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The study documents the presence of the box jellyfish Carybdea marsupialis in the waters of the Ionian Sea in Italy, which constitutes important data for the knowledge of new areal distribution of this species along the coasts of the Mediterranean basin. Carybdea marsupialis belongs to the phylum Cnidaria, class Cubozoa, and is known for its stinging and potentially dangerous stings for humans, making it a species of significant ecological and health interest. The species has previously been observed in other areas of the western Mediterranean, but the report in the Ionian Sea represents an eastward expansion of its distribution range. Results suggest that climate change, influenced by global warming processes and anthropogenic activities, facilitated the expansion of this species into the rest of the Mediterranean Sea. The work highlights the importance of continuous monitoring of indigenous and non-indigenous species and calls for international cooperation to manage any ecological impacts linked to the spread of these marine species.

Challenges associated with cubozoan jellyfish detection and the limitations of current detection techniques limit the ability of scientists to fill critical knowledge gaps surrounding their ecology. Environmental DNA (eDNA), however, has proven useful as an ecological survey tool to detect and study these deadly jellyfish. This study aimed to leverage the power of eDNA to detect and explore the distribution of the Australian box jellyfish (Chironex fleckeri), encompassing both its medusae and polyp life history stages, within an open coastal bay (Horseshoe Bay) of Magnetic Island, Queensland, Australia. Our investigation focused on a hypothesis concerning the source locations of the jellyfish within Horseshoe Bay and, through a comparison of both life history stage distributions, aimed to determine potential population stock boundaries. eDNA results aligned with the predicted nearshore distribution of medusae. Further, the elusive benthic polyp stage was also detected. These findings confirmed Horseshoe Bay as a source location of the jellyfish. Moreover, our evidence supported a model that the area likely represents a population stock of the species. This adds to growing evidence suggesting some cubozoan jellyfish have population stocks of small spatial scales in both open and relatively closed ecosystems such as estuaries. In conclusion, this study serves as a notable example of eDNA’s ability to resolve critical knowledge gaps surrounding cubozoan ecology and to enhance the management ability of these deadly jellyfish to reduce envenomations.

Challenges associated with cubozoan jellyfish detection and the limitations of current detection techniques limit the ability of scientists to fill critical knowledge gaps surrounding their ecology. Environmental DNA (eDNA), however, has proven useful as an ecological survey tool to detect and study these deadly jellyfish. This study aimed to leverage the power of eDNA to detect and explore the distribution of the Australian box jellyfish (Chironex fleckeri), encompassing both its medusae and polyp life history stages, within an open coastal bay (Horseshoe Bay) of Magnetic Island, Queensland, Australia. Our investigation focused on a hypothesis concerning the source locations of the jellyfish within Horseshoe Bay and, through a comparison of both life history stage distributions, aimed to determine potential population stock boundaries. eDNA results aligned with the predicted nearshore distribution of medusae. Further, the elusive benthic polyp stage was also detected. These findings confirmed Horseshoe Bay as a source location of the jellyfish. Moreover, our evidence supported a model that the area likely represents a population stock of the species. This adds to growing evidence suggesting some cubozoan jellyfish have population stocks of small spatial scales in both open and relatively closed ecosystems such as estuaries. In conclusion, this study serves as a notable example of eDNA's ability to resolve critical knowledge gaps surrounding cubozoan ecology and to enhance the management ability of these deadly jellyfish to reduce envenomations. [ABSTRACT FROM AUTHOR]

In Mexico, the study of the class Cubozoa has been limited. Most studies have addressed ecological or toxicological issues. In Mexican territory, Carybdea marsupialis (Linnaeus, 1758) has been historically reported off the Caribbean and the southern Gulf of Mexico. This species, however, was recently established as the Mediterranean type species, while C. xaymacana Conant, 1897 was established as that of the Caribbean region. Despite this, C. xaymacana is not reported in the last checklists of Mexican medusozoans. Thus, the taxonomic identity of Mexican populations remains uncertain. Herein, we report the occurrence of C. xaymacana off Mexican coasts and provide the first morphological description for Mexican populations. Specimens were collected in the northeast of the Mexican Caribbean. The species was defined based on the shape, structure, and features of the phacellae, pedalia, and velarial canals. This record has important implications for the creation of jellyfish stings protocols since there exist reports of the Irukandji syndrome occurring in the Caribbean in adjacent zones to the study area, and this species has been associated with this syndrome. The present study evidences the importance of conducting more taxonomical research on the cubozoans from Mexico in order to clarify the identity of other possible misidentified species and make new records in the area, which would contribute to having a clearer picture of the cubozoan diversity in Mexico. [ABSTRACT FROM AUTHOR]

Medusozoans are diverse in species number (4100) and life stages and are of ecological and social importance worldwide. However, studies of medusozoans in the Mexican Pacific (MP) are limited and scattered. Given that its maritime (2,320,380 km2) and coastal (7828 km) regions are the most extensive in Mexico, as well as its geomorphological and ecosystem complexity, the medusozoan fauna of the MP needs better documentation. To that end, this work summarises medusozoan diversity data of the MP based on a review of refereed publications (1897–2023) and the examination of recently collected specimens, field observations, and photographs (2015–2022). Information gathered from the literature search and the collections was compiled into an annotated list of species. As a result, 423 accepted medusozoan species were found in the MP, corresponding to 10% of the 4100 medusozoan species known worldwide. This study highlights three important decades of published work: taxonomic works in the 1930s, ecological works in the 1980s, and recognition of biodiversity under multidisciplinary works in the 2010s. Of the taxa collected in the present work, Cirrholovenia sp., Linuche sp., and Monotheca flexuosa are new records for the MP. Furthermore, Hydrocoryne sp. and Coryne pusilla are new records for the Gulf of California. [ABSTRACT FROM AUTHOR]

Jellyfish stings can result in local tissue damage and systemic pathophysiological sequelae. Despite constant occurrences of jellyfish stings in oceans throughout the world, the toxinological assessment of these jellyfish envenomations has not been adequately reported in quantitative as well as in qualitative measurements. Herein, we have examined and compared the in vivo toxic effects and pathophysiologic alterations using experimental animal models for two representative stinging jellyfish classes, i.e., Cubozoa and Scyphozoa. For this study, mice were administered with venom extracts of either Carybdea brevipedalia (Cnidaria: Cubozoa) or Nemopilema nomurai (Cnidaria: Scyphozoa). From the intraperitoneal (IP) administration study, the median lethal doses leading to the deaths of mice 24 h post-treatment after (LD50) for C. brevipedalia venom (CbV) and N. nomurai venom (NnV) were 0.905 and 4.4697 mg/kg, respectively. The acute toxicity (i.e., lethality) of CbV was much higher with a significantly accelerated time to death value compared with those of NnV. The edematogenic activity induced by CbV was considerably (83.57/25 = 3.343-fold) greater than NnV. For the evaluation of their dermal toxicities, the epidermis, dermis, subcutaneous tissues, and skeletal muscles were evaluated toxinologically/histopathologically following the intradermal administration of the venoms. The minimal hemorrhagic doses (MHD) of the venoms were found to be 55.6 and 83.4 μg/mouse for CbV and NnV, respectively. Furthermore, the CbV injection resulted in extensive alterations of mouse dermal tissues, including severe edema, and hemorrhagic/necrotic lesions, with the minimum necrotizing dose (MND) of 95.42 µg/kg body weight. The skin damaging effects of CbV appeared to be considerably greater, compared with those of NnV (MND = 177.99 µg/kg). The present results indicate that the toxicities and pathophysiologic effects of jellyfish venom extracts may vary from species to species. As predicted from the previous reports on these jellyfish envenomations, the crude venom extracts of C. brevipedalia exhibit much more potent toxicity than that of N. nomurai in the present study. These observations may contribute to our understanding of the toxicities of jellyfish venoms, as well as their mode of toxinological actions, which might be helpful for establishing the therapeutic strategies of jellyfish stings. [ABSTRACT FROM AUTHOR]

Cubozoan jellyfish pose a risk of envenomation to humans and a threat to many businesses, yet crucial gaps exist in determining threats to stakeholders and understanding their ecology. Environmental DNA (eDNA) provides a cost-effective method for detection that is less labour intensive and provides a higher probability of detection. The objective of this study was to develop, optimise and trial the use of eDNA to detect the Australian box jellyfish, Chironex fleckeri. This species was the focus of this study as it is known to have the strongest venom of any cubozoan; it is responsible for more than 200 recorded deaths in the Indo-Pacific region. Further, its ecology is poorly known. Herein, a specific and sensitive probe-based assay, multiplexed with an endogenous control assay, was developed, and successfully utilised to detect the deadly jellyfish species and differentiate them from closely related taxa. A rapid eDNA decay rate of greater than 99% within 27 h was found with no detectable influence from temperature. The robustness of the technique indicates that it will be of high utility for detection and to address knowledge gaps in the ecology of C. fleckeri; further, it has broad applicability to other types of zooplankton. [ABSTRACT FROM AUTHOR]

Jellyfish (Cnidaria and Ctenophora) are an essential component of marine ecosystems and represent a potential effect, positive or negative, for several economic activities. Jellyfish blooms and non-indigenous species (NIS) introduction can shift ecological community structure and energy transfer. Despite their importance in ecosystem function and services, knowledge of jellyfish fauna diversity and phenology are largely lacking for the southern Mediterranean Sea. Here, we present an overview of the current state of jellyfish biodiversity in Tunisia. Based on a comprehensive literature survey, historical records and unpublished data, 66 jellyfish species, including 11 non-indigenous species, have been recorded in Tunisia between 1994 and 2020. Additionally, based on field surveys and a citizen science sighting program between 2004 and 2020, we present data on the spatial distribution of 13 conspicuous jellyfish taxa and the phenology of the eight most frequently detected species (Aurelia solida , Cotylorhiza tuberculata, Pelagia noctiluca , Phyllorhiza punctata , Rhizostoma pulmo , Rhopilema nomadica , Olindias muelleri and Velella velella) in Tunisian two ecoregions, the Western Mediterranean and the Tunisian Plateau. The 17 year survey showed a shift in R. pulmo , A. solida and P. noctiluca phenology. Additionally, citizen science revealed an increase in the spatial range of P. punctata (NIS) and the distinct phenologies of populations in the two ecoregions. [ABSTRACT FROM AUTHOR]

Cubomedusae, or box jellyfish, have a complex visual system comprising 24 eyes of four types. Like other cnidarians, their photoreceptor cells are ciliary in morphology, and a range of different techniques together show that at least two of the eye types--the image-forming upper and lower lens eyes--express opsin as the photopigment. The photoreceptors of these two eye types express the same opsin (Tc LEO), which belongs to the cnidarian-specific clade cnidops. Interestingly, molecular work has found a high number of opsin genes in box jellyfish, especially in the Caribbean species Tripedalia cystophora, most of which are of unknown function. In the current study, we raised antibodies against three out of five opsins identified from transcriptomic data from T. cystophora and used themtomap the expression patterns. These expression patterns suggest one opsin as the photopigment in the slit eyes and another as a putative photoisomerase found in photoreceptors of all four eyes types. The last antibody stained nerve-like cells in the tentacles, in connection with nematocytes, and the radial nerve, in connection with the gonads. This is the first time photopigment expression has been localized to the outer segments of the photoreceptors in a cnidarian ocellus (simple eye). The potential presence of a photoisomerase could be another interesting convergence between box jellyfish and vertebrate photoreceptors, but it awaits final experimental proof. [ABSTRACT FROM AUTHOR]

Cubomedusae, or box jellyfish, have a complex visual system comprising 24 eyes of four types. Like other cnidarians, their photoreceptor cells are ciliary in morphology, and a range of different techniques together show that at least two of the eye types—the image-forming upper and lower lens eyes—express opsin as the photopigment. The photoreceptors of these two eye types express the same opsin (Tc LEO), which belongs to the cnidarian-specific clade cnidops. Interestingly, molecular work has found a high number of opsin genes in box jellyfish, especially in the Caribbean species Tripedalia cystophora, most of which are of unknown function. In the current study, we raised antibodies against three out of five opsins identified from transcriptomic data from T. cystophora and used them to map the expression patterns. These expression patterns suggest one opsin as the photopigment in the slit eyes and another as a putative photoisomerase found in photoreceptors of all four eyes types. The last antibody stained nerve-like cells in the tentacles, in connection with nematocytes, and the radial nerve, in connection with the gonads. This is the first time photopigment expression has been localized to the outer segments of the photoreceptors in a cnidarian ocellus (simple eye). The potential presence of a photoisomerase could be another interesting convergence between box jellyfish and vertebrate photoreceptors, but it awaits final experimental proof.

Cubozoan jellyfish pose a risk of envenomation to humans and a threat to many businesses, yet crucial gaps exist in determining threats to stakeholders and understanding their ecology. Environmental DNA (eDNA) provides a cost-effective method for detection that is less labour intensive and provides a higher probability of detection. The objective of this study was to develop, optimise and trial the use of eDNA to detect the Australian box jellyfish, Chironex fleckeri. This species was the focus of this study as it is known to have the strongest venom of any cubozoan; it is responsible for more than 200 recorded deaths in the Indo-Pacific region. Further, its ecology is poorly known. Herein, a specific and sensitive probe-based assay, multiplexed with an endogenous control assay, was developed, and successfully utilised to detect the deadly jellyfish species and differentiate them from closely related taxa. A rapid eDNA decay rate of greater than 99% within 27 h was found with no detectable influence from temperature. The robustness of the technique indicates that it will be of high utility for detection and to address knowledge gaps in the ecology of C. fleckeri; further, it has broad applicability to other types of zooplankton.

Human interaction with marine creatures holds both positive and negative dimensions. Coastal communities benefit from marine environments, relying on them for sustenance and livelihoods. Fishing activities support economies, and marine biodiversity contributes to overall ecosystem health. However, challenges like overfishing, habitat destruction, and pollution pose threats to both marine life and human communities. Recently, there has been widespread concern regarding the potential increase in jellyfish populations across global marine ecosystems, attributed mainly to environmental factors such as climate drivers and anthropogenic forces, or their complex interactions. Encounters with hazardous marine species, such as box jellyfish, exemplify the dangers associated with coastal activities. Unintended interactions may lead to stings, injuries, and even fatalities, necessitating proactive measures and advanced technologies. This study addresses the inadequacies of existing measures in preventing box jellyfish incidents by introducing environmental DNA (eDNA) assays for detecting the deadly Chiropsoides buitendijki and focuses on developing qPCR and dPCR-based eDNA assays. Emphasising prevention over treatment, the study establishes a proactive system to assess C. buitendijki distribution across 63 tourist beaches in the Gulf of Thailand. Comparative analysis highlights the superior performance of dPCR over qPCR and traditional surveys. The dPCR experiment yielded positive results for all eDNA samples collected at sites where C. buitendijki had previously been identified. Remarkably, the eDNA testing also detected positive results in 16 additional sample locations where no physical specimens were collected, despite reported jellyfish stings at some of these sites. These findings underscore the precision and efficacy of the proposed eDNA detection technology in the early detection and assessment of box jellyfish distribution. This advancement therefore not only aids ecological research but also serves as a valuable tool for safeguarding public health, providing an early warning system for potential jellyfish encounters. Balancing positive human-marine interactions with effective risk mitigation strategies is crucial for sustainable coexistence, the preservation of marine ecosystems, and human well-being., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Jellyfish stings can result in local tissue damage and systemic pathophysiological sequelae. Despite constant occurrences of jellyfish stings in oceans throughout the world, the toxinological assessment of these jellyfish envenomations has not been adequately reported in quantitative as well as in qualitative measurements. Herein, we have examined and compared the in vivo toxic effects and pathophysiologic alterations using experimental animal models for two representative stinging jellyfish classes, i.e., Cubozoa and Scyphozoa. For this study, mice were administered with venom extracts of either Carybdea brevipedalia (Cnidaria: Cubozoa) or Nemopilema nomurai (Cnidaria: Scyphozoa). From the intraperitoneal (IP) administration study, the median lethal doses leading to the deaths of mice 24 h post-treatment after (LD50) for C. brevipedalia venom (CbV) and N. nomurai venom (NnV) were 0.905 and 4.4697 mg/kg, respectively. The acute toxicity (i.e., lethality) of CbV was much higher with a significantly accelerated time to death value compared with those of NnV. The edematogenic activity induced by CbV was considerably (83.57/25 = 3.343-fold) greater than NnV. For the evaluation of their dermal toxicities, the epidermis, dermis, subcutaneous tissues, and skeletal muscles were evaluated toxinologically/histopathologically following the intradermal administration of the venoms. The minimal hemorrhagic doses (MHD) of the venoms were found to be 55.6 and 83.4 μg/mouse for CbV and NnV, respectively. Furthermore, the CbV injection resulted in extensive alterations of mouse dermal tissues, including severe edema, and hemorrhagic/necrotic lesions, with the minimum necrotizing dose (MND) of 95.42 µg/kg body weight. The skin damaging effects of CbV appeared to be considerably greater, compared with those of NnV (MND = 177.99 µg/kg). The present results indicate that the toxicities and pathophysiologic effects of jellyfish venom extracts may vary from species to species. As predicted from the previous reports on these jellyfish envenomations, the crude venom extracts of C. brevipedalia exhibit much more potent toxicity than that of N. nomurai in the present study. These observations may contribute to our understanding of the toxicities of jellyfish venoms, as well as their mode of toxinological actions, which might be helpful for establishing the therapeutic strategies of jellyfish stings.

Box jellyfish have an elaborate visual system and perform advanced visually guided behaviors. However, the rhopalial nervous system (RNS), believed to be the main visual processing center, only has 1000 neurons in each of the four eye carrying rhopalia. We have examined the detailed structure of the RNS of the box jellyfish Tripedalia cystophora, using immunolabeling with antibodies raised against four putative neuropeptides (T. cystophora RFamide, VWamide, RAamide, and FRamide). In the RNS, T. cystophora RF‐, VW‐, and RAamide antibodies stain sensory neurons, the pit eyes, the neuropil, and peptide‐specific subpopulations of stalk‐associated neurons and giant neurons. Furthermore, RFamide ir+ neurites are seen in the epidermal stalk nerve, whereas VWamide antibodies stain the gastrodermal stalk nerve. RFamide has the most widespread expression including in the ring and radial nerves, the pedalium nerve plexus, and the tentacular nerve net. RAamide is the putative neurotransmitter in the motor neurons of the subumbrellar nerve net, and VWamide is a potential marker for neuronal differentiation as it is found in subpopulations of undifferentiated cells both in the rhopalia and in the bell. The results from the FRamide antibodies were not included as only few cells were stained, and in an unreproducible way. Our studies show hitherto‐unseen details of the nervous system of T. cystophora and allowed us to identify specific functional groups of neurons. This identification is important for understanding visual processing in the RNS and enables experimental work, directly addressing the role of the different neuropeptides in vision. [ABSTRACT FROM AUTHOR]

There is a long-lasting quest of demarcating a minimally representational behavior. Based on neurophysiologically-informed behavioral studies, we argue in detail that one of the simplest cases of organismic behavior based on low-resolution spatial vision–the visually-guided obstacle avoidance in the cubozoan medusa Tripedalia cystophora–implies already a minimal form of representation. We further argue that the characteristics and properties of this form of constancy-employing structural representation distinguish it substantially from putative representational states associated with mere sensory indicators, and we reply to some possible objections from the liberal representationalists camp by defending and qualitatively demarcating the minimal nature of our case. Finally, we briefly discuss the implications of our thesis within a naturalistic framework.

There is a long-lasting quest of demarcating a minimally representational behavior. Based on neurophysiologically-informed behavioral studies, we argue in detail that one of the simplest cases of organismic behavior based on low-resolution spatial vision–the visually-guided obstacle avoidance in the cubozoan medusa Tripedalia cystophora –implies already a minimal form of representation. We further argue that the characteristics and properties of this form of constancy-employing structural representation distinguish it substantially from putative representational states associated with mere sensory indicators, and we reply to some possible objections from the liberal representationalists camp by defending and qualitatively demarcating the minimal nature of our case. Finally, we briefly discuss the implications of our thesis within a naturalistic framework. [ABSTRACT FROM AUTHOR]

Abstract Background The phyla Cnidaria, Placozoa, Ctenophora, and Porifera emerged before the split of proto- and deuterostome animals, about 600 million years ago. These early metazoans are interesting, because they can give us important information on the evolution of various tissues and organs, such as eyes and the nervous system. Generally, cnidarians have simple nervous systems, which use neuropeptides for their neurotransmission, but some cnidarian medusae belonging to the class Cubozoa (box jellyfishes) have advanced image-forming eyes, probably associated with a complex innervation. Here, we describe a new transcriptome database from the cubomedusa Tripedalia cystophora. Results Based on the combined use of the Illumina and PacBio sequencing technologies, we produced a highly contiguous transcriptome database from T. cystophora. We then developed a software program to discover neuropeptide preprohormones in this database. This script enabled us to annotate seven novel T. cystophora neuropeptide preprohormone cDNAs: One coding for 19 copies of a peptide with the structure pQWLRGRFamide; one coding for six copies of a different RFamide peptide; one coding for six copies of pQPPGVWamide; one coding for eight different neuropeptide copies with the C-terminal LWamide sequence; one coding for thirteen copies of a peptide with the RPRAamide C-terminus; one coding for four copies of a peptide with the C-terminal GRYamide sequence; and one coding for seven copies of a cyclic peptide, of which the most frequent one has the sequence CTGQMCWFRamide. We could also identify orthologs of these seven preprohormones in the cubozoans Alatina alata, Carybdea xaymacana, Chironex fleckeri, and Chiropsalmus quadrumanus. Furthermore, using TBLASTN screening, we could annotate four bursicon-like glycoprotein hormone subunits, five opsins, and 52 other family-A G protein-coupled receptors (GPCRs), which also included two leucine-rich repeats containing G protein-coupled receptors (LGRs) in T. cystophora. The two LGRs are potential receptors for the glycoprotein hormones, while the other GPCRs are candidate receptors for the above-mentioned neuropeptides. Conclusions By combining Illumina and PacBio sequencing technologies, we have produced a new high-quality de novo transcriptome assembly from T. cystophora that should be a valuable resource for identifying the neuronal components that are involved in vision and other behaviors in cubomedusae.

Okinawa prefecture is a popular tourist destination due to its beaches and reefs. The reefs host a large variety of animals, including a number of venomous species. Because of the popularity of the reefs and marine activities, people are frequently in close contact with dangerous venomous species and, thus, are exposed to potential envenomation. Commonly encountered venomous animals throughout Okinawa include the invertebrate cone snail, sea urchin, crown-of-thorns starfish, blue-ringed octopus, box jellyfish, and fire coral. The vertebrates include the stonefish, lionfish, sea snake, and moray eel. Treatment for marine envenomation can involve first aid, hot water immersion, antivenom, supportive care, regional anesthesia, and pharmaceutical administration. Information on venomous animals, their toxins, and treatment should be well understood by prehospital care providers and physicians practicing in the prefecture.

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Biotelemetry has revealed daily 15-h behavioral sleep periods in a cubomedusan jellyfish, Chironex fleckeri. Its sleep is expected to be phylogenetically most primitive, since jellyfish possess only two germ layers. They belong to the phylum Cnidaria, the 'simplest' multicellular organisms with an organized nervous system. Cubomedusae have a complex visual system with 24 eyes of four different types, each type specialized for a different task. Input to these eyes during visually guided fast-swimming predation requires enormous amounts of neural processing, possibly nearly saturating the capacity of their comparatively simple nervous system. These heavy neural demands may account for the need for fifteen hours of sleep. C. fleckeri is the only animal known for which sleep may be either present or absent, dependent on lifestyle. Limited knowledge of behavior of some other cubomedusae suggests that they also possess this faculty. The finding of sleep in C. fleckeri supports current proposals of sleep's origin and basic function. Evolutionary analyses link sleep to a conflict produced by excessive processing demands on multifunctional neural circuitry for detailed focal vision by complex lensed eyes. The conflict arises between the enormous demands of complex visual analysis and needs for split-second control of actions, on the one hand, and non-urgent processing of memories of ongoing and stored events, on the other. Conflict is resolved by deferring the non-urgent processing to periods of sleep. Without sleep, selection would favor the evolution of circuitry 'dedicated' to single or but few tasks, with corresponding lesser efficiency. Had complex lensed eyes of medusae originated as a consequence of selection for increased mating success of males pursuing females, it could have occurred before the evolution of fast-swimming bilateral (three-germ-layered) prey. But if it was a consequence of selection for increased prey-hunting success, the origin of such eyes probably awaited the coexistence of bilateral prey.

We report the first discovery of barklice preserved in copula from amber dating back to the mid-Cretaceous, thus documenting the oldest preserved reproductive behaviour of Psocodea. The new finding provides new insight into the evolution of copulatory behaviour in Trogiomorpha. Moreover, we describe and illustrate the new fossil material of Burmempheria densuschaetae (= Latempheria kachinensis) in the extinct family Empheriidae and Longiantennum fashengi in the extinct family Archaeatropidae, two diverse and widely distributed groups during the Cretaceous. No significant sexual dimorphism is recorded, apart from variation in size where males are larger. The taxonomy of Cretaceous empheriids from Burmese amber is revised and discussed.

Introduction: The dermatological effects of box jellyfish envenomation among stinging victims in Thailand are not well reported, particularly concerning chronic effects. For first aid, different recommendations indicate the necessity for the removal of tentacles in life-threatening situations. This study aimed to describe the dermatological effects of box jellyfish envenomation and propose recommendations regarding first aid for victims in urgent care or life-threatening situations., Methods: Surveillance systems and Toxic Jellyfish Networks were established to improve detection and investigation. The networks investigated all severe victims of jellyfish envenomation. A retrospective study was conducted, and victims of stinging by box jellyfish investigated from 1999 to 2021 were included., Results: One hundred and twenty-four victims were recorded. The majority of victims were males (55%), tourists (69%), and Thai nationals (49%). Direct contact had more severe consequences than indirect contact. Dermatological effects included edema, erythematous caterpillar track-like rash, blistering, bullae, papular eruption, necrosis, digital gangrene, recurrent dermatitis, dermal hypersensitivity, numbness, lichenification, hyperpigmentation, keloids, and scarring. Suffering and healing continued from several weeks to many years. Victims with multiple-tentacle box jellyfish stings had papular eruptions and greater severity of skin issues. All fatally envenomed victims collapsed within a few minutes and received incorrect/no first aid. The proposed first aid for life-threatening box jellyfish stings is continuous irrigation of the wound with vinegar for at least 30 s and initiation of cardiopulmonary resuscitation if there is no respiration or heartbeat. Tentacles often detach spontaneously, and removal is not always necessary, thus saving time., Conclusions: The findings provide input for improving diagnosis and treatment guidelines., (Copyright © 2023 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)

Understanding the hierarchy of populations from the scale of metapopulations to mesopopulations and member local populations is fundamental to understanding the population dynamics of any species. Jellyfish by definition are planktonic and it would be assumed that connectivity would be high among local populations, and that populations would minimally vary in both ecological and genetic clade-level differences over broad spatial scales (i.e., hundreds to thousands of km). Although data exists on the connectivity of scyphozoan jellyfish, there are few data on cubozoans. Cubozoans are capable swimmers and have more complex and sophisticated visual abilities than scyphozoans. We predict, therefore, that cubozoans have the potential to have finer spatial scale differences in population structure than their relatives, the scyphozoans. Here we review the data available on the population structures of scyphozoans and what is known about cubozoans. The evidence from realized connectivity and estimates of potential connectivity for scyphozoans indicates the following. Some jellyfish taxa have a large metapopulation and very large stocks (>1000 s of km), while others have clade-level differences on the scale of tens of km. Data on distributions, genetics of medusa and polyps, statolith shape, elemental chemistry of statoliths and biophysical modelling of connectivity suggest that some of the ~50 species of cubozoans have populations of surprisingly small spatial scales and low levels of connectivity. Despite their classification as plankton, therefore, some scyphozoans and cubozoans have stocks of small spatial scales. Causal factors that influence the population structure in many taxa include the distribution of polyps, behavior of medusa, local geomorphology and hydrodynamics. Finally, the resolution of patterns of connectivity and population structures will be greatest when multiple methods are used.

Cubozoan nematocyst venoms contain known cytolytic and hemolytic proteins, but small molecule components have not been previously reported from cubozoan venom. We screened nematocyst extracts of Alatina alata and Chironex yamaguchii by LC-MS for the presence of small molecule metabolites. Three isomeric compounds, cnidarins 4A (1), 4B (2), and 4C (3), were isolated from venom extracts and characterized by NMR and MS, which revealed their planar structure as cyclic γ-linked tetraglutamic acids. The full configurational assignments were established by syntheses of all six possible stereoisomers, comparison of spectral data and optical rotations, and stereochemical analysis of derivatized degradation products. Compounds 1−3 were subsequently detected by LC-MS in tissues of eight other cnidarian species. The most abundant of these compounds, cnidarin 4A (1), showed no mammalian cell toxicity or hemolytic activity, which may suggest a role for these cyclic tetraglutamates in nematocyst discharge.

Operant conditioning - learning to do something for a desired outcome - has never been convincingly demonstrated in Cnidaria. A study now shows that box jellyfish, Tripedalia cystophora, can learn to avoid bumping into an obstacle based on visual cues., Competing Interests: Declaration of interests The author declares no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The triage process in emergency departments (EDs) relies on the subjective assessment of medical practitioners, making it unreliable in certain aspects. There is a need for a more accurate and objective algorithm to determine the urgency of patients. This paper explores the application of advanced data-synthesis algorithms, machine learning (ML) algorithms, and ensemble models to predict patient mortality. Patients predicted to be at risk of mortality are in a highly critical condition, signifying an urgent need for immediate medical intervention. This paper aims to determine the most effective method for predicting mortality by enhancing the F1 score while maintaining high area under the receiver operating characteristic curve (AUC) score. This study used a dataset of 7325 patients who visited the Yonsei Severance Hospital's ED, located in Seoul, South Korea. The patients were divided into two groups: patients who deceased in the ED and patients who didn't. Various data-synthesis techniques, such as SMOTE, ADASYN, CTGAN, TVAE, CopulaGAN, and Gaussian Copula, were deployed to generate synthetic patient data. Twenty two ML models were then utilized, including tree-based algorithms like Decision tree, AdaBoost, LightGBM, CatBoost, XGBoost, NGBoost, TabNet, which are deep neural network algorithms, and statistical algorithms such as Support Vector Machine, Logistic Regression, Random Forest, k-nearest neighbors, and Gaussian Naive Bayes, as well as Ensemble Models which use the results from the ML models. Based on 21 patient information features used in the pandemic influenza triage algorithm (PITA), the models explained previously were applied to aim for the prediction of patient mortality. In evaluating ML algorithms using an imbalanced medical dataset, conventional metrics like accuracy scores or AUC can be misleading. This paper emphasizes the importance of using the F1 score as the primary performance measure, focusing on recall and specificity in detecting patient mortality. The highest-ranked model for predicting mortality utilized the Gaussian Copula data-synthesis technique and the CatBoost classifier, achieving an AUC of 0.9731 and an F1 score of 0.7059. These findings highlight the effectiveness of machine learning algorithms and data-synthesis techniques in improving the prediction performance of mortality in EDs., (© 2023. Springer Nature Limited.)

The objective of this study was to develop a novel copula-based time series (CTS) model to forecast COVID-19 cases and trends based on wastewater SARS-CoV-2 viral load and clinical variables. Wastewater samples were collected from wastewater pumping stations in five sewersheds in the City of Chesapeake VA. Wastewater SARS-CoV-2 viral load was measured using reverse transcription droplet digital PCR (RT-ddPCR). The clinical dataset included daily COVID-19 reported cases, hospitalization cases, and death cases. The CTS model development included two steps: an autoregressive moving average (ARMA) model for time series analysis (step I), and an integration of ARMA and a copula function for marginal regression analysis (step II). Poisson and negative binomial marginal probability densities for copula functions were used to determine the forecasting capacity of the CTS model for COVID-19 forecasts in the same geographical area. The dynamic trends predicted by the CTS model were well suited to the trend of the reported cases as the forecasted cases from the CTS model fell within the 99 % confidence interval of the reported cases. Wastewater SARS CoV-2 viral load served as a reliable predictor for forecasting COVID-19 cases. The CTS model provided robust modeling to predict COVID-19 cases., Competing Interests: Declaration of competing interest All the authors don't have any financial and personal relationships with organizations that could inappropriately influence (bias) their work. The project was supported by the Data Science Seed Grant from Old Dominion University. The funding source had no such involvement in study design, data collection, analysis, and interpretation of data., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Box jellyfish Chiropsoides buitendijki from the coastal zone along the Andaman Sea, southwestern Thailand are characterized by a box-shaped body with unilateral branched tentacles and lack of interradial furrows. Tentacular banding was first reported in the present study with 1-3-2-3-2-3-2-3-1 patterns (1-major band, 2-thicker minor band and 3-thinner minor band). The DNA sequences of 18 S ribosomal RNA genes indicated that the specimen examined were genetically similar to C. buitendijki that was previously identified from the Nam Bor Bay, Phuket, Thailand, and distinct to the other known taxa in the order Chirodropida. In addition, a significant genetic divergence based on 16S mitochondrial gene was observed within the C. buitendijki samples. This indicates a population genetic differentiation but needs further confirmation. [ABSTRACT FROM AUTHOR]

We describe here Sinaster petalon gen. et sp. nov., a new embryonic form from the c. 535 million-year-old Kuanchuanpu Formation of South China (Ningqiang, Shaanxi Province). The excellent three-dimensional, phosphatic preservation of these microfossils allowed us to use x-ray microtomographic techniques to make accurate reconstructions of their internal structures and to compare their anatomy point-by-point with that of extant cnidarians and other animal groups. Sinaster petalon has anatomical features typical of extant Medusozoa (Cnidaria), such as coronal muscles, perradial and adradial frenula, interradial septa, accessory septa, gonad-lamellae, tentacle buds and perradial pockets. Although Sinaster cannot be straightforwardly assigned to any crown -group within Medusozoa, the presence of marginal lappets and endodermal lamellae suggests that it is closer to Cubozoa and Scyphozoa than to any other group of modern cnidarians. The tentative placement of Sinaster within the stem-group Cubozoa is justified by the presence of a velarium supported by a frenulum. The cubozoan affinities of Sinaster are also supported by cladistic analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] All known cubozoans, box jellyfish, have a similar visual system. They possess four sensory structures called rhopalia, which carry-six eyes each. Two of these six eyes are true image-forming camera type eyes in several ways similar to vertebrate eyes. The rhopalia hang by a thin flexible stalk and in the distal end, there is a high-density crystal. In an earlier study of the Caribbean species Tripedalia cystophora , we showed that the crystals act as weights ensuring that the rhopalia are always upright no matter the orientation of the medusa and the vertical part of the visual field of the eyes thus kept relatively constant. Here we have examined the horizontal part of the visual field under different experimental conditions including different visual environments. We find that the horizontal gaze direction is largely controlled by the anatomy of the rhopalium and rhopalial stalk, similar to what has previously been shown for the vertical gaze direction. In a vertically oriented medusa, the rhopalia are kept with a 90° angle between them with the lower lens eyes (LLE) pointing inwards. This 90° shift is kept in horizontally swimming medusa, resulting in the left LLE gazing right, the right gazing left, the bottom gazing orally (backwards compared to swimming direction), and the top LLE gazing aborally (forwards compared to swimming direction). The light environment was manipulated to test if the visual input influences this seemingly strict horizontal gaze direction but even in complete darkness there is tight mechanistic control. [ABSTRACT FROM AUTHOR]

The position of the counterion in animal rhodopsins plays a crucial role in maintaining visible light sensitivity and facilitating the photoisomerization of their retinal chromophore. The counterion displacement is thought to be closely related to the evolution of rhodopsins, with different positions found in invertebrates and vertebrates. Interestingly, box jellyfish rhodopsin (JelRh) acquired the counterion in transmembrane 2 independently. This is a unique feature, as in most animal rhodopsins, the counterion is found in a different location. In this study, we used Fourier Transform Infrared spectroscopy to examine the structural changes that occur in the early photointermediate state of JelRh. We aimed to determine whether the photochemistry of JelRh is similar to that of other animal rhodopsins by comparing its spectra to those of vertebrate bovine rhodopsin (BovRh) and invertebrate squid rhodopsin (SquRh). We observed that the N-D stretching band of the retinal Schiff base was similar to that of BovRh, indicating the interaction between the Schiff base and the counterion is similar in both rhodopsins, despite their different counterion positions. Furthermore, we found that the chemical structure of the retinal in JelRh is similar to that in BovRh, including the changes in the hydrogen-out-of-plane band that indicates a retinal distortion. Overall, the protein conformational changes induced by the photoisomerization of JelRh yielded spectra that resemble an intermediate between BovRh and SquRh, suggesting a unique spectral property of JelRh, and making it the only animal rhodopsin with a counterion in TM2 and an ability to activate G s protein., Competing Interests: Conflicts of interest All authors declare that they have no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The phylum Cnidaria consists of several morphologically diverse classes including Anthozoa, Cubozoa, Hydrozoa, Polypodiozoa, Scyphozoa, Staurozoa, and Myxozoa. Myxozoa comprises two subclasses of obligate parasites-Myxosporea and Malacosporea, which demonstrate various degrees of simplification. Myxosporea were previously reported to lack the majority of core protein domains of apoptotic proteins including caspases, Bcl-2, and APAF-1 homologs. Other sequenced Cnidaria, including the parasite Polypodium hydriforme from Polypodiozoa do not share this genetic feature. Whether this loss of core apoptotic proteins is unique to Myxosporea or also present in its sister subclass Malacosporea was not previously investigated. We show that the presence of core apoptotic proteins gradually diminishes from free-living Cnidaria to Polypodium to Malacosporea to Myxosporea. This observation does not favor the hypothesis of catastrophic simplification of Myxosporea at the genetic level, but rather supports a stepwise adaptation to parasitism that likely started from early parasitic ancestors that gave rise to Myxozoa., (© 2023. The Author(s).)

Preserved specimens make it difficult to study nematocysts. We tested an hydration protocol on ethanol preserved tentacles of Chiropsalmus quadrumanus (Cubomedusae) during a period of ten days, and quantified the success of retrieval of information. After six days of hydration, it was possible to observe discharged and undischarged capsules of the three types of nematocysts. We conclude that hydration is a possible solution to study various aspects of the cnidome, recovering information otherwise lost.

Cubomedusae all have a similar set of six eyes on each of their four rhopalia. Still, there is a great variation in activity patterns with some species being strictly day active while others are strictly night active. Here we have examined the visual ecology of the medusa of the night active Copula sivickisi from Okinawa using optics, morphology, electrophysiology, and behavioural experiments. We found the lenses of both the upper and the lower lens eyes to be image forming but under-focused, resulting in low spatial resolution in the order of 10 – 15 degrees. The photoreceptor physiology is similar in the two lens eyes and they have a single opsin peaking around 460 nm and low temporal resolution with a flicker fusion frequency (fff) of 2.5 Hz indicating adaptions to vision in low light intensities. Further, the outer segments have fluid filled swellings, which may concentrate the light in the photoreceptor membrane by total internal reflections, and thus enhance the signal to noise ratio in the eyes. Finally our behavioural experiments confirmed that the animals use vision when hunting. When they are active at night they seek out high prey-concentration by visual attraction to areas with abundant bioluminescent flashes triggered by their prey.