Entity

Time filter

Source Type


Vonk R.,Netherlands Center for Biodiversity Naturalis Section | Hoeksema B.W.,Netherlands Center for Biodiversity Naturalis | Jaume D.,CSIC - Mediterranean Institute for Advanced Studies
ZooKeys | Year: 2011

Psammogammarus wallacei sp. n. is described from the shallow marine interstitial of a sand and coral rubble beach on the Gura Ici islands (North Moluccas; Indonesia). This is the first record of this circumtropical genus from SE Asia, with the geographically closest relative inhabiting the Ryukyu archipelago in Japan. The new species is highly distinctive by the display of sexual dimorphism on pleopod II, with the medial margin of the male proximal article of exopod provided with a comb of short, blunt curved spinules; no other representative of the genus is known to display sexually-dimorphic appendages aside of the gnathopods. The new species is also noteworthy by the outline of the palm margin of male gnathopod II, hardly excavated, and by showing a carpus broader than long. An overview of the genus Psammogammarus with 14 species to date is provided. Copyright Ronald Vonk et al. Source


Osorio L.,Catholic University of Leuven | Trujillo E.,Catholic University of Leuven | Van Vuure A.W.,Catholic University of Leuven | Lens F.,Netherlands Center for Biodiversity Naturalis Section | And 3 more authors.
ECCM 2012 - Composites at Venice, Proceedings of the 15th European Conference on Composite Materials | Year: 2012

Bamboo fibres are an attractive alternative to reinforce polymers in the new era of green composite materials. A new mechanical process has been developed to extract long bamboo fibres from the Colombian species Guadua angustifolia. The mechanical properties of technical fibres have been studied, the tensile strength and Young's Modulus are around 800 MPa and 43 GPa respectively. To fully explore these excellent mechanical properties and to make an adequate use of this new material as reinforcement, it is indispensable to have a complete understanding of fibre behaviour as a function of the microstructure. Observations have provided us with a vast knowledge of the complex microstructure of this fibre from the macro down to the micro scale level, where different features like the distribution of the elementary fibres within the fibre bundle, dimensions and the layering pattern of the elementary fibres and the main microfibril angles could be measured. Source


Couvreur T.L.P.,IRD Montpellier | Porter-Morgan H.,New York Botanical Garden | Porter-Morgan H.,City University of New York | Wieringa J.J.,Netherlands Center for Biodiversity Naturalis Section | And 2 more authors.
BMC Evolutionary Biology | Year: 2011

Background: The tropical rain forests (TRF) of Africa are the second largest block of this biome after the Amazon and exhibit high levels of plant endemism and diversity. Two main hypotheses have been advanced to explain speciation processes that have led to this high level of biodiversity: allopatric speciation linked to geographic isolation and ecological speciation linked to ecological gradients. Both these hypotheses rely on ecology: in the former conservation of ecological niches through time is implied, while in the latter adaptation via selection to alternative ecological niches would be a prerequisite. Here, we investigate the role of ecology in explaining present day species diversity in African TRF using a species level phylogeny and ecological niche modeling of two predominantly restricted TRF tree genera, Isolona and Monodora (Annonaceae). Both these genera, with 20 and 14 species, respectively, are widely distributed in African TRFs, with a few species occurring in slightly less humid regions such as in East Africa. Results: A total of 11 sister species pairs were identified most of them occurring in allopatry or with little geographical overlap. Our results provide a mixed answer on the role of ecology in speciation. Although no sister species have identical niches, just under half of the tests suggest that sister species do have more similar niches than expected by chance. PCA analyses also support little ecological differences between sister species. Most speciation events within both genera predate the Pleistocene, occurring during the Late Miocene and Pliocene periods. Conclusions: Ecology is almost always involved in speciation, however, it would seem to have had a little role in species generation within Isolona and Monodora at the scale analyzed here. This is consistent with the geographical speciation model for TRF diversification. These results contrast to other studies for non-TRF plant species where ecological speciation was found to be an important factor of diversification. The Pliocene period appears to be a vital time in the generation of African TRF diversity, whereas Pleistocene climatic fluctuations have had a smaller role on speciation than previously thought. Ecological niche modeling, species level phylogeny, ecological speciation, African tropics, Isolona, Monodora, Annonaceae. © 2011 Couvreur et al; licensee BioMed Central Ltd. Source


Ruffinatto F.,University of Turin | Macchioni N.,CNR Tree and Timber Institute | Boetto G.,University of Turin | Baas P.,Netherlands Center for Biodiversity Naturalis Section | Zanuttini R.,University of Turin
IAWA Journal | Year: 2010

Species identification is a crucial step in the study of wooden artefacts, but sampling is frequently impossible. The objective of this study is to evaluate the efficacy of reflected light microscopy, including the use of polarising and narrow-band blue filters, as a non-invasive identification tool. Different surfacing and finishing techniques copying historical manufacturing methods were applied to selected species. The visibility of anatomical features was evaluated on the basis of a four level scale. Two indexes were created: an Identifiable Anatomical Features index (IAF) to evaluate the effect of treatments on the complex of microstructural characters, and a Feature Recognition Index (FRI) to estimate the susceptibility of each anatomical feature towards different treatments. Surfacing affected the visibility of anatomical features to different degrees of severity depending both on the technique used and on the species. The visibility could be partially improved or decreased by the presence of finishes, depending on their transparency. Each anatomical feature showed different susceptibilities towards treatments. Both polarising and narrow-band blue filters considerably increased visibility of several anatomical features. Possibilities to recognise individual character states were encouraging, except when obscured by low transparency finishes. Much diagnostic anatomical information can be obtained by the use of non-invasive, reflected light microscopy, although the step from feature recognition to species identification may still require further analysis. Source


Jacquemyn H.,Catholic University of Leuven | Merckx V.,Netherlands Center for Biodiversity Naturalis Section | Brys R.,Research Institute for Nature and Forest | Tyteca D.,Catholic University of Louvain | And 4 more authors.
New Phytologist | Year: 2011

The specificity of orchids for their fungi can vary substantially, from highly specialist interactions to more generalist interactions, but little is known about the evolutionary history of the mycorrhizal specificity of orchids. • Here, we used a network analysis approach to investigate orchid mycorrhizal associations in 16 species of the genus Orchis sampled across 11 different regions in Europe. We first examined in detail the structure of the network of associations and then tested for a phylogenetic signal in mycorrhizal specificity and identified the fungi with which the orchids associated. • We found 20 different fungal lineages that associated with species of the genus Orchis, most of them being related to members of the Tulasnellaceae (84.33% of all identified associations) and a smaller proportion being related to members of the Ceratobasidiaceae (9.97%). Species associations formed a nested network that is built on asymmetric links among species. Evolution of mycorrhizal specificity in Orchis closely resembles a Brownian motion process, and the interaction between Orchis and Tulasnellaceae fungi is significantly influenced by the phylogenetic relationships between the Orchis species. • Our results provide evidence of the presence of phylogenetic conservatism in mycorrhizal specificity in orchids and demonstrate that evolutionary processes may be an important factor in generating patterns of mycorrhizal associations. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust. Source

Discover hidden collaborations