200 research outputs found

    A taxonomic revision of ten whitefish species from the lakes Lucerne, Sarnen, Sempach and Zug, Switzerland, with descriptions of seven new species (Teleostei, Coregonidae)

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    The taxonomy of the endemic whitefish of the lakes of the Reuss River system (Lucerne, Sarnen, Zug) and Lake Sempach, Switzerland, is reviewed and revised. Lake Lucerne harbours five species. Coregonus intermundia sp. nov. and C. suspensus sp. nov., are described. Coregonus nobilis Haack, 1882, C. suidteri Fatio, 1885, and C. zugensis Nüsslin, 1882, are redescribed. Genetic studies have shown that C. suidteri and C. zugensis are composed of several distinct species endemic to different lakes. The names C. suidteri and C. zugensis are restricted to the species of lakes Sempach and Zug, respectively. The whitefish populations previously referred to as C. suidteri and C. zugensis from Lake Lucerne are described as C. litoralis sp. nov. and C. muelleri sp. nov., respectively. Furthermore, the whitefish from Lake Zug that were previously referred to as C. suidteri are described as C. supersum sp. nov. A holotype is designated for C. supersum that was previously one of two syntypes of C. zugensis. The other syntype is retained for C. zugensis. Coregonus obliterus sp. nov. is described from Lake Zug, and C. obliterus and C. zugensis from Lake Zug are extinct. Finally, we describe C. sarnensis sp. nov. from lakes Sarnen and Alpnach. Coregonus suidteri from Lake Sempach shows strong signals of introgression from deliberately translocated non-native whitefish species, which questions if the extant population still carries a genetic legacy from the original species and thus may need to be considered extinct. Coregonus suspensus is genetically partially of allochthonous origin, closely related to the radiation of Lake Constance. It is therefore compared to all known and described species of Lake Constance: C. wartmanni Bloch, 1784, C. macrophthalmus Nüsslin, 1882, C. arenicolus Kottelat,1997, and C. gutturosus Gmelin, 1818

    A taxonomic revision of the whitefish of lakes Brienz and Thun, Switzerland, with descriptions of four new species (Teleostei, Coregonidae)

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    The alpha taxonomy of the endemic whitefish of lakes Brienz and Thun, Switzerland, is revised. We evaluate the status of seven known species: Coregonus steinmanni sp. nov., Coregonus profundussp. nov.and Coregonus acrinasussp. nov.are endemic to Lake Thun; Coregonusbrienzii sp. nov. is endemic to Lake Brienz; and C. alpinus, C. albellus, and C. fatioi from lakes Brienz and Thun are redescribed. One of these species, C. alpinus, is revised, since the lectotype for this species is incongruent with the species descrip-tion given by Kottelat (1997) and Kottelat and Freyhof (2007). The name C. alpinus is thus retained for the lectotype designated by Kottelat (1997) and a new description of this taxon provided. For the species otherwise described by Kottelat (1997) and Kottelat and Freyhof (2007) as C.alpinus the new name C. profundus is designated. Coregonusacrinasus is genetically partially of allochthonous origin, closely related to the radiation of Lake Constance, and we therefore compare it to all recognized species of Lake Constance, C. wartmanni, C.macrophthalmus, C. arenicolus,and C. gutturosus

    Female preference for male color is necessary and sufficient for assortative mating in 2 cichlid sister species

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    One fish, two fish, red fish, blue fish: in two cichlid fish species beauty is in the eye of the beholder. Females choose mates based on colour, blue or red, and chemical cues but only colour triggers divergent female preferences. Reliance on one prime male characteristic may have facilitated speciation in this species-pair, but in murky waters the opportunity for visual communication is dim and the fate of the two species uncertai

    Radiographies du thorax et de l’abdomen sans préparation à l’ère du choosing wisely [The chest and plain abdominal radiography in the era of choosing wisely]

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    Chest x-ray and plain abdominal radiography are widely used in the daily practice of the emergency physician. The concept of « Choosing Wisely » implies a more efficient medicine that encourages, among other things, the avoidance of investigations that do not have a significant impact on the therapeutic management of patient. In this context, indications for these two imaging examinations were reviewed, whether in the context of a consultation in the emergency department, a hospital admission or a preoperative check-up

    A Field‐Capable Rapid Plant DNA Extraction Protocol Using Microneedle Patches for Botanical Surveying and Monitoring

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    Premise: A novel protocol for rapid plant DNA extraction using microneedles is proposed, which supports botanic surveys, taxonomy, and systematics. This protocol can be conducted in the field with limited laboratory skills and equipment. The protocol is validated by sequencing and comparing the results with QIAGEN spin-column DNA extractions using BLAST analyses. Methods and Results: Two sets of DNA extractions were conducted on 13 species spanning various leaf anatomies and phylogenetic lineages: (i) fresh leaves were punched with custom polymeric microneedle patches to recover genomic DNA, or (ii) QIAGEN DNA extractions. Three plastid (matK, rbcL, and trnH-psbA) and one nuclear ribosomal (ITS) DNA regions were amplified and sequenced using Sanger or nanopore technology. The proposed method reduced the extraction time to 1 min and yielded the same DNA sequences as the QIAGEN extractions. Conclusions: Our drastically faster and simpler method is compatible with nanopore sequencing and is suitable for multiple applications, including high-throughput DNA-based species identifications and monitoring

    Species-specific relationships between water transparency and male coloration within and between two closely related Lake Victoria cichlid species

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    Environmental variation in signalling conditions affects animal communication traits, with possible consequences for sexual selection and reproductive isolation. Using spectrophotometry, we studied how male coloration within and between populations of two closely related Lake Victoria cichlid species (Pundamilia pundamilia and P. nyererei) covaries with water transparency. Focusing on coloration patches implicated in sexual selection, we predicted that in clear waters, with broad-spectrum light, (1) colours should become more saturated and (2) shift in hue away from the dominant ambient wavelengths, compared to more turbid waters. We found support for these predictions for the red and yellow coloration of P. nyererei but not the blue coloration of P. pundamilia. This may be explained by the species difference in depth distribution, which generates a steeper gradient in visual conditions for P. nyererei compared to P. pundamilia. Alternatively, the importance of male coloration in intraspecific sexual selection may differ between the species. We also found that anal fin spots, that is, the orange spots on male haplochromine anal fins that presumably mimic eggs, covaried with water transparency in a similar way for both species. This is in contrast to the other body regions studied and suggests that, while indeed functioning as signals, these spots may not play a role in species differentiation.</p

    Genomic architecture of adaptive radiation and hybridization in Alpine whitefish

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    Adaptive radiations represent some of the most remarkable explosions of diversification across the tree of life. However, the constraints to rapid diver- sification and how they are sometimes overcome, particularly the relative roles of genetic architecture and hybridization, remain unclear. Here, we address these questions in the Alpine whitefish radiation, using a whole-genome dataset that includes multiple individuals of each of the 22 species belonging to six ecologically distinct ecomorph classes across several lake-systems. We reveal that repeated ecological and morphological diversification along a common environmental axis is associated with both genome-wide allele fre- quency shifts and a specific, larger effect, locus, associated with the gene edar. Additionally, we highlight the possible role of introgression between species from different lake-systems in facilitating the evolution and persistence of species with unique trait combinations and ecology. These results highlight the importance of both genome architecture and secondary contact with hybridization in fuelling adaptive radiation

    A Third Measure-Metastable State in the Dynamics of Spontaneous Shape Change in Healthy Human's White Cells

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    Human polymorphonuclear leucocytes, PMN, are highly motile cells with average 12-15 µm diameters and prominent, loboid nuclei. They are produced in the bone marrow, are essential for host defense, and are the most populous of white blood cell types. PMN also participate in acute and chronic inflammatory processes, in the regulation of the immune response, in angiogenesis, and interact with tumors. To accommodate these varied functions, their behavior is adaptive, but still definable in terms of a set of behavioral states. PMN morphodynamics have generally involved a non-equilibrium stationary, spheroid Idling state that transitions to an activated, ellipsoid translocating state in response to chemical signals. These two behavioral shape-states, spheroid and ellipsoid, are generally recognized as making up the vocabulary of a healthy PMN. A third, “random” state has occasionally been reported as associated with disease states. I have observed this third, Treadmilling state, in PMN from healthy subjects, the cells demonstrating metastable dynamical behaviors known to anticipate phase transitions in mathematical, physical, and biological systems. For this study, human PMN were microscopically imaged and analyzed as single living cells. I used a microscope with a novel high aperture, cardioid annular condenser with better than 100 nanometer resolution of simultaneous, mixed dark field and intrinsic fluorescent images to record shape changes in 189 living PMNs. Relative radial roundness, R(t), served as a computable order parameter. Comparison of R(t) series of 10 cells in the Idling and 10 in the Treadmilling state reveals the robustness of the “random” appearing Treadmilling state, and the emergence of behaviors observed in the neighborhood of global state transitions, including increased correlation length and variance (divergence), sudden jumps, mixed phases, bimodality, power spectral scaling and temporal slowing. Wavelet transformation of an R(t) series of an Idling to Treadmilling state change, demonstrated behaviors concomitant with the observed transition
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