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Luxembourg, Luxembourg

Habel J.C.,Natural History Museum Luxembourg | Schmitt T.,University of Trier
Biological Conservation | Year: 2012

In general, species with large ecological amplitudes are equipped with high genetic diversities. In contrast, more specialised species with narrow ecological amplitudes show low levels of genetic diversity. Generalist species are mostly rather marginally affected by recent land-use changes; specialist can be supported by specific conservation measures. We argue that, in the light of Conservation Genetics, species being ecologically intermediate between these two extremes are the most seriously affected ones by recent environmental changes. Such species which formerly occurred in large population networks have to sustain their high level of genetic variability via gene flow. Today, species from the latter group are negatively affected by rapid habitat collapses causing sudden lacks of population interconnectivity. Therefore, species with intermediate habitat demands and originally high genetic diversity might be at highest risk due to inbreeding depressions. © 2011 Elsevier Ltd. Source

Habel J.C.,Natural History Museum Luxembourg | Husemann M.,Baylor University | Schmitt T.,University of Trier | Dapporto L.,Istituto Comprensivo Materna Elementare Media Convenevole da Prato | And 2 more authors.
Journal of Heredity | Year: 2013

Numerous studies addressing the impact of habitat fragmentation on genetic diversity have been performed. In this study, we analyze the effects of a seemingly nonpermeable matrix on the population structure of the forest-dwelling butterfly Pararge aegeria in geographically isolated oases at the northern margin of the Sahara desert using microsatellites, morphological characters, and species distribution modeling. Results from all analyses are mostly congruent and reveal 1) a split between European and North African populations, 2) rather low divergence between populations from the eastern and western part of North Africa (Morocco vs. Tunisia), 3) a lack of differentiation between the oasis and Atlas Mountain populations, 4) as well as among the oasis populations, and 5) no reduction of genetic variability in oasis populations. However, one exception to this general trend resulted from the analyses of wing shape; wings of butterflies from oases are more elongated compared with those from the other habitats. This pattern of phenotypic divergence may suggest a recent colonization of the oasis habitats by individuals, which might be accompanied by a rather dispersive behavior. Species distribution modeling suggests a fairly recent reexpansion of the species' climatic niche starting in the Holocene at about 6000 before present. The combined results indicate a rather recent colonization of the oases by highly mobile individuals from genetically diverse founder populations. The colonization was likely followed by the expansion and persistence of these founder populations under relatively stable environmental conditions. This, together with low rates of gene flow, likely prevented differentiation of populations via drift and led to the maintenance of high genetic diversity. © The American Genetic Association. 2012. All rights reserved. Source

Ishida Y.,Kamiogi | Fujita T.,National Museum of Nature and Science | Thuy B.,Natural History Museum Luxembourg
Paleontological Research | Year: 2015

Well preserved specimens of two ophiuroid species, both assignable to an unknown family (formerly Ophiolepididae) and here placed in Ophiomusium and Ophiosphalma have been recovered from lower Miocene deep-sea formations in Japan. The material consists of an assemblage of over 75 articulated body fossils and numerous semiarticulated arm segments from the lower Miocene Oi Formation (Ichishi Group), Mie Prefecture, central Japan, identified as the extant species Ophiomusium lymani Wyville Thomson and a single articulated body fossil assigned to the extant Ophiosphalma cancellata (Lyman) from the lower Miocene Shida Formation (Oigawa Group), Shizuoka Prefecture, central Japan. These occurrences constitute the oldest fossil record of these present-day brittlestar species. The latter is the first fossil record for the genus Ophiosphalma. The new material documents that the closely related genera Ophiomusium and Ophiosphalma had already diverged by the early Miocene. Furthermore our findings suggest that the ancient Ophiomusium lymani and Ophiosphalma cancellata inhabited the same upper bathyal environment as their Recent counterparts. © by the Palaeontological Society of Japan 2015. Source

Thuy B.,Natural History Museum Luxembourg | Stohr S.,Swedish Museum of Natural History
PLoS ONE | Year: 2016

Ophiuroid systematics is currently in a state of upheaval, with recent molecular estimates fundamentally clashing with traditional, morphology-based classifications. Here, we attempt a long overdue recast of a morphological phylogeny estimate of the Ophiuroidea taking into account latest insights on microstructural features of the arm skeleton. Our final estimate is based on a total of 45 ingroup taxa, including 41 recent species covering the full range of extant ophiuroid higher taxon diversity and 4 fossil species known from exceptionally preserved material, and the Lower Carboniferous Aganaster gregarius as the outgroup. A total of 130 characters were scored directly on specimens. The tree resulting from the Bayesian inference analysis of the full data matrix is reasonably well resolved and well supported, and refutes all previous classifications, with most traditional families discredited as poly- or paraphyletic. In contrast, our tree agrees remarkably well with the latest molecular estimate, thus paving the way towards an integrated new classification of the Ophiuroidea. Among the characters which were qualitatively found to accord best with our tree topology, we selected a list of potential synapomorphies for future formal clade definitions. Furthermore, an analysis with 13 of the ingroup taxa reduced to the lateral arm plate characters produced a tree which was essentially similar to the full dataset tree. This suggests that dissociated lateral arm plates can be analysed in combination with fully known taxa and thus effectively unlocks the extensive record of fossil lateral arm plates for phylogenetic estimates. Finally, the age and position within our tree implies that the ophiuroid crown-group had started to diversify by the Early Triassic. © 2016 Thuy, Stöhr. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Habel J.C.,Natural History Museum Luxembourg | Habel J.C.,University of Trier | Ivinskis P.,Natural History Museum | Schmitt T.,University of Trier
Acta Zoologica Academiae Scientiarum Hungaricae | Year: 2010

Responses to climate warming vary considerably. Cold-adapted species mostly escape rising temperatures by latitudinal and/or altitudinal range shifts, and often today occur in isolated remnants. In the present study we discuss the genetic consequences of climate warming for five butterfly taxa (Lycaena helle, Erebia epiphron, Erebia sudetica inalpina, Coenonympha darwiniana and C. macromma) which currently show relict-like distributions at least in parts of their distribution ranges. For all these species, genetic data (microsatellite and/or allozyme polymorphisms) already exist. In general, the situation for such high montane/alpine species in the Alps differs from that in the low-altitude mountains, as the considerably higher elevations of the Alps mean that there is still possibility for further altitudinal shifts, while no such possibilities exist in lower mountain ranges. However, there are considerable differences in the general genetic situation of the five taxa analysed. The genetic structure of the Alpine L. helle populations is quite similar to that of the populations in the northern Alps forelands and the lowlands of eastern Europe. However, the lower mountain systems of western Europe all represent considerably differentiated gene pools for this species, so that these might be endangered by climate change. At the contrary, the relict population of E. epiphron in the Jesenik Mts is genetically not differentiated from the northern Alps. Taxa such as Erebia sudetica inalpina, Coenonympha darwiniana and C. macromma, which are all confined to certain parts of the Alps, represent endemic gene-pools. Of these taxa, E. sudetica inalpina shows low population genetic diversity, while the other two species have high allozyme diversity. Therefore, climate change accompanied by altitudinal range shifts might not have an effect on the genetic composition of the former, but might cause losses of genetic diversity in the latter two taxa. In conclusion, the data of these five taxa show that climate change will have different effects on different species of relict-like distributions. Source

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