1,720,983 research outputs found
Larvae of Sulcascaris sulcata (Nematoda: Anisakidae), a parasite of sea turtles, infect the edible purple dye murex Bolinus brandaris in the Tyrrhenian Sea
No full textAnisakid nematodes are among the most common helminth parasites of the marine realm, particularly important for their implications with human infections and/or allergies. Members of the Anisakidae use aquatic mammals, birds and fish as definitive hosts, and crustaceans, fish and molluscs as intermediate/paratenic hosts. Sulcascaris sulcata, the only species in the monotypic genus Sulcascaris, represents the exception being a parasite of sea turtles as adult. The recent findings of larvae of S. sulcata in scallops (Pecten jacobeus and Aequipecten opercularis) and Mediterranean mussels Mytilus galloprovincialis intended for human consumption from the Mediterranean Sea caused concern regarding the sanitary control of edible molluscs and consumer safety. Herein, we investigated the larval anisakids collected from the purple dye murex, Bolinus brandaris, harvested for human consumption from the Central Mediterranean Sea (Tyrrhenian Sea). Morphological study and sequence analysis of the internal transcribed spacer regions of the ribosomal DNA and the mitochondrial cytochrome c oxidase subunit 2 gene locus revealed the occurrence of fourth stage larvae of S. sulcata in 16% of the purple dye murex examined. The present study adds the purple dye murex to the list of the known intermediate hosts of this parasite in the Mediterranean Sea and the northern coast of Campania region as site where individuals of loggerhead turtle and purple dye murex may become infected. This is the first study reporting an anisakid nematode in edible gastropods. Epidemiological features of infection in the purple dye murex and implications for gastropod safety and risk for consumers are discussed
A DNA-barcoding approach to the phenotypic diversity of Mediterranean species of Felimare Ev. Marcus & Er. Marcus, 1967 (Mollusca: Gastropoda), with a preliminary phylogenetic analysis
Full text linkABSTRACT: The chromodorid nudibranchs Felimare tricolor (Cantraine, 1835), F. fontandraui (Pruvot-Fol, 1951) and F. picta (Shultz in Philippi, 1836) typically show highly variable colour patterns that are misleading for species identification. Their taxonomy has long been confused, and their identification can be difficult if based only on morphological characters. We carried out molecular genetic analyses using the mitochondrial cytochrome c oxidase subunit I (COI) and 16S rDNA markers on Mediterranean samples of these three taxa representing a large part of their range of chromatic variation. Results proved the usefulness of the DNA-barcoding approach in assessing species delimitation in this group, and in identification of specimens with body colours not clear for species recognition. We inferred preliminary phylogenetic relationships among one third of the currently recognised species of Felimare: they indicated with good support sister species relationship among Felimare tricolor and F. fontandraui, and suggested (with low support) potential relationships among F. picta, F. verdensis, F. californiensis and F. agassizi. © 2016 Unione Zoologica Italiana
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
Sympatric sibling species: The case of Caloria elegans and Facelina quatrefagesi (Gastropoda: Nudibranchia)
Full text linkThe aeolid nudibranch Caloria elegans (Facelinidae) is quite common in the Mediterranean Sea and eastern Atlantic Ocean and is easily recognized by the presence of a typical black spot at the apical portion of its cerata. Facelina quatrefagesi (Facelinidae) was long considered as a synonym of C. elegans until recently, when it was re-evaluated as a valid species based mainly on rhinophore morphology. In order to definitively assess the status of these aeolid taxa, we employed an integrative taxonomy approach using the nuclear H3 and the two mitochondrial cytochrome oxidase subunit I and 16S markers. The molecular analyses clearly showed that, although morphologically closely related to C. elegans, F. quatrefagesi is a valid species
First record of Calma gobioophaga Calado and Urgorri, 2002 (Gastropoda: Nudibranchia)in the Mediterranean sea
Full text linkSpecimens of the nudibranch genus Calma were observed under boulders at two Croatian localities while feeding on gobiid eggs. Some ambiguous morphological features compared with the original descriptions of the known species of the genus, C. glaucoides and C. gobioophaga hampered easy identification. Genetic data (COI and 16S sequences) confirmed the distinction between the two species of the genus Calma, and allowed unambiguous identification of the Croatian specimens as Calma gobioophaga. This is the first record of this species for the Mediterranean and extends its distribution range remarkably. Finally, the eggs consumed by the Croatian C. gobioophaga specimens have been taxonomically identified by using the 12S rDNA marker as Gobius cobitis
A molecular framework for the systematics of the Mediterranean spindle-shells (Gastropoda, Neogastropoda, Fasciolariidae, Fusininae)
Full text linkA remarkably high diversity of native small spindle-shells (Gastropoda, Fasciolariidae, Fusininae) has been recently invento- ried in the Mediterranean Sea, with 23 species identified based on shell morphology. They have almost invariably been classified in the genus Fusinus, and a few of them recently moved to other genera (Aptyxis Troschel 1868, Aegeofusinus Russo, 2017 and Gracilipurpura Jousseaume, 1880), mostly based on the sole shell features. We have reconstructed a molecular phylogenetic framework for the Mediterranean Fusininae, focusing on native species representative of the genus-level taxa. Our results con- firmed that Fusinus s.s. (type species Murex colus Linnaeus, 1758) should be restricted to a group of large-shelled species from the Indo-West Pacific and does not fit any of the small-shelled Mediterranean fusinines. We confirm that Murex syracusanus Linnae- us, 1758 represents a distinct lineage, and show that for all the remaining species the pattern is suggestive of a single monophyletic radiation of small Mediterranean fusinines, for which the name Pseudofusus Monterosato, 1884 must be used
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
- …
