria pectinifera that we call standing-ontiptoe behavior. We examined whether the starfish uses this technique to catch shore crab Gaetice depressus in laboratory experiments. Patiria pectinifera in an aquarium with live crabs showed standing-on-tiptoe behavior at a significantly higher frequency (20 out of 47 cases) than those with dead crabs (one out of 23 cases) or no crabs (one out of 23 cases). Nine out of the twenty starfish showing this behavior succeeded in catching and consuming the shore crabs. This behavior could be a tactic for foraging for agile prey, such as shore crabs. [ABSTRACT FROM AUTHOR]

This study describes and illustrates the biodiversity of macroinvertebrates associated to Sargassum and Dictyota seaweed habitats in the Alcatrazes archipelago, the largest Marine Protected Area (MPA) in the state of São Paulo, southeast Brazil. Assemblages were sampled during the summers of 2018, 2019 and 2020 and winter of 2018 at two sites on the main island. Macroalgae containing the associated fauna were collected at approximately 10 meters deep, with six samples at each site and in each sampling campaign. Sargassum fronds prevailed during summer collections, whilst were absent in the winter campaigns, when Dictyota was the most frequent seaweed. Among invertebrates, 32 species were exclusively found on summer months, associated to Sargassum beds, while 12 species were only registered on winter collection, in association with Dictyota. In total, 91 species were identified, belonging to 60 families, 19 orders, 7 classes and 3 phyla, including Arthropoda (Malacostraca and Pycnogonida), Mollusca (Gastropoda, Bivalvia and Polyplacophora), and Echinodermata (Ophiuroidea and Echinoidea). Among the 91 species found, 73 species are new records for the Alcatrazes archipelago marine area, thus revealing the expressive invertebrate biodiversity living in association with macroalgae beds in that area, which has still been little explored. No significant difference in species diversity was found between the two sites of Alcatrazes. In addition, few specimens of two invasive species were found: Perna perna (Mollusca: Bivalvia) and Ophiothela mirabilis (Echinodermata: Ophiuroidea), which underscores the importance of monitoring different habitats within MPAs to check for possible changes in the fauna over the years. As far as our knowledge, this is the first illustrated inventory of the seaweed-associated macroinvertebrate fauna within the Alcatrazes Archipelago, one of the largest MPAs in the Brazilian coast; besides unravelling its notorious biodiversity, this can act as a reference for future monitoring of local coastal diversity. [ABSTRACT FROM AUTHOR]

The first quantitative video survey of the benthic megafauna was carried out on a transect in the eastern part of the Kara Sea from the slope of the Voronin Trough to the upper shelf in the depth range from 1680 to 70 metres. The data were obtained using the TUV "Videomodule" during the 89th cruise of the R/V Akademik Mstislav Keldysh in autumn 2022. It was shown that the megabenthos in this area differs significantly from that of the western part of the sea and Blagopoluchiya Bay (Novaya Zemlya). In the eastern part of the Kara Sea, echinoderms dominated, among which ophiuroids were in the first place, whereas in the western part of the sea and the Blagopoluchiya Bay, the key component of the megafauna was the snow crab Chionoecetes opilio. Single adults of Ch. opilio were recorded for the first time at almost all stations in the eastern part of the sea, but, in contrast to the western area, the snow crab has not yet become dominant here and has not influenced the benthic communities. [ABSTRACT FROM AUTHOR]

The sea star Hymenodiscus coronata is the only Mediterranean representative of the deep-sea order Brisingida. In the North-eastern Atlantic Ocean, this species is known to create dense aggregations, while, in the Mediterranean basin, it is generally reported as scattered individuals. Through the analysis of the video footage obtained from an extensive ROV campaign carried out in the northern Strait of Sicily in 2021, over 2850 specimens were counted. The specimens, observed between 310 m and 714 m depth, showed a large variability in size and number of arms. It was noted that 17% of the specimens displayed the peculiar "sail position", with all the arms extended vertically in the water column, possibly increasing the filtration rate. Almost the totality of the individuals was noted on soft bottoms, in accordance with the ecological preferences of the species. The density of H. coronata in each site varied between 0.01 and 0.81 individuals m−2, with the highest densities reported in sites characterized by large muddy areas among rocky outcrops and turbulent hydrodynamic conditions. Although the trawling areas exploited in 2021 did not seem to interfere with the presence of H. coronata in the study area, a precautionary approach should be assumed to protect the largest ever reported Mediterranean aggregation of this poorly known species. [ABSTRACT FROM AUTHOR]

Elongation of very long-chain fatty acid (Elovl) proteins is the critical rate-limiting enzyme that catalyzes the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs). Echinoderms are extremely important research objects in various fields, such as regeneration studies and developmental biology. However, to date, the genome-wide characterization and analysis of Elovl genes in echinoderms have not been investigated. In this study, the identification and analysis of Elovl genes in 10 representative echinoderms were performed using bioinformatics methods. A total of 117 Elovl genes have been found in the studied echinoderms. The phylogenetic tree showed that all Elovl genes from echinoderms can be subdivided into 6 classes, Elovl3-like class, Elovl4-like class, Elovl5-like class, Elovl6-like class, Elovl7-like class, and Elovl8-like class. Furthermore, the selection pressure analysis suggested that Elovl genes in echinoderms were mainly constrained by strong purifying selection events. In general, this study provides a molecular basis for echinoderm Elovl genes and may serve as a reference for in-depth phylogenomics. [ABSTRACT FROM AUTHOR]