Urchin Species Research Articles

Evolutionary Changes in the Chromatin Landscape Contribute to Reorganization of a Developmental Gene Network During Rapid Life History Evolution in Sea Urchins.

Chromatin configuration is highly dynamic during embryonic development in animals, exerting an important point of control in transcriptional regulation. Yet there exists remarkably little information about the role of evolutionary changes in chromatin configuration to the evolution of gene expression and organismal traits. Genome-wide assays of chromatin configuration, coupled with whole-genome alignments, can help address this gap in knowledge in several ways. In this study we present a comparative analysis of regulatory element sequences and accessibility throughout embryogenesis in three sea urchin species with divergent life histories: a lecithotroph Heliocidaris erythrogramma, a closely related planktotroph H. tuberculata, and a distantly related planktotroph Lytechinus variegatus. We identified distinct epigenetic and mutational signatures of evolutionary modifications to the function of putative cis-regulatory elements in H. erythrogramma that have accumulated nonuniformly throughout the genome, suggesting selection, rather than drift, underlies many modifications associated with the derived life history. Specifically, regulatory elements composing the sea urchin developmental gene regulatory network are enriched for signatures of positive selection and accessibility changes which may function to alter binding affinity and access of developmental transcription factors to these sites. Furthermore, regulatory element changes often correlate with divergent expression patterns of genes involved in cell type specification, morphogenesis, and development of other derived traits, suggesting these evolutionary modifications have been consequential for phenotypic evolution in H. erythrogramma. Collectively, our results demonstrate that selective pressures imposed by changes in developmental life history rapidly reshape the cis-regulatory landscape of core developmental genes to generate novel traits and embryonic programs.

Comparative multi-species analysis of potassium cyanide toxicity

Potassium cyanide (KCN), a highly water soluble and bioaccumulative cyanide salt, is examined to determine the toxic effects by using two green algae (Dunaliella viridis, Nannochloropsis oculata) and genetically different two sea urchin (Paracentrotus lividus, Arbacia lixula) species. To determine the toxic effects on the early developmental stages of sea urchin embryos, 72-hour embryotoxicity studies were conducted. Potassium cyanide toxicity at cellular level was also investigated and 6-hour embryos of both sea urchin species were used to determine genotoxic effects of KCN. Since plutei naturally feed on microalgae, two species of plankton were used to reveal phytotoxic effects of KCN. KCN was found to be embryo- geno- and phytotoxic. EC50's for P. lividus and A. lixula were found 7.96 and 6.52 μM. IC50's for N. oculata for 48 h and 72 h were found 23.66 and 80.45 μM. IC50's for D. viridis for 48 h and 72 h were found 14.31 and 23.36 μM.

Sea urchins: an update on their pharmacological properties.

Sea urchins are a group of benthic invertebrates characterized by having rigid globose bodies, covered in spines, and have an innate immune system that has allowed them to survive in the environment and defend against many pathogens that affect them. They are consumed for their unique flavor, but also for possessing a rich source of bioactive compounds which make them a source for a wide array of medicinal properties. Thus, these may be used to discover and develop new drugs such as anti-bacterials, anti-carcinogenics and anti-virals. Precisely for those reasons, this revision is centered on the known biological activities in various sea urchin species. Recently, the potential pharmacological benefits of nine sea urchin species [Diadema antillarum (Philippi 1845), Echinometra mathaei (de Blainville), Evechinus chloroticus (Valenciennes), Mesocentrotus nudus (Agassiz, 1863), Paracentrotus lividus (Lamarck, 1816), Scaphechinus mirabilis (Agazzis, 1863), Stomopneustes variolaris (Lamarck, 1816), Tripneustes depressus (Agassiz, 1863), and Tripneustes ventricosus (Lamarck, 1816)] have been evaluated. Our work includes a comprehensive review of the anti-fungal, anti-parasitic, anti-inflammatory, hepatoprotective, anti-viral, anti-diabetic, anti-lipidemic, gastro-protective and anti-cardiotoxic effects. Furthermore, we revised the compounds responsible of these pharmacological effects. This work was intended for a broad readership in the fields of pharmacology, drugs and devices, marine biology and aquaculture, fisheries and fish science. Our results suggest that organic extracts, as well as pure compounds obtained from several parts of sea urchin bodies are effective in vitro and in vivo pharmacological models. As such, these properties manifest the potential use of sea urchins to develop emergent active ingredients.

Sea Urchins in Acute High Temperature and Low Oxygen Environments: The Regulatory Role of microRNAs in Response to Environmental Stress

Strongylocentrotus intermedius is an economically valuable sea urchin species in China. However, its growth and survival are severely constrained by ocean warming and the hypoxia that often accompanies high water temperatures. MicroRNAs (miRNAs) are important regulators of gene expression in response to environmental change. In this study, high-throughput RNA sequencing was used to investigate changes in miRNA expression in S. intermedius under heat (25°C), hypoxia (2 mg/L O2), and combined heat and hypoxia stresses. Twelve small RNAs libraries were constructed and 17, 14, and 23 differentially expressed miRNAs (DEMs) were identified in the heat, hypoxia, and combined stress groups (P<0.05), respectively. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway functional analyses of putative target genes of the DEMs suggested that these miRNAs were important in basal metabolism, apoptosis, oxidative stress, and immune-related pathways. By co-analysis with published transcriptome data, key DEMs (miR-193, miR-184, miR-133, miR-125, miR-2008) and their key target genes (EGF3, ABCB4, CYCL, PAN2, CALN) were identified. Quantitative real-time PCR analysis of the expression of 10 DEMs and their key target genes confirmed the RNA sequencing results. These results provide information on gene expression regulation of the molecular mechanisms underlying the response of S. intermedius to multi-cause environmental stresses.

Reproductive adaptations of sea urchins with planktotrophic larvae

The brief review summarizes the authors' original data on the role of environmental factors in triggering and synchronization of spawning in natural populations of two species of sea urchins with planktotrophic larvae. It is shown that both species exhibit similar reproductive adaptations aimed at enhancing reproductive success. The high sensitivity of sea urchins, primarily males, to environmental signal(s), most likely to phytoplankton, can be considered as a large-scale adaptation characteristic of many marine invertebrates with external fertilization and planktotrophic larvae and promoting the development of mass spawning events. Night time, as well as the new moon and full moon phases, are modulating factors that increase the likelihood of mass spawning. Longer duration of spawning in males compared to females, longer duration of sperm release during mass spawning compared to that during solitary spawning, longer duration of spawning in males living in an environment with higher level of phytoplankton, and approach of males and females during mass spawning can be considered as small-scale adaptations that increase the likelihood of fertilization.

Influence of Winter Storms on the Sea Urchin Pathogen Assemblages

In recent years, recurrent sea urchin mass mortalities in the Canary Islands have been registered. These mortality-related events have decimated 93% of the eastern Atlantic populations of the barren-forming sea urchin Diadema africanum. Two severe episodes of rough southeastern seas led to winter storms in February 2010 (Xynthia) and February 2018 (Emma) and preceded the last mass mortality event. We hypothesized that these events are related to the mass mortalities registered during the February in those years. Previous studies identified Neoparamoeba branchiphila as the causal agent of the disease, possibly acting in synergy with Vibrio alginolyticus and/or other pathogens. To determine the link between winter storms and the sea urchin pathogen community, we monitored the marine pathogen assemblage before and after the winter storm Filomena (February 2020) on Tenerife Island, on different habitats (sea water, sediment and algae) and in four species of sea urchin hosts (D. africanum, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis). A total of six pathogens, including N. branchiphila, Vexillifera minutissima, Acanthamoeba sp., Vahlkampfia sp., V. alginolyticus and green colonies of Vibrio spp., were identified. Only small amoebas were found in sea urchins, while Vibrio species were more common in seawater, sediment and algae substrates. V. alginolyticus was occasionally detected in three sea urchins specimens, while N. branchiphila was found in the coelom of all four sea urchin studied. As previously hypothesized, a significant pathogen increment in seawater and in the sea urchin species D. africanum and P. lividus, was found after Filomena. Our results confirmed the relationship between the winter storms and marine pathogen dynamics. However, further studies are needed to demonstrate the direct relationship between these pathogen increases and the sea urchin mass mortalities.

Staying in place and moving in space: Contrasting larval thermal sensitivity explains distributional changes of sympatric sea urchin species to habitat warming.

For marine ectotherms, larval success, planktonic larval duration and dispersal trajectories are strongly influenced by temperature, and therefore, ocean warming and heatwaves have profound impacts on these sensitive stages. Warming, through increased poleward flow in regions with western boundary currents, such as the East Australia Current (EAC), provides opportunities for range extension as propagules track preferred conditions. Two sea urchin species, Centrostephanus rodgersii and Heliocidaris tuberculata, sympatric in the EAC warming hotspot, exhibit contrasting responses to warming. Over half a century, C. rodgersii has undergone marked poleward range extension, but the range of H. tuberculata has not changed. We constructed thermal performance curves (TPC) to determine if contrasting developmental thermal tolerance can explain this difference. The temperatures tested encompassed present-day distribution and forecast ocean warming/heatwave conditions. The broad and narrow thermal optimum (Topt) ranges for C. rodgersii and H. tuberculata larvae (7.2 and 4.7°C range, respectively) matched their realized (adult distribution) thermal niches. The cool and warm temperatures for 50% development to the feeding larva approximated temperatures at adult poleward range limits. Larval cool tolerances with respect to mean local temperature differed, 6.0 and 3.8°C respectively. Larval warm tolerances were similar for both species as are the adult warm range edges. The larvae of both species would be sensitive to heatwaves. Centrostephanus rodgersii has stayed in place and shifted in space, likely due to its broad cold-warm larval thermal tolerance and large thermal safety margins. Phenotypic plasticity of the planktonic stage of C. rodgersii facilitated its range extension. In contrast, larval cold intolerance of H. tuberculata explains its restricted range and will delay poleward extension as the region warms. In a warming ocean, we show that intrinsic thermal biology traits of the pelagic stage provide an integrative tool to explain species-specific variation in range shift patterns.

Interactive effects of ocean acidification, ocean warming, and diurnal temperature cycling on antioxidant responses and energy budgets in two sea urchins Strongylocentrotus intermedius and Tripneustes gratilla from different latitudes

To accurately predict the fitness of marine ectotherms under the climate change scenarios, interactive effects from multiple environmental stressors should be considered, such as ocean acidification (OA), ocean warming (OW) and diurnal temperature cycling (DTC). In this work, we evaluated and compared the antioxidant capacity and metabolism homeostasis of two sea urchins, viz. the temperate species Strongylocentrotus intermedius and the tropical species Tripneustes gratilla, in response to oceanic conditions under a climate change scenario. The two species were treated separately/jointly by acidic (pH 7.6), thermal (ambient temperature + 3 °C), and temperature fluctuating (5 °C fluctuations daily) seawater for 28 days. The activities of antioxidant enzymes (catalase and superoxide dismutase) and the cellular energy allocation in the urchins' gonads were assessed subsequently. Results showed that exposure to OA, OW, and DTC all induced antioxidant responses associated with metabolism imbalance in both S. intermedius and T. gratilla. The physiological adjustments and energy strategies towards exposure of OA, OW, and DTC are species specific, perhaps owing to the different thermal acclimation of species from two latitudes. Moreover, decrease of cellular energy allocation were detected in both species under combined OA, OW, and DTC conditions, indicating unsustainable bioenergetic states. The decrease of cellular energy allocation is weaker in T. gratilla than in S. intermedius, implying higher acclimation capacity to maintain the energy homeostasis in tropical urchins. These results suggest that climate change might affect the population replenishment of the two sea urchins species, especially for the temperate species.

Effect of High-Pressure Processing on Fresh Sea Urchin Gonads in Terms of Shelf Life, Chemical Composition, and Microbiological Properties.

Paracentrotus lividus is a widespread sea urchin species appreciated worldwide for the taste of its fresh gonads. High-pressure processing (HPP) can provide a thermal equivalent to pasteurization, maintaining the organoleptic properties of the raw gonads. This study evaluated HPP technology’s effect at 350 MPa and 500 MPa on microbial inactivation and biochemical characteristics of P. lividus gonads. HPP at 350 MPa resulted in a higher decrease in protein and free amino acids associated with a loss of olfactory, color, and gustatory traits and a visual alteration of the texture. On the other hand, gonad samples stored for 40 days after treatments at 500 MPa showed a good organoleptic profile similar to fresh gonads. Furthermore, only 500 MPa effectively reduced mesophilic bacteria contamination among the two HPP treatments carried out. Total lipids increased during storage; however, the SAFA/PUFA rate was homogeneous during HPP trials ranging from 2.61–3.91 g/100 g. Total protein decreased more than 40% after HPP at 350 MPa, whereas, after 500 MPa, it remained stable for 20 days. The amount of free amino acid constantly decreased during storage after HPP at 350 MPa and remained constant at 500 MPa. HPP can effectively remove the bacterial flora and inactivate enzymes, maintaining the properties of the fresh sea urchin gonads.

New Records of Rare Species of Marine Invertebrates in the Eastern Mediterranean, Syria

Conducting further research and exerting more effort into field studies will aid the detection and recording of new, rare species of invertebrates in the Mediterranean and allow the examination of their biological and environmental characteristics. This article provides information on four species of sea crab (one of which is alien), two species of sea star, one species of sea urchin and two species of octopus, which have all been documented for the first time in Syrian waters. Samples were collected by fishing nets from a coastal area at medium depths (20–630 meters) from Ras al-Basit, Lattakia and Banias during 2020 and 2021. These species are: Actaea savignii (H. Milne Edwards, 1834); Dromia personata (Linnaeus, 1758);Geryon longipes (A. Milne-Edwards, 1882); Homola barbata (Fabricius, 1793); Peltaster placenta (Müller and Troschel, 1842); Chaetaster longipes (Bruzelius, 1805); Sphaerechinus granularis (Lamarck, 1816); Tremoctopus violaceus (Delle Chiaje, 1830);Ocythoe tuberculate (Rafinesque, 1814). Documenting the presence of these rare species is very important from an environmental and scientific perspective, and recording more of them requires coordination with the marine fishing sector in Syria. KEYWORDS Cephalopods, crustaceans, echinoderms, marine biodiversity, non-indigenous species,zoobenthos

Toxicity of arsenic(

Environmental context High-quality ecotoxicology data are required to derive reliable water quality guideline values that ensure long-term protection of marine biota from arsenate. Tropical and temperate marine biota have sensitivity to arsenate covering three to four orders of magnitude due to the range of arsenate detoxification mechanisms used to reduce toxicity. The water quality guideline values derived in this study will contribute to robust risk assessments of arsenate in marine environments. Rationale There are very few high-quality chronic inorganic arsenate (AsV) toxicity data to assess the risks to marine ecosystems. We aimed to determine the range in chronic toxicity of AsV to marine biota and derive reliable water quality guideline values (GVs) for the long-term protection of marine ecosystems. Methodology We generated chronic toxicity data based on measured dissolved (<0.45 µm filtered) AsV concentrations for 13 marine species representing seven taxonomic groups from temperate and tropical environments. Effect concentrations at the 10% level (EC10) were used in a species sensitivity distribution (SSD) to derive water quality GVs. Results The range of concentrations causing chronic 10, 20 and 50% adverse effects were 13–26 000, 18–34 000 and 32–330 000 µg AsV L–1, respectively. Increased phosphate and nitrate concentrations were found to reduce the toxicity of AsV to certain microalgal, sea urchin and bivalve species. The range in effect concentrations for tropical versus temperate species overlapped at all effect levels. The GVs for the long-term protection of 80, 90, 95 and 99% of marine biota were: 48, 22, 12 and 4.8 µg AsV L–1, respectively. Discussion Recommendations on performing toxicity tests with arsenic to prevent artefacts associated with arsenic speciation were made to improve future research on arsenic toxicity. The new data will improve the reliability status of the Australian and New Zealand AsV GVs for marine water quality and fill a data gap for global risk assessments of AsV for marine biota.

Dorsal-ventral axis formation in sea urchin embryos.

Most sea urchin species produce planktonic feeding larvae with distinct dorsal-ventral polarity. Such morphological indicators of polarity arise after gastrulation, when several morphogenesis and cell differentiation events occur differentially along the dorsal-ventral axis. For instance, the gut bends toward the ventral side where the mouth will form, skeletogenesis occurs initially near the ventral side with the forming skeleton extending dorsally, and pigment cells differentiate and embed in the dorsal ectoderm. The patterning mechanisms and gene regulatory networks underlying these events have been extensively studied. Two opposing TGF-β signaling pathways, Nodal and BMP, play key roles in all three germ layers to respectively pattern the sea urchin ventral and dorsal sides. In this chapter, I describe our current understanding of sea urchin dorsal-ventral patterning mechanisms. Additionally, differences in the patterning mechanisms observed in lecithotrophic sea urchins (nonfeeding larvae) and in cidaroid sea urchins are also discussed, along with evolutionary insights gained from comparative analyses.

Multiple-choice feeding preference assay on two sea urchin species from the Gulf of Mannar, South East coast of India

A multiple-choice feeding experiment was conducted on the two sea urchins, viz ., Salmacis virgulata and Temnopleurus toreumaticus, in four feeding assays with 12 varieties of seagrass and seaweed. The results of the study have revealed that the species Caulerpa peltata , C. racemosa , Kappaphycus alvarezii and Padina tetrastromatica occupied the top feeding positions in the descending order for S. virgulata . But for T. toreumaticus , the order of preference was observed to decrease sequentially for C. peltata , Cymodocea serrulata , C. racemosa and Syringodium isoetifolium . This study further revealed that there was a leaning preference towards seagrass species in T. toreumaticus which was conspicuously absent in S . virgulata . This kind of studies would pave way to better understand sea urchin ecology and its urchin barren phenomenon.

Gene expression patterns of sea urchins (Strongylocentrotus intermedius) exposed to different combinations of temperature and hypoxia

Strongylocentrotus intermedius is one of the most economically valuable sea urchin species in China, and its growth and survival are severely constrained by ocean warming and the hypoxia that often accompanies high water temperatures. To elucidate the molecular mechanisms of S. intermedius that regulate gene expression in response to multi-causal environmental stresses. We performed a de novo transcriptome analysis of coelomocyte from S. intermedius to heat (25 °C), hypoxia (2 mg/L), and the combined stress. We identified 35,635, 29,107, and 29,440 differentially expressed genes (DEGs) in S. intermedius cultured under high temperature, low oxygen, and combined stress, respectively. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analyses revealed that these DEGs mainly enriched the functional categories of “Protein processing in endoplasmic reticulum,” and “Glutathione metabolism” by heat stress, such as HSP70, GSTO1, PDIA4. After hypoxic stress, “Notch signaling pathway” and metabolism-related pathways such as “Glycerolipid metabolism”, “Pyruvate metabolism” were significantly enriched. Exposure to combined stress resulted in a two-factor additive effect at the transcriptome level and have a more extensive impact on the immune correlated pathways in S. intermedius than single stress, the expression of related immune genes (C3, C5, and AIFM2) were up-regulated. Quantitative real-time PCR (qRT-PCR) analysis of the expression of 18 DEGs confirmed the RNA-Seq results. Observations in the present study will improve the understanding of the molecular mechanism of S. intermedius in response to multi-causal environmental stress.

Mechanical defensive adaptations of three Mediterranean sea urchin species.

In the Mediterranean, Paracentrotus lividus and Sphaerechinus granularis are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid Diadema setosum, which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea. This region serves as a gateway for invasive species to the Mediterranean Sea. Crushing test was conducted on live individuals, while 3‐point bending test was used to estimate spine stiffness. Porosity and mineralogy of the test and spine, thickness of the test, and breaking length of the spine were measured and compared, while the microstructural architecture was also determined. The test of S. granularis was the most robust (194.35 ± 59.59 N), while the spines of D. setosum (4.76 ± 2.13 GPa) exhibited highest flexibility. Increased porosity and thickness of the test were related to increased robustness, whereas increased flexibility of the spine was attributed to high porosity, indicating that porosity in the skeleton plays a key role in preventing fracture. The spines of S. granularis exhibited highest length after fracture % (71.54 ± 5.5%). D. setosum exhibited higher values of Mg concentration in the test (10%) compared with the spines (4%). For the first time, the mineralogy of an invasive species is compared with its native counterpart, while a comparison of the mechanical properties of different species of the same ecosystem also takes place. This study highlights different ways, in which sea urchins utilize their skeleton and showcases the ecological significance of these adaptations, one of which is the different ways of utilization of the skeleton for defensive purposes, while the other is the ability of D. setosum to decrease the Mg % of its skeleton degrading its mechanical properties, without compromising its defense, by depending on venomous bearing spines. This enables this species to occupy not only tropical habitats, where it is indigenous, but also temperate like the eastern Mediterranean, which it has recently invaded.

Current Progress in Lipidomics of Marine Invertebrates.

Marine invertebrates are a paraphyletic group that comprises more than 90% of all marine animal species. Lipids form the structural basis of cell membranes, are utilized as an energy reserve by all marine invertebrates, and are, therefore, considered important indicators of their ecology and biochemistry. The nutritional value of commercial invertebrates directly depends on their lipid composition. The lipid classes and fatty acids of marine invertebrates have been studied in detail, but data on their lipidomes (the profiles of all lipid molecules) remain very limited. To date, lipidomes or their parts are known only for a few species of mollusks, coral polyps, ascidians, jellyfish, sea anemones, sponges, sea stars, sea urchins, sea cucumbers, crabs, copepods, shrimp, and squid. This paper reviews various features of the lipid molecular species of these animals. The results of the application of the lipidomic approach in ecology, embryology, physiology, lipid biosynthesis, and in studies on the nutritional value of marine invertebrates are also discussed. The possible applications of lipidomics in the study of marine invertebrates are considered.

First Record and Massive Spread of Tropical Long-Spined Sea Urchin Diadema antillarum in the Mediterranean Sea (Syrian Coast)

The biological structure of the Syrian marine environment still shows a rapid and steady increase in the number of warm water species, many of which have become dominant and invasive. In the latest field data during 2020-2021, the presence of the black sea urchin Diadema antillarum (Philippi, 1845) was recorded for the first time in several locations in Latakia and Ras al-Bassit coast, and its massive spread at depths of 5-8 m, accompanied by invasive species of macroalgae, sponges, crustaceans and mollusks.. It is noteworthy that this species is one of the most widespread and important species of sea urchins in some tropical areas, and this is the first record in the Mediterranean Sea and the Syrian coast It is important as it prey on macroalgae and has an effective role in the health of some of the most important areas of biodiversity in the world.

Algal supplements in formulated feeds: Effects on sea urchin gonad quality

In the effort to increase the commercial value of urchin gonads produced via roe enhancement aquaculture, a variety of formulated feeds have been tested to increase gonad production and improve colour and taste. The addition of dried algal supplements to formulated feeds can further enhance gonad quality, but the level of improvement is highly variable and algae or urchin species dependent. Here we test whether the inclusion of three types of dried algal supplements (Sargassum fallax, Ecklonia radiata, and Durvillea potatorum) added to a pellet-based formulated aquaculture feed could further enhance the colour, taste and gonad quality in the temperate urchin Heliocidaris erythrogramma during two 12 wk. gonad enhancement periods, April to June, and July to September. All feed types resulted in urchins with gonad indices (GIs) of commercially acceptable quantities (Apr-Jun: GI = 14.6%, Jul-Sep: GI = 14.9%). The proportion of marketable gonads (A + B grades) was significantly higher during the Jul-Sep (87.9 ± 3%, mean ± SE) compared to the Apr-Jun (76.6 ± 3%, mean ± SE) enhancement period, however, algal supplement type did not improve gonad colour, taste, or the proportion of marketable gonads when compared to the control feed. We conclude that additional algal supplements may fail to further improve roe quality if the base formulated feed used to roe enhance is already of a standard that produces a sufficient proportion (>70%) of marketable roe.

De novo Assembly and Analysis of Tissue-Specific Transcriptomes of the Edible Red Sea Urchin Loxechinus albus Using RNA-Seq.

Simple SummaryEdible red sea urchin (Loxechinus albus) is an endemic species of echinoderm distributed along the Chilean coasts. This resource has been overexploited in recent years, depleting their natural populations. At present, there are few reported gene sequences available in public databases, restricting the molecular studies associated with aquaculture for this species. The aim of this study was to present the first annotated reference transcriptome of L. albus using NGS technologies and the differential expression transcripts analysis of the evaluated tissues. The transcriptome data obtained in this study will serve as a reference for future molecular research in the edible red sea urchin and other sea urchin species.Edible red sea urchin (Loxechinus albus) is an endemic echinoderm species of the Chilean coasts. The worldwide demand for high-quality gonads of this species has addressed the depletion of its natural populations. Studies on this sea urchin are limited, and genomic information is almost nonexistent. Hence, generate a transcriptome is crucial information that will considerably enrich molecular data and promote future findings for the L. albus aquaculture. Here, we obtained transcriptomic data of the edible red sea urchin by Illumina platform. Total RNA was extracted from gonads, intestines, and coelomocytes of juvenile urchins, and samples were sequenced using MiSeq Illumina technology. A total of 91,119,300 paired-end reads were de novo assembled, 185,239 transcripts produced, and a reference transcriptome created with 38.8% GC content and an N50 of 1769 bp. Gene ontology analysis revealed notable differences in the expression profiles between gonads, intestines, and coelomocytes, allowing the detection of transcripts associated with specific biological processes and KEGG pathways. These data were validated using 12 candidate transcripts by real-time qPCR. This dataset will provide a valuable molecular resource for L. albus and other species of sea urchins.

Intensive exploitation of marine crabs and sea urchins during the middle holocene in the eastern Arabian peninsula offers new perspectives on ancient maritime adaptations

Maritime adaptation is a key component of the Neolithization process in Eastern Arabia. It is expressed by the development of diversified fishing techniques, the exploitation of hard marine animal materials (e.g., seashells, shark teeth, stingray's barbs, etc.) for both tools and personal adornments production, advanced seafaring, and colonization of offshore islands. Although a diet based mainly on the consumption of marine fish and mollusks, the importance of other seafood has been greatly underestimated in previous zooarchaeological studies. Large quantities of marine crabs (NISP = 10,619) and sea urchins (NISP = 2454) have been retrieved from newly excavated Neolithic sites in the United Arab Emirates. These data highlight local developments of interest for specific seafood and their intensive exploitation over several centuries of human occupation. This study focuses on methods for identifying the main edible marine crab and sea urchin species retrieved from archaeological sites in Eastern Arabia. Results from the Neolithic sites of Delma Island and the Umm al-Quwain lagoon are discussed.