Cubozoan Species Research Articles

Copula lucentia sp. nov., a new box jellyfish (Cnidaria: Cubozoa: Carybdeida) from Western Mediterranean Sea

A new species of box jellyfish, Copula lucentia sp. nov., is described from El Campello, Spain, and compared to the holotype of Copula sivickisi that was successfully recovered after being lost for almost 60 years. So far, the only cubozoan species recorded in the Western Mediterranean was Carybdea marsupialis. The genus Copula just included the type species (Copula sivickisi) reported from different localities in the Pacific, Atlantic, and Indian Oceans. Morphologically, this new species possesses the typical characteristics of the genus Copula (four adhesive pads on the apex and a vertical keyhole-shaped rhopalial niche ostium) but it can be differentiated from the C. sivickisi holotype by the velarial canal pattern. In C. lucentia sp. nov., the velarial canal roots taper towards the velarial rim and each root bears one to two narrow triangular canals with sharp tips, resembling a bird beak. In contrast, the velarial canal roots of C. sivickisi bear two short, broad canals that increase breadth towards the velarial rim and split up into three- to six-lobed, finger-like canals with rounded tips, giving the canal pattern a paw-like appearance. Molecular analyses of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 16S ribosomal DNA genes confirm the distinction of the new species and show that there are even more Copula species than expected, but which will not be focused on here. This study highlights not only that there are species yet to be discovered in the Mediterranean Sea but that a revision of the genus Copula is necessary.

Back to the roots, Part 1—early life cycle data of Rhopaliophora (Scyphozoa, Cubozoa and Staurozoa)

The phylogeny of the Rhopaliophora (Scyphozoa, Cubozoa and Staurozoa) has been discussed and modified extensively up to the present day. Attempting to finally solve this question, the morphology and development of the different early life history stages stages of 17 scyphozoan, 2 staurozoan and 8 cubozoan species were investigated. Due to the magnitude of the study, the findings will be published in two parts. This first part will focus on the comparison of early life cycle stages, the second part (to be published in the following issue of Plankton & Benthos Research) will focus on the evolutionary connection and systematics. The present part of the study focused on the morphology of different types of sessile stages (polyps), the processes of strobilation and metamorphosis, and the resulting products (residues and ephyrae/young medusa) and their further development. The different morphological characters in the polyps helped to categorize them into types. By using the strobilation rates and information on the way morphological characters changed during the process of strobilation/metamorphosis, the strobilae were able to be separately categorized.

Population Structures and Levels of Connectivity for Scyphozoan and Cubozoan Jellyfish

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.

Validation of eDNA as a viable method of detection for dangerous cubozoan jellyfish

AbstractStings from certain species of cubozoan jellyfish are dangerous to humans and their seasonal presence in tropical marine waters poses a significant risk to coastal communities. The detection of cubozoans is difficult due to high spatial and temporal variation in their occurrence and abundance. Environmental DNA (eDNA) has the potential to detect rare species and therefore offers potential to detect cubozoans, not only pelagic medusae, but presence of cryptic polyp life stages. The objective of this study was to validate the use of eDNA as a viable detection method for four cubozoan species (Chironex fleckeri, Copula sivickisi, Carybdea xaymacana, and Carukia barnesi). Species‐specific primers were developed for each of these four cubozoans and an eDNA approach validated utilizing both laboratory and field trials. Laboratory DNA degradation experiments demonstrated that C. sivickisi DNA degraded quickly but could still be detected in sea water for up to 9 days post‐jellyfish removal. Positive detection was found for C. fleckeri, C. xaymacana, and C. sivickisi medusae in the waters surrounding Magnetic Island, Queensland, in the Austral spring/summer (September‐January). Based on visual surveys, there was a poor relationship between concentration of eDNA and abundance of jellyfish. Positive eDNA amplification was also found from water sampled near the substratum when C. sivickisi medusae were out of season and absent. This suggests the eDNA analysis was likely detecting C. sivickisi polyps located within the substratum. Consequently, eDNA is an effective tool to detect both the medusae and likely polyps of cubozoans. This approach provides the means to reduce the risk of envenomation to swimmers and enhance our knowledge of cubozoan ecology.

Rapid and Accurate Species-Specific PCR for the Identification of Lethal Chironex Box Jellyfish in Thailand.

Box jellyfish are extremely potent venom-producing marine organisms. While they have been found worldwide, the highest health burden has been anticipated to be the tropical Indo-Pacific of Southeast Asia (SEA). At least 12 Cubozoan species have now been documented in Thai waters, and many of them inflict acutely lethal strings, especially those under the order Chirodropida. Our previous study has successfully differentiated species of box jellyfish using DNA sequencing to support the morphological study. In this study, we specifically designed polymerase chain reaction (PCR) primers for the 16S ribosomal RNA (rRNA) gene and the mitochondrial DNA cytochrome oxidase subunit I (COI) gene of lethal Thai Chironex species. The SYBR green-based real-time PCR panel was performed for rapid species identification. The sensitivity and specificity of the panel were determined by testing samples of different species. Moreover, we applied the panel to the tentacle sample from a real patient, which helped confirm the animal-of-cause of envenomation. Our results show a success for species identification of box jellyfish using 16S rRNA and COI PCR panel, which revealed congruence between molecular and morphological identification. Furthermore, the panel worked very well with the unknown samples and jellyfish tissue from the real envenomation case. The results demonstrated that molecular panels were able to identify three species of Chironex box jellyfish both rapidly and accurately, and can be performed without having a complete specimen or morphological study.

Experimental validation of the relationships between cubozoan statolith elemental chemistry and salinity and temperature

Knowledge surrounding the movements of jellyfish is limited, but elemental chemistry has the potential to elucidate these movements. The objective of this study was to experimentally validate elemental chemistry as a technique which may provide insight into the movements of cubozoans. The approach used a laboratory experiment on the well-known cubozoan species Chironex fleckeri, examining the relationship between statolith elemental chemistry and temperature and salinity. Strong evidence was found that statolith Sr:Ca varied with temperature and that this was independent of variation in salinity. Sr:Ca ratios in saltwater varied little with variation in temperature or salinity. Accordingly, a physiological mechanism within C. fleckeri must have affected statolith Sr:Ca, causing it to vary with temperature. Based on the experimental data from this study and correlative evidence that Sr:Ca varied with temperature in another cubozoan, Copula sivickisi, we provide robust evidence that statolith Sr:Ca can be utilised as a proxy for temperature and may be applicable to other species of cubozoans. Ba:Ca in statoliths was found to vary with both temperature and salinity. As a result, it was determined that Ba:Ca profiles in statoliths have the potential to help resolve jellyfish movements in some circumstances. The use of elemental chemistry to elucidate horizontal or vertical movements of cubozoan species has significant potential and application.

The pathology of Chironex fleckeri venom and known biological mechanisms.

The large box jellyfish Chironex fleckeri is found in northern Australian waters. A sting from this cubozoan species can kill within minutes. From clinical and animal studies, symptoms comprise severe pain, welts, scarring, hypotension, vasospasms, cardiac irregularities and cardiac arrest. At present, there is no cure and opioids are used to manage pain. Antivenom is available but controversy exists over its effectiveness. Experimental and combination therapies performed in vitro and in vivo have shown varied efficacy. These inconsistent results are likely a consequence of the different methods used to extract venom. Recent omics analysis has shed light on the systems of C. fleckeri venom action, including new toxin classes that use pore formation, cell membrane collapse and ion channel modulation. This review covers what is known on C. fleckeri pathomechanisms and highlights current gaps in knowledge. A more complete understanding of the mechanisms of C. fleckeri venom-induced pathology may lead to novel treatments and possibly, the discovery of novel cell pathways, novel drug scaffolds and novel drug targets for human disease.

Histomorphological comparison of testes in species of box jellyfish (Cnidaria; Cubozoa): does morphology differ with mode of reproduction and fertilization?

Cubozoa jellyfish species exhibit either internal or external fertilization, and reproductive behavior involving spermcasting or complex copulatory sexual behavior, but male gonad morphology has not been investigated broadly in cubozoans. In this study, a histological comparison was conducted of the testes of four cubozoan species in two orders: Carybdea marsupialis (Carybdeidae), Morbakka virulenta (Carukiidae), and Tamoya cf. haplonema (Tamoyidae) in Carybdeida and Chiropsalmus quadrumanus (Chiropsalmidae) in Chirodropida. Our results show spermatic follicles present in all species, with spermatogenesis occurring in two layers, the gastrodermis and the gonadal mesoglea. Specimens were either immature males or unspawned males, except in the case of Tamoya cf. haplonema which displayed rupture sites in the wall of the follicles, indicating prior release of sperm. Interspecific comparative histological study revealed that spermatogenesis generally occurs in a polarized manner towards the lumen of the spermatic follicle, with mature spermatozoa in the center awaiting gonadal rupture and release for either internal or external fertilization. Furthermore, we provide a synopsis of the histological findings to date on cubozoan testes, emphasizing incidences of conserved male gonad morphology regardless of mode of fertilization, in addition to separate novelties that have arisen in two internally fertilizing lineages, each exhibiting unique reproductive behavior. Further taxon-sampling of additional species at different development stages may reveal a broader diversity in testes morphology across Cubozoa and serve as a basis for a deeper investigation into the emergence of novel modes of sexual reproduction in non-bilaterian animals.

Ocean acidification causes mortality in the medusa stage of the cubozoan Carybdea xaymacana

Ocean pH is decreasing due to anthropogenic activities, and the consequences of this acidification on marine fauna and ecosystems are the subject of an increasing number of studies. Yet, the impact of ocean acidification (OA) on several abundant and ecologically important taxa, such as medusozoans, is poorly documented. To date there have been no studies on the effect of post-2050 OA projections on the medusa stage of jellyfish. As medusae represent the reproductive stage of cnidarians, negative impacts on adult jellyfish could severely impact the long-term survival of this group. Using a laboratory experiment, we investigated the effect of 2300 OA projections (i.e. pH of 7.5) on the mortality rate of the medusa-stage of the cubozoan species Carybdea xaymacana, compared to ambient seawater pH conditions (i.e. pH of 8.1). After a 12-h exposure to OA, C. xaymacana medusae suffered higher mortality rates compared to ambient conditions. This study represents the first evidence of the potential lethal effects of post-2050 OA projections on jellyfish. The higher metabolic rates of cubozoans compared to other cnidarians might make box jellyfish more vulnerable to OA. A decrease in the density of cnidarians could lead to harmful ecological events, such as algal blooms.

Spermatogenesis and gonadal cycle in male Tamoya haplonema and Chiropsalmus quadrumanus (Cnidaria, Cubozoa)

Spermatogenesis has been little studied in cubozoans. This work describes spermatogenesis of two cubozoan species from Brazil, Tamoya haplonema and Chiropsalmus quadrumanus, using light microscopy and histochemical techniques to highlight and contrast stages of the gonadal cycle. Specimens were collected by hand at the water surface or with shrimp trawls in three areas in the state of São Paulo (SE Brazil): Cananéia lagoon estuarine system (south), Santos and São Vicente Bay (central), and São Sebastião and Ubatuba (north). Male box jellyfish gonads are located between the mesoglea and gastrodermis in a thin and independent layer, organized in elongated follicles, macroscopically resembling a fingerprint pattern. After subsampling, serial sections were performed on male gonad tissue. The resulting slides were stained with hematoxylin and eosin and methods for staining proteins, acidic materials and neutral polysaccharides. Light microscopy revealed that the follicle wall of the male gonads of both cubozoan species is composed of spermatogonia. Spermatocytes are found peripherally near the follicle wall, while spermatids and spermatozoa are located towards the center. Sperm release occurs through rupture of the follicular wall into the gastric pockets. Four stages of gonad development were documented for T. haplonema and three for C. quadrumanus. The sperm of C. quadrumanus has a rounded head while in T. haplonema the sperm head is conical with an elongated apical projection. In both species, there was no positive histochemical reaction for putative acrosomal vesicles precursors.

Medusae (Scyphozoa and Cubozoa) from southwestern Atlantic and Subantarctic region (32 60S, 34 70W): species composition, spatial distribution and life history traits

In this study, we reported the species composition and spatial distribution of Scyphomedusae and Cubomedusae from the southwestern Atlantic and Subantarctic region and reviewed the available knowledge of life history traits of these species. We gathered the literature records and presented new information collected from oceanographic and fishery surveys carried out between 1981 and 2017, encompassing an area of approximately 6,7 million km 2 (32-60°S, 34-70°W). We confirmed the occurrence of 15 scyphozoans and 1 cubozoan species previously reported in the region. Lychnorhiza lucerna and Chrysaora lacte a were the most numerous species, reaching the highest abundances/biomasses during summer/autumn period. Desmonema gaudichaudi , Chrysaora plocamia , and Periphylla periphylla were frequently observed in low abundances, reaching high numbers only occasionally. Phacellophora camtschatica, Aurelia sp., Drymonema gorgo , Atolla chuni , Stygiomedusa gigantea and Pelagia cf. noctiluca were observed always in low numbers. Atolla wyvillei , Stomolophus meleagris , Desmonema comatum and Tamoya haplonema were reported just a few times and mostly individually. Although new species/reports can be found as surveys are undertaken, these results are considered to be the reliable baseline for further ecological studies seeking to understand the ecological role that these jellyfish play in marine ecosystems.

Gonadal histology of box jellyfish (Cnidaria: Cubozoa) reveals variation between internal fertilizing species Alatina alata (Alatinidae) and Copula sivickisi (Tripedaliidae).

Cubozoans (box jellyfish) are gonochoristic cnidarians with distinct reproductive strategies. This comparative histological study examines the gonad organization of Alatina alata and Copula sivickisi, two box jellyfish species that exhibit different modes of internal fertilization. A. alata reproduces via spermcasting aggregations while C. sivickisi reproduces via copulation; in both cases, internal fertilization occurs in the gastrovascular cavity. Herein, we provide the first histological description of subgastric sacs-structures unique to C. sivickisi. Although previously thought to function as sperm storage sacs, our findings reveal that subgastric sacs are nematocyst nests lacking sperm entirely. Conversely, we discovered that velarial spots in C. sivickisi females correspond to actual sperm storage structures. Histological examination of cubozoan sperm packages revealed that while sperm packages from both species have motile flagella, A. alata males produce nonencapsulated sperm bundles (i.e., "spermatozeugmata"), and C. sivickisi males produce encapsulated packages (i.e., "spermatophores"). Our findings corroborate the presence of several types of nematocysts in C. sivickisi embryo strands and spermatophores, and indicate their provenance to be both female and male gonads respectively, as well as subgastric sacs (i.e., nematocyst nests). In contrast to our findings of velarial spots as sperm storages structures in C. sivickisi females, and of nematocysts in the gonads of both sexes, we report that A. alata medusae lack both sperm storage structures and gonadal nematocysts. Finally, we discuss our findings on reproductive morphology of C. sivickisi and A. alata in light of the respective reproductive behavior of these two cubozoan species.

First Record of Box Jellyfish, Carybdea brevipedalia (Cnidaria: Cubozoa: Carybdeidae) from Korean Coastal Waters: Morphology and Molecular Descriptions

We firstly described a box jellyfish, Carybdea brevipedalia collected from the southern coasts of Korea. It is morphologically characterized by gastric phacellae, a special digestive system of cubozoan jellyfish, and velarium, the thin muscle flap forming the opening of the subumbrellar cavity. The phacellae are linear-shaped, comprising numerous cirri branched from multiple roots. Each root also has multiple numbers of cirrus bundles. Basis of velarial cannels parts into two branches in each octant of velarium. Its geographic distributions were limited to Jejudo and the middle-southern coasts where the organisms are seriously hazardous to bathers in summer. Numerous individuals and/or large-sized populations were observed specifically from beaches at Jeju-do, Namhae-do and a small fishing port of Namildae, while only a small amount of the individuals was observed in Gamak Bay, Jaran- Goseung Bay, and Geoje-do. We confirmed molecular identity of the Korean C. brevipedalia with comparison of nuclear ribosomal DNA sequences. Until now, Carybdea brevipedalia is the only cubozoan species reported to be distributed in Korean waters.

Statolith morphometrics as a tool to distinguish among populations of three cubozoan species

Little is known on cubomedusae population structure, and what is known for many species is mostly from rare occurrences or from a metapopulation perspective. Knowledge on population units is critical for understanding population dynamics as well as predicting potential risk to swimmers. Otolith shape analysis is a proven stock identification technique in fishes; here, we applied shape analysis to cubomedusae statoliths. Medusae of three species were collected from three distinct populations around the coastline and nearshore islands of northern Queensland, Australia. Canonical discriminant analysis was performed on normalised elliptical fourier coefficients for statolith proximal, oral and lateral faces and combinations of statolith faces for each species. Significant discrimination of sampling populations was achieved in two species (Copula sivickisi statolith proximal face and Chironex fleckeri oral + lateral faces). Differences in statolith shape, therefore, were capable of successful discrimination among sampling locations but was not capable for one species. The ecological niche, and associated ecological pressures, of some cubozoan species (e.g. Carukia barnesi) may not vary enough for differences in statolith shape among locations to occur. Statolith shape in combination with other stock identification techniques, such as genetics and/or elemental chemistry, will help to discriminate the spatial scales of cubozoan populations.

Preliminary Taxonomic Survey and Molecular Documentation of Jellyfish Species (Cnidaria: Scyphozoa and Cubozoa) in Malaysia.

Mohammed Rizman-Idid, Abu Bakar Farrah-Azwa, and Ving Ching Chong (2016) Scientific enquiries into jellyfish blooms and associated problems are often deterred by the lack of taxonomical and ecological studies worldwide. Taxonomic difficulty is attributed to the high degree of morphological variations among and within species. To date, only two scyphozoan jellyfish species have been documented from field surveys in Malaysian waters, whereas another four Malaysian scyphozoan and two cubozoan jellyfish species have been mentioned in toxicological studies. None of these species have; however, been verified. This study thus aimed to document and resolves the uncertainty of earlier identified species in the region using morphology and molecular DNA sequencing. Jellyfish specimens were collected from Malaysian waters in the Straits of Malacca, South-China Sea and the Sulu-Sulawesi Sea over two years (June 2008 to October 2010), and their DNA sequences were compared with those from the Atlantic and Pacific regions. Ten scyphozoan and two cubozoan species were recorded in Malaysian waters (South China Sea and Straits of Malacca). These jellyfish included eight species from the order Rhizostomeae (Rhizostomatidae, Lobonematidae, Mastigiidae, Catostylidae and Cepheidae), two species from Semaestomeae (Pelagiidae and Cyaneidae) and two species from class Cubozoa; one from order Carybdeida (family Carukiidae) and another from order Chirodropida (family Chiropsalmidae). Molecular identification of species using phylogenetic approaches was based on DNA sequences of partial cytochrome oxidase I (COI), 16S and internal transcribed spacer (ITS1) regions. The COI phylogenetic tree of Cubozoa and Scyphozoa species from the Atlantic and Pacific regions showed distinct clustering of six Malaysian jellyfish species. However, most of the deeper divergences and relationships between the families were unresolved, which were also observed in the 16S and ITS1 phylogenetic trees. The Malaysian edible species Lobonemoides robustus, Rhopilema hispidum and Rhopilema esculentum were grouped within Rhizostomeae, whereas other scyphozoans showed phylogenetic affinities to Semaestomeae and Kolpophorae. Chrysaora and Cyanea appeared non-monophyletic; however their paraphyly was not confirmed. This study has provided the much needed baseline information on the taxonomy of Malaysian jellyfish species which have been substantiated by partial COI, 16S and ITS1 sequences. A total of 12 putative species of jellyfish were identified, which encompassed 12 genera.

Statolith Morphometrics Can Discriminate among Taxa of Cubozoan Jellyfishes

Identification of potentially harmful cubomedusae is difficult due to their gelatinous nature. The only hard structure of medusae, the statolith, has the potential to provide robust measurements for morphometric analysis. Traditional morphometric length to width ratios (L: W) and modern morphometric Elliptical Fourier Analysis (EFA) were applied to proximal, oral and lateral statolith faces of 12 cubozoan species. EFA outperformed L: W as L: W did not account for the curvature of the statolith. Best discrimination was achieved with Canonical Discriminant Analysis (CDA) when analysing proximal + oral + lateral statolith faces in combination. Normalised Elliptical Fourier (NEF) coefficients classified 98% of samples to their correct species and 94% to family group. Statolith shape agreed with currently accepted cubozoan taxonomy. This has potential to assist in identifying levels of risk and stock structure of populations in areas where box jellyfish envenomations are a concern as the severity of envenomation is family dependent. We have only studied 12 (27%) of the 45 currently accepted cubomedusae, but analyses demonstrated that statolith shape is an effective taxonomic discriminator within the Class.

First record of the box jellyfishTripedalia cystophora(Cnidaria: Cubozoa: Tripedaliidae) in the Gulf of Mexico

Abstract Although observations of the box jellyfish Tripedalia cystophora have been widely documented since it was first recorded in Jamaica in 1897, to date there are no published reports of its occurrence in the Gulf of Mexico. Eighteen specimens of Tripedalia cystophora (Cubozoa: Tripedaliidae), 12 and 6, respectively, were collected from a mangrove waterway near Bonita Springs, Florida, in 2010 and a brackish canal in Englewood, Florida, in 2015. Additional records from Tampa Bay (2007–2015) and Everglades City (2015), Florida, were documented with photography. Within the past few years, new records of T. cystophora from other localities, including Hawai‘i, northern Australia, and the east coast of Florida, have been reported. This study represents the first published report of the species from the Gulf of Mexico. Several other species of cubozoans have been reported from the Gulf region, but the presence of three pedalia at each corner of the swimming bell (12 tentacles total), its small size up to 1...

Mass occurrence of the cubomedusa Copula sivickisi (Cnidaria: Cubozoa) at Seto Harbor, Shirahama, Wakayama, Japan, in summer of 2013; a possible recent example of global warming

More than 200 very young medusae of Copula sivickisi (Stiasny) were collected within totally 60 minutes at two nights in June, 2013 at the Seto Harbor, Shirahama, Wakayama, Japan. This mass occurrence might be related to recent global warming at Shirahama, known as the northernmost distributional locality of this cubozoan species. It is assumed that the polyp stage of this species may live in the surrounding areas, because there jellyfish were small size (most are less than 1.6 mm height) that was conceivable as the newly released one from the polyp.

Redescription of Alatina alata (Reynaud, 1830) (Cnidaria: Cubozoa) from Bonaire, Dutch Caribbean.

Here we establish a neotype for Alatina alata (Reynaud, 1830) from the Dutch Caribbean island of Bonaire. The species was originally described one hundred and eighty three years ago as Carybdea alata in La Centurie Zoologique-a monograph published by René Primevère Lesson during the age of worldwide scientific exploration. While monitoring monthly reproductive swarms of A. alata medusae in Bonaire, we documented the ecology and sexual reproduction of this cubozoan species. Examination of forty six A. alata specimens and additional archived multimedia material in the collections of the National Museum of Natural History, Washington, DC revealed that A. alata is found at depths ranging from surface waters to 675 m. Additional studies have reported it at depths of up to 1607 m in the tropical and subtropical Atlantic Ocean. Herein, we resolve the taxonomic confusion long associated with A. alata due to a lack of detail in the original description and conflicting statements in the scientific literature. A new cubozoan character, the velarial lappet, is described for this taxon. The complete description provided here serves to stabilize the taxonomy of the second oldest box jellyfish species, and provide a thorough redescription of the species.

A novel proteinaceous cytotoxin from the northern Scyphozoa Cyanea capillata (L.) with structural homology to cubozoan haemolysins

It is well known that jellyfish are producers of complex mixtures of proteinaceous toxins for prey capture and defence. Nevertheless, studies on boreal scyphozoans concerning venom composition and toxic effects are rare. Here the isolation of a novel cytotoxic protein from the fishing tentacle venom of Cyanea capillata (L. 1758) using bioactivity-guided, multidimensional liquid chromatography is described. The crude venom was purified utilising preparative size-exclusion, ion-exchange, and reversed-phase chromatography. The cytotoxicity of resulting chromatographic fractions has been proven by a dye-uptake assay with the human hepatocyte cell line HepG2. The final purification step yielded, among other fractions, a fraction containing a single protein (named CcTX-1) with a molecular weight of its main isoform of 31.17 kDa The purification process leads to an increased cytotoxic activity per protein equivalents and the finally isolated CcTX-1 caused a nearly total loss of cell viability at a protein concentration of 1.3 μg mL−1 corresponding to 0.4 μg/105 cells. De novo sequencing of CcTX-1 was conducted after enzymatic digestion and subsequent matrix-assisted laser desorption ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-ToF/ToF MS/MS). The obtained sequence data provide an approximate 85% description of the amino acid sequence. This sequence information partially matched that of two known haemolytic proteins of two cubozoan species: CaTX-1 from Carybdea alata Reynaud, 1830 and CrTX-1 from Carybdea rastonii Haacke, 1886.