1,721,005 research outputs found
Identification of Monogenea made easier: a new statistical procedure for an automatic selection of diagnostic linear measurements in closely related species
No full textWe introduce a new statistical method to select which morphological
characters are most useful to identify monogenean species. The method
estimates the average size overlap of candidate diagnostic structures
among a set of species to individuate those that mostly differ between
the species. To demonstrate our approach, we report a comprehensive
analysis conducted on two of the most species-rich monogenean genera:
Dactylogyrus Diesing, 1850 and Gyrodactylus von Nordmann, 1832. We
demonstrate that, in contrast to common taxonomic practice, very few but
highly diagnostic measurements are necessary to correctly identify a
specimen. In particular, we found that most of Dactylogyrus and
Gyrodactylus species can be classified on the basis of the width of the
supplementary connecting bar and of the length of the hook sickle,
respectively
Nestedness for Dummies (NeD): A User-Friendly Web Interface for Exploratory Nestedness Analysis
Full text linkRecent theoretical advances in nestedness analysis have led to the introduction of several alternative metrics to overcome most of the problems biasing the use of matrix 'temperature' calculated by Atmar's Nestedness Temperature Calculator. However, all of the currently available programs for nestedness analysis lack the user friendly appeal that has made the Nestedness Temperature Calculator one of the most popular community ecology programs. The software package NeD is an intuitive open source application for nestedness analysis that can be used online or locally under different operating systems. NeD is able to automatically handle different matrix formats, has batch functionalities and produces an output that can be easily copied and pasted to a spreadsheet. In addition to numerical results, NeD provides a graphic representation of the matrix under examination and of the corresponding maximally packed matrix. NeD allows users to select among the most used nestedness metrics, and to combine them with different null models. Integrating easiness of use with the recent theoretical advances in the field, NeD provides researchers not directly involved in theoretical debates with a simple yet robust statistical tool for a more conscious performance of nestedness analysis. NeD can be accessed at http: //purl.oclc.org/ned
Description of Turritopsoides marhei sp. nov. (Hydrozoa, Anthoathecata) from the Maldives and its phylogenetic position
No full textPteroclava krempfi-octocoral symbiosis: new information from the Indian Ocean and the Red Sea
No full textECo: A new measure evaluating the degree of consistency between environmental factors and spatial arrangement of species assemblages
Full text linkWe introduce a measure of Environmental Consistency (ECo), which assesses the probability of reducing homogeneity in the environmental factors within a species' distribution by randomly displacing its occurrences. ECo is computed by applying null model analysis to a species incidence matrix where each locality is associated with a set of environmental values. Environmental homogeneity is measured, for each species, as the average multiparametric distance between any pair of localities where the species occurs. ECo can account for the effect of species interactions and resource availability by using different null models that permit or forbid occurrence displacements altering species local abundance or species prevalence. ECo provides researchers with a flexible statistical framework to address a wide range of ecological and biogeographical issues. We investigated in depth the properties and the potentialities of ECo, showing how it integrates the concepts of Eltonian and Grinnelian niches. We demonstrate that a close relationship exists between niche breadth at species level and environmental consistency of species assemblages. In addition, we provide evidence that ecological consistency is closely related to species range. (C) 2014 Elsevier Ltd. All rights reserved
FIGURE 3 Kudacoryne diaphana. Polyps from A, B in Integrative systematics illuminates the relationships in two sponge-associated hydrozoan families (Capitata: Sphaerocorynidae and Zancleopsidae)
No full textFIGURE 3 Kudacoryne diaphana. Polyps from A, B) Red Sea and C, D) Maldives. E) Hypostome. F) Capitulum. G) Polyps with medusa buds a few hours before release. H) Newly released medusa. I) Large stenoteles (ls), small stenoteles (ss), and desmonemes (d) from the polyp stage. J) Macrobasic mastigophore from the polyp stage. K) Small stenoteles (ss) and microbasic mastigophores (mi) from the newly released medusa. Scale bars: A-D, G) 0.2 mm; E, H) 50 µm; F) 20 µm; I-K) 5 µm.Published as part of Maggioni, Davide, Schuchert, Peter, Arrigoni, Roberto, Hoeksema, Bert W., Huang, Danwei, Strona, Giovanni, Seveso, Davide, Berumen, Michael L., Montalbetti, Enrico, Collins, Richard, Galli, Paolo & Montano, Simone, 2021, Integrative systematics illuminates the relationships in two sponge-associated hydrozoan families (Capitata: Sphaerocorynidae and Zancleopsidae), pp. 487-525 in Contributions to Zoology 90 on page 503, DOI: 10.1163/18759866-BJA10023, http://zenodo.org/record/834332
Kudacoryne Maggioni 2021, gen. nov.
No full textKudacoryne Maggioni gen. nov. http://zoobank.org/ urn:lsid:zoobank.org:act: 8BF43568-3611-402F-A24D-C54B060AA119 Diagnosis: Hydroids like in Sphaerocoryne; medusae unknown. Genetic diagnosis: 45 molecular diagnostic characters differentiate Kudacoryne from other genera in the family, specifically 12 in the 16S, 17 in the COX1, 14 in the COX3, 1 in the 18S, and 1 in the 28S (table 2). Etymology: The generic name derives from the combination of ‘Kuda’, meaning ‘little’ in Divehi (Maldivian) language, reflecting the smaller size of polyps compared to other sphaerocorynid species, and - coryne. Type species: Kudacoryne diaphana Maggioni sp. nov.Published as part of Maggioni, Davide, Schuchert, Peter, Arrigoni, Roberto, Hoeksema, Bert W., Huang, Danwei, Strona, Giovanni, Seveso, Davide, Berumen, Michael L., Montalbetti, Enrico, Collins, Richard, Galli, Paolo & Montano, Simone, 2021, Integrative systematics illuminates the relationships in two sponge-associated hydrozoan families (Capitata: Sphaerocorynidae and Zancleopsidae), pp. 487-525 in Contributions to Zoology 90 on page 500, DOI: 10.1163/18759866-BJA10023, http://zenodo.org/record/834332
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
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