Damm S.,ITZ |
Dijkstra K.-D.B.,National Museum of Natural History Naturalis |
Hadrys H.,ITZ |
Hadrys H.,Yale University
Molecular Phylogenetics and Evolution | Year: 2010
In the last few million years, tropical Africa has experienced pronounced climatic shifts with progressive aridification. Such changes must have had a great impact on freshwater biota, such as Odonata. With about forty species, Trithemis dominates dragonfly communities across Africa, from rain-pools to streams, deserts to rainforests, and lowlands to highlands. Red-bodied species tend to favor exposed, standing and often temporary waters, have strong dispersal capacities, and some of the largest geographic ranges in the genus. Those in cooler habitats, like forest streams, are generally dark-bodied and more sedentary. We combined molecular analyses of ND1, 16S, and ITS (ITSI, 5.8S, and ITSII) with morphological, ecological, and geographical data for 81% of known Trithemis species, including three Asian and two Madagascan endemics. Using molecular clock analyses, the genus's origin was estimated 6-9 Mya, with multiple lineages arising suddenly around 4 Mya. Open stagnant habitats were inferred to be ancestral and the rise of Trithemis may have coincided with savannah-expansion in the late Miocene. The adaptation of red species to more ephemeral conditions leads to large ranges and limited radiation within those lineages. By contrast, three clades of dark species radiated in the Plio-Pleistocene, each within distinct ecological confines: (1) lowland streams, (2) highland streams, and (3) swampy habitats on alternating sides of the Congo-Zambezi watershed divide; together giving rise to the majority of species diversity in the genus. During Trithemis evolution, multiple shifts from open to more forested habitats and from standing to running waters occurred. Allopatry by habitat fragmentation may be the dominant force in speciation, but possibly genetic divergence across habitat gradients was also involved. The study demonstrates the importance of combining ecological and phylogenetic data to understand the origin of biological diversity under great environmental change. © 2009 Elsevier Inc. All rights reserved.
Voros J.,Hungarian Natural History Museum |
Arntzen J.W.,National Museum of Natural History Naturalis
Amphibia Reptilia | Year: 2010
Nuclear genetic variation and population structure were assessed in 140 individuals from 16 populations across the range of the Danube crested newt (Triturus dobrogicus) using 40 enzyme loci. Intraspecific hybridization with other crested newt species (Triturus carnifex, T. cristatus, T. macedonicus and T. arntzeni) affected 33 individuals in 11 populations at the range edge and reduced operational sample size to 107 T. dobrogicus in 14 populations. Allele diversity was high, and we inferred a high level of gene flow among T. dobrogicus populations, possibly associated with flooding conditions and the relatively continous habitat along rivers. Triturus dobrogicus showed weak but significant genetic structure between tributaries of the three main river systems of Danube, Sava and Tisza. The highest genetic diversity was observed in the Sava drainage, suggesting that this area might have been a Pannonian refugium during the most recent glacial maximum. The relatively high level of genetic variation observed suggests that a genetic bottleneck during this period has not been extreme. © 2010 Koninklijke Brill NV, Leiden.
Breure A.S.H.,National Museum of Natural History Naturalis |
Schlogl J.,Comenius University
Zootaxa | Year: 2010
Two new species are described from Venezuelan Guayana, Chimantá massif: Plekocheilus (P.) vlceki and P. (Eurytus) breweri. Some remarks are made on the ecology of the latter species in relation to birds. Finally some notes on conservation issues are made, highlighting possible threats by climate change. Copyright © 2010 Magnolia Press.
Yan P.,Peking University |
Lv Y.,Chinese Institute of Materia Medica |
Van Ofwegen L.,National Museum of Natural History Naturalis |
Proksch P.,Heinrich Heine University Dusseldorf |
Lin W.,Peking University
Organic Letters | Year: 2010
Seven new biscembranoids, lobophytones A-G (1-7), together with three known biscembranes were isolated from the Chinese soft coral Lobophytum pauciflorum. Their structures were elucidated by the analysis of 1D and 2D NMR (COSY, HSQC, HMBC, and NOESY) data in association with IR and MS experiments. The absolute configurations of compound 1 were determined by X-ray diffraction using the Flack parameter. Lobophytones A-G differ from the "normal" biscembranoids due to the antipodal Diels-Alder cycloaddition between cembranoid-diene and cembranoid-dienophile. The biogenetic pathway of the isolated compounds is depicted. Compound 4 showed significant inhibition toward LPS-induced nitric oxide (NO) in mouse peritoneal macrophage with IC 50 = 4.70 μM. © 2010 American Chemical Society.
Schilthuizen M.,National Museum of Natural History Naturalis |
Schilthuizen M.,Universiti Malaysia Sabah |
Haase M.,University of Greifswald
Journal of Zoology | Year: 2010
In theory, snails can come in two enantiomorphs: either dextral (coiling clockwise) or sinistral (coiling counter-clockwise). In snail species where both forms are actually present, coiling direction is determined by a single gene with delayed maternal inheritance; there is no predictable relationship between a snail's own coiling genotype and its actual coiling direction. Because of this genetic decoupling, it might be expected that dextral and sinistral individuals would be exact mirror images of one another. However, indications exist that there is a subtle but detectable shape difference between dextral and sinistral individuals that derive from the same gene pool. In this paper, we attempt to detect such differences in 50 dextral and 50 sinistral individuals of Amphidromus inversus, a species of land snail that is consistently chirally dimorphic. Four out of 18 volunteers who measured the shells with Vernier calipers found that sinistrals are stouter to a significant degree. A similar result was found by one out of five volunteers who measured the shells from photographs. These results do not allow distinguishing between real shape differences and a handling bias of sinistral as compared with dextral shells. However, when the same set of shells was subjected to a geometric morphometric analysis, we were able to show that sinistrals indeed exhibit a slight but significant widening and twisting of the shell near the palatal and parietal apertural areas. This result is surprising because species of the subgenus Amphidromus s. str. share a long history of chiral dimorphism, and the species would be expected to have been purged from disadvantageous interactions between direction of coil and general shell shape. We conclude that selection on the shape differences is either very weak or constrained by the fact that the pleiotropic effects of the chirality gene are of importance very early in development only. © 2010 The Authors. Journal of Zoology © 2010 The Zoological Society of London.