The Kalibeng Formation of Sangiran Dome geological outcrop (Indonesia) in is an area where various fossils have been found, including ancient human fossils (Homo erectus), vertebrate fauna, and marine biota such as coral reefs. To date, the species diversity of fossil corals and sponges in Sangiran Dome and Indonesia, in general, is not widely known. The Sangiran stratigraphy is divided into several layers, with the lowest layer being the Kalibeng Formation, which was an ancient shallow sea, according to Brasseur et al. (2015). Further study can be conducted on the ancient corals and sponges’ in Sangiran to reveal the past environmental conditions, particularly during the Pleistocene period in the Sangiran Dome area. Fossilised corals and sponges with well-preserved conditions can serve as a basis for identifying various genera member of the Phylum Porifera and Cnidaria, using specific morphological characteristics for identification. The objective of this study is to determine the genus diversity also to define diagnostic characteristics, and habitat of corals and sponges’ fossils in the Plio-Pleistocene Period at Sangiran. The method used for identifying fossil samples was morphological comparison against type specimens and references. The results indicated that the identified corals and sponges were grouped into seven families that inhabits in the neritic zone. This study concludes that each coral genus (phylum Cnidaria) has distinctive corallite characteristics, while sponge genus (phylum Porifera) has distinctive spicules that are useful for identification.

The discovery of Physalia mikazuki sp. nov. from the temperate waters of Gamo Beach, Sendai Bay (Miyagi Prefecture) in the Tohoku (northeast) region of Japan, represents a significant addition to the taxonomic and ecological understanding of this genus. Morphological analysis reveals key diagnostic traits, distinguishing it from all known Physalia species. Phylogenetic analyses of the 16S rRNA gene and COI (cytochrome c oxidase subunit 1) regions further confirm its classification as a distinct species, forming a well-supported monophyletic clade separate from other Physalia species. Oceanographic data and Lagrangian particle trajectory simulations suggest that P. mikazuki may have dispersed northward via the recent 100 km northward extension of the Kuroshio Current (KE) in tandem with record-breaking sea surface temperature changes (SST) of more than 2°C in the Tohoku region between 2022 and 2024. Long-term monitoring confirmed no previous reports of Physalia at the type locality of Gamo Beach, Sendai City (Tohoku) prior to 2023, indicating a likely recent introduction. Molecular barcode sequences matching samples from both Pakistan and Mexico indicate a broad Indo-Pacific connectivity for the new species. The occurrence of P. mikazuki sp. nov. in the Tohoku region poses potential ecological and public health concerns, particularly due to its predation on fish larvae and risk of envenomation during beach recreation. This study underscores the importance of integrative experimental design combining taxonomy, molecular data, and oceanographic modeling to understand species range shifts and cryptic diversity in a changing ocean.

The evolutionary expansion of extracellular matrix (ECM) molecules has been crucial for the establishment of cell adhesion and the transition from unicellular to multicellular life. Members of the early diverging metazoan phylum Cnidaria offer an exceptionally rich perspective into the metazoan core adhesome and its original function in developmental and morphogenetic processes. Here, we present the ensemble of ECM proteins and associated factors for the starlet sea anemone Nematostella vectensis based on in silico prediction and quantitative proteomic analysis of decellularized mesoglea from different life stages. The integration of the matrisome with single-cell transcriptome atlases shows that gastrodermal cells are the primary producers of Nematostella's complex ECM, confirming the homology of the cnidarian inner cell layer with bilaterian mesoderm. The transition from larva to polyp is marked by an upregulation of metalloproteases and basement membrane components including all members of an unusually diversified SVEP1/Polydom family, suggesting massive epithelial remodeling. The enrichment of Wnt/PCP pathway factors during this process further indicates directed cell rearrangements as a key contributor to the polyp's morphogenesis. Mesoglea maturation in adult polyps involves wound response proteins indicating shared molecular patterns in growth and regeneration. Our study identifies conserved matrisomal networks that coordinate transitions in Nematostella's life history.

The evolutionary expansion of extracellular matrix (ECM) molecules has been crucial for the establishment of cell adhesion and the transition from unicellular to multicellular life. Members of the early diverging metazoan phylum Cnidaria offer an exceptionally rich perspective into the metazoan core adhesome and its original function in developmental and morphogenetic processes. Here, we present the ensemble of ECM proteins and associated factors for the starlet sea anemone Nematostella vectensis based on in silico prediction and quantitative proteomic analysis of decellularized mesoglea from different life stages. The integration of the matrisome with single-cell transcriptome atlases shows that gastrodermal cells are the primary producers of Nematostella’s complex ECM, confirming the homology of the cnidarian inner cell layer with bilaterian mesoderm. The transition from larva to polyp is marked by an upregulation of metalloproteases and basement membrane components including all members of an unusually diversified SVEP1/Polydom family, suggesting massive epithelial remodeling. The enrichment of Wnt/PCP pathway factors during this process further indicates directed cell rearrangements as a key contributor to the polyp’s morphogenesis. Mesoglea maturation in adult polyps involves wound response proteins indicating shared molecular patterns in growth and regeneration. Our study identifies conserved matrisomal networks that coordinate transitions in Nematostella’s life history.

Neuropeptides play a critical role in neurotransmission and organismal development. Members of the phylum Cnidaria, with a diffused nervous system, are one of the earliest divergent animals and might provide insights into the fundamentals of the emergence of neuronal communications. The neuropeptide diversity in Hydra (a cnidarian model) has been extensively studied using various strategies, each with certain limitations. Here, we have developed an in silico pipeline which identified both reported peptides and many new potential candidates. A comparative analysis within Cnidaria suggests a rapid divergence of neuropeptides which might be involved in complex behaviours. We identified new Hydra neuropeptides that belong to the RFamide and PRXamide families and a novel class of peptides lacking amidation (LW-peptides). A detailed expression and functional analysis of a new LW-peptide indicates its role in the longitudinal contraction of Hydra polyps. This study provides compelling evidence for the existence of intricate peptidergic communication in early neuronal circuits. The extensive diversity of neuropeptides within this phylum underscores their rapid evolutionary adaptability. This current pipeline also proves to be simple and adaptable to perform neuropeptide identification in other multicellular organisms.

IntroductionRapidly acting and highly effective management approaches are critically needed for potentially life-threatening and career-ending stings by box jellyfish (phylum Cnidaria, class Cubozoa) among underwater-operation warfighters working in austere environments. Cubozoan envenomation results in venom load- and time-dependent complex sequelae, including acute-phase hemolysis, cardiorespiratory collapse, hypovolemic shock, and death. Despite previously published studies demonstrating the failure of various generally advised, lay first-aid approaches (including fresh-water rinsing, ice-pack application, and skin scraping) to inhibit box jellyfish venom-induced hemolysis and tissue damage in vitro, ineffective and even deleterious management practices persist. In this report, we compared the efficacy of generally used first-aid measures and recently developed copper gluconate (CuGluc)-containing formulations in halting venom-associated tissue damage using a variety of assay systems, including an in vivo anesthetized piglet model.Materials and MethodsThe comparative efficacy of common first-aid approaches, including vinegar dousing, hot- and cold-pack applications, gasoline, topical 2-hydroxypropyl-β-cyclodextrin (HPβCD), and novel therapeutics, including CuGluc-containing formulations, was assessed using a variety of platforms, including in vitro hemolytic assays, live-tentacle sting tissue-model assays on blood agar or freshly excised porcine skin, and an in vivo piglet model.ResultsSequential topical application of CuGluc-containing formulations (StingNoMore Spray followed by StingNoMore Cream) surpassed all other management approaches in reducing sting-induced hemolysis and tissue damage in all in vitro and in vivo assay platforms. To a lesser extent, vinegar dousing of the sting site, followed by application of heat (42–45 °C) by hot pack for 45 minutes, also directly and irreversibly inhibited venom activity. Saltwater rinse and ice pack were totally ineffective and led to more tissue damage than the untreated sting itself.ConclusionsCompared to all other tested first-aid approaches, CuGluc-containing topical spray and cream formulations resulted in far less cubozoan venom-associated tissue damage and represents the most effective method to manage box jellyfish stings.

Coastal areas have high ecosystem productivity and are characterized by abundant fish species and coral reefs. However, these ecosystems are vulnerable to environmental pressures caused by human activities and natural dynamics. Coral reefs, consisting of organisms from the class Anthozoa within the order Scleractinia, which produce calcium carbonate structures, are key indicators of coastal ecosystem health. Coral reefs share biological characteristics with soft corals, hydras, and sea anemones as part of the phylum Cnidaria. Their existence is highly sensitive to environmental changes, whether natural or anthropogenic. In Indonesia, coral reef conditions have experienced significant degradation, with 36.18% in the damaged condition, only 6.56% categorized as very good, and 22.96% as good. The remaining 34.3% fall under the poor category, particularly around Karimunjawa and Kemujan Islands. Accurate data-based monitoring and management are essential for conserving these ecosystems. One method used to map and analyze coral reef distribution is the Lyzenga algorithm, which can distinguish shallow-water characteristics from coral reef habitats using satellite imagery. In this study, the Lyzenga algorithm was applied to SPOT 6 imagery for the Karimunjawa and Kemujan regions, covering an area of 8.46 km². The results showed that live coral reefs cover approximately 46% of the area, while dead coral reefs account for 56%, indicating a level of degradation that requires further attention in conservation and ecosystem recovery strategies. This study highlights the critical state of coral reefs in Indonesia, particularly in the Karimunjawa and Kemujan regions, emphasizing the necessity for conservation efforts driven by precise monitoring techniques such as the Lyzenga algorithm.

Abstract The genus Aurelia (Phylum Cnidaria, Class Scyphozoa) is characterized by a convoluted taxonomic history due to the presence of cryptic species and high morphological plasticity. We describe a new species of Aurelia (Cnidaria, Scyphozoa) collected from offshore Gulf of Mexico. Two adult specimens, including one carrying planulae, were collected in July 2017, approximately 80 miles offshore in the Northern Central Gulf of Mexico. Molecular analysis showed its specific distinction from other Aurelia species. Polyps were obtained from planulae, and a culture of this species was established in the laboratory. Asexual reproduction, such as budding, was observed. Strobilation was induced, and ephyrae were morphologically analyzed and reared under laboratory conditions. We report relevant morphological characters of the polyp, ephyra, and medusa, compare them to those of other Aurelia species, and confirm the uniqueness of Aurelia profunda.

Many cnidarian animals possess multiple opsins, including a type known as cnidopsin, which is found throughout the phylum Cnidaria and is divided into several subgroups. Previous studies have suggested that cnidopsins from jellyfish and coral can light-dependently elevate intracellular cAMP levels, likely via activation of Gs-type G protein in cultured cells. However, their spectroscopic properties remain largely unclear, with the exception of jellyfish opsins. We recently identified eight cnidopsins from the reef-building coral Acropora tenuis and showed that they phylogenetically belong to different cnidopsin subgroups. Here, we spectroscopically analyzed one A. tenuis cnidopsin from each subgroup as a representative. We successfully obtained the absorption spectrum of one purified cnidopsin and found that it was blue-sensitive, with an absorption maximum at ∼460 nm. Blue light irradiation (460 nm) resulted in a red-shifted absorption spectrum, while subsequent irradiation with orange light (> 560 nm) caused a blue-shift. The difference spectra of after versus before repeated irradiation with alternating blue and orange light produced mirror images, indicating a bistable nature. We also successfully observed the absorption spectra of one of two other cnidopsins belonging to the same subgroup as the blue-sensitive A. tenuis cnidopsin. The spectral changes suggested that it was also a bistable opsin. These results suggest that these two coral cnidopsins, which belong to the same cnidopsin subgroup, are bistable-unlike jellyfish opsins, which belong to a different cnidopsin subgroup.

A moon jellyfish (Aurelia aurita) is a representative of the phylum Cnidaria, commonly found in the northern seas of the globe. The regenerative abilities of cnidarians have recently been associated with extracellular vesicles (EVs) secreted by these organisms. In this study, a method for the isolation of EVs from the oral arms of A. aurita is presented. The methodology includes differential centrifugation, size-exclusion chromatography, and ultrafiltration. The isolates were characterized with tunable resistive pulse sensing, cryogenic transmission electron microscopy, capillary electrophoresis (CE), and electrophoretic light scattering (ELS). Small (<150 nm in diameter) EVs were abundant in the isolates. The EVs were found to carry nucleic acids, indicating their role in signaling. Additionally, the difference in zeta potential values measured with ELS and CE indicates high glycation in the vesicles analyzed. Although the method developed was effective in isolating EVs from small sample volumes (0.5 mL), the EV yield was insufficient for omics analysis. Thus, the scaling up of the isolation process is required for comprehensive biochemical analysis and biological activity assessment in A. aurita-derived EVs.

Anthropogenic pollution is driving an increase in the frequency and severity of seawater hypoxic events in coastal marine ecosystems. Although hypoxia decreases physiological performance in coral and sea anemone (phylum Cnidaria) larvae, the underlying cellular mechanisms remain unexplored. Here, larvae of the reef-building corals Galaxea fascicularis and Porites astreoides and the estuarine sea anemone Nematostella vectensis were exposed to normoxia or a simulated hypoxic event (6 h at <2 mg dissolved O2 l-1), and their metabolomic response was quantified at the end of the exposure period using targeted liquid chromatography-mass spectrometry. Baseline metabolite profiles (81 amino acids, acylcarnitines, organic acids and nucleotides) were broadly divergent between the three species, with the corals displaying a reliance on nitrogen cycling through amino acid metabolism, whereas N. vectensis relied on nucleotide metabolism. By contrast, several changes in metabolite abundances under hypoxia were shared (e.g. increases in lactate) and suggest the upregulation of glycolysis, lactic acid fermentation and fatty acid β-oxidation as conserved mechanisms for energy production under hypoxia. Changes in these pathways were correlated with adverse physiological outcomes, including conserved declines in swimming behavior and growth. Importantly, life history traits affecting metabolism influenced hypoxia responses. For example, P. astreoides larvae, which possess algal endosymbionts, displayed the least severe metabolic response to hypoxia among these species, possibly owing to symbiont resources. Overall, these findings demonstrate that hypoxia disrupts metabolic performance in coral and sea anemone larvae through conserved and divergent pathways, emphasizing the need to limit drivers of ocean deoxygenation.

ABSTRACT Conulariids are extinct benthic marine cnidarians whose affinity with the phylum Cnidaria is well established. This group was studied in the Paraná basin in the early 20th century and the early 21st century. However, significant advances in the taxonomy of the group over the past decades, combined with the analysis of numerous new specimens previously unaddressed in the literature, have highlighted the need for a taxonomic revision of the group within the basin. This revision aims to clarify the actual diversity and geographic distribution of these organisms. Five species were identified in the basin: Conularia quichua Ulrich (in Steinmann & Doderlein, 1890), Paraconularia africana (Sharpe, 1856), Paraconularia ulrichana (Clarke, 1913), Reticulaconularia caetensis Guedes et al. 2023, and Reticulaconularia baini (Ulrich, 1892). New descriptions of P. ulrichana, R. baini and R. caetensis were provided, with the identification of previously unreported features in their thecae. The first formal description of R. baini in the Paraná Basin was made in the literature. Additionally, a unique feature in the theca of the species Conularia quichua was observed after intense weathering. This distinctive characteristic of Conularia quichua can assist in the taxonomic identification of heavily weathered specimens that have lost their diagnostic morphological features.

Coral reefs are one of the coastal ecosystems that have an important role as a place to look for food, shelter, and breeding grounds for other biota. Corals are invertebrates that are included in the phylum Coelenterata (hollow animal) or Cnidaria. Whereas coral reefs are a collection of millions of polyps. Natural phenomena and various anthropogenic activities threaten the health and existence of coral reefs in the waters of Bunaken National Park, Popareng Village. The purpose of this study is to determine the condition of coral reefs in the waters of Bunaken National Park, Popareng Village. CPCe (Coral Points Count with Excel extension) is used to observe or monitor reef ecosystems. The photo that will be taken using the Underwater Photo Transect (UPT) method from 3 observation stations in Popareng’s Waters will be used as this research database. The photos consist of 50 slides for each station. Photos were taken to represent Popareng’s waters. Each photo was processed in the CPCe by using 30 random points. The condition of the coral reefs in Popareng was moderate. The results of coral reef health conditions at three stations in Popareng reveal poor (21.67%) in station 1; good (54.53%) in station 2; and moderate (32.37%) in station 3.

Sanderia malayensis is a species from the phylum Cnidaria, class Scyphozoa, and order Semaeostomeae, found in tropical waters, including the Red Sea, Indian Ocean, and Malaysian waters. Its distribution extends to the waters of Australia and Japan. This study aimed to evaluate the effects of salinity on the growth and survival of Sanderia malayensis ephyrae and to determine its optimal salinity range. The experimental design included two temperature conditions (20 °C and 24 °C) and three salinity levels (21 PSU, 24 PSU, and 27 PSU). The results indicated that growth and feeding abilities were significantly higher in 24 PSU and 27 PSU environments compared to 21 PSU, with the best results observed at both temperatures. Survival rates were higher at 24 PSU (20 °C: 90%, 24 °C: 79%) and 27 PSU (20 °C: 87%, 24 °C: 86%) compared to 21 PSU (20 °C: 70%, 24 °C: 55%). Despite lower survival at 21 PSU, the species demonstrated wide environmental adaptability. These findings suggest that Sanderia malayensis ephyrae are highly adaptable to varying salinity conditions, indicating the potential for the species to expand its distribution into South Korean waters and other East Asian marine ecosystems, including China and Japan, which are impacted by climate change.

Phylum Cnidaria occupies an early branching position in the evolution of eukaryotes, establishing both close and distant relationships with most other eukaryotic metazoans. Budding encompasses the complete processes of cell proliferation, differentiation, and tissue regeneration, making it an ideal model for exploring various aspects of cellular function and evolution. Additionally, budding serves as the primary reproductive method for increasing the cnidarian population. This asexual reproductive phase is critical for managing and mitigating cnidarian outbreaks. This paper summarizes the common factors influencing budding, the signaling pathways involved and their associated functions, and the methodologies employed in relevant research, providing a theoretical foundation for the prevention and control of cnidarian populations.

Myxozoans are obligate endoparasites that belong to the phylum Cnidaria. Compared with their closest free-living relatives, they have evolved highly simplified body plans and reduced genomes. Kudoa iwatai, for example, has lost upwards of two-thirds of genes thought to have been present in its ancestors. However, little is known about myxozoan genome architecture because of a lack of sufficiently contiguous genome assemblies. This work presents two new Kudoa genomes, one of them near-chromosomal, built entirely from low-coverage long reads from infected fish samples. The results illustrate the potential of using unsupervised learning methods to disentangle sequences from different sources, and facilitate producing genomes from undersampled taxa. Extracting distinct components of chromatin interaction networks allows scaffolds from mixed samples to be assigned to their source genomes. Meanwhile, low-dimensional embeddings of read composition permit targeted assembly of potential parasite reads. Despite drastic changes in genome architecture in the lineage leading to Kudoa and considerable sequence divergence between the two genomes, gene order is highly conserved. Although parasitic cnidarians show rapid protein evolution compared with their free-living relatives, there is limited evidence of less efficient selection. While deleterious substitutions may become fixed at a higher rate, large evolutionary distances between species make robustly analyzing patterns of molecular evolution challenging. These observations highlight the importance of filling in taxonomic gaps, to allow a comprehensive assessment of the impacts of parasitism on genome evolution.

All the members of the phylum Cnidaria are characterized by the production of venom in specialized structures, the nematocysts. Venom of jellyfish (Medusozoa) and sea anemones (Anthozoa) has been investigated since the 1970s, revealing a remarkable molecular diversity. Specifically, sea anemones harbour a rich repertoire of neurotoxic peptides, some of which have been developed in drug leads. However, venoms of the vast majority of Anthozoa species remain uncharacterized, particularly in the class Octocorallia. To fill this gap, we applied a proteo-transcriptomic approach to investigate venom composition in Eunicella singularis, a gorgonian species common in Mediterranean hard-bottom benthic communities. Our results highlighted the peculiarities of the venom of E. singularis with respect to sea anemones, which is reflected in the presence of several toxins with novel folds, worthy of functional characterization. A comparative genomic survey across the octocoral radiation allowed us to generalize these findings and provided insights into the evolutionary history, molecular diversification patterns and putative adaptive roles of venom toxins. A comparison of whole-body and nematocyst proteomes revealed the presence of different cytolytic toxins inside and outside the nematocysts. Two instances of differential maturation patterns of toxin precursors were also identified, highlighting the intricate regulatory pathways underlying toxin expression.

Cells are constantly exposed to mechanical forces. These stimuli must be detected and transduced to maintain homeostasis. Due that reason, mechano-sensory systems (MS) are present in all the organisms to generate appropriate responses. Piezo proteins are a recently discovered family of mechano-gated ion channels that responds to mechanical changes of the plasma membrane, allowing the influx of cations, mainly Ca2+. Piezo MS channels are widely represented in Metazoa, acting in several physiological systems. Hydra sp. is a freshwater member of the phylum Cnidaria which is assumed as the sister group of Bilateria. Despite the existence of Piezo channels in Hydra is known, their physiological roles remain unknown. In this work we delve into the physiological relevance of MS Piezo in responses associated to mechanical stimuli in Hydra sp. We analysed the effects of Jedi1 (a specific agonist of Piezo1) on the contractile behaviours, and cnidocyst discharge, and compared them with responses caused by natural stimuli. The results show that the activation of Piezo channels increases the contractile behaviour, stimulating the occurrence of contraction burst, a sudden kind of retraction observed in response to touch and osmotic stress. Cnidocyst discharge was also induced by Jedi1, resembling the response caused by the contact of the prey. The effects of both Jedi1 and natural stimuli were avoided in the presence of the inhibitor of MS channels GdCl3. The bioinformatic analysis shows that the protein predicted by Hydra genome has the characteristic motifs of Piezo proteins. These results are consistent with the existence of Piezo channels in Hydra, unveiling their physiological roles. Because of the relevance of Piezo channels in several pathological conditions and the high level of conservation in metazoans, Hydra could provide a significative experimental model to assay biological and pharmacological issues.

Mitochondrial tRNA gene loss and cytosolic tRNA import are two common phenomena in mitochondrial biology, but their importance is often under-appreciated in animals. This is because the mitochondrial DNA (mtDNA) of most bilaterally symmetrical animals (Bilateria) encodes a complete set of tRNAs required for mitochondrial translation. By contrast, the mtDNA of nonbilaterian animals (phyla Cnidaria, Ctenophora, Porifera, and Placozoa) often contains a reduced set of tRNA genes, necessitating tRNA import from the cytosol. Interestingly, in many nonbilaterian lineages, tRNA gene content appears to be set early in evolution and remains conserved thereafter. Here, we report that Clade B of haplosclerid sponges (CBHS) represents an exception to this pattern, displaying considerable variation in tRNA gene content even among relatively closely related species. We determined mt-genome sequences for eight CBHS species and analyzed them in conjunction with six previously available sequences. Additionally, we sequenced mt-genomes for two species of haplosclerid sponges outside the CBHS and used them with eight previously available sequences as outgroups. We found that tRNA gene content varied widely within CBHS, ranging from three in an undescribed Haliclona species (Haliclona sp. TLT785) to 25 in Xestospongia muta and X. testudinaria. Furthermore, we found that all CBHS species outside the genus Xestospongia lacked the atp9 gene, with some also lacking atp8. Analysis of nuclear sequences from Niphates digitalis revealed that both atp8 and atp9 had transferred to the nuclear genome, while the absence of mt-tRNA genes indicated their genuine loss. We argue that CBHS can serve as a valuable system for studying mt-tRNA gene loss, mitochondrial import of cytosolic tRNAs, and the impact of these processes on mitochondrial evolution.

This research was conducted in January 2024 on Kasiak Island, Pariaman City, West Sumatra Province. This research aims to identify nematocytes found in the body tissue of the Acropora formosa coral. The method used in this research is a survey method with direct observation and sampling in the field. Determination of the type of nematocytes from A. formosa coral was carried out using an Olympus microscope with an objective lens magnification of 10X40 (400) at the Marine Biology Laboratory, Faculty of Fisheries and Marine, Universitas Riau. Of the 25 main types of nematocytes known in the phylum Cnidaria, one type was found in this species. The results of the research show that there is a type of Holotrichous isohiza in the A. formosa coral. This type of nematocyte is thought to be used to attack and kill prey