1,720,987 research outputs found
Updating Ceramium (Rhodophyta, Ceramiales) biodiversity in the North Adriatic Sea (Mediterranean): Ceramium rothianum sp. nov. and rediscovery of three forgotten species
No full textThe cosmopolitan genus Ceramium Roth (Ceramiaceae), with over 200 currently accepted species, is one of the largest in the Rhodophyta. The genus is characterized by cylindrical or slightly compressed thalli, with axial cells incompletely to completely covered by cortical cells, alternate to pseudo-dichotomous branching and straight to inrolled apices. Despite recent studies, the nomenclature and taxonomy of this genus are still very problematic, linked to the high degree of variation in morphological characters, small thallus sizes, epiphytic habit and the existence of cryptic species. The Mediterranean Sea is reported to have a particularly high diversity of Ceramium species: the North Adriatic Sea, in particular Venice and nearby coasts, was a favourite classical collecting area from where several species were described. In this study we characterize Ceramium sampled from transitional waters of the Venice Lagoon (Italy) by molecular and morphological approaches. Through phylogenetic analyses, using the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) as molecular marker, we identify six distinct taxonomic entities, of which four represent taxa not currently recognized in the Venice Lagoon or the wider Mediterranean Sea. One of these is the poorly known species Ceramium connivens Zanardini, which is non-spiny and fully corticated when mature with short naked internodes developing in older axes. Two entities with erect partially corticated thalli without spines, probably misidentified up to now as Ceramium diaphanum (Lightfoot) Roth, correspond to the new species Ceramium rothianum Wolf et al. and to the forgotten species Ceramium nodosum (Kützing) A.W. Griffiths & Harvey. The last entity, characterized by prostrate axes giving rise to narrow erect incompletely corticated, non-spiny axes, is identified as the rare, poorly known species Ceramium incospicuum Zanardini
Molecular assessment of the tribes Streblocladieae and Polysiphonieae (Rhodomelaceae, Rhodophyta) in the British Isles reveals new records and species that require taxonomic revision
No full textThe use of molecular tools often shows that regional species diversity differs from what we know from assessments based on morphological identifications. The seaweed flora of the British Isles has been well established over a long period from foundational work published during the xviii-xix centuries to more recent revisions based on molecular tools. The application of these tools (primarily rbcL sequences), alongside morphological observations, to the study of the tribes Streblocladieae and Polysiphonieae in the British Isles led us to three new records of species, as well as two species that require taxonomic revision. Polysiphonia morrowii Harvey, P. delicata Díaz-Tapia and Vertebrata tripinnata (Harvey) Kuntze are recorded for the first time in the British Isles. Finding P. morrowii and P. delicata, which are considered introduced or cryptogenic in Europe, is not surprising and these new records improve our knowledge of their distribution. Vertebrata tripinnata had previously been recorded in southern Europe and collecting it on the northern coast of Ireland considerably expands its known distribution. We also found that rbcL and cox1 sequences for the morphologically divergent V. simulans (Harvey) Kuntze and P. ceramiiformis P.Crouan & H.Crouan(which has never been transferred to Vertebrata) from the British Isles were identical, and we propose to reduce the latter to a synonym of the former. Finally, we found two pseudo-cryptic species represented in specimens morphologically assigned to V. fruticulosa (Wulfen) Kuntze, and we propose the resurrection of V. martensiana (Kützing) Piñeiro-Corbeira, Maggs & Díaz-Tapia. This work further evidences the relevance of reassessing red algal species diversity using molecular tools, even in regions where floras are considered well-known
Molecular phylogeny and phylogeography of maerl-forming corallines in northern Europe
No full textAbstract 3A.3 - Fifth European Phycological Congres
Merging the cryptic genera radicilingua and calonitophyllum (Delesseriaceae, rhodophyta): Molecular phylogeny and taxonomic revision
Full text linkRadicilingua Papenfuss and Calonitophyllum Aregood are two small genera of the family Delesseriaceae that consist of only three and one taxonomically accepted species, respectively. The type species of these genera, Radicilingua thy-sanorhizans from England and Calonitophyllum medium from the Americas, are morphologically very similar, with the only recognized differences being vein size and procarp development. To date, only other two species were recognized inside the genus Radicilingua: R. adriatica and R. reptans. In this study, we analysed specimens of Radicilingua collected in the Adriatic and Ionian Sea (Mediterranean), including a syntype locality of R. adriatica (Trieste, northern Adriatic Sea), alongside material from near the type locality of R. thysanorhizans (Torpoint, Cornwall, UK). The sequences of the rbcL-5P gene fragment here produced represent the first molecular data available for the genus Radicilingua. Phylogenetic reconstruction showed that the specimens from the Adriatic and Ionian Seas were genetically distinct from the Atlantic R. thysanorhizans, even if morphologically overlapping with this species. A detailed morphological descrip-tion of the Mediterranean specimens, together with an accurate literature search, suggested that they were distinct also from R. adriatica and R. reptans. For these reasons, a new species was here described to encompass the Mediterranean specimens investigated in this study: R. mediterranea Wolf, Sciuto & Sfriso. Moreover, in the rbcL-5P tree, sequences of the genera Radicilingua and Calonitophyllum grouped in a well-supported clade, distinct from the other genera of the subfamily Nitophylloideae, leading us to propose that Calonitophyllum medium should be transferred to Radicilingua
Rhodomela (Rhodophyta, Ceramiales) in the North Atlantic: preliminary results of a molecular investigation.
No full textMolecular analyses were carried out on different Rhodomela specimens to survey how many species of this genus are present in the North Atlantic
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
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