1,721,104 research outputs found
Molecular and Morphological differentiation between steganacarid mites (Acari: Oribatida) from the Canary islands
No full textTwo steganacarid species, Steganacarus (Steganacarus)tenerifensis and S. (S.)carlosi, the first endemic to Tenerife and the second to La Gomera and Tenerife, were found to have such wide morphological variability as to cast doubt on their specific limits. Cluster analysis and MDS ordering were used to quantify morphological variation, and biochemical procedures were used to assess genetic variation in the two entities. The results revealed disagreement between the morphological and genetic data as reported in previous studies on steganacarid mites. Morphological traits were highly heterogeneous in the Canary island populations and genetic structure was homogeneous with very low heterozygosity. The separation of the two Canary island species, not to mention the phenotypes close to carlosi, is difficult to justify due to their very high genetic identity. The presence of morphological intermediates suggests the same conclusion. However, the sympatry of some phenotypes and previous data on this animal group are a source of doubt and suggest that further investigations are needed before conclusions can be reached in this regard. Correlations between morphological differentiation and known palaeogeographic events are suggested in the light of the possible evolutionary history of the steganacarid mites on the Canary islands
F in Taxonomic revision of Amerus troisi (Berlese, 1883) (Acari, Oribatida, Ameridae) using morphological and biochemical characters
No full textF. 6. Cladogram based on UPGMA clustering of the genetic distance data showing genetic relationships between populations.Published as part of AVANZATI, A. M., SALOMONE, N., BARATTI, M. & BERNINI, F., 2003, Taxonomic revision of Amerus troisi (Berlese, 1883) (Acari, Oribatida, Ameridae) using morphological and biochemical characters, pp. 797-819 in Journal of Natural History 37 (7) on page 815, DOI: 10.1080/00222930110097662, http://zenodo.org/record/527427
Genetic and morphological analysis of some European species of the “coriaceus group” of Carabodes (Acari, Oribatida, Carabodidae) and description of C. tyrrhenicus sp. nov.
No full textThe oribatid mite Carabodes reticulatus Berlese, 1913 is redescribed from typical and topotypical material. A new species, C. tyrrhenicus, widespread in Sardinia and other Tyrrhenian islands, is also described on the basis of morphological evidence. Scanning electron microscpy was used to study intra- and inter-specific variation, in order todetermine diagnostic characters. The morphology-based taxonomy was tested through allozyme analysis of the two species and of two closely related species, namely C. coriaceus C.L. Koch, 1836 and C. arduinii Valle, 1955. Allozyme data are largely congruent with morphological evidence, indicating that the four entities represent well-differentiated evolutionary lineages. Molecular results show large inter-specific genetic differentiation, suggesting that these taxa arose from ancient cladogenetic events
Oribatid mites (Acari Oribatida) of the Farma Valley (Southern Tuscany). Notulae Oribatologicae. 66
No full textThe results of research on the oribatid mite fauna of the Farma Valley (Southern Tuscany) are reported. 195 species were collected, two of which are new and will be described in a coming paper. The species Acaronychus traegardhi, Liochthonius hystricinus, L. lapponicus, L. strenzkei, Sellnickochthonius zelawaiensis, Phthiracarus membranifer, Liacarus perezinigoi, L. subterraneus and Zetomimus furcatus are reported in Italy for the first time. Phthiracarus clavatus, Hafenrefferia gilvipes, Autogneta longilamellata, Raphigneta numidiana, Podoribates longipes, Lauritzenia tenuifusus and Globozetes longipilus are rare and give rise to interesting considerations in relation to geographic distribution. The naturalistic value of the area is discussed on the basis of ecological elements such as rarity, pattern of occurrence and distribution in the many biotopes of the individual oribatid mites species. The authors report that "exposure effect" has a slight effect on oribatid fauna and confirm the high naturalistic value of the area
Genetic variation in Sardinian populations of the Green oak leaf roller Tortrix viridana L. (Lepidoptera, Tortricidae)
No full textTicks in the box: Argas persicus occurrence in nest boxes of secondary cavity-nesting bird species in Italy
Full text linkMigratory organisms can be vectors of parasitic host organisms that can then be transported along seasonal migratory journeys and spread across continents. Ornithophilic nidicolous ticks (e.g. soft ticks) include species responsible for the transmission of pathogens and bacteria, thus representing a health problem not only for wild species that are directly parasitized, but also for those that share the same environments or reproductive sites with them. In this regard, artificial nests for birds may turn out to be site-sources of parasites. Here, we document the occurrence of different life stages of Argas persicus ticks in nest boxes of wild birds in a natural area (not associated with poultry activities) of central coastal Italy (Maremma Regional Park, Tuscany). Between 2018 and 2022, 168 ticks were collected from nest boxes occupied by different secondary cavity-nesting birds, such as European rollers Coracias garrulus and scops owl Otus scops. Ticks were analysed morphologically, and selected specimens were also identified by mitochondrial ribosomal 16S (16S) subunit gene to ascertain their taxonomic status. All ticks were identified as Argas persicus. This finding not only suggests that this tick species has formed a viable population in this Italian region, but also further confirms the previously doubtful natural origin of the species at country level and sheds new light on its underestimated and little investigated distribution. Possible pathways of introduction and its potential impacts on local avian community are discussed
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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