1,720,987 research outputs found
Reproductive mode and genetic polymorphism in different populations of the tardigrade Richtersius coronifer (Eutardigrada, Macrobiotidae)
No full text
Relazioni filogenetiche tra alcuni Eutardigrada: dati molecolari e morfologici a confronto
No full textPhylogenetic analysis in Macrobiotidae (Eutardigrada, Parachela): a combined morphological and molecular approach
No full textCombined analyses of morphological and molecular data were used to resolve the phylogenetic relationships within Macrobiotidae (Eutardigrada). Morphological data were analysed, by a cladistic approach using a matrix composed of 15 taxa with 16 characters to obtain a phylogenetic reconstruction. Molecular data were obtained by sequencing the Cytochrome c Oxidase subunit I gene in seven species of Macrobiotidae and one of Eohypsibiidae (used as outgroup). Neither morphological nor molecular analyses supports a monophyletic clade for Macrobiotidae, whereas both support a well defined evolutionary line (Murrayinae) within the family. We propose to elevate this clade to family level (Murrayidae) and to keep temporarily valid the family Macrobiotidae whilst amending its diagnosis. Murrayidae opens an interesting evolutionary prospective, because the entire line has differentiated without sexual reproduction, constituting an example of evolution of asexual lineages
GENETIC POLYMORPHISM IN AMPHIMICTIC AND AUTOMICTIC POPULATIONS OF THE EUTARDIGRADE RICHTERSIUS CORONIFER (TARDIGRADA, MACROBIOTIDAE)
No full textMacrobiotus pseudohufelandi Iharos as a model for cytotaxonomic study in populations of eutardigrades (Tardigrada).
No full textThe paper illustrate a cytophotometric approach able to furnish cytotaxonomic information regarding Macrobiotus pseudohufelandi Iharos (Tardigrada)
Increasing knowledge of Antarctic biodiversity: new endemic taxa of tardigrades (Eutardigrada; Ramazzottiidae) and their evolutionary relationships
No full textThe underestimation of biodiversity and scarce knowledge of the biogeographic distributions of terrestrial meiofaunal component limit our understanding of the origin of Antarctic fauna. One of its main components is tardigrades; nonetheless studies on tardigrade diversity are still few in the continental Antarctic area. In order to increase our knowledge of the underreported terrestrial meiofaunal communities within continental Antarctica, as well as to provide new information for biogeographic and evolutionary analysis of these communities, the tardigrade diversity of 11 samples collected along the coast of Victoria Land was considered. The application of an integrative approach in which morphological (Light - LM, scanning electron - SEM, and confocal laser scanning microscopy - CSLM) and molecular analysis (18S, 28S, cox1 genes) were combined allowed us to characterize the tardigrade fauna inhabiting mosses, lichens, and cyanobacterial mats of Victoria Land. These analyses allowed the detection of two tardigrade species new to science (Cryoconicus antiarktos sp. nov., Ramazzottius sabatiniae sp. nov.), and the emendation of known species ((Hebesuncus ryani Dastych and Harris, 1994, Ramazzottius nivalis Dastych, 2006, Cryoconicus ljudmilae comb. nov. (Biserov, 1997/98), and Cryoconicus cataphractus (Maucci, 1974)), together with the genus Cryoconicus. The Ramazzottius type of claws was redefined identifying three subtypes. Also, we investigated the phylogenetic position of some problematic/unresolved lineages all belonging to the family Ramazzottiidae. These data increased the knowledge of the biodiversity in Victoria Land, the number of endemic tardigrades in Antarctica, and provided evidence on the origin of Antarctic endemism. Lastly, new methods for integrative taxonomic studies on tardigrades were presented and discussed
PHYLOGENETIC RELATIONSHIPS IN MACROBIOTIDAE (TARDIGRADA). II. MOLECULAR (MTDNA) AND MORPHOLOGICAL APPROACHES
No full text
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
- …
