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17 záznamů v Medvik Filtry

Článek

Systematic position of Ascopus Marshall, Oreosecus Marshall, Perarogula Hoffmann and Rhadinocopes Hustache (Coleoptera: Curculionidae: Entiminae) with description of a new species of Ascopus from Guinea

Borovec, Roman
Autor Borovec, Roman Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Department of Forest Protection and Entomology, Kamýcká 1176, CZ-165 21 Praha 6-Suchdol, Czech Republic.. romanborovec@mybox.cz
Perrin, Hélène
Autor Perrin, Hélène

Zootaxa. 2019 ; 4668 (2) : zootaxa.4668.2.5. [pub] 20190910

ISSN 1175-5334
Medvik
Zdroj

Type material of the described species of Ascopus Marshall, 1951, Oreosecus Marshall, 1950, Perarogula Hoffmann, 1963 and Rhadinocopes Hustache, 1931 was examined and their taxonomic status is discussed. Oreosecus Marshall, 1950 and Rhadinocopes Hustache, 1931 are proposed as junior synonyms of Tapinomorphus Hartmann, 1904, Perarogula Hoffmann, 1963 is proposed as a junior synonym of Ascopus Marshall, 1951. Rhadinocopes curvipes Hustache, 1931, R. echinatus Marshall, 1951 and Perarogula lamottei Hoffmann, 1963 are transferred as valid species to the genus Ascopus, Rhadinocopes alticola Hustache, 1939, R. orientalis Hustache, 1931 and Oreosecus porculus Marshall, 1950 are transferred as valid species to the genus Tapinomorphus. Lectotypes of Rhadinocopes orientalis Hustache, 1931 and Rhadinocopes alticola Hustache, 1939 are designated. Ascopus girardi sp. nov. from Guinea, Mt. Nimba, is described and compared with all other species of the genus. Male and female genitalia of Ascopus are described and illustrated for the first time. A key to Ascopus species is presented.

Článek

Idiosyncratic responses to climate-driven forest fragmentation and marine incursions in reed frogs from Central Africa and the Gulf of Guinea Islands

Molecular ecology. 2017 ; 26 (19) : 5223-5244. [pub] 20170824

Mol Ecol
ISSN 1365-294X
Medvik
Zdroj

Organismal traits interact with environmental variation to mediate how species respond to shared landscapes. Thus, differences in traits related to dispersal ability or physiological tolerance may result in phylogeographic discordance among co-distributed taxa, even when they are responding to common barriers. We quantified climatic suitability and stability, and phylogeographic divergence within three reed frog species complexes across the Guineo-Congolian forests and Gulf of Guinea archipelago of Central Africa to investigate how they responded to a shared climatic and geological history. Our species-specific estimates of climatic suitability through time are consistent with temporal and spatial heterogeneity in diversification among the species complexes, indicating that differences in ecological breadth may partly explain these idiosyncratic patterns. Likewise, we demonstrated that fluctuating sea levels periodically exposed a land bridge connecting Bioko Island with the mainland Guineo-Congolian forest and that habitats across the exposed land bridge likely enabled dispersal in some species, but not in others. We did not find evidence that rivers are biogeographic barriers across any of the species complexes. Despite marked differences in the geographic extent of stable climates and temporal estimates of divergence among the species complexes, we recovered a shared pattern of intermittent climatic suitability with recent population connectivity and demographic expansion across the Congo Basin. This pattern supports the hypothesis that genetic exchange across the Congo Basin during humid periods, followed by vicariance during arid periods, has shaped regional diversity. Finally, we identified many distinct lineages among our focal taxa, some of which may reflect incipient or unrecognized species.

Článek online

No measurable adverse effects of Lassa, Morogoro and Gairo arenaviruses on their rodent reservoir host in natural conditions

Parasites & vectors. 2017 ; 10 (1) : 210. [pub] 20170427

Parasit Vectors
ISSN 1756-3305
Medvik
Zdroj

BACKGROUND: In order to optimize net transmission success, parasites are hypothesized to evolve towards causing minimal damage to their reservoir host while obtaining high shedding rates. For many parasite species however this paradigm has not been tested, and conflicting results have been found regarding the effect of arenaviruses on their rodent host species. The rodent Mastomys natalensis is the natural reservoir host of several arenaviruses, including Lassa virus that is known to cause Lassa haemorrhagic fever in humans. Here, we examined the effect of three arenaviruses (Gairo, Morogoro and Lassa virus) on four parameters of wild-caught Mastomys natalensis: body mass, head-body length, sexual maturity and fertility. After correcting for the effect of age, we compared these parameters between arenavirus-positive (arenavirus RNA or antibody) and negative animals using data from different field studies in Guinea (Lassa virus) and Tanzania (Morogoro and Gairo viruses). RESULTS: Although the sample sizes of our studies (1297, 749 and 259 animals respectively) were large enough to statistically detect small differences in body conditions, we did not observe any adverse effects of these viruses on Mastomys natalensis. We did find that sexual maturity was significantly positively related with Lassa virus antibody presence until a certain age, and with Gairo virus antibody presence in general. Gairo virus antibody-positive animals were also significantly heavier and larger than antibody-free animals. CONCLUSION: Together, these results suggest that the pathogenicity of arenaviruses is not severe in M. natalensis, which is likely to be an adaptation of these viruses to optimize transmission success. They also suggest that sexual behaviour might increase the probability of M. natalensis to become infected with arenaviruses.