901 research outputs found

    Depth distribution of Cidaris cidaris (Linnaeus, 1758) and Stylocdaris affinis (Philippi, 1845) (Echinodermata, Echinoidea) around the Maltese Islands

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    The sea urchins Stylocidaris affinis and Cidaris cidaris (family Cidaridae) are abundant on circalittoral and deeper bottoms off the Maltese Islands. Different authors quote different depth ranges for the two species. The depth distribution in Maltese waters was studied based on material from MEDITS surveys. S. affinis was found at depths of 50-550m with the highest relative abundance between 50m and 150m, predominantly on maerl or coarse sedimentary substrata. C. cidaris was found from ca. 50m to depths greater than 550m, mostly on sandy-mud.peer-reviewe

    Predation by West Coast rock lobsters (Jasus lalandii) on two species of winkle (Oxystele sinensis and Turbo cidaris)

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    Rock lobsters, Jasus lalandii, may play an important role in structuring the communities on shallow reef ecosystems and have recently increased in density in the area between Cape Hangklip and Danger Point on the southwest coast of South Africa. This has probably resulted in increased predation on natural populations of smooth turban shells (Turbo cidaris) and pink-lipped topshells (Oxystete sinensis), both of which are proposed targets for small-scale commercial fisheries. This study examines the size selectivity, prey species preferences and consumption rates of rock lobsters feeding on these two winkle species. Rock lobsters showed a strong preference for small O. sinensis, and were limited to taking a maximum (or critical) size of prey, which increased linearly with rock-lobster size. By contrast, rock lobsters of all size classes tested were able to crack and consume a full size range of T. cidaris, and no size preferences were evident. When the two gastropods were offered simultaneously, rock lobsters preferentially consumed the thinner shelled O. sinensis.Consumption rates increased linearly with rock-lobster size. Population consumption rates indicate that rock lobsters will have a profound effect on winkle stocks in the area, even if winkles constituted less than 1% of the diet. This in turn suggests that commercial exploitation of these stocks is unlikely to remain sustainable

    Listado con primeros registros de los equinodermos del norte de TĂșnez (MediterrĂĄneo central)

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    Tunisia occupies a strategic biogeographic position in the Mediterranean Sea and the Strait of Sicily is considered a biogeographical boundary that separates the eastern and western basins. Despite the importance of marine biodiversity in Tunisia, the few studies of Echinodermata fauna in this region data from long ago. In order to update and produce a validated checklist of the echinoderms that occur in northern Tunisia, a study of this phylum was carried out between 2012 and 2016. Forty-five species were inventoried and distributed into the five living Echinodermata classes (Crinoidea, Asteroidea, Ophiuroidea, Echinoidea and Holothuroidea). New occurrences of four species from Tunisian marine waters [Asterina pancerii (Gasco, 1876), Luidia atlantidea (Madsen, 1950), Ophiactis virens (Sars, 1859) and Leptopentacta tergestina (Sars, 1857)], are cited and discussed here for the first time.TĂșnez ocupa un ĂĄrea biogeogrĂĄfica estratĂ©gica en el MediterrĂĄneo. El estrecho tunecino-siciliano es considerado una frontera biogeogrĂĄfica que separa las cubetas oriental y occidental. Sin embargo, a pesar de su interĂ©s, los estudios sobre la fauna de equinodermos de TĂșnez son antiguos y escasos. Con el fin de elaborar el inventario de los equinodermos de la regiĂłn septentrional del mar de TĂșnez, se realizĂł un estudio de este filum entre los años 2012 y 2016. Se han inventariado cuarenta y cinco especies pertenecientes a las cinco clases actuales de Echinodermata (Crinoidea, Asteroidea, Ophiuroidea, Echinoidea y Holothuroidea). Cuatro especies [Asterina pancerii (Gasco, 1876), Luidia atlantidea (Madsen, 1950), Ophiactis virens (Sars, 1859) y Leptopentacta tergestina (Sars, 1857)] se han recolectado por primera vez en estas aguas

    Catalogue of the type fossils stored in the Palaeontological Museum of "Sapienza" University of Rome. 3

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    This paper is a third contribution towards a catalogue of all types stored in the Palaeontological Museum of "Sapienza" University of Rom

    Offshore Neopycnodonte oyster reefs in the Mediterranean Sea

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Angeletti, L., & Taviani, M. Offshore Neopycnodonte oyster reefs in the Mediterranean Sea. Diversity, 12(3), (2020): 92, doi:10.3390/d12030092.Oysters are important ecosystem engineers best known to produce large bioconstructions at shallow depth, whilst offshore deep-subtidal oyster reefs are less widely known. Oyster reefs engineered by Neopycnodonte cochlear (family Gryphaeidae) occur at various sites in the Mediterranean Sea, between 40 and 130 m water depths. Remotely Operated Vehicle surveys provide new insights on this rather neglected reef types with respect to their shape, dimensions and associated biodiversity. We suggest that these little contemplated reefs should be taken in due consideration for protection.This work was partly supported by the EU FP-VI and VII HERMES and HERMIONE, by the ‘Convenzione MATTM-CNR per i Programmi di Monitoraggio per la Direttiva sulla Strategia Marina (MSFD, Art. 11, Dir. 2008/56/CE), and is part of the DG Environment programme IDEM (grant agreement no. 11.0661/2017/750680/SUB/EN V.C2)

    Population dynamics and potential yield of three species of giant winkles in the Western Cape, South Africa

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    Of the southern African intertidal and shallow subtidal trochid and turbinid gastropods, Turbo sarmaticus, T. cidaris and Oxystele sinensis, are the most abundant large species, and therefore obvious targets for a winkle fishery. T. sarmaticus is harvested by recreational snorkel divers, and an application has been made for a permit to experimentally harvest the other two species commercially. This study involves four major aspects, namely morphometrics and flesh yield, shore-based abundance estimates, subtidal abundance estimates, and an estimate of the potential yield for each of the three species off the South-Western Cape, South Africa. Abundance and biomass of the winkles increased from west to east, highest densities being recorded in the low intertidal regions to 2 m depth. Low biomasses of the three species were recorded west of Cape Hangklip and are unlikely to support a fishery there. East of Cape Hangklip, invasion of rock lobsters Jasus lalandii has had a considerable impact on T. cidaris and O. sinensis populations. Consequently, a boat-based fishery with an estimated annual total allowable catch of 75.5 tons for T. cidaris, with a bycatch of 9.9 tons for O. sinensis, can only be considered in the easternmost fisheries-management area between Kleinbaai and Quoin Point. Because previous studies on the harvesting potential of T. sarmaticus off the Western Cape concluded that it was not commercially sustainable, a total allowable catch for that species was not considered. Management options deserving considerations before the commencement of a giant winkle fishery are discussed. Keywords: commercial exploitation, Oxystele sinensis, stock assessment, Turbo cidaris, Turbo sarmaticus, yieldAfrican Journal of Marine Science 2002, 24: 161–18

    The Indo-Pacific affinities of some Maltese tertiary fossils

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    A review of the Maltese fossil record reveals an unsuspected marked IndoPacific affinity, suggesting a biostratigraphic link between the central Mediterranean and the Indo-Pacific in mid-Tertiary times. The family and sometimes even the genus of some Maltese Oligo-Miocene fossils still survive in the Indo-Pacific province after having become completely extinct from the Mediterranean region. The fossils reviewed in this paper are the Cidaridae (which are also revised to reveal the presence of Prionocidaris and Phyllacanthus) , Coelopleurus, Echinoneus, Laganum, Apatopygus, Clypeaster, Tomistoma, Trionyx, Trilasmis, J{ uphus, and Nautilus - all of which have an Indo-Pacific affinity. The survival of such a fauna in the Indo-Pacific region is attributed to two main factors: the former connection of Tethys to the Indo-Pacific, thereby allowing eastward migration of the central Mediterranean fauna into this Ocean, and climatic and other ecological conditions prevailing in the central Mediterranean region during mid-Tertiary times having been analogous to those now prevailing in the Indo-Pacific.peer-reviewe

    New deep-water cnidarian sites in the southern Adriatic Sea

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    Recent ROV (Remotely Operated Vehicle) exploration and bottom sampling in the southern Adriatic Sea (Apulian and Montenegrin margins) resulted in the discovery of cnidarian-rich deep-sea habitats in the depth range of ca. 400-700 m. In particular, ROV inspection of Montenegrin canyons reveals the existence of megabenthic communities dominated by a variety of cnidarians, including scleractinians (Madrepora oculata, Lophelia pertusa, Dendrophyllia cornigera),antipatharians (Leiopathes glaberrima) and gorgonians (Callogorgia verticillata) as major habitat forming taxa, often in association with sponges and, subordinately, serpulids. All such cnidarians are new records for the south-eastern side of the Adriatic Sea. Our investigation indicates that an almost continuous belt of patchy cold water coral sites occurs along the entire south-western margin (Apulian),basically connecting the Adriatic populations with those inhabiting the Ionian margin (Santa Maria di Leuca coral province)

    El Género Phaeocollybia R. Heim (Cortinariaceae) en la Península Ibérica

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    The genus Phaeocollybia R. Heim (Cortinariaceae) in the Iberian Peninsula. In this article P. Arduennensis Bon and P. Festiva (Fr.) R. Heim are reported, both new to the Iberian Peninsula. New localities are also quoted for P. Lugubris (Fr.) R. Heim and P. Jennyae (P. Karst) Rornagn. In addition, Iberian material of P. Christinae (Fr.) R. Heim has been revised, and a part of it has been ascribed to P. Cidaris (Fr.) Romagn. A full macroscopic and microscopic description of all the species of Phaeocollybia is provided.El género Phaeocollybia R. Heim (Cortinariaceae) en la Península Ibérica. En este artículo son citadas P. Arduennensis Bon y P. Festiva (Fr.) R. Heim, ambas nuevas para la Península Ibérica. Tambien se aportan nuevas localidades de P. Lugubris (Fr.) R. Heim y P. Jennyae (P. Karst) Romagn., ademås de haberse revisado el material ibérico de P. Christinae (Fr.) R. Heim, parte del cual ha resultado corresponder a P. Cidaris (Fr.) Romagn. Se ofrecen descripciones detalladas, tanto macroscópicas como microscópicas, de todas las especies