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Fujisawa, Japan

Hamano T.,Gifu University | Terasawa F.,Enoshima Aquarium | Tachikawa Y.,Gifu World Fresh Water Aquarium | Murai A.,Gifu University | And 4 more authors.
Journal of Veterinary Medical Science

A 4-year and 2-month-old male capybara (Hydrochoerus hydrochaeris) was diagnosed with squamous cell carcinoma on the buttocks after chronic recurrent dermatosis. The capybara was euthanized, examined by computed tomography and necropsied; the tumor was examined histologically. Computed tomography showed a dense soft tissue mass with indistinct borders at the buttocks. Histological examination of the tumor revealed islands of invasive squamous epithelial tumor cells with a severe desmoplastic reaction. Based on the pathological findings, the mass was diagnosed as a squamous cell carcinoma. This is the first study to report squamous cell carcinoma in a capybara. © 2014 The Japanese Society of Veterinary Science. Source

Toshino S.,Kitasato University | Miyake H.,Kitasato University | Ohtsuka S.,Hiroshima University | Okuizumi K.,Tsuruoka Kamo Aquarium | And 5 more authors.
Plankton and Benthos Research

The giant cubozoan Morbakka virulenta was collected from the central part of the Seto Inland Sea, western Japan in October 2009, in order to observe its development and polyp formation. Fertilization occurred externally. Demersal fertilized eggs were obtained during the incubation of mature females and males kept at a temperature of ca. 17 to 21°C. From the two-cell stage onwards, fertilized eggs developed into blastulae within 4 h. The development of the blastulae stopped for 21 days after forming blastocysts. This formation of blastocysts is up to now unique within the Cnidaria. The planulae, which developed inside the cysts and lacked larval ocelli, this being characteristic for the Cubozoa, finally metamorphosed into polyps bearing only a single tentacle. The 16-tentacled-stage in polyps was reached about three months after this metamorphosis. Budding occurred in eight-tentacled polyps and swimming polyps were released nine days after the commencement of budding. These unique developmental features of M. virulenta may shed additional light on the evolution of life history strategies in the Cnidaria. © The Plankton Society of Japan. Source

Adachi A.,Enoshima Aquarium
Der Zoologische Garten

Even today there is still a lot to learn regarding the biology of the diverse group of coelenterates. With a better knowledge the husbandry can be improved, too. Only since less than 40 years is it possible to keep and cultivate corals, and since almost 50 years some jellyfish species can be kept and bred successfully in an aquarium. But nevertheless it is still difficult to breed certain other jellyfish species for prolonged periods of time.The Enoshima Aquarium, which was opened in 1954, tried right from its beginning to be a pioneer amongst the Japanese aquariums for new husbandry and exhibition methods (Fig. 1). In the 1970s the Enoshima Aquarium became famous also outside of Japan for the trained fish shows (Gewalt, 1973). But already in 1973 the Enoshima Aquarium started to exhibit Moon jellyfish for the regular exhibition. Today 50 jellyfish species are shown in the exhibition. © 2015. Source

Shibata H.,Kitasato University | Miyake H.,Kitasato University | Goto T.,Iwate Fisheries Technology Center | Adachi A.,Enoshima Aquarium | And 2 more authors.
Plankton and Benthos Research

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. © The Plankton Society of Japan. Source

Nakamura K.,Japan Agency for Marine - Earth Science and Technology | Watanabe H.,Japan Agency for Marine - Earth Science and Technology | Miyazaki J.,Japan Agency for Marine - Earth Science and Technology | Takai K.,Japan Agency for Marine - Earth Science and Technology | And 17 more authors.

Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called 'scaly-foot' gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynthetic symbioses in its various tissues. Despite increasing interest in the faunal assemblages at Indian Ocean hydrothermal vents, only two hydrothermal vent fields have been investigated in the Indian Ocean. Here we report two newly discovered hydrothermal vent fields, the Dodo and Solitaire fields, which are located in the Central Indian Ridge (CIR) segments 16 and 15, respectively. Chemosynthetic faunal communities at the Dodo field are emaciated in size and composition. In contrast, at the Solitaire field, we observed faunal communities that potentially contained almost all genera found at CIR hydrothermal environments to date, and even identified previously unreported taxa. Moreover, a new morphotype of 'scaly-foot' gastropod has been found at the Solitaire field. The newly discovered 'scaly-foot' gastropod has similar morphological and anatomical features to the previously reported type that inhabits the Kairei field, and both types of 'scaly-foot' gastropods genetically belong to the same species according to analyses of their COI gene and nuclear SSU rRNA gene sequences. However, the new morphotype completely lacks an iron-sulfide coating on the sclerites, which had been believed to be a novel feature restricted to 'scaly-foot' gastropods. Our new findings at the two newly discovered hydrothermal vent sites provide important insights into the biodiversity and biogeography of vent-endemic ecosystems in the Indian Ocean. © 2012 Nakamura et al. Source

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