1,720,959 research outputs found
Phylogenetic relationships and hierarchical classification of the supergeneric taxa of pannote mayflies (Ephemeroptera)
No full textPhylogeny and supergeneric classification of the pannote mayflies are proposed by way of a strict cladistic analysis. Fifteen monophyletic groups of genera served as the operational taxonomic units. The operational taxonomic units were characterized on the basis of all genera of pannote mayflies, and comparative character states of each group were tabulated in a character matrix and subjected to cladistic analysis. A strict phylogenetic hierarchical classification is formulated from the cladistic results, and previous paraphyletic and polyphyletic family concepts within the study group have been corrected. Four superfamilies and eleven families are recognized: Baetiscoidea (Baetiscidae and Prosopistomatidae), Caenoidea (Caenidae and Neoephemeridae), Ephemerelloidea (Teloganodidae and Ephemerellidae), and Tricorythoidea superfam. nov. (Teloganellidae fam. nov., Leptohyphidae, Ephemerythidae stat. nov., Tricorythidae, and Dicercomyzidae stat. nov.). Distinctive primary clades within families are recognized as subfamilies: Caenidae (Caeninae and Brachycercinae), Ephemerellidae (Ephemerellinae and Timpanoginae stat. nov.), Teloganodidae (Austremerellinae and Teloganodinae), and Leptohyphidae (Leptohyphinae and Machadorythinae). The description, diagnosis, taxa makeup (genera for subfamily, subfamilies for family, and families for superfamily), and distribution are given for each subfamily, family, and superfamily. A stage correlated identification key to the revised superfamilies, families, and subfamilies is included. Two hundred and fifty-one morphological figures are provided
Diversity and identification of heptageniid mayflies (Insecta: Ephemeroptera) of the world
No full textThe purpose of the present study was to collate existing information on the mayfly family Heptageniidae in order to facilitate further studies on this speciesrich and ecologically significant group. A catalog of heptageniid taxa was compiled using nearly 700 publications. Three subfamilies, 14 tribes, 32 genera, 607 species, and 24 subspecies are recognized as valid. The number of valid names, synonyms, and combinations include 59 genus-group names, 1505 species, and 66 subspecies. Epeorus soldani Nguyen & Bae is a junior secondary homonym of Epeorus soldani (Braasch) and is herein renamed Epeorus nguyeni Webb & McCafferty. The following species are herein designated as nomina nuda: Rhithrogena carnivora Kluge; R. gunti Kluge; R. pamirica Kluge; R. californica Day; Ecdyonurus tener Braasch; E. vulgatus Braasch. The following new combinations are proposed: Afronurus separatus (Nguyen & Bae); Electrogena apicata (Braasch); Electrogena bilineata (Braasch); Electrogena pakistanica (Braasch); Electrogena signata (Braasch); Electrogena subfusca (Kimmins); Electrogena wittmeri (Braasch); Epeorus papillatus (Braasch); Epeorus suspicatus (Braasch). New name emendations include: Cinygma rubescente You; Cinygma xiasimaense You; Cinygmula sapporensis (Matsumura); Epeorus alpicola (Eaton); Epeorus sylvicola (Pictet); Rhithrogena binervis Kluge; Rhithrogena johanni Belfiore; Epeorus montanus intermedius (Brodsky); Epeorus montanus minutus (Brodsky); Epeorus montanus montanus (Brodsky); Epeorus montanus nigromaculatus (Brodsky). Illustrated keys for the larvae and males of the genera of the world, female adults of the North American genera, larvae of the species of Trichogenia Braasch & Soldán, and larvae of the eastern North American Epeorus vitreus species group were developed. The following synonymies were established: Heptagenia elegantula (Eaton, 1883)[=H. diabasia Burks, 1946]; Epeorus vitreus (Walker, 1853) [=E. rubidus Traver, 1933]; Ecdyogymnurus Kluge [=Siberionurus McCafferty]; Rhithrogena [=Himalogena Kluge.; =Sibirigena Kluge; =Tumungula Zhou & Peters]; Epeorus [=Alpiron Braasch; =Albertiron Kluge; = Caucasiron Kluge; =Proepeorus Kluge]; Compsoneuria [=Siamoneuria Braasch]. The following new taxa were described: Darthus Webb & McCafferty; Darthus vadorus Webb & McCafferty; Trichogenia ulmeri Braasch & Webb; T. hubleyi Webb & McCafferty; Heptagenia whitingi Webb & McCafferty. Previously unknown life stages were described for Epeorus aculeatus Braasch and E. punctatus (McDunnough). The relationships and status of the North American species of Heptagenia Walsh were analyzed using morphological characters and the mitochondrial gene cytochrome oxidase I
Atlas and biogeographic review of the North American mayflies (Ephemeroptera)
No full textAn atlas detailing state and provincial distributions of 663 North American Ephemeroptera species is presented. Biogeographic affinities of 95 North American genera are discussed and their hypothesized origins reviewed. Historical events in regards to vicariance and dispersal were important factors influencing the evolution of the North American fauna. Lineages found in North America are a result of Northern Hemisphere vicariant events (e.g., plate tectonics) and periods of dispersalist invasion, notably via the Isthmus of Panama and Beringia. The North American fauna is composed predominantly of Nearctic endemics/relicts, and lineages with Laurasian or Neotropical affinities. Although Cloeodes and Ephoron are hypothesized to have a Gondwanan origin and invaded North America via the Neotropics and Laurasia, respectively. Caenis may be of ancient Pangean origin, and in North America may consist of elements of recent boreal and austral affinities. The Nearctic endemic/relict element is comprised of 33 genera, with Litobrancha and Siphloplecton considered relictual based on fossil evidence. Thirty-one North American genera are hypothesized to be of Nearctic origin, although Analetris and Baetisca, because of cladistic data, are relictual in the Nearctic. Thirty-seven genera have a Laurasian affinity and hypothesized origin. Afghanurus, Baetopus, and Cloeon are hypothesized to have an east Laurasian origin. Twenty-five North American genera have Neotropical affinities and hypothesized origin. Moribaetis, Varipes, Ableptemetes, Hydrosmilodon, and Euthyplocia occur only in the Neotropics, and most others are found mainly in southwestern North America, Callibaetis and Tortopus being notable exceptions. North American species are arranged under fifteen distribution patterns. It is evident there are distinct eastern and western faunas. One-hundred and sixty-one species are widespread Eastern, 36 are Northeastern, and 75 are Southeastern. Sixty-eight species are widespread Western, 100 are Northwestern, and 66 are Southwestern. Forty species are known only from Neotropical Mexico. Certain species have discontinuous distributions, which are either an artifact of incomplete collection data (e.g., Plauditus cestus) or true disjunctions resulting from events such as Pleistocene glaciation (e.g., Cinygmula subaequalis) or disjunction of specific habitats (e.g., Dolania americana). Remaining patterns comprise a small element of the North American fauna (12 species), including Northwest+Northeast, Far North+Northeast, East+Northwest, Far North+Northwest+Northeast, and Northwest+Northeast+Southwest
Systematic studies of Baetidae (Insecta: Ephemeroptera), with emphasis on biodiversity in the southern hemisphere
No full textThirty-two new genera and 63 new species of small minnow mayflies (Insecta: Ephemeroptera: Baetidae) are described from the Afrotropical. (15 genera, 30 species), Neotropical (13 genera, 24 species), Australian (three genera, 19 species), and Nearctic (one genus) regions. New Afrotropical genera include Barnumus, Bugilliesia, Crassabwa, Dabulamanzia, Delouardus, Demoreptus, Edmulmeatus Glossidion, Herbrossus, Kivua, Maliqua, Nesydemius, Peuhlella, Susua, and Xyrodromeus. New Neotropical genera include Adebrotus, Andesiops, Aturbina, Cryptonympha, Deceptiviosa, Nanomis, Prebaetodes, Rivudiva, Spiritiops, Tomedontus, Varipes, Waltzoyphius, and Zelusia. New Australian genera include Edmundsiops, Offadens , and Papuanatula. The new Nearctic genus is Plauditus. New regional generic reports involve Cloeodes and Pseudocloeon from Australia; Apobaetis from the Neotropics; and Pseudocloeon from the Afrotropics, Nearctic, and Palearctic. The generic concepts of Afroptilum, Baetis (in part), and Pseudocloeon are revised, resulting in numerous synonyms, establishment of new genera, and reassignments of species. Percentages of endemism of the six major world biogeographic regions show that the Neotropical region has the most distinctive fauna, with 96% endemic genera; it is followed by the Afrotropics (84%), Australia (44%), Orient (38%), Nearctic (15%), and Palearctic (14%). Determination of Sorensen\u27s coefficient of biotic affinities is used to discuss baetid faunistics in each biogeographic region, and partly corroborates previous models indicating major centers of evolution. Current problems and prospects in the taxonomy and systematics of Baetidae are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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