1,720,960 research outputs found
Traveling around the Mediterranean Sea: the bryozoan Amathia verticillata (Delle Chiaje, 1822) together with non-indigenous and endemic overlooked nudibranchs (Mollusca, Gastropoda)
Full text linkThe Mediterranean Sea is recognized as a hot spot of biodiversity, but the ever-increasing commercial and recreational marine traffic and global warming pose significant threats to its fauna by enabling and facilitating, respectively, the introduction of non-indigenous species (NIS). To mitigate negative effects in the native communities, greater efforts are being made to generate updated lists of NIS and to monitor their spread over space and time. In this regard, Amathia verticillata (delle Chiaje, 1822), a worldwide distributed arborescent bryozoan, can play an important role as a vector of NIS due to its ability to be a species ‘carrier of other species’. Despite its importance, a detailed study on the highly specialized Nudibranchia molluscs associated with A. verticillata is still lacking. Given that some nudibranchs serve as powerful bioindicators of changes in the Mediterranean Sea, and considering that A. verticillata is an invasive species capable to facilitating the establishment and spread of NIS, a broad bibliographic study coupled with field investigations in different anthropized areas of the Central Mediterranean Sea were conducted. The nudibranch fauna associated with A. verticillata in the Mediterranean Sea was assessed for the first time. Nine species were found associated with this bryozoan, five of which were directly observed and analysed using morphological and molecular techniques. A case of cryptic diversity was revealed, with Polycerella recondita Schmekel, 1965 resurrected as a valid species, and the neglected Tenellia granosa (Schmekel, 1966) reported for the fourth time in the Mediterranean Sea. Notably, only three out of the nine species are Indo-Pacific, while the remaining six taxa have an Atlantic/Mediterranean distribution. This finding prompted further phylogenetic and haplotype network analyses on the two nudibranch species directly associated with A. verticillata: Bermudella polycerelloides and P. recondita. These analyses revealed different and previously unknown ecological traits of the spread of these two species
Ecology and distribution of the Mediterranean Dondice trainitoi Furfaro and Mariottini, 2020 (Mollusca: Nudibranchia)
No full textDuring scientific technical dives in a marine animal forest (MAF) environment, the nudibranch Dondice trainitoi Furfaro & Mariottini 2020 was recorded on a rocky bottom at 50 m depth in the Salento Peninsula, Southern Italy, Eastern Mediterranean Sea. Further in situ explorations and broad bibliographic research within both the scientific and grey literature revealed that D. trainitoi is widely distributed across the Mediterranean Sea, despite what was previously known. Herein are the first records for the Adriatic Sea and the Apulia region of Italy, together with the deepest record of this species. An analysis of collected samples and both in situ and laboratory photographs of the hydrozoan colonies associated with D. trainitoi revealed its ecology and trophic behaviour; we conclude that the hydrozoan Obelia bidentata Clark, 1875 is its preferred prey, but that it also feeds on the athecate hydroid Eudendrium glomeratum Picard, 1952. These findings shed some light on the little-known ecology and distribution, on both a geographical and a bathymetric scale, of this species, which are fundamental to increasing knowledge on Mediterranean biodiversity and its ecosystem functions
Intertidal biodiversity hotspot strikes again: first record of Caliphylla mediterranea A. Costa, 1867 (Mollusca, Sacoglossa) in the Adriatic Sea, Italy
No full textThe Mediterranean Sea is considered a hotspot of molluscan diversity even if many marine envi- ronments are still poorly explored and could mask rare and/or neglected diversity. During a night survey in a rocky tide pool in the Adriatic Sea, near Ancona, Italy, Caliphylla mediterranea A. Costa, 1867, a rare sacog- lossan mollusc, was observed and documented. This finding constitutes the first record of this species for the Adriatic Sea and one of the few for the whole Mediterranean basin extending the known distributional range of this poorly known species
A Rather Unusual ”Pearl”: Biological Observations of the Hidden Pearlfish Carapus acus (Brünnich, 1768) and Its First Report from Apulian Waters (Salento Peninsula, Southern Italy)
Full text linkThe Salento peninsula in southern Italy (Mediterranean Sea) is a strip of land between the Adriatic and the Ionian Seas, both characterized by local regimes of currents, different geological and physical backgrounds, and quite diversified fauna. In this area, specimens of the sea cucumber Holothuria tubulosa (Brünnich, 1768) (Echinodermata) were collected at four stations in the spring and autumn of 2020 to investigate a possible symbiotic association with the inquiline fish Carapus acus (Brünnich, 1768). Among the collected holothurians, five pearlfish specimens were found in the body cavity of four H. tubulosa collected at 10 m of depth, in autumn, at “Grotta Verde” in Marina di Andrano, Lecce (Ionian Sea). More than half of the sea cucumbers from the latter station hosted the symbiont, suggesting the presence of a shallow population of C. acus inhabiting this coastal area. Furthermore, morphometric analysis carried out on the collected fish helped to shed light on the population dynamics characterizing this neglected species. This is the first report of C. acus from Apulian waters, allowing us to unite previously disjoined areas and providing essential baseline knowledge for planning future in-depth analysis of this difficult-to-study fish in a geographical area that is strategic in terms of the conservation of Mediterranean biodiversity. Furthermore, the range of preferred host species is extended, as C. acus was previously known to prefer other sea cucumber species such as Parastichopus regalis (Cuvier, 1817) instead of H. tubulosa. Finally, the finding of C. acus in a single station and in only one season is not trivial and delivers baseline useful information for future conservation purposes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Being Safe, but Not Too Safe: A Nudibranch Feeding on a Bryozoan-Associated Hydrozoan
Full text linkNudibranchs have a mostly carnivorous diet, and they prey on a wide variety of other animal taxa. Many species, mainly belonging to the Cladobranchia suborder, feed on cnidarians, including member of the class Hydrozoa. Several hydrozoan species display a symbiotic lifestyle, being associated with other benthic invertebrates, including for instance bryozoans, corals, octocorals, and sponges. In our knowledge, no record of nudibranch predation on symbiotic hydrozoans has been reported so far, possibly thanks to the protective action by the host towards its symbiotic hydrozoan. Here, we show the unexpected case of a nudibranch belonging to the recently described species Sakuraeolis marhe (Fernández-Simón and Moles, 2023) feeding on Zanclea sp. 2, a hydrozoan associated with the cheilostome bryozoan Celleporaria sp. This trophic association is confirmed by the presence and storage of the nematocysts into the nudibranch cnidosacs. Moreover, the nudibranch appears to selectively store mostly a single type of nematocyst, that is large size stenotele. The observation here reported represents the first well-documented record of a nudibranch feeding on a symbiotic hydrozoan and the first confirmed case of predation on Zanclea polyps. Moreover, we provide additional genetic information and the first description of the internal anatomy of S. marhe
An Analysis of Microplastics Ingested by the Mediterranean Detritivore Holothuria tubulosa (Echinodermata: Holothuroidea) Sheds Light on Patterns of Contaminant Distribution in Different Marine Areas
Full text linkMicroplastic pollution constitutes a serious environmental problem that requires more effective scientific research to describe its potential impacts on marine fauna. The interaction between microplastics and marine biota can have significant negative effects through the trophic chain, up to human health. To date, several steps forward have been made in our understanding of this phenomenon; however, large knowledge gaps still exist for several taxa and areas. In particular, the pattern of spatial and temporal distribution of microplastics in marine sediments and their interaction with benthic detritivore species still needs to be addressed. The Mediterranean Sea is one of the most impacted areas of the world, and its biota is deeply affected by microplastic pollution. To investigate the effects of the presence of microplastics in the sediments in this area, the echinoderm Holothuria tubulosa was chosen as a model species, and specimens were collected along the Salento peninsula in Apulia, Southern Italy. This peculiar geographic area extends between two ecoregions of the Mediterranean Sea, the Northern Ionian and the Southern Adriatic seas, characterized by peculiar and distinct currents and submarine topologies, resulting in a complex and dynamic ecosystem affected by seasonal fluctuations that make the Salento peninsula an interesting natural laboratory for predictions of future dispersion events on a wider scale. Microplastics were analyzed by investigating the gut contents of H. tubulosa individuals, and the SEM/EDX method was used to confirm the plastic material extracted. Results revealed microplastics in all the specimens analyzed and with a homogeneous pattern of distribution in time and some differences in space, suggesting that the presence of this anthropogenic material is constant throughout the year and its quantity is only slightly affected by the level of conservation and management strategies characterizing the sampling sites
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