Search

The benthic ctenophore Vallicula multiformis Rankin, 1956 (Ctenophora, Platyctenida) was originally described from Jamaica. We found the species in an aquarium during our survey of jellyfish from Palawan Island, the Philippines. Molecular analysis of the species confirmed the morphology-based identification of the samples. This discovery is the first report of the occurrence of species from the western Pacific area. [ABSTRACT FROM AUTHOR]

Envenomation by toxic box jellyfish species is known to be a serious problem to public health. In order to elucidate the problem, it becomes necessary to predict the occurrence of box jellyfishes, as well as understanding their ecology and life cycle. Mature medusae of Carybdea brevipedalia (Cubozoa: Carybdeida), which is a common species of box jellyfish in Japan, were collected from northern Japan to observe its early life history, including polyp formation. Fertilization occurred externally, and blastulae developed into planulae. Free swimming planulae settled and metamorphosed into tiny primary polyps with two forms, i.e. settled and creeper. Adult polyps formed cysts at temperatures below 15°C or when water replacement and/or feeding was stopped. Budding occurred in four-tentacled polyps, and the buds were released after commencement of budding. Complete metamorphosis of a whole polyp into a single medusa occurred at stable temperatures between 18 to 25°C (18, 20, 23, 25°C, respectively) or when temperatures were raised from 20 to 25°C. Newly released medusae had four tentacles. Our study demonstrated that polyps of C. brevipedalia survive and propagate over a wide range of water temperatures and that developmental features resemble closely those of some tripedaliid species, namely Tripedalia cystophora and Copula sivickisi, rather than Carybdea marsupialis. The morphological affinities of polyp in C. brevipedalia, T. cystophora and C. sivickisi support recent molecular results. However, further studies are needed to confirm the morphological contradiction between C. brevipedalia and C. marsupialis in the future. [ABSTRACT FROM AUTHOR]

Mass aggregations of Aurelia limbata have been reported along the Pacific coast of northern Japan, from spring to fall. The polyp stage is important for understanding the factors leading to mass occurrences of jellyfish, because polyps reproduce asexually and are responsible for the release of many ephyrae. Until the present report, the polyps of A. limbata had not been found in the wild and their ecology remained unknown. We found 18 polyps of A. limbata attached to two pieces of deep-sea debris, an aluminum beverage can and a plastic bottle, collected by bottom trawl at depths of 296 m and 392 m, respectively. Strobilation of the polyps was observed at 4°C without temperature change stimulation. This raises the possibility that strobilation occurs in low-temperature environments throughout the year. A large quantity of debris had sunk to the seafloor off the coast because of the tsunami tidal wave after the Great East Japan Earthquake, increasing the available substrate for A. limbata polyps. Additional ecological research on polyps and medusae in deep waters is necessary to predict future blooms of A. limbata. [ABSTRACT FROM AUTHOR]

The stings of box jellyfishes can be fatal, so knowing the fauna of a certain area is important to save lives. Five described and two still-undescribed species of Cubozoa have been reported from Thailand: Chironex indrasaksajiae, Chironex sp., Chiropsella sp., Chiropsoides buitendijki, Copula sivickisi, Morbakka fenneri, and Tripedalia cystophora. We made detailed observations of the morphology of two of the species newly recorded in Thailand: Alatina morandinii and Tripedalia binata. The molecular phylogeny of these species is also discussed. Additional investigations are needed to understand the diversity of Cubozoa in Thailand. [ABSTRACT FROM AUTHOR]

In this study, we investigated the trophic interactions between the Japanese giant box jellyfish, Morbakka virulenta, and fish in the central part of the Seto Inland Sea, western Japan, in autumn and winter. Occurring in the surface waters at nighttime, these cubomedusae, regardless of their size (1.5 to 22.5 cm in bell height), were found to be piscivorous, feeding mainly on the Japanese anchovy, as shown by their stomach contents analysis. This finding was supported by a stable isotopic analysis and by an unchanged cnidome, irrespective of the bell height of medusae. Their nocturnal occurrence near the surface often took place around the slack tide, during which the medusae were foraging with tentacles fully extended. Other associations between the medusae and fish were also observed at this time: presumed commensalism with juvenile Japanese horse mackerel, and predation by black scraper. [ABSTRACT FROM AUTHOR]