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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]

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]

Previous molecular phylogenetic reconstructions have highlighted frequent convergences and iterations of external morphological characters during the evolution of crinoids. Classifications of extant and fossil crinoids based on these characters need to be thoroughly revised. This is particularly the case for the Isocrinida. We propose a new classification of this order based on molecular data and ontogenetic analysis of the derived characters displayed on ossicles and their articulations. The argument is strengthened by the discovery and description of a species belonging to a new genus (Panglaocrinus isseliformis gen. nov. sp. nov.) closely related to the genus Isselicrinus , which was abundant and widespread during the Late Cretaceous and Eocene. Extant Isocrinida appear to be divided into two major lineages that we interpret as two distinct families: Isocrinidae and Balanocrinidae. Isocrinidae are represented by the subfamily Metacrininae (genera Metacrinus and Saracrinus), while Balanocrinidae comprise four subfamilies: Balanocrininae (Neocrinus), Diplocrininae (Endoxocrinus and Teliocrinus), Isselicrininae (Panglaocrinus), and Proisocrininae (Proisocrinus). In the absence of molecular data, the genus Cenocrinus has not been attributed to any subfamily, but its close relationship to Balanocrinidae is suggested. Possible relationships between Mesozoic and modern taxa are discussed, although descriptions of arms in the palaeontological record are often important details. [ABSTRACT FROM AUTHOR]

This research explores the significance of rapid burial in preserving fossils, with a particular focus on free-living echinoderms. Experiments were based on ophiuroids to simulate burial under different turbiditic flows. The results showed that a bed thickness of around 10 cm is a limit for the preservation of whole skeletons in most cases. The type of sediment can affect the integrity of the buried skeletons, with sand deposition resulting in higher rates of autotomy. However, mud deposition did not show any numbing effect, as previously believed for echinoderms. In contrast, freshwater-rich sediments can play a critical role, paralysing specimens and preventing escape postures through rapid changes in salinity. From this, the study highlights the importance of extrabasinal turbidites, generated outside the marine basin, in the fossilization of marine invertebrates. Such sediments are rich in fresh water and can be more efficient burial traps compared to other intrabasinal deposits generated by storm waves or submarine landslides. [ABSTRACT FROM AUTHOR]

Echinoderm skeletons are composed of calcium carbonate ossicles that join in a variety of ways to form flexible or, more rarely, fixed joints. Ossicle "fusion" in echinoderms has been widely reported in the literature to form various types of fixed joint, but fusion in the sense of chemical union (ankylosis) of the calcitic ossicles has rarely been demonstrated. The arm skeleton of ophiuroids is primarily composed of a series of vertebral ossicles; each vertebra is a compound ossicle that consists of paired ambulacral ossicles united by a fixed joint, often reported to be fused. Development of vertebral ossicles in the amphiurid brittlestar Ophiophragmus filograneus from the arm tip to the oral frame was examined using scanning electron microscopy to follow ontogeny of the vertebra. As an ambulacral ossicle grew, its stereomal trabeculae interdigitated and interlocked by hooking around those of its paired ambulacral, forming the characteristic sinuous suture line central to ophiuroid vertebrae. This three‐dimensional interlocking of stereom formed the joint between paired ambulacrals. With further growth of the vertebra, limited fusion of trabeculae of the paired ambulacrals added to the structure of the joint, primarily at the articular surfaces between successive vertebrae. The joint found here with interlocked trabeculae between ambulacral ossicles of O. filograneus appears to be the same type described in the literature in some echinoids and other ophiuroids. This unique type of fixed joint is described here and named the "campylogomphosis" (Greek: campylos, bent; gomphos, bolt). This newly recognized joint might have implications in echinoderm phylogeny, comparative biology, medicine, and materials science. [ABSTRACT FROM AUTHOR]

Alternation of left and right antimeres of segmental structures, generally known as the glide-reflection symmetry, was found to be unexpectedly widespread in deuterostomes. It occurs in both somatic and visceral organs. Its distribution in echinoderms, acorn worms, cephalochordates, ascidians, hagfishes, and chimaeras might suggest its ancestral nature in deuterostomes. It could have been inherited from Precambrian ancestors. There is a lead of the left segments against their right counterparts in all deuterostomes with glide-reflection symmetry, where the leading side is known. This allows us to presume an inherent left-to-left-side and right-to-right-side homology across all deuterostomes, contradicting a hypothesis of the whole-body dorsoventral inversion in chordates. The features of inversion could be alternatively explained by a transformation of the gastrulation process, which has caused an inversion of dorsoventral polarity in some parts of the body, but did not affect the left–right polarity. It is suggested that this process had involved the animal-vegetal extension of the blastopore along embryonic dorsal side in basal deuterostomes that was followed by the shift of the left–right organizer from the dorsal lip of the blastopore to the anterior tip of archenteron in non-chordate deuterostomes, which has caused roof-to-floor relocation of the notochordal area in their archenteron. [ABSTRACT FROM AUTHOR]

Morphologically cryptic and pseudo-cryptic species pose a challenge to taxonomic identification and assessments of species diversity and distributions. Such is the case for the sea cucumber Stichopus horrens, commonly confused with Stichopus monotuberculatus. Here, we used mitochondrial cytochrome oxidase subunit I (COI) and microsatellite markers to examine genetic diversity in Stichopus cf. horrens throughout the Philippine archipelago, to aid species identification and clarify species boundaries. Phylogenetic analysis reveals two recently diverged COI lineages (Clade A and Clade B; c. 1.35–2.54 Mya) corresponding to sequence records for specimens identified as S. monotuberculatus and S. horrens, respectively. Microsatellite markers reveal two significantly differentiated genotype clusters broadly concordant with COI lineages (Cluster 1, Cluster 2). A small proportion of individuals were identified as later-generation hybrids indicating limited contemporary gene flow between genotype clusters, thus confirming species boundaries. Morphological differences in papillae distribution and form are observed for the two species, however tack-like spicules from the dorsal papillae are not a reliable diagnostic character. An additional putative cryptic species was detected within Clade B-Cluster 2 specimens warranting further examination. We propose that these lineages revealed by COI and genotype data be referred to as Stichopus cf. horrens species complex. [ABSTRACT FROM AUTHOR]

Deep-sea holothurian specimens were collected during five scientific expeditions (2018–2023) using the submersible vehicle ‘Shenhaiyongshi’. Our examination of specimens of Deimatidae from the South China Sea and the Mariana fore-arc area revealed three new species, which were described as Oneirophanta idsseica sp. nov., Oneirophanta brunneannulata sp. nov., and Oneirophanta lucerna sp. nov. These species were distinguished from each other and from congeners by the arrangement, and number of ventrolateral tube feet and ossicle types. We also reported Oneirophanta mutabilis mutabilis Théel, 1879 for the first time from the Mariana fore-arc area, and we recorded Deima validum validum for the second time from the South China Sea. The taxonomy of these new species and new records is discussed, and a phylogenetic analysis based on a concatenated dataset of 16S and COI genes was conducted. Additionally, the inter- and intraspecific genetic divergences we calculated among deimatid species. The results support the assignment of these new species to the genus Oneirophanta and their separation from congeners. A description of the main morphological characters of Oneirophanta species is also provided. The data were collected from geographically diverse areas and suggest that species of Deimatidae were abundant in the Pacific Ocean and occupied a wide range of depths. [ABSTRACT FROM AUTHOR]

One specimen belonging to the family Comatellinae was collected from the Zhenbei Seamount (332.5–478.2 m) in the South China Sea in July 2022. Based on the morphological characters, the specimen was identified as Palaeocomatella hiwia McKnight, 1977. It is first recorded from China Sea and redescribed in detail. This specimen differs from the original description from New Zealand for never showing syzygy at br4+5 or br5+6 on interior and br1+2 on exterior arms. However, it is much conform to the redescription to specimens from Indonesia, with only differences in position of the second syzygy and distalmost pinnule comb. Specimen is deposited in the Institute of Oceanology, Chinese Academy of Sciences. Phylogenetic analyses based on the mitochondrial c oxidase subunit I (COI) and 16S rRNA genes indicated that P. hiwia was nested within the tribe Phanogeniini and clustered with Aphanocomaster pulcher. Furthermore, P. hiwia showed same morphological features in terms of mouth placement, comb location, and number of comb teeth rows as other genera of Phanogeniini. Therefore, we suggest that the genus Palaeocomatella should be put in the tribe Phanogeniini. [ABSTRACT FROM AUTHOR]

The Cambrian and Ordovician radiations marked the origins of all major echinoderm clades and established their Phanerozoic ecological blueprint. Recent claims of modest innovation of early echinoderms and other animals suggest constraints on novelty during the origins of phyla. Here, we document the life‐habit richness, body size, tiering, habitat usage, mobility, diet and foraging habits of 366 Cambrian–Ordovician echinoderm genera across a time‐scaled phylogeny to identify the timing and impact of novelty. Most early echinoderms were sedentary, filter‐feeding microbivores, and their body sizes, diets and modes of locomotion were largely unchanged through time, despite major volatility in taxonomic composition. Cambrian echinoderms lived close to the seafloor, with stylophorans first evolving semi‐infaunality. Many Ordovician echinoderms lived farther from the seafloor, with more complex filter‐feeding organs and tiering structure, often using other organisms as substrates. Mobile carnivores and mass‐feeders emerge then, too, across diverse asterozoans and echinozoans. Most of these novelties coincide with the origins of individual clades during the early and late Cambrian (Terreneuvian/Series 2 and Furongian), and 10–20 million years pass before most become ecologically important. Life‐habit evolution within most taxa involved new variations in these traits, with crinoids and asterozoans better able to shift strategies. The Ordovician radiation records more new variability in pre‐existing Cambrian life habits rather than radical re‐invention, with important novelties (like mobile carnivory and mass‐feeding, increased height off the seafloor, and biotic substrates) becoming ecologically more impactful. Taxa with these strategies were those best able to capitalize on the newly heterogeneous Ordovician world. [ABSTRACT FROM AUTHOR]

Simple Summary: Anticancer peptides are short aminoacidic chains, which display selective cytotoxicity mostly against tumor, but not healthy, cells through interference with intracellular biological events. The marine environment features an ever-growing level of biodiversity and, therefore, seas and oceans are indeed poorly exploited mines in terms of natural products of biomedical interest. Adaptation processes to extreme and competitive environmental conditions led marine species to produce unique metabolites, which have found broad use for various applications in healthcare management, due to their anticancer, anti-angiogenic, anti-inflammatory and regeneration abilities. The aim of this review is to pick and list selected studies that report on the isolation of marine animal-derived peptides and the identification of their anticancer activity in in vitro cultures of cancer cells. Anticancer peptides are short and structurally heterogeneous aminoacidic chains, which display selective cytotoxicity mostly against tumor cells, but not healthy cells, based on their different cell surface properties. Their anti-tumoral activity is carried out through interference with intracellular homeostasis, such as plasmalemma integrity, cell cycle control, enzymatic activities and mitochondrial functions, ultimately acting as angiogenesis-, drug resistance- and metastasis-inhibiting agents, immune stimulators, differentiation inducers and necrosis or extrinsic/intrinsic apoptosis promoters. The marine environment features an ever-growing level of biodiversity, and seas and oceans are poorly exploited mines in terms of natural products of biomedical interest. Adaptation processes to extreme and competitive environmental conditions led marine species to produce unique metabolites as a chemical strategy to allow inter-individual signalization and ensure survival against predators, infectious agents or UV radiation. These natural metabolites have found broad use in various applications in healthcare management, due to their anticancer, anti-angiogenic, anti-inflammatory and regeneration abilities. The aim of this review is to pick selected studies that report on the isolation of marine animal-derived peptides and the identification of their anticancer activity in in vitro cultures of cancer cells, and list them with respect to the taxonomical hierarchy of the source organism. [ABSTRACT FROM AUTHOR]

Xyloplax is a genus of three species of sea stars previously found only on sunken wood in the deep ocean. Their circular and petaloid bodies, which lend them their common name "sea daisy", and their presumed exclusive diet of wood make them an unusual and rare element of deep-sea ecosystems. We describe here the fourth species of Xyloplax from the eastern Pacific Ocean, Xyloplax princealberti n. sp., which ranges from offshore Canada to the Gulf of California (Mexico) and Costa Rica. Though sampled geographically close to another described species of Xyloplax from the northeastern Pacific, X. janetae, this new species is unique morphologically and according to available DNA data. The short abactinal spines are the most obvious feature that distinguishes X. princealberti n. sp. from other Xyloplax. The minimum distance for mitochondrial cytochrome c oxidase subunit I from Xyloplax princealberti n. sp. to the only other available Xyloplax, X. janetae, was 13.5%. We also describe Ridgeia vestimentiferan tubeworm bushes from active hydrothermal vents as a new Xyloplax habitat, the first record of a non-wood substrate, and a new reproductive strategy, simultaneous hermaphroditism, for this genus. We generated the first mitochondrial genome for a member of Xyloplax and analyzed it with other available asteroid data using nucleotide-coding or amino acid (for protein-coding genes) plus nucleotide coding (for rRNA genes). The nucleotide-coding results place Xylopax as part of the clade Velatida, consistent with a previous phylogenomic analysis that included Xyloplax princealberti n. sp. (as Xyloplax sp.), though the placement of Velatida within Asteroidea differed. The amino acid plus nucleotide coding recovered Velatida to be a grade with X. princealberti n. sp. as sister group to all other Asteroidea. [ABSTRACT FROM AUTHOR]

The Cosmonaut Sea is an under-studied area and a "white spot" for macrobenthos research. Here, we report on the species diversity and community structure of macrobenthos collected using tringle trawls on the 38th Chinese National Antarctic Research Expedition (CHINARE) in the Cosmonaut Sea, East Antarctica. A total of 11 tringle trawls were deployed at different depths across the shelf, slope and seamount of the Cosmonaut Sea. A total of 275 macrobenthic species were found from 207 to 1994 m. The species richness per station varied from 23 to 89. Echinoderms (100 species), arthropods (48 species) and mollusks (36 species) were the most dominant groups. Echinoderms and arthropods dominated in abundance at seamount stations, and echinoderms, arthropods and polychaetes dominated in abundance at slope stations, while bryozoans, corals, ascidians and sponges were abundant on the Cosmonaut Sea shelf. Depth was the major driving force influencing the distribution of macrobenthos. The main components were two core communities. One was dominated by sessile suspension feeders and associated fauna. Variants of this community include sponges and bryozoans. The other core community was dominated by mobile deposit feeders, infauna and grazers–epifauna, which included arthropods and echinoderms. The results showed that the slope (40–50° E, 65–67° S) of the Cosmonaut Sea may be an important area with complex ecological processes. The results of this study contribute to the knowledge of species diversity and communities of macrobenthos in the Cosmonaut Sea and provide monitoring data for future ecosystem health assessments and better protection. [ABSTRACT FROM AUTHOR]

Simple Summary: Marine organisms are facing multifaceted changes in their environment due to near-future ocean warming and acidification. We aimed to analyze the impacts of concurrent climate change stressors (seawater warming and acidification) on the embryo/larval development and gene expression patterns of the sea cucumber Apostichopus japonicus. Elevated temperatures have been found to expedite the embryo–larval development of A. japonicus, while decreased pH inhibited these processes, but the effect of combining the former two seemed to be slight. At the transcriptomic level, acidification induced attenuated biomineralization and skeletogenesis, and triggered the risk of extracellular acid–base imbalance and oxidative injury; warming introduced a noticeable stress response; while dual stresses strengthened these stress responses, resulting in reduced immune resistance and heightened system instability. This study provides new insights into the potential adaptive mechanisms employed by sea cucumbers and projects the potential effects of climate change on marine organisms and ecosystems. Ocean acidification (OA) and ocean warming (OW) are potential obstacles to the survival and growth of marine organisms, particularly those that rely on calcification. This study investigated the single and joint effects of OA and OW on sea cucumber Apostichopus japonicus larvae raised under combinations of two temperatures (19 °C or 22 °C) and two pCO2 levels (400 or 1000 μatm) that reflect the current and end-of-21st-century projected ocean scenarios. The investigation focused on assessing larval development and identifying differences in gene expression patterns at four crucial embryo–larval stages (blastula, gastrula, auricularia, and doliolaria) of sea cucumbers, using RNA-seq. Results showed the detrimental effect of OA on the early development and body growth of A. japonicus larvae and a reduction in the expression of genes associated with biomineralization, skeletogenesis, and ion homeostasis. This effect was particularly pronounced during the doliolaria stage, indicating the presence of bottlenecks in larval development at this transition phase between the larval and megalopa stages in response to OA. OW accelerated the larval development across four stages of A. japonicus, especially at the blastula and doliolaria stages, but resulted in a widespread upregulation of genes related to heat shock proteins, antioxidant defense, and immune response. Significantly, the negative effects of elevated pCO2 on the developmental process of larvae appeared to be mitigated when accompanied by increased temperatures at the expense of reduced immune resilience and increased system fragility. These findings suggest that alterations in gene expression within the larvae of A. japonicus provide a mechanism to adapt to stressors arising from a rapidly changing oceanic environment. [ABSTRACT FROM AUTHOR]

Exceptional fossils preserve non-biomineralized tissues in the geological record and provide crucial information on the evolution of life on Earth. Exceptionally preserved fossils are rarely discovered complete, challenging their morphological description and their palaeontological interpretation. Although decay experiments reconstructing degradation sequences in modern animals are necessary to better understand taphonomic processes involved in exceptional preservation, their applicability to some enigmatic and/or extinct fossil taxa remains limited. Here, based on a representative sample of 423 specimens collected from a single stratigraphic level from the Early Ordovician Fezouata Biota, we reconstruct the degradation sequence of both skeletal remains and soft tissues of stylophorans, an extinct clade of echinoderms. The rare preservation of the water vascular system can be explained by the rapid post-mortem opening of the cover plates resulting from the fast decay of associated muscles and the action of ligaments. In contrast, the proximal aulacophore and associated stylocone formed a particularly decay-resistant closed module, thus favouring the preferential preservation of included soft parts (fore-gut). The non-random location and frequency of pyritised intra-skeletal structures strongly suggest that skeletal elements dictated the preservation of underlying soft parts. As such, taphonomic investigations should not only focus on the environment surrounding a decaying animal, but also on the different environments created within a particular carcass. [ABSTRACT FROM AUTHOR]

Seawater magnesium (Mg) and calcium (Ca) have undergone secular fluctuations throughout the Phanerozoic, controlling whether the dominant calcium carbonate precipitant is calcite or aragonite + high-Mg calcite. Although these oscillations in seawater Mg/Ca ratios have been implicated as an important control on Phanerozoic diversification of calcifying marine organisms, determining the degree to which Mg/Ca ratios affected different clades requires integration of experimental data with historical patterns of biodiversity from the fossil record. We explore short-term and long-term responses of echinoderms to shifting calcite-aragonite seas by combining experimental and deep-time biodiversity investigations. While experimental results support a strong relationship between Mg/Ca ratios and shortterm echinoderm regeneration rates, patterns of Phanerozoic echinoderm diversification dynamics show no correspondence with Mg/Ca ratios or calcite-aragonite sea transitions. This decoupling between short- and long-term responses of echinoderms to seawater Mg/ Ca ratios suggests echinoderms were relatively unaffected by seawater chemistry throughout their evolutionary history, possibly due to their ability to alter skeletal Mg fractionation and/or adapt to gradual shifts in seawater chemistry. Notably, our results indicate a strict uniformitarian extrapolation of experimental results over geological time scales may not be appropriate for many calcifying marine invertebrates. Instead, the effect of seawater Mg/ Ca ratios should be evaluated for individual clades using both experimental and deep-time biodiversity data in a time series. [ABSTRACT FROM AUTHOR]

The study of disarticulated ossicles of recent sea cucumbers from Campos Basin, Rio de Janeiro, Brazil, from various Holocene strata, obtained by micropaleontological methods, resulted in the identification of at least eight holothurian taxa, belonging to the five of the seven orders of Holothuroidea: Apodida (Synaptidae, Chiridotidae), Dendrochirotida (Psolidae and Cucumariidae), Holothuriida (Holothuria), and Molpadiida (Molpadiidae, Eupyrgidae). Our paper endorses the importance of studies of recent fauna based on isolated ossicles for taxonomy, biostratigraphy, and ecology. This study represents the first effort at the study of recent fauna of sea cucumbers based on the analysis of preserved ossicles in marine sediments. [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]

Hypertension, a major health concern linked to heart disease and premature mortality, has prompted a search for alternative treatments due to side effects of existing medications. Sustainable harvesting of low-trophic marine organisms not only enhances food security but also provides a variety of bioactive molecules, including peptides. Despite comprising only a fraction of active natural compounds, peptides are ideal for drug development due to their size, stability, and resistance to degradation. Our review evaluates the anti-hypertensive properties of peptides and proteins derived from selected marine invertebrate phyla, examining the various methodologies used and their application in pharmaceuticals, supplements, and functional food. A considerable body of research exists on the anti-hypertensive effects of certain marine invertebrates, yet many species remain unexamined. The array of assessments methods, particularly for ACE inhibition, complicates the comparison of results. The dominance of in vitro and animal in vivo studies indicates a need for more clinical research in order to transition peptides into pharmaceuticals. Our findings lay the groundwork for further exploration of these promising marine invertebrates, emphasizing the need to balance scientific discovery and marine conservation for sustainable resource use. [ABSTRACT FROM AUTHOR]

Two new species of cornutan stylophora of the genus Phyllocystis are described from the Volkhov Regional Stage (Middle Ordovician, Dapingian) of Baltica. This indicates a biogeographic connection between the Afro-European part of Gondwana and Baltica since the very beginning of the Middle Ordovician. Both species were confined to cold-water, shallow basins with low water mobility. Analysis of the axial symmetry of stylophorans and the location of the hydropore indicates the absence of torsion in their ontogeny and the location of the ambulacral system to the right of their anteroposterior axis. To explain this morphology, two alternative hypotheses are proposed: (1) inversion in the development of right and left coeloms; (2) inverted state of stylophorans compared to other invertebrates, in which respect they resemble chordates in terms of the position of the dorsal and ventral sides. [ABSTRACT FROM AUTHOR]

This study reports the presence of 'Endangered' sea cucumber Holothuria scabra for the first time from the mixed seagrasses of Havelock Island, and the 'Vulnerable' Actinopyga mauritiana from the monospecific Thalassia hemprichii meadows from Neil Island of Ritche's Archipelago of Andaman & Nicobar Islands (ANI). Both species were found during field survey of intertidal seagrass ecosystems of Ritche's Archipelago. Morphometric measurements were carried out in the field using a vernier caliper, and identification was confirmed using the identification guide for sea cucumbers of ANI provided by the Zoological Survey of India. The total body length of the H. scabra specimen was 15.7 cm, mouth width of 3.2 cm and body circumference of 5.7 cm. The specimen was a juvenile, grey in color with a total of 17 black and yellow transverse stripes along the body. The average body length of A. mauritiana specimens examined differed between those from seagrass meadows (20.4 cm) non-seagrass areas (15.7 cm) as did mouth width and total circumference. Mono and mixed seagrass meadows of ANI are critical habitats for sea cucumbers and require monitoring and protection for conservation of declining populations. [ABSTRACT FROM AUTHOR]

Crinoids, as integral echinoderms, play a crucial ecological role in benthic communities, serving as significant indicators reflecting the health of marine ecosystems. However, the phylogenetic relationships within crinoids are unclear. More molecular data can help to facilitate biodiversity assessment and elucidate evolutionary relationships by the phylogenetic tree. In this study, 13 complete mitochondrial genomes of the Crinoidea class were sequenced, annotated, and compared with other same class species available on NCBI. The results reveal five different gene order patterns among these mitochondrial genomes, indicating that crinoids have undergone gene rearrangements during evolution. The complete mitochondrial genome length of crinoids ranges from 15,772 bp to 16,850 bp. High A + T content, ranging from 64.5% to 74.2%, was observed. Additionally, our analysis of protein-coding genes highlights a preference for A + T nucleotides, along with specific start and stop codon usage, offering insights into codon bias and its implications for protein synthesis and function. The phylogenetic topology shows that the stalkless crinoid and stalked crinoid are distinct, and the phylogenetic trees generated based on maximum likelihood and Bayesian inference are almost identical at the family and order topology levels. The phylogenetic relationships of each family were fully clarified in four orders. A total of eleven positive selection sites were detected within six genes: cytb, nad2, nad3, nad4, nad4L and nad5. This study reveals the phylogenetic relationships of crinoid species, the mitochondrial gene differences, and the selective pressure on the evolution of stalked crinoids. This study significantly enhanced the crinoid mitochondrial genome database and contributed to a better understanding of the phylogenetic relationships among crinoid echinoderms. [ABSTRACT FROM AUTHOR]

Solutans were among the most enigmatic pre-radial and asymmetric echinoderms. A new species Dehmicystis ariasi sp. nov. is described from the upper part of the Llagarinos Formation, lower Ludlow (Silurian) of Northwest Spain. This is the first solutan formally described from Iberia and the first from the Silurian worldwide. Dehmicystis was previously known based on a small number of poorly preserved specimens from the Emsian, Lower Devonian Hunsrück Slate of Germany. New observations based on the newly studied material suggest that Dehmicystis displayed a feeding appendage facing towards the substrate, and the periproct on the opposite face of the theca. Comparisons with other solutans and new data suggest that Dehmicystis was a detritus feeder that moved over the substrate capturing organic particles from the sediment with a single feeding arm.

The mid-Ordovician mitrocystitid mitrate Mitrocystella incipiens was one of the most widespread stylophorans in the high latitude Mediterranean Province, with occurrences in the Armorican Massif (France), the Iberian Peninsula (Portugal and Spain) and the Prague Basin (Czech Republic), all restricted so far to the late Darriwilian (Hustedograptus teretiusculus Zone). The description of this taxon in the Corréjou Member (Postolonnec Formation) of the Crozon Peninsula (western Brittany, France) not only extends its spatial distribution within the Armorican Massif, but also its stratigraphic range into the mid-Darriwilian (Didymograptus artusZone). The remarkable preser­vation of the new material and associated sedimentological evidence both suggest rapid burial by storm deposits.

Solutans are relatively common members of echinoderm assemblages in the Saint-Chinian Formation (upper Tremadocian) of the Montagne Noire (France). The revision of all available material confirms that most specimens can be assigned to Minervaecystis vidali, which is here reconstructed for the first time. The occurrence of Plasiacystis mobilis is evidenced based on a single, well-preserved dististele. The interpretation of the small-sized individual as a putative dendrocystitid is rejected: it corresponds to a juvenile specimen of M. vidali. Early Ordovician solutans from the Montagne Noire partly fill the gap between Laurentian midâlate Cambrian syringocrinids and Avalonian-Gondwanan EarlyâMiddle Ordovician taxa.

Hypertension, a major health concern linked to heart disease and premature mortality, has prompted a search for alternative treatments due to side effects of existing medications. Sustainable harvesting of low-trophic marine organisms not only enhances food security but also provides a variety of bioactive molecules, including peptides. Despite comprising only a fraction of active natural compounds, peptides are ideal for drug development due to their size, stability, and resistance to degradation. Our review evaluates the anti-hypertensive properties of peptides and proteins derived from selected marine invertebrate phyla, examining the various methodologies used and their application in pharmaceuticals, supplements, and functional food. A considerable body of research exists on the anti-hypertensive effects of certain marine invertebrates, yet many species remain unexamined. The array of assessments methods, particularly for ACE inhibition, complicates the comparison of results. The dominance of in vitro and animal in vivo studies indicates a need for more clinical research in order to transition peptides into pharmaceuticals. Our findings lay the groundwork for further exploration of these promising marine invertebrates, emphasizing the need to balance scientific discovery and marine conservation for sustainable resource use.

The transition from sessile suspension to active mobile detritus feeding in early echinoderms (c.a. 500 Mya) required sophisticated locomotion strategies. However, understanding locomotion adopted by extinct animals in the absence of trace fossils and modern analogues is extremely challenging. Here, we develop a biomimetic soft robot testbed with accompanying computational simulation to understand fundamental principles of locomotion in one of the most enigmatic mobile groups of early stalked echinoderms--pleurocystitids. We show that these Paleozoic echinoderms were likely able to move over the sea bottom by means of a muscular stem that pushed the animal forward (anteriorly). We also demonstrate that wide, sweeping gaits could have been the most effective for these echinoderms and that increasing stem length might have significantly increased velocity with minimal additional energy cost. The overall approach followed here, which we call "Paleobionics," is a nascent but rapidly developing research agenda in which robots are designed based on extinct organisms to generate insights in engineering and evolution. [ABSTRACT FROM AUTHOR]

Accurate taxonomy and descriptions of species are key to understanding biodiversity. The echinoid genus Tripneustes is an ecologically and commercially important taxon that includes the tropical Tripneustes gratilla gratilla and the recently described T. kermadecensis from Australia and New Zealand. While examining the Australian Museum collections to clarify the distributions of these two species in eastern Australia we found potential senior type material for T. kermadecensis. These specimens from Sydney Harbour were originally described in 1878 as Evechinus australiae by Tenison-Woods but neither illustrated nor redescribed in any subsequent report. We undertook molecular and morphological analysis of these specimens to determine whether T. kermadecensis and E. australiae represent two distinct taxa or not. This included micro-computed tomography, quantification of test traits and molecular genetic analysis. The COI sequence and morphology of Evechinus australiae matched that of Tripneustes kermadecensis. As such, T. kermadecensis is a junior synonym of Evechinus australiae. The correct designation of this taxon is therefore Tripneustes australiae (Tenison-Woods, 1878). [ABSTRACT FROM AUTHOR]

The overexploitation of the western Pacific Ocean has expanded the sea cucumber fishery into new regions to supply the Asian market. In 2013, sea cucumbers were removed from the Croatian marine protected species list, and commercial fishery took place for a short period (2017–2018) in the Eastern Adriatic Sea. However, holothuroid species are difficult to distinguish. Holothuria mammata is a species that has rarely been reported in this region and strongly resembles the common species Holothuria tubulosa. This is the first study to assess the genetic diversity of sea cucumbers in the Adriatic Sea using genetic barcoding of the mitochondrial gene cytochrome c oxidase subunit 1 (COI). Specimens for barcoding were collected from the northern and central Adriatic, along with a specimen that had been previously identified as H. sp. cf. mammata based on its morphological characteristics. While genetic analyses showed identified this specimen as H. tubulosa, 30% of the collected specimens were genetically identified as H. mammata. These results call into question the historically accepted sea cucumber assemblage in the Adriatic Sea, which regarded H. mammata as a rare species and generally disregarded its presence in large census studies. Such species distribution data are extremely important in developing and monitoring a sustainable fishery. [ABSTRACT FROM AUTHOR]

Sea stars are a diverse and important component of the Southern Ocean benthos. However, scarce information is available regarding their diversity, distribution, evolution, and taxonomic uncertainties persist for multiple taxa. The Magellanic Region (south of Chile) remains under-sampled despite its pivotal location for species distribution and diversity, being located at the crossroad of three ocean basins. In this study, we assessed the biodiversity of coastal Magellanic sea stars and their affinities with other oceanic bioregions. An integrative approach combining morphological identification with DNA barcoding was implemented to highlight taxonomic discrepancies such as suspected synonymy and unrecognised diversity. Firstly, we identified a total of 15 species from the coastal Magellanic Region and reported the occurrence of Cycethra frigida Koehler, 1917 for the first time in this region. The distribution of these 15 species ranged from only in South America to circumpolar, bipolar, or possibly cosmopolitan. Secondly, we highlighted possible synonymy in two species pairs within the genera Anasterias and Odontaster. This preliminary biodiversity assessment forms an important baseline for monitoring and conservation purposes, especially in the face of distribution shifts as a response to climate change and the increased presence of invasive species. Developmental mode has previously been suggested to be important in shaping biogeographical patterns. However, developmental mode was insufficient to explain the observed patterns, and other factors (e.g., physiological constraints, competition, bathymetrical range, and the possibility of passively rafting on kelp) are suggested to be at least equally important. Finally, an increase in barcoding effort is needed to better capture phylogeographic patterns for each species, both by increasing the number of specimens investigated and by covering a broader geographical range. [ABSTRACT FROM AUTHOR]

Simple Summary: This study discusses the moral issues surrounding the study of echinoderms, a class of marine animals that is attracting interest from scientists. The significance of safely handling these animals is stressed and promotes an ethical standard that is customized to their needs. Our strategy was heavily influenced by the 3Rs principle, which advocates for substituting aware living vertebrates with non-sentient material in research. Echinoderms are excellent models for experimental inquiry because they are typically thought to be non-sentient. Although it is not possible to assess their mental states at this time, there is ample evidence of social behavior in many species, suggesting that ignoring interactions with them could be detrimental to their wellbeing. Recently, progress has been made toward developing an ethical framework for invertebrates, such as crustaceans, echinoderms, and cephalopods. To protect the welfare of echinoderms even in the absence of specific standards, we suggest an enlarged version of the 5Rs framework that includes responsibility and respect. In addition to advancing our knowledge of these interesting species, this research establishes a critical standard for the responsible and sympathetic care of all animals in scientific research. This paper explores the ethical considerations surrounding research on echinoderms, a group of invertebrates that has recently garnered attention in the scientific community. The importance of responsible animal handling and the need for an ethical framework that encompasses echinoderms are emphasized. The 3Rs principle, advocating for the replacement of conscious living vertebrates with non-sentient material in research, is discussed as a guiding tool in current animal research practices. As invertebrates are generally classified as non-sentient animals, the replacement dimension tends to favor them as prevalent models in experimental research. While it currently lacks the means to assess the mental states of invertebrates, there is undeniable evidence of social behavior in many species, suggesting that a lack of interactions with these organisms could potentially adversely affect their wellbeing. In the last few years, considerable progress has been made in developing an ethical framework that takes invertebrates into account, particularly cephalopods, crustaceans, and echinoderms. In this context, we discuss the development of a broader conceptual framework of 5Rs that includes responsibility and respect, which may guide practices ensuring welfare in echinoderms, even in the absence of any particular normative. [ABSTRACT FROM AUTHOR]

Quantifying patterns of gene flow is critical for predicting the future resilience of local marine communities. Brooding species may be particularly susceptible to extirpation, as the lack of a pelagic larval phase may limit dispersal capacity and increase the risk of local extinction. Here, we investigate the population genetic structure of Leptasterias sp., a brooding sea star and important intertidal predator. Dispersal in this genus occurs primarily by crawling, but some have suggested that occasional "rafting" events can move individuals long distances. We used microsatellite markers to estimate genotypic variation across six collection sites of varying distances apart along the Oregon coast. We found evidence of strong population structure at the level of capes, and especially high divergence between two sites within Cape Blanco. Although cape-level genetic structure is broadly consistent with isolation-by-distance, additional mechanisms may be required to explain the elevated magnitude of genetic divergence on a finer scale. We propose that a known offshore water jet off Cape Blanco may act as phylogeographic barrier, hindering transport of rafting individuals from neighboring sites. This pattern suggests, indirectly, that rafting may be more important than previously appreciated in generating long-term genetic isolation between nearby sites. Our findings suggest that even for a sessile brooding species, connectivity and genetic structure can vary on a fine spatial scale and may be subject to environmental and oceanographic forces. [ABSTRACT FROM AUTHOR]

A large favositid tabulate coral colony from the Middle Devonian Edgecliff Member of the Onondaga Formation, collected from Port Colborne, southernmost Ontario, is described herein because of several noteworthy paleontological features preserved via overgrowth by the coral. The initial substratum colonized and subsequently overgrown by the favositid was a large solitary rugose coral, and outward growth resulted in overgrowth of multiple macrofossils, including relatively long portions of large-diameter (probably camerate) crinoid columns. The crinoid columns, which likely represent portions of robust, recumbent dististelar attachment structures, are otherwise known almost entirely from isolated columnals at the collection locality and similar high-energy biostromal lithofacies in the Edgecliff Member elsewhere. One of the crinoid columns is encrusted by a stenolaemate bryozoan containing several examples of a parasitic bioclaustration structure similar to Catellocaula. Hence, the composite coral–crinoid–bryozoan association contains two forms of bioimmuration: preservation of the relatively intact crinoid columns via overgrowth and eventual incorporation into the base of the tabulate coral and preservation of the outline of the bioclaustrated organism (potentially an ascidian tunicate) via embedment in the bryozoan. This specimen serves as a testament to the diversity of biotic interactions and preservational mechanisms that occurred in Paleozoic carbonate build-ups. [ABSTRACT FROM AUTHOR]

Sea cucumbers, belonging to the phylum Echinodermata, are known to possess valuable bioactive compounds that have medicinal properties. In several countries, such as Korea, China, and Japan, they are cultured in the aquaculture industries for food and medicinal purposes. Research has shown that different species of sea cucumbers each possesses unique medicinal values. As a result, we strive towards finding species with better health resilience in aquaculture system to be cultured for nutritional and medicinal purposes. In this paper, we compared the physiological and immunological parameters of three species of sea cucumbers, Cucumaria frondosa (C. frondosa), Isostychopus badionotus (I. badionotus), and Pentacta pygmaea (P. Pygmaea) from the waters of the eastern United States as they have not been studied extensively. Four different cells of sea cucumbers, phagocytic, red spherule, white spherule, and vibratile cells, that contribute to their immunity were counted. C. frondosa exhibited the highest concentrations of phagocytic cells, white spherule cells, and vibratile cells, compared to the two other species. Due to its high phagocytic cell concentration, the highest phagocytic capacity was seen in C. frondosa although it was not statistically significant. We also observed that C. frondosa had the highest total cell count and the highest concentration of coelomic protein among the three species. Lastly, C. frondosa possessed the highest lysozyme activity. Taken together, we concluded that C. frondosa is the best of the three species compared to be reared in the aquaculture systems for use in the food and biomedicine industries due to its immunological and physiological properties. [ABSTRACT FROM AUTHOR]

Epitomapta aumakua sp. nov. occurs at a depth of 2.5 m in Kualoa, O'ahu, Hawai'i, living in coarse sand. It is distinctive in having 12 pinnate tentacles, each tentacle with three pairs of digits and 6-8 sensory cups. The body wall bears papillae or oval bumps, and the length of body reaches a maximum length of 18.4 mm after relaxation. [ABSTRACT FROM AUTHOR]

Microbes play a critical role in the development and health of marine invertebrates, though microbial dynamics across life stages and host generations remain poorly understood in most reef species, especially in the context of climate change. Here, we use a 4‐year multigenerational experiment to explore microbe–host interactions under the Intergovernmental Panel on Climate Change (IPCC)‐forecast climate scenarios in the rock‐boring tropical urchin Echinometra sp. A. Adult urchins (F0) were exposed for 18 months to increased temperature and pCO2 levels predicted for years 2050 and 2100 under RCP 8.5, a period which encompassed spawning. After rearing F1 offspring for a further 2 years, spawning was induced, and F2 larvae were raised under current day and 2100 conditions. Cross‐generational climate effects were also explored in the microbiome of F1 offspring through a transplant experiment. Using 16S rRNA gene sequence analysis, we determined that each life stage and generation was associated with a distinct microbiome, with higher microbial diversity observed in juveniles compared to larval stages. Although life‐stage specificity was conserved under climate conditions projected for 2050 and 2100, we observed changes in the urchin microbial community structure within life stages. Furthermore, we detected a climate‐mediated parental effect when juveniles were transplanted among climate treatments, with the parental climate treatment influencing the offspring microbiome. Our findings reveal a potential for cross‐generational impacts of climate change on the microbiome of a tropical invertebrate species. [ABSTRACT FROM AUTHOR]

Simple Summary: The sea urchin (Heliocidaris crassispina) is an ecologically important invertebrate in structuring marine benthic communities. Most dwell within intertidal regions, rendering them highly susceptible to elevated artificial light at night. However, their potential acclimation to artificial light exposure remains largely unexplored. This study investigates the changes of prolonged artificial light pollution on the fitness-related traits of sea urchins. Following a six-week exposure to artificial light at night, survival remained unaffected, while behavioral responses exhibited slower reactions. Concurrently, growth inhibition was observed in sea urchins, which might be attributed to reduced mouthparts weight and decreased food consumption. This study also revealed that sea urchin gonads are more susceptible to artificial light than guts. Pax6 gene expression may serve as a sensitive indicator to assess the impact on the photosensitive system of sea urchins. These results increase our understanding of the effects of artificial light at night on sea urchins and provide valuable information about coastal animals' safety. Limited data are available regarding the effects of elevated coastal artificial light at night (ALAN) on intertidal echinoderms. In this study, we investigated the behavioral, morphological, and physiological responses of the sea urchin (Heliocidaris crassispina) after continuous exposure to ALAN at light intensities of 0.1, 300, and 600 Lux for 6 weeks. Our findings revealed that ALAN at 300 Lux substantially reduced food consumption, Lantern weight, and gonadosomatic index (GSI). On the other hand, ALAN at 600 Lux notably prolonged the righting and covering response times and elevated the 5-HIAA/5-HT ratio, while concurrently decreasing food consumption, body weight, Lantern weight, GSI, and Pax6 gene expression. These results indicated that continuous exposure to ALAN could cause an adverse effect on fitness-related traits, including behavioral responses, growth, reproductive performance, and photoreception of sea urchins. The present study provides new insights on the impact of light pollution on echinoderms. [ABSTRACT FROM AUTHOR]

This publication presents an unusual behavior of a comatulid crinoid that was tentatively attributed to Heliometria glacialis (Echinodermata, Crinoidea, Heliometrinae). This unstalked crinoid was observed clinging on Hyas sp. crabs in the inner part of the Spitsbergen fjords heavily loaded with suspension runoff. In situ observations were made using a 16-h and 45-min time-lapse sequence showing the decompositions of Atlantic cod. During the exposure, apart from typical organisms such as carrion crustaceans, crabs, and starfish, three individuals of crinoids were observed. One of the crinoids was clinging to the edge of the platform for most of the exposure. The remaining two individuals were observed attached to the carapace of Hyas sp. crabs for 6 h 55 min. It was also found, based on analysis of the video material from 202 locations examined in the summer season between 2015 and 2020 using a drop camera, two additional locations showing comatulid crinoids. Both locations in the Ekmanfjorden and in the interior of the Vanmijenfjorden are areas under the strong influence of a glacier meltwater plum or a glacial river runoff. So far, comatulid crinoids have been found mainly in locations outside of the influence of turbid waters from fjords. We interpret this new behavior within comatulid crinoids as an adaptation that help colonize new regions gradually exposed by the retreating glaciers. [ABSTRACT FROM AUTHOR]

Simple Summary: Various physiological activities of organisms, including movement, feeding, reproduction, breathing, excretion, etc., all require the participation of their neuromuscular systems. Echinoderms, a phylum closely related to chordates, possess a well-differentiated but simpler muscular system, which provides a great opportunity to trace the evolutionary origins of the vertebrate muscular system. Here, we review the morphology of different musculatures and the effects of different neurotransmitters and neuropeptides involved in muscle regulation in echinoderms. In addition, we highlight the potential molecular mechanisms underpinning the action of these chemical messengers on echinoderm muscles. The muscular systems of echinoderms play important roles in various physiological and behavioral processes, including feeding, reproduction, movement, respiration, and excretion. Like vertebrates, echinoderm muscle systems can be subdivided into two major divisions, somatic and visceral musculature. The former usually has a myoepithelial organization, while the latter contains muscle bundles formed by the aggregation of myocytes. Neurons and their processes are also detected between these myoepithelial cells and myocytes, which are capable of releasing a variety of neurotransmitters and neuropeptides to regulate muscle activity. Although many studies have reported the pharmacological effects of these chemical messengers on various muscles of echinoderms, there has been limited research on their receptors and their signaling pathways. The muscle physiology of echinoderms is similar to that of chordates, both of which have the deuterostome mode of development. Studies of muscle regulation in echinoderms can provide new insights into the evolution of myoregulatory systems in deuterostomes. [ABSTRACT FROM AUTHOR]

Spatangoid echinoids belonging to Heteraster found in the Lower Cretaceous limestones and calcareous deposits of the Tirgan and Sarcheshmeh formations (Barremian–Aptian) in the Bahman jan‐Bala stratigraphic section on the northern flank of the Borouj syncline, situated in the eastern Kopet‐Dagh Basin, northeastern Iran are assessed as a sexually dimorphic species. Sexual dimorphism is a common feature in echinoids and, in this study of Heteraster renngarteni Poretzkaja, 1961, sexual dimorphism has been detected for the first time in the family Toxasteridae. [ABSTRACT FROM AUTHOR]

Vasopressin/oxytocin (VP/OT)-type neuropeptide is an ancient neurophysin-associated neuropeptide and has been intensively studied to be involved in multiple physiological processes in protostomian and deuterostome vertebrates. However, little is known about the functions of VP/OT-type neuropeptide in deuterostome invertebrates especially in echinoderms. Here, we firstly report VP/OT-type neuropeptide signaling in an important economic species, Apostichopus japonicus, which is widely cultured in Asia, with high nutritional and medicinal values. Molecular characterization analysis of holotocin and its precursor revealed the highly conserved features of VP/OT family. The candidate receptor for holotocin (AjHOR) was confirmed to be able to activate the signaling via cAMP-PKA and possible Ca2+-PKC pathway, and further activated the downstream ERK1/2 cascade. Holotocin precursor expression profile showed that they were mainly concentrated in circumoral nerve ring. Furthermore, in vitro pharmacological experiments demonstrated that holotocin caused contractile responses in preparations from A. japonicus. And in vivo functional studies indicated that short-term injection of holotocin resulted in body bloat and long-term injection resulted in reduced body mass, suggesting potential roles of holotocin in osmoregulation and feeding co-inhibition with holotocin–CCK. Our findings provided a comprehensive description of AjHOR–holotocin signaling, revealed ancient roles of holotocin in osmoregulation and feeding inhibition by controlling muscle contractions. [ABSTRACT FROM AUTHOR]

A diverse echinoderm fauna lived in reef and non-reef Silurian facies of the upper Midwestern USA. However, these faunas are dominantly preserved in dolostones with moldic preservation, and fossils from dolostone facies have not been documented to the extent of Silurian crinoids in nondolostone strata. Herein, an echinoderm fauna is described from the dolostones of the Cedarville Member of the Laurel Limestone (Wenlock, Homerian) from the Pepcon Cement Quarry in west-central Ohio. The described fauna contains blastoids, hemicosmitoids, and crinoids, including Troosticrinus subcylindricus (Hall and Whitfield, 1875); Caryocrinites sp. indet.; an unidentifiable diplobathrid camerate; Periechocrinus tennesseensis (Hall and Whitfield, 1875); Periechocrinus egani ? (Miller, 1881); Stiptocrinus farringtoni (Slocom, 1908); Calliocrinus primibrachialis Busch, 1943; Calliocrinus poepplemani new species; Calliocrinus hadros new species; and Lecanocrinus sp. indet. Generic concepts for the Eucalyptocrinitidae are clarified; and, surprisingly, Eucalyptocrinites Goldfuss, 1831 is absent from this fauna. Additionally, lectotypes and paralectotypes are designated for Periechocrinus tennesseensis and Calliocrinus primibrachialis. UUID: http://zoobank.org/a8c8e7e3-9bc3-4078-83bd-5572816366e5 [ABSTRACT FROM AUTHOR]

Evidence from the earliest-known crinoids (Tremadocian, Early Ordovician), called protocrinoids, is used to hypothesize initial steps by which elements of the calyx evolved. Protocrinoid calyces are composed of extraxial primary and surrounding secondary plates (both of which have epispires along their sutures) that are unlike those of more crownward fossil and extant crinoids in which equivalent calycinal plating is strongly organized. These reductions inspired several schemes by which to name the plates in these calyces. However, the primary-secondary systems seen in protocrinoids first appeared among Cambrian stem radial echinoderms, with primaries representing centers around which secondaries were sequentially added during ontogeny. Therefore, the protocrinoid calyx represents an intermediate condition between earliest echinoderms and crownward crinoids. Position and ontogeny indicate certain primaries remained as loss of secondaries occurred, resulting in abutting of primaries into the conjoined alternating circlets characteristic of crinoids. This transformative event included suppression of secondary plating and modification or, more commonly, elimination of respiratory structures. These data indicate subradial calyx plate terminology does not correspond with most common usage, but rather, supports an alternative redefinition of these traditional expressions. Extension and adoral growth of fixed rays during calyx ontogeny preceded conjoined primaries in earliest crinoids. Restriction with modification or elimination of calyx respiratory structures also accompanied this modification. Phylogenetic analyses strongly support crinoid origination from early pentaradiate echinoderms, separate from blastozoans. Accordingly, all Tremadocian crinoids express a distinctive aggregate of plesiomorphic and apomorphic commonalities; all branch early within the crinoid clade, separate from traditional subclass-level clades. Nevertheless, each taxon within this assemblage expresses at least one diagnostic apomorphy of camerate, cladid, or disparid clades. [ABSTRACT FROM AUTHOR]

Hypercoagulability, a major complication of metastatic cancers, has usually been treated with heparins from natural sources, or with their synthetic derivatives, which are under intense investigation in clinical oncology. However, the use of heparin has been challenging for patients with risk of severe bleeding. While the systemic administration of heparins, in preclinical models, has shown primarily attenuating effects on metastasis, their direct effect on established solid tumors has generated contradictory outcomes. We investigated the direct antitumoral properties of two sulfated fucans isolated from marine echinoderms, FucSulf1 and FucSulf2, which exhibit anticoagulant activity with mild hemorrhagic potential. Unlike heparin, sulfated fucans significantly inhibited tumor cell proliferation (by ~30–50%), and inhibited tumor migration and invasion in vitro. We found that FucSulf1 and FucSulf2 interacted with fibronectin as efficiently as heparin, leading to loss of prostate cancer and melanoma cell spreading. The sulfated fucans increased the endocytosis of β1 integrin and neuropilin-1 chains, two cell receptors implicated in fibronectin-dependent adhesion. The treatment of cancer cells with both sulfated fucans, but not with heparin, also triggered intracellular focal adhesion kinase (FAK) degradation, with a consequent overall decrease in activated focal adhesion kinase levels. Finally, only sulfated fucans inhibited the growth of B16-F10 melanoma cells implanted in the dermis of syngeneic C57/BL6 mice. FucSulf1 and FucSulf2 arise from this study as candidates for the design of possible alternatives to long-term treatments of cancer patients with heparins, with the advantage of also controlling local growth and invasion of malignant cells. [ABSTRACT FROM AUTHOR]

In spite of considerable progress during the last few years, the fossil record of the ophiuroids, or brittle stars, is still poorly known, especially with respect to taxa restricted to specific environments. Here, we describe new ophiuroid fossils collected from an Upper Cretaceous rocky shore in Ivö Klack, southern Sweden, consisting of fully disarticulated skeletal remains retrieved from the sediments deposited between boulders and hummocks. The fossils are identified as a new species of the extant ophiocomid genus Ophiocoma. In a critical revision of the ophiocomid fossil record, we show that all fossils previously assigned to the Ophiocomidae belong to other families. Thus, the fossil record of the Ophiocomidae is currently restricted to the new species described herein, and Amphiura? gigantiformis from the Miocene of Austria which, in fact, is a species of Ophiocoma. Since recent species of Ophiocoma exclusively occur in tropical to subtropical shallow subtidal environments, our discovery of a fossil Ophiocoma species in the rocky shore sediments of Ivö therefore conforms with the previously assumed subtropical palaeotemperatures prevailing in southern Sweden during the Late Cretaceous. Most notably, it represents the northernmost occurrence of an ophiocomid recorded to date. [ABSTRACT FROM AUTHOR]

Class Ophiuroidea groups the most diverse and abundant organisms of the phylum Echinodermata, having approximately 2100 described species. They have a simple body plan, consisting of a central disk, where their main internal organs are located, and to which the arms are attached. Species are identified based mostly on external morphological characters. However, many species present similar diagnostic characters in several families, which makes their phylogenetic reconstruction quite complex. Furthermore, many of these characters undergo changes during post-larval development and growth. Therefore, ontogenetic studies become relevant. Progress is still slow in this field, however, mainly due to difficulties in identifying some species in these stages. Despite significant advances in the number of species described for the Northeast region of Brazil, studies on the growth series of species of Ophiuroidea reported for this region are still scarce. The present work describes the intraspecific variations of Ophionereis reticulata (Say, 1825), Ophionereis squamulosa Koehler, 1914, and Amphipholis squamata (Delle Chiaje, 1828), considering young and adult specimens. The morphometry of individuals and aspects of microstructure are included. The description of morphological characters in growth series allowed us to identify typical characteristics of certain stages. Some structures remained almost unchanged, while others underwent most of the changes, being used to characterize different growth stages. Such stages are helpful for the correct identification of these species. In addition, the study of morphological variations between young and adult specimens contributes to our understanding on evolutionary relationships within Ophiuroidea. [ABSTRACT FROM AUTHOR]

The fine structure of the mesodermal organs (water-vascular system, somatocoel derivatives, connective tissue, and mesenchymal cells) in late doliolaria, pentactula, and 1-month-old juveniles of the holothurian Apostichopus japonicus was studied. It has been shown that all the structures of the water-vascular system, the longitudinal muscle band anlagen, extracellular matrix, and different types of mesenchymal cells are present at the late doliolaria stage. However, even in 1-month-old juveniles, many organs do not reach their full development as in adults. During the developmental period under study, several stages of myogenesis can be distinguished, ranging from the appearance of single myoepithelial cells to the beginning of muscle bundle formation. These data are consistent with our hypothesis of the origin, development, and evolution of the muscular system in echinoderms. One-month-old juveniles already have all the main types of coelomocytes characteristic of adults. This means that the immune system of A. japonicus is already formed. [ABSTRACT FROM AUTHOR]

A branching body pattern with one head and many "tails", unique for recent Bilateria, was found in three species of endosymbiotic polychaetes of the family Syllidae (McIntosh, 1879; Glasby et al., 2012; Aguado et al., 2015, 2022). Among recent echinoderms, many species of crinoids, brittle stars, and holothurians have dendriform branching bodies with many distal, posterior ends of their arms, rays, and tentacles, which include the typical axial ambulacral complex. Multiple bifurcations of the posterior (distal) parts create fractal branching of the body pattern, representing a macroevolutionary transformation of the ancestral body plan in Bilateria. [ABSTRACT FROM AUTHOR]