282 research outputs found

    Updated status of Anostraca, Notostraca and Spinicaudata (Crustacea Branchiopoda) in Sicily (Italy): review and new records.

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    A survey on distribution, phenology and status of large branchiopod crustaceans (Branchiopoda: Anostraca, Notostraca, Spinicaudata) in Sicily and in circum-Sicilian islands was carried out from autumn 2000 to winter 2004/2005 with the purpose of providing an organised contribution to the knowledge of the distribution of these crustaceans in the region. Data from literature on Sicilian large branchiopods has been briefly reviewed, and field surveys allowed us to add new data on their actual consistency in the area. Current Sicilian large branchiopod fauna is characterised by a low species richness and diversity, having possibly been impoverished by the high anthropic impact which has interested the Sicilian wetlands. The need for further surveys directed towards getting the knowledge necessary in order to correctly understand and manage temporary pools, the elective habitat of a rich and peculiar biota whose large branchiopods are “flagship species”, is stressed

    An account on the taxonomy and molecular diversity of a marine rock-pool dweller, Tigriopus fulvus (Copepoda, Harpacticoida)

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    The copepod genus Tigriopus Norman, 1869 is distributed worldwide in coastal rock pools and it is currently considered to include 14 valid species. Tigriopus fulvus (Fischer 1860), with its subspecies Tigriopus fulvus adriaticus Van Douwe 1913 and Tigriopus fulvusalgiricus Monard 1935, and Tigriopus minutus Bozic 1960 are currently reported to occur in the Mediterranean area, but the actual diversity of the genus is currently unknown. We aimed to assess the actual identity of Mediterranean Tigriopus populations and to elucidate their taxonomy and pattern of genetic diversity. In order to reach these goals, a fragment of a mitochondrial DNA gene (cytochrome c oxidase subunit I, COI) was sequenced to be used as a reference marker. Our data suggest the presence of a single species characterized by a noteworthy geographi-cally based genetic structure in the whole study area. The observed diversity pattern is tentatively ascribed here to a strong monopolization of the rock pools by the first immigrants that reached them. However, such a monopolization is periodically disrupted by local extinction events, which are frequent in the intrinsically unstable rock pool habitats. We propose the name “clockwork monopolization” for this pattern.El género de copépodos Tigriopus Norman, 1869 se distribuye en todo el mundo en charcas de rocas costeras y se considera que actualmente incluye 14 especies válidas. Tigriopus fulvus (Fischer 1860), con sus subespecies Tigriopus fulvus adriaticus Van Douwe 1913 y Tigriopus fulvus algiricus Monard 1935, y Tigriopus minutus Bozic 1960 han sido descritos para el área del Mediterráneo, pero la diversidad real del género es desconocida actualmente. El objetivo de este estudio fue evaluar la identidad real de las poblaciones mediterráneas de Tigriopus y dilucidar su taxonomía y patrón de diversidad genética. Con este fin, se secuenció un fragmento del gen de ADN mitocondrial (citocromo c oxidasa subunidad I, COI) como marcador de referencia. Los resultados sugieren la presencia de una sola especie caracterizada por una estructuración genética con una notable base geográfica en toda el área de estudio. El patrón de diversidad observado aquí se atribuye tentativamente a una fuerte monopolización de las charcas de las costas rocosas por parte de los primeros inmigrantes que las alcanzan. Sin embargo, tal monopolización se interrumpe periódicamente por los eventos de extinción local, los cuales son frecuentes en los hábitats de charcas de rocas que son intrínsecamente inestables. Aquí proponemos para este patrón el nombre de “monopolización periódica” (“clockwork monopolization”)

    Primo reperto di una lenticchia d'acqua alloctona in Sicilia: Lemna minuta KUNTH (Araceae Lemnoideae)

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    La presenza di Lemna minuta, una lenticchia d’acqua originaria delNord America, viene segnalata per la prima volta in Sicilia nel gorgo di Santa Rosalia, uno stagno temporaneo mediterraneo localizzato sul promontorio di Monte Pellegrino, Palermo. Lo specchio d’acqua risulta completamente ricoperto da questa pleustofita galleggiante, che impedisce la penetrazione della luce nella colonna d’acqua e non consente la crescita della vegetazione micro- e macroalgale. La repentina e perdurante invasione di Lemna minuta nello stagno, creando condizioni di ipossia nella colonna d’acqua, costituisce un potenziale rischio per l’intero biota del sito.Lemna minuta, an allochthonous duckweed from North America, has been collected for the first time in Sicily. This floating species completely covers the water surface of the Santa Rosalia pond, a small Mediterranean temporary water body located on Monte Pellegrino, Palermo, and inhibits the growth of algal vegetation because of its shading effect. The sudden and enduring invasion of Lemna minuta in the pond is causing hypoxic condition in the water column, which can potentially threaten the aquatic biota

    First record of a representative of the subfamily Paradiaptominae (Copepoda Calanoida Diaptomidae) in Italy: Metadiaptomus chevreuxi (Guerne & Richard, 1894)

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    Metadiaptomus chevreuxi (Guerne & Richard 1894), a diaptomid calanoid copepod belonging to the subfamily Paradiaptominae, has been found in two neighbouring temporary pools in the Egadi Archipelago (Sicily, southern Italy). This finding constitutes the first record of a representative of this subfamily in Italy and the second known European record for this species. M. chevreuxi, commonly found in the arid areas of Maghreb, has already been reported to occur in Mallorca Island (Balearic Archipelago, Spain), while it seems to be rare in the eastern quadrants of the Mediterranean basin. The characteristics of the new Italian site are briefly described and drawings of morphological details of adult specimens are provided. The occurrence of M. chevreuxi in Western Sicily is in accordance with the supposed merging of North-eastern and South-western freshwater calanoid faunas in this area. Additional information on the distribution of calanoid species in the island and its biogeographic significance is also offered

    A review on the animal xenodiversity in Sicilian inland waters (Italy)

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    This paper reviews the available knowledge about faunal xenodiversity in Sicilian inland waters (Italy). The aim is to provide an updated checklist and bibliography of those non-indigenous species (NIS) which occur in the island, and to identify possible threats to its native biological diversity. Data were collected through an extensive literature search which encompassed also local journals, books, congress abstracts, and other grey literature. All the collected data were critically revised and, when possible, verified by consulting available collections or through dedicated sampling surveys. Only those data contained in reports indicating precise occurrence localities, which were confirmed by our own observations and\or by at least two independent sources including at least a peer-reviewed publication, were considered as certain. Data in literature that did not meet these criteria were considered doubtful and reported separately as unverified data. The information provided by websites has been excluded as it often contains unfounded and\or erroneous data. The fauna of Sicilian inland waters host at present 31 confirmed NIS. In addition, the presence of further 11 taxa is dubious. Among the verified data, invertebrate and vertebrate taxa are nearly equally represented, with 15 and 16 taxa, respectively. With 16 species, the phylum Chordata is by far the most represented, followed by Mollusca (8 species) and Arthropoda (6 species). Most of these species were detected in the last 30 years due to the lack of previous regular studies on Sicilian freshwaters. With few exceptions (e.g., the recent introduction of Xenopus laevis, the African clawed frog), NIS' effects on native biota have not extensively studied in the island yet. Although the top-down effects caused by introduced vertebrate taxa are known to deeply modify the native structure of the biota, little information is available on the impacts caused by invertebrate taxa, especially the microscopic ones. The presence in Sicily of 11 non-native species of bony fish is probably the most impacting threat to autochthonous fauna through predation, competition and hybridisation. The results shown in the paper highlight the importance and the urgency of more exhaustive investigations on NIS in Sicilian inland waters with special regard to less charismatic taxa whose effects on the native biota have never been evaluated yet

    First record and morphological features of Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909) (Copepoda, Calanoida) in Italy

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    During a survey, carried out to assess the consistency of microcrustacean fauna inhabiting temporary ponds in Sicily, Hemidiaptomus (Occidodiaptomus) ingens (Gurney, 1909), a large calanoid copepod up to now known only for North-African ponds, Camargue and Corse, was found in the north-western part of the island. Due to its central location in the Mediterranean Sea, Sicily represents a transition zone where several chorological zones of the West Palearctic merge and converge. A brief summary of the existing literature regarding this taxon is given with some morphological considerations on the recently found population which represents the first record for Italy. In particular, the morphological features of the Sicilian population are closely related to those described by Gurney for the specimens collected in the locus typicus (Oued Tindja, Tunisia) and slightly differ from the other European populations

    A century of research on micro-organisms from the inland waters of the largest Mediterranean island

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    The first studies on the micro-organisms inhabiting Sicilian inland waters date back to the middle of the XIX century. However, these were based on single samples and mainly addressed at compiling faunistic and floristic inventories. It was in the first decades of the XX century that the first methodical studies were performed, which focussed on assessing microbial diversity in saline and hypersaline inland waters. Studies on plankton dynamics in ponds and reservoirs of the island started at the beginning of the 1980s and, since the end of the 1990s, temporary waters have also been intensively sampled, especially as regards phytoplankton and micro-crustaceans. These intensified sampling efforts contributed to increasing our knowledge of the composition, structure and functioning of the planktic compartment. On the contrary, studies on benthic microflora and fauna are still numerically scarce and mostly based on occasional collections. Also, running waters have received little attention and the methodical analysis of their micro-organisms is still in its infancy

    L’univers du téléphone portable. Microrites, paraboles et récits

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    Le téléphone portable n’est pas seulement une exceptionnelle réussite commerciale. Sa diffusion transforme peu à peu la façon même de communiquer, et par suite les modes de relation sociale. À cet égard, le plus intéressant du point de vue sémiotique est d’observer comment cet objet technologique suscite l’émergence de formes d’hybridation inédites entre sujets et objets – corps et machines – toujours plus étroitement imbriqués les uns aux autres. D’où l’impossibilité de s’en tenir à la distinction entre une intersubjectivité exclusivement humaine et une interobjectivité purement technologique. La dimension anthropomorphe et la dimension objectale forment désormais une seule (et très complexe) réalité sociale, et aucune forme d’intersubjectivité n’est plus pensable indépendamment d’une interobjectivité.The popularity of the cellular phone is not merely a commercial phenomenon. It has transformed ours ways of communicating and, as a consequence, our social relations. More importantly, from a semiotic point of view, this technological object has contributed to the creation of new body, a hybrid, where body and machine meet, where human subjects and non-human objects coalesce. Thus, it becomes impossible to distinguish between an entirely human intersubjectivity and an exclusively technological inter-objectivity. Both the anthropomorphic and the “ objectal ” dimensions merge in one complex social reality, and inter-subjectivity cannot be conceived anymore without a concurrent interobjectivity

    Covid-19 Impact on Platform Economy. A Preliminary Outlook

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    With this report, PLUS consortium wants to contribute to a large debate on the role of platform economy and on how to deal with labour transformations after Covid-19 outbreak. Considering the ongoing very unpredictable situation, the observations contained in the report should be considered as explorative to further investigations. In any case, we would suggest to avoid framing Covid-19 outbreak in 2020 as outstanding event clearly dividing what occurred before from what will occur shortly after. Rather, one of the purposes of this report is to test if some of the hypothesis we produced during the first year and half of the project are still persuasive even after virus appearance. At first sight it seems that Covid-19 pandemic highlights and, if anything, emphasizes very well some platforms characteristics we had already identified: the lack of social protections for platform workers, the becoming essential infrastructures of platforms, the digitalization of services, the changing nature of urban economies
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