1,720,966 research outputs found
Revision of Mediterranean and NE Atlantic Raphitomidae (Gastropoda, Conoidea) 8: The genus Leufroyia Monterosato, 1884
Full text linkThe four recent species of the genus Leufroyia Monterosato, 1884 are revised based on an integrative taxonomy approach: L. leufroyi (Michaud, 1828), L. concinna (Scacchi, 1836), L. erronea Monterosato, 1884 and L. villaria (Pusateri & Giannuzzi-Savelli, 2008)
Molecular identity of Nemoura lacustris (Plecoptera: Nemouridae) throughout its distributional range
No full textThe recent report of Nemoura lacustris Pictet, 1865 in Great Britain has raised doubts on its identity, given the isolation with respect to the Mediterranean and continental populations of this species. Using molecular analyses, we tested if populations from the United Kingdom and the Iberian Peninsula were conspecific and tested the hypotheses of a recent colonization event versus a more ancient origin for the British populations. Phylogenetic analysis of the mitochondrial marker COI allowed us to conclude that the United Kingdom specimens morphologically ascribed to N. lacustris were conspecific with populations from France and the Iberian Peninsula. Based on the genetic divergence of the two reciprocally monophyletic clades from the Iberian Peninsula and Great Britain/France, respectively, the present distribution of N. lacustris can be postulated as a relatively recent dispersal or introduction into Great Britain from France. Finally, we note the isolated position displayed by N. lacustris in the phylogenetic tree of Nemoura species based on COI sequences, as the sister to all included species of the genus. This isolated position corresponds with the specific morphology of N. lacustris genitalia and requires additional studies to ascertain clearer generic boundaries within the Nemouridae
Candidate cases of poecilogony in Neogastropoda: Implications for the systematics of the genus Raphitoma Bellardi, 1847
No full textPoecilogony is the intraspecific variation in developmental mode, with larvae of different types produced by the same individual, population or species. It is very rare among marine invertebrates, and in gastropods has long been described only in a few opisthobranchs. The physiological and regulatory mechanisms underlying larval evolutionary transitions, such as loss of planktotrophy that occurred repeatedly in many caenogastropod lineages, are still largely unknown. We have studied the inter- v. intraspecific variation in larval development in the north-east Atlantic neogastropod genus Raphitoma Bellardi, 1847, starting with an iterative taxonomy approach: 17 morphology-based Preliminary Species Hypotheses were tested against a COI molecular-distance-based method (ABGD), and the retained species hypotheses were eventually inspected for reciprocal monophyly on a multilocus dataset. We subsequently performed an ancestral state reconstruction on an ultrametric tree of the 10 Final Species Hypotheses, time-calibrated by fossils, revealing that the interspecific changes were planktotrophy > lecithotrophy, and all have occurred in the Pleistocene, after 2.5 million years ago. This is suggestive of a major role played by Pleistocene Mediterranean oceanographic conditions-enhanced oligotrophy, unpredictable availability of water column resources-likely to favour loss of planktotrophy. Within this group of species, which has diversified after the Miocene, we identified one pair of sibling species differing in their larval development, Raphitoma cordieri (Payraudeau, 1826) and R. horrida (Monterosato, 1884). However, we also identified two Final Species Hypotheses, each comprising individuals with both larval developmental types. Our working hypothesis is that they correspond to one or two poecilogonous species. If confirmed by other nuclear markers, this would be the first documentation of poecilogony in the Neogastropoda, and the second in the whole Caenogastropoda. Although sibling species with different developmental strategies may offer good models to study some evolutionary aspects, poecilogonous taxa are optimally suited for identifying regulatory and developmental mechanisms underlying evolutionary transitions
Three new species of Raphitoma Bellardi, 1847 (Mollusca, Gastropoda, Raphitomidae) from Croatian waters (NE Adriatic Sea)
No full textThree new species of the neogastropod family Raphitomidae Bellardi, 1875, are described from the Croatian waters of the Adriatic Sea: Raphitoma petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp., R. pusaterii Prkić & Giannuzzi-Savelli n. sp. and R. stanici Prkić, Giannuzzi-Savelli & Pusateri n. sp. The new species are diagnosed by teleoconch characters and by genetic data (COI sequences) in an integrative taxonomy framework. They belong to a group of species with microgranules on the external surface of all teleoconch whorls and all three have a multispiral protoconch indicating a planktotrophic larval phase. The first two species are so far known only from material found in Croatia. R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. and R. stanici Prkić, Giannuzzi-Savelli & Pusateri n. sp. are predominantly shallow-water species, whereas R. pusaterii Prkić & Giannuzzi-Savelli n. sp. has been so far collected only from deeper bottoms with presence of the red coral, Corallium rubrum (Linnaeus, 1758). Syntypes of Murex echinatusBrocchi, 1814 are figured and commented
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
Characterization of prevalence and genetic subtypes of Blastocystis sp. in wild and domestic Suidae of central Italy aided by amplicon NGS
Full text linkBlastocystis spp. is a common single-celled intestinal symbiont, comprising several genetic subtypes (ST) and trans-
missible by animal-to-animal, human-to-human, animal-to-human and, possibly, human-to-animal routes. This work
was designed to explore the presence of Blastocystis in sympatric domestic and wild suids and their ability to carry
zoonotic STs, in a condition of widespread opportunity to come in contact with the microorganism through their
shared water and food resources, and other carriers. We sampled 42 and 37 stool samples from wild boars and
domestic pigs, respectively. STs were first identified by PCR followed by Sanger sequencing. Sequences represented in
double-band PCR products or in Sanger chromatograms displaying multiple peaks, were resolved by next generation
sequencing (NGS). Twenty-six (61.9%) wild boar and 26 (70.2%) pig samples were PCR-positive, respectively. ST3,
ST5 and ST15 were found in 3.8%, 38.4% and 80.8% of the positive wild boars and 11.5%, 88.5%, 11.5% of the
positive pigs, respectively. ST1 was found only in pigs (3.8%). STs 5 and 15 were common in both groups of animals,
but in reversed proportions, suggesting preferential colonization. We found significantly different ST distributions
among wild boars and domestic pigs. This might indicate that lifestyle differences between the two populations
influence their risk for contracting certain subtypes, or that ST5 and ST15 can colonize preferentially wild or domestic
animals. Based on the STs described here, wild boars and domestic pigs can act as reservoirs with zoonotic potential.
The ability of suids to carry zoonotic STs appears to be higher when using NGS than Sanger sequencing, and resolution
of complex sequencing profiles is imperative before excluding the presence of STs of human concern
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