5 resultados para horridus species group

em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain


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A new troglobitic species, Nesticus baeticus sp. n. (♂♀), inhabiting the karst landscapes of the high part of the Cazorla, Segura and Las Villas Natural Park (NE Jaén, Spain) where it has been found in 8 caves is diagnosed and described, its distribution and habitat are also analyzed.The new species belongs to the Iberian species group that includes Nesticus luquei, Nesticus lusitanicus and Nesticus murgis. Evolutionary relationships of the Iberian Nesticus species are discussed on the basis of morphological and molecular data (cox1 and rrnL). Arachnida, Araneae, taxonomy, description, new species, caves, Iberian Peninsula, Mediterranean basin

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A new species of the spider genus Loxosceles, L. mrazig sp. n., found in Tunisia is described and illustrated. The male bulb shows a high degree of morphological similarity to that of L. gaucho from Brazil, but the pro- portions of the palpal segments and the general colouration of the body reveal significant differences between the two species. A distance analysis of the sequences of the mitochondrial gene cox1 reveals that the specimen from Tunisia shows high genetic distance from L. gaucho (more than 20%). The American species L. gaucho and L. laeta form a sister group to the Mediterranean representatives (L. rufescens and the Tunisian specimen). Taxonomy, Araneae, Loxosceles, new species, Tunisia.

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Schmidtea mediterranea (Platyhelminthes, Tricladida, Continenticola) is found in scattered localities on a few islands and in coastal areas of the western Mediterranean. Although S. mediterranea is the object of many regeneration studies, little is known about its evolutionary history. Its present distribution has been proposed to stem from the fragmentation and migration of the Corsica-Sardinia microplate during the formation of the western Mediterranean basin, which implies an ancient origin for the species. To test this hypothesis, we obtained a large number of samples from across its distribution area. Using known and new molecular markers and, for the first time in planarians, a molecular clock, we analysed the genetic variability and demographic parameters within the species and between its sexual and asexual populations to estimate when they diverged. Results: A total of 2 kb from three markers (COI, CYB and a nuclear intron N13) was amplified from ~200 specimens. Molecular data clustered the studied populations into three groups that correspond to the west, central and southeastern geographical locations of the current distribution of S. mediterranea. Mitochondrial genes show low haplotype and nucleotide diversity within populations but demonstrate higher values when all individuals are considered. The nuclear marker shows higher values of genetic diversity than the mitochondrial genes at the population level, but asexual populations present lower variability than the sexual ones. Neutrality tests are significant for some populations. Phylogenetic and dating analyses show the three groups to be monophyletic, with the west group being the basal group. The time when the diversification of the species occurred is between ~20 and ~4 mya, although the asexual nature of the western populations could have affected the dating analyses. Conclusions: S. mediterranea is an old species that is sparsely distributed in a harsh habitat, which is probably the consequence of the migration of the Corsica-Sardinia block. This species probably adapted to temperate climates in the middle of a changing Mediterranean climate that eventually became dry and hot. These data also suggest that in the mainland localities of Europe and Africa, sexual individuals of S. mediterranea are being replaced by asexual individuals that are either conspecific or are from other species that are better adapted to the Mediterranean climate.

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A study on the taxonomy, morphology and anatomy of the lichenicolous species of the genus Cercidospora (Dothideales, incertae sedis) growing on lichens of the genera Lecanora (Lecanoraceae), specifically of the L. polytropa group and the L. saxicola group (i.e. L. muralis sensu auct. group, Protoparmeliopsis spp.), Rhizoplaca (Lecanoraceae) and Squamarina (Stereocaulaceae) is presented. The following species are proposed as new: Cercidospora barrenoana on Rhizoplaca peltata, and C. melanophthalmae on Rhizoplaca melanophthalma. C. stenotropae is proposed provisionally; this fungus grows on Lecanora stenotropa and other taxa of the L. polytropa group. A key for the species of the genus Cercidospora treated is provided.

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Planarians are a group of free-living platyhelminths (triclads) best-known largely due to long-standing regeneration and pattern formation research. However, the group"s diversity and evolutionary history has been mostly overlooked. A few taxonomists have focused on certain groups, resulting in the description of many species and the establishment of higher-level groups within the Tricladida. However, the scarcity of morphological features precludes inference of phylogenetic relationships among these taxa. The incorporation of molecular markers to study their diversity and phylogenetic relationships has facilitated disentangling many conundrums related to planarians and even allowed their use as phylogeographic model organisms. Here, we present some case examples ranging from delimiting species in an integrative style, and barcoding them, to analysing their evolutionary history on a lower scale to infer processes affecting biodiversity origin, or on a higher scale to understand the genus level or even higher relationships. In many cases, these studies have allowed proposing better classifications and resulted in taxonomical changes. We also explain shortcomings resulting in a lack of resolution or power to apply the most up-to-date data analyses. Next-generation sequencing methodologies may help improve this situation and accelerate their use as model organisms.