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Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    RAINBIO : A mega-database of tropical African vascular plants distributions
    Dauby, Gilles ; Zaiss, Rainer ; Blach-Overgaard, Anne ; Catarino, Luís ; Damen, T.H.J. ; Deblauwe, Vincent ; Dessein, Steven ; Dransfield, John ; Droissart, Vincent ; Duarte, Maria Cristina ; Engledow, Henry ; Fadeur, Geoffrey ; Figueira, Rui ; Gereau, Roy E. ; Hardy, Olivier J. ; Harris, David J. ; Heij, Janneke De; Janssens, Steven ; Klomberg, Yannick ; Ley, Alexandra C. ; Mackinder, Barbara A. ; Meerts, Pierre ; Poel, Jeike van de; Sonké, Bonaventure ; Sosef, M.S.M. ; Stévart, Tariq ; Stoffelen, Piet ; Svenning, Jens Christian ; Sepulchre, Pierre ; Burgt, Xander Van Der; Wieringa, J.J. ; Couvreur, T.L.P. - \ 2016
    Herbarium specimens - tropical forests - georeferencing - taxonomic backbone - habit - digitization - native species - cultivated species - biodiversity assessment
    The tropical vegetation of Africa is characterized by high levels of species diversity but is undergoing important shifts in response to ongoing climate change and increasing anthropogenic pressures. Although our knowledge of plant species distribution patterns in the African tropics has been improving over the years, it remains limited. Here we present RAINBIO, a unique comprehensive mega-database of georeferenced records for vascular plants in continental tropical Africa. The geographic focus of the database is the region south of the Sahel and north of Southern Africa, and the majority of data originate from tropical forest regions. RAINBIO is a compilation of 13 datasets either publicly available or personal ones. Numerous in depth data quality checks, automatic and manual via several African flora experts, were undertaken for georeferencing, standardization of taxonomic names and identification and merging of duplicated records. The resulting RAINBIO data allows exploration and extraction of distribution data for 25,356 native tropical African vascular plant species, which represents ca. 89% of all known plant species in the area of interest. Habit information is also provided for 91% of these species.
    RAINBIO : A mega-database of tropical African vascular plants distributions
    Dauby, Gilles ; Zaiss, Rainer ; Blach-Overgaard, Anne ; Catarino, Luís ; Damen, Theo ; Deblauwe, Vincent ; Dessein, Steven ; Dransfield, John ; Droissart, Vincent ; Duarte, Maria Cristina ; Engledow, Henry ; Fadeur, Geoffrey ; Figueira, Rui ; Gereau, Roy E. ; Hardy, Olivier J. ; Harris, David J. ; Heij, Janneke de; Janssens, Steven ; Klomberg, Yannick ; Ley, Alexandra C. ; Mackinder, Barbara A. ; Meerts, Pierre ; Poel, Jeike L. van de; Sonké, Bonaventure ; Sosef, Marc S.M. ; Stévart, Tariq ; Stoffelen, Piet ; Svenning, Jens Christian ; Sepulchre, Pierre ; Burgt, Xander van der; Wieringa, Jan J. ; Couvreur, Thomas L.P. - \ 2016
    Phytokeys 74 (2016). - ISSN 1314-2011 - p. 1 - 18.
    Biodiversity assessment - Cultivated species - Digitization - Georeferencing - Habit - Herbarium specimens - Native species - Taxonomic backbone - Tropical forests

    The tropical vegetation of Africa is characterized by high levels of species diversity but is undergoing important shifts in response to ongoing climate change and increasing anthropogenic pressures. Although our knowledge of plant species distribution patterns in the African tropics has been improving over the years, it remains limited. Here we present RAINBIO, a unique comprehensive mega-database of georeferenced records for vascular plants in continental tropical Africa. The geographic focus of the database is the region south of the Sahel and north of Southern Africa, and the majority of data originate from tropical forest regions. RAINBIO is a compilation of 13 datasets either publicly available or personal ones. Numerous in depth data quality checks, automatic and manual via several African flora experts, were undertaken for georeferencing, standardization of taxonomic names and identification and merging of duplicated records. The resulting RAINBIO data allows exploration and extraction of distribution data for 25,356 native tropical African vascular plant species, which represents ca. 89% of all known plant species in the area of interest. Habit information is also provided for 91% of these species.

    A new subfamilial and tribal classification of the pantropical flowering plant family Annonaceae informed by molecular phylogenetics
    Chatrou, L.W. ; Pirie, M.D. ; Erkens, R.H.J. ; Couvreur, T.L.P. ; Neubig, K.M. ; Abbott, J.R. ; Mols, J.B. - \ 2012
    Botanical Journal of the Linnean Society 169 (2012)1. - ISSN 0024-4074 - p. 5 - 40.
    historical biogeography - anaxagorea annonaceae - maximum-likelihood - uvaria annonaceae - character evolution - taxonomic revision - neotropical genera - sequence data - mixed models - missing data
    The pantropical flowering plant family Annonaceae is the most species-rich family of Magnoliales. Despite long-standing interest in the systematics of Annonaceae, no authoritative classification has yet been published in the light of recent molecular phylogenetic analyses. Here, using the largest, most representative, molecular dataset compiled on Annonaceae to date, we present, for the first time, a robust family-wide phylogenetic tree and subsequent classification. We used a supermatrix of up to eight plastid markers sequenced from 193 ingroup and seven outgroup species. Some of the relationships at lower taxonomic levels are poorly resolved, but deeper nodes generally receive high support. Annonaceae comprises four major clades, which are here given the taxonomic rank of subfamily. The description of Annonoideae is amended, and three new subfamilies are described: Anaxagoreoideae, Ambavioideae and Malmeoideae. In Annonoideae, seven tribes are recognized, one of which, Duguetieae, is described as new. In Malmeoideae, seven tribes are recognized, six of which are newly described: Dendrokingstonieae, Fenerivieae, Maasieae, Malmeeae, Monocarpieae and Piptostigmateae. This new subfamilial and tribal classification is discussed against the background of previous classifications and characters to recognize subfamilies are reviewed
    Keys to the genera of Annonaceae
    Couvreur, T.L.P. ; Maas, P.J.M. ; Meinke, S. ; Johnson, D.M. ; Kessler, P.J.A. - \ 2012
    Botanical Journal of the Linnean Society 169 (2012)1. - ISSN 0024-4074 - p. 74 - 83.
    historical biogeography - pseuduvaria annonaceae - uvaria annonaceae - genus - revision - delimitation - phylogeny - evolution - lineage
    Identification keys are provided for all genera currently recognized in Annonaceae. Separate keys are presented for the Neotropics (34 genera), Africa-Madagascar (40 genera) and Asia-Australasia (42 genera). These keys are based on a combination of vegetative and fertile characters. (c) 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 7483.
    Radiations and key innovations in an early branching angiosperm lineage (Annonaceae; Magnoliales)
    Erkens, R.H.J. ; Chatrou, L.W. ; Couvreur, T.L.P. - \ 2012
    Botanical Journal of the Linnean Society 169 (2012)1. - ISSN 0024-4074 - p. 117 - 134.
    rain-forest trees - species-rich genus - adaptive radiation - diversification rates - rapid diversification - goniothalamus annonaceae - molecular phylogenetics - ecological opportunity - guatteria annonaceae - flowering plants
    Biologists are fascinated by species-rich groups and have attempted to discover the causes for their abundant diversification. Comprehension of the causes and mechanisms underpinning radiations and detection of their frequency will contribute greatly to the understanding of the evolutionary origin of biodiversity and its ecological structure. A dated and well-resolved phylogenetic tree of Annonaceae was used to study diversification patterns in the family in order to identify factors that drive speciation and the evolution of morphological (key) characters. It was found that, except for Goniothalamus, the largest genera in the family are not the result of radiations. Furthermore, the difference in species numbers between subfamilies Annonoideae (former long branch clade) and Malmeoideae (former short branch clade) cannot be attributed to significant differences in the diversification rate. Most of the speciation in Annonaceae is not distinguishable from a random branching process (i.e. chance), and no special explanations are therefore necessary for the distribution of species richness across the major part of the phylogenetic tree for Annonaceae. Only for a small number of clades can key innovations be invoked to explain the elevated rate of diversification
    Little ecological divergence associated with speciation in two African rain forest tree genera
    Couvreur, T.L.P. ; Porter-Morgan, H. ; Wieringa, J.J. ; Chatrou, L.W. - \ 2011
    BMC Evolutionary Biology 11 (2011). - ISSN 1471-2148 - 19 p.
    species distribution models - phylogenetic niche conservatism - climate-change - correlated evolution - tropical africa - sample-size - diversification - annonaceae - distributions - pleistocene
    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
    Revision of the African Genus Hexalobus (Annonaceae)
    Botermans, M. ; Sosef, M.S.M. ; Chatrou, L.W. ; Couvreur, T.L.P. - \ 2011
    Systematic Botany 36 (2011)1. - ISSN 0363-6445 - p. 33 - 48.
    pollen morphology - families - diversity - evolution - monodora
    The genus Hexalobus consists of five species characterized by six basally fused petal lobes that are transversally folded in bud, which is unique within Annonaceae. The genus is widespread across tropical Africa occurring in rain forest, savanna, and woodland. The species H. callicarpus, occurring in Madagascar, is excluded from Hexalobus, so the genus is now restricted to continental Africa. The present revision provides a synthesis of previously published information and discussions on morphology, taxonomy, phylogeny, and palynology. Conservation status assessments are provided for each species, as well as a diagnostic key and detailed species descriptions. Furthermore, four species are illustrated and all species are mapped
    The impact of climate change on the origin and future of East African rainforest trees.
    Chatrou, L.W. ; Wieringa, J.J. ; Couvreur, T.L.P. - \ 2011
    In: Climate Change, Ecology and Systematics / Hodkinson, T.R., Jones, M.B., Waldren, S., Parnell, J.A.N., Cambridge : Cambridge University Press - ISBN 9780521766098 - p. 304 - 319.
    Early evolutionary history of the flowering plant family Annonaceae: steady diversification and boreotropical geodispersal
    Couvreur, T.L.P. ; Pirie, M.D. ; Chatrou, L.W. ; Saunders, M. ; Su, Y. ; Richardson, J.E. ; Erkens, R.H.J. - \ 2011
    Journal of Biogeography 38 (2011)4. - ISSN 0305-0270 - p. 664 - 680.
    of-india dispersal - rain-forest trees - divergence times - anaxagorea annonaceae - molecular phylogenies - rapid diversification - northern-hemisphere - character evolution - explosive radiation - geographic range
    Aim Rain forest-restricted plant families show disjunct distributions between the three major tropical regions: South America, Africa and Asia. Explaining these disjunctions has become an important challenge in biogeography. The pantropical plant family Annonaceae is used to test hypotheses that might explain diversification and distribution patterns in tropical biota: the museum hypothesis (low extinction leading to steady accumulation of species); and dispersal between Africa and Asia via Indian rafting versus boreotropical geodispersal. Location Tropics and boreotropics. Methods Molecular age estimates were calculated using a Bayesian approach based on 83% generic sampling representing all major lineages within the family, seven chloroplast markers and two fossil calibrations. An analysis of diversification was carried out, which included lineage-through-time (LTT) plots and the calculation of diversification rates for genera and major clades. Ancestral areas were reconstructed using a maximum likelihood approach that implements the dispersal–extinction–cladogenesis model. Results The LTT plots indicated a constant overall rate of diversification with low extinction rates for the family during the first 80 Ma of its existence. The highest diversification rates were inferred for several young genera such as Desmopsis, Uvariopsis and Unonopsis. A boreotropical migration route was supported over Indian rafting as the best fitting hypothesis to explain present-day distribution patterns within the family. Main conclusions Early diversification within Annonaceae fits the hypothesis of a museum model of tropical diversification, with an overall steady increase in lineages possibly due to low extinction rates. The present-day distribution of species within the two largest clades of Annonaceae is the result of two contrasting biogeographic histories. The ‘long-branch clade’ has been diversifying since the beginning of the Cenozoic and underwent numerous geodispersals via the boreotropics and several more recent long-distance dispersal events. In contrast, the ‘short-branch clade’ dispersed once into Asia via the boreotropics during the Early Miocene and further dispersal was limited.
    A new species of Uvariopsis (Annonaceae), endemic to the Eastern Arc Mountains of Tanzania
    Couvreur, T.L.P. ; Luke, W.R.Q. - \ 2010
    Blumea 55 (2010)1. - ISSN 0006-5196 - p. 68 - 72.
    tropical africa - biodiversity - conservation - families
    The Eastern Arc Mountains of Tanzania enclose high levels of plant and animal diversity with many yet to be described species. Here we describe a new species of the pan-tropical plant family Annonaceae named Uvariopsis lovettiana. It closely resembles another Eastern Arc endemic species, U. bisexualis, and its possible relationships with this species are discussed. A description with illustrations is presented as well as a suggestion for the IUCN conservation status of this new taxon
    Insights into the influence of priors in posterior mapping of discrete morphological characters: a case study in Annonaceae
    Couvreur, T.L.P. ; Gort, G. ; Richardson, J.E. ; Sosef, M.S.M. ; Chatrou, L.W. - \ 2010
    PLoS ONE 5 (2010)5. - ISSN 1932-6203 - 13 p.
    bayesian phylogenetics - prior distributions - flowering plants - evolution - likelihood - states - reconstruction - inference - model - rates
    Background - Posterior mapping is an increasingly popular hierarchical Bayesian based method used to infer character histories and reconstruct ancestral states at nodes of molecular phylogenies, notably of morphological characters. As for all Bayesian analyses specification of prior values is an integrative and important part of the analysis. He we provide an example of how alternative prior choices can seriously influence results and mislead interpretations. Methods/Principal Findings - For two contrasting discrete morphological characters, namely a slow and a fast evolving character found in the plant family Annonaceae, we specified a total of eight different prior distributions per character. We investigated how these prior settings affected important summary statistics. Our analyses showed that the different prior distributions had marked effects on the results in terms of average number of character state changes. These differences arise because priors play a crucial role in determining which areas of parameter space the values of the simulation will be drawn from, independent of the data at hand. However, priors seemed to fit the data better if they would result in a more even sampling of parameter space (normal posterior distribution), in which case alternative standard deviation values had little effect on the results. The most probable character history for each character was affected differently by the prior. For the slower evolving character, the same character history always had the highest posterior probability independent of the priors used. In contrast, the faster evolving character showed different most probable character histories depending on the prior. These differences could be related to the level of homoplasy exhibited by each character. Conclusions - Although our analyses were restricted to two morphological characters within a single family, our results underline the importance of carefully choosing prior values for posterior mapping. Prior specification will be of crucial importance when interpreting the results in a meaningful way. It is hard to suggest a statistically sound method for prior specification without more detailed studies. Meanwhile, we propose that the data could be used to estimate the prior value of the gamma distribution placed on the transformation rate in posterior mapping
    Molecular Phylogenetics, Temporal Diversification, and Principles of Evolution in the Mustard Family (Brassicaceae)
    Couvreur, T.L.P. ; Franzke, A. ; Al-Shehbaz, I.A. ; Bakker, F.T. ; Koch, M.A. ; Mummenhoff, K. - \ 2010
    Molecular Biology and Evolution 27 (2010)1. - ISSN 0737-4038 - p. 55 - 71.
    internal transcribed spacer - nuclear ribosomal dna - trnl intron sequences - arabidopsis-thaliana - maximum-likelihood - genome duplication - divergence times - allied genera - missing data - improves resolution
    Brassicaceae is an important family at both the agronomic and scientific level. The family not only inlcudes several model species, but it is also becoming an evolutionary model at the family level. However, resolving the phylogenetic relationships within the family has been problematic, and a large-scale molecular phylogeny in terms of generic sampling and number of genes is still lacking. In particular, the deeper relationships within the family, for example between the three major recognized lineages, prove particularly hard to resolve. Using a slow-evolving mitochondrial marker (nad4 intron 1), we reconstructed a comprehensive phylogeny in generic representation for the family. In addition, and because resolution was very low in previous single marker phylogenies, we adopted a supermatrix approach by concatenating all checked and reliable sequences available on GenBank as well as new sequences for a total 207 currently recognized genera and eight molecular markers representing a comprehensive coverage of all three genomes. The supermatrix was dated under an uncorrelated relaxed molecular clock using a direct fossil calibration approach. Finally, a lineage-through-time-plot and rates of diversification for the family were generated. The resulting tree, the largest in number of genera and markers sampled to date and covering the whole family in a representative way, provides important insights into the evolution of the family on a broad scale. The backbone of the tree remained largely unresolved and is interpreted as the consequence of early rapid radiation within the family. The age of the family was inferred to be 37.6 (24.2–49.4) Ma, which largely agrees with previous studies. The ages of all major lineages and tribes are also reported. Analysis of diversification suggests that Brassicaceae underwent a rapid period of diversification, after the split with the early diverging tribe Aethionemeae. Given the dates found here, the family appears to have originated under a warm and humid climate approximately 37 Ma. We suggest that the rapid radiation detected was caused by a global cooling during the Oligocene coupled with a genome duplication event. This duplication could have allowed the family to rapidly adapt to the changing climate
    From Africa via Europe to South America: migrational route of a species-rich genus of Neotropical lowland rain forest trees (Guatteria, Annonaceae)
    Erkens, R.H.J. ; Maas, J.W. ; Couvreur, T.L.P. - \ 2009
    Journal of Biogeography 36 (2009)12. - ISSN 0305-0270 - p. 2338 - 2352.
    long-distance dispersal - chloroplast sequence data - historical biogeography - dna-sequences - northern-hemisphere - plastid rbcl - phylogenetic-relationships - molecular phylogenetics - vicariance analysis - flowering plants
    Aim Several recent studies have suggested that a substantial portion of today's plant diversity in the Neotropics has resulted from the dispersal of taxa into that region rather than by vicariance. In general, three routes have been documented for the dispersal of taxa onto the South American continent: (1) via the North Atlantic Land Bridge, (2) via the Bering Land Bridge, or (3) from Africa directly onto the continent. Here a species-rich genus of Neotropical lowland rain forest trees (Guatteria, Annonaceae) is used as a model to investigate these three hypotheses. Location The Neotropics. Methods The phylogenetic relationships within the long-branch clade of Annonaceae were reconstructed (using maximum parsimony, maximum likelihood and Bayesian inference) in order to gain insight in the phylogenetic position of Guatteria. Furthermore, Bayesian molecular dating and Bayesian dispersal-vicariance (Bayes-DIVA) analyses were undertaken. Results Most of the relationships within the long-branch clade of Annonaceae were reconstructed and had high support. However, the relationship between the Duguetia clade, the Xylopia-Artabotrys clade and Guatteria remained unclear. The stem node age estimate of Guatteria ranged between 49.2 and 51.3 Ma, whereas the crown node age estimate ranged between 11.4 and 17.8 Ma. For the ancestral area of Guatteria and its sister group, the area North America-Africa was reconstructed in 99% of 10,000 DIVA analyses, while South America-North America was found just 1% of the time. Main conclusions The estimated stem to crown node ages of Guatteria in combination with the Bayes-DIVA analyses imply a scenario congruent with an African origin followed by dispersal across the North Atlantic Land Bridge in the early to middle Eocene and further dispersal into North and Central America (and ultimately South America) in the Miocene. The phylogenetically and morphologically isolated position of the genus is probably due to extinction of the North American and European stem lineages in the Tertiary
    Spatio-temporal dynamism of hotspots enhances plant diversity
    Chatrou, L.W. ; Couvreur, T.L.P. ; Richardson, J.E. - \ 2009
    Journal of Biogeography 36 (2009)9. - ISSN 0305-0270 - p. 1628 - 1629.
    vicariance - biogeography - dispersal - multiple - diversification - phylogeny - history - time
    Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees
    Couvreur, T.L.P. ; Chatrou, L.W. ; Sosef, M.S.M. ; Richardson, J.E. - \ 2008
    BMC Biology 6 (2008). - ISSN 1741-7007 - 10 p.
    crato formation brazil - eastern arc mountains - divergence times - chloroplast dna - absolute rates - data sets - evolution - biogeography - annonaceae - angiosperm
    Background - Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. Results - Our results provide strong evidence that East African endemic lineages of Annonaceae have multiple origins dated to significantly different times spanning the Oligocene and Miocene epochs. Moreover, these successive origins (c. 33, 16 and 8 million years ¿ Myr) coincide with known periods of aridification and geological activity in Africa that would have recurrently isolated the Guineo-Congolian rain forest from the East African one. All East African taxa were found to have diversified prior to Pleistocene times. Conclusion - Molecular phylogenetic dating analyses of this large pan-African clade of Annonaceae unravels an interesting pattern of diversification for rain forest restricted trees co-occurring in West/Central and East African rain forests. Our results suggest that repeated reconnections between the West/Central and East African rain forest blocks allowed for biotic exchange while the break-ups induced speciation via vicariance, enhancing the levels of endemicity. These results provide an explanation for present day distribution patterns and origins of endemicity for African rain forest trees. Moreover, given the pre-Pleistocene origins of all the studied endemic East African genera and species, these results also offer important insights for setting conservation priorities in these highly diversified but threatened
    A revision of the genus Scleroperma (Aracaceae)
    Valkenburg, J.L.C.H. van; Sunderland, T. ; Couvreur, T.L.P. - \ 2008
    Kew Bulletin 63 (2008)1. - ISSN 0075-5974 - p. 75 - 86.
    Summary A taxonomic revision of the palm genus Sclerosperma (Arecaceae) is presented. Three species are recognised: S. mannii H. Wendl., which is relatively widespread from Liberia to the Democratic Republic of Congo; S. walkeri A. Chev., which is apparently confined to the interior of Gabon and a band along the Congo River; and S. profiziana, a new species previously considered conspecific to S. mannii that is found in southwest Ghana, Congo, the Democratic Republic of Congo and Angola. The taxonomic history, morphology, distribution and conservation status of the genus and each species are discussed
    Pollen morphology within the Monodora clade, a diverse group of five African Annonaceae genera
    Couvreur, T.L.P. ; Botermans, M. ; Heuven, B.J. Van; Ham, R.W.J.M. van der - \ 2008
    Grana 47 (2008)3. - ISSN 0017-3134 - p. 185 - 210.
    flowering plants - phylogeny - pollination - evolution - characters - syncarpy - families - wall
    Pollen morphology has played a major role in elucidating infrafamiliar-level systematics and evolution within Annonaceae, especially within the African genera. The Monodora clade is composed of five genera, Asteranthe, Hexalobus, Isolona, Monodora and Uvariastrum, which are restricted to Africa and contain together c. 50 species. A molecular phylogeny of the family showed that the monophyly of the Monodora clade is strongly supported and that it is part of a larger clade of 11 African genera. In order to support classification a detailed survey was made of the pollen morphological variation within the Monodora clade, using scanning and transmission electron microsopy. For the two most species-rich genera, Isolona and Monodora, a molecular species-level phylogeny was used to assess the taxonomic usefulness of the pollen characters. The survey showed a wide range of pollen morphological diversity. The most conspicuous variation concerned the occurrence of monads without a thicker outer foliation in the basal exine layer in Isolona in contrast to tetrads with a thicker outer foliation in Asteranthe, Hexalobus, Monodora and Uvariastrum. At the infrageneric level, Hexalobus, Isolona and Monodora showed the largest diversity, with various pollen types based on tectum morphology. Hexalobus is exceptional with three types within only five species. The pollen types defined in this study are hardly useful in characterizing major groups identified within both Isolona and Monodora, but they do illustrate relationships within smaller groups.
    Reciprocal introgression between wild and cultivated peach palm (Bactris gasipaes Kunth, Aracaceae) in Western Ecuador.
    Pintaud, J.C. ; Couvreur, T.L.P. ; Lara, C. ; Ludena, B. ; Pham, J.L. - \ 2008
    In: Crop Wild Relative Conservation and Use / Kell, S.P. Maxted, N., Ford-Lloyd, B.V., Dulloo, M.E., Turok, J., Wallingford (UK) : CAB International - ISBN 9781845930998 - p. 296 - 308.
    Evolution of syncarpy and other morphological characters in African Annonaceae: A posterior mapping approach
    Couvreur, T.L.P. ; Richardson, J.E. ; Sosef, M.S.M. ; Erkens, R.H.J. ; Chatrou, L.W. - \ 2008
    Molecular Phylogenetics and Evolution 47 (2008)1. - ISSN 1055-7903 - p. 302 - 318.
    phylogenetic-relationships - historical biogeography - anaxagorea annonaceae - basal angiosperms - flowering plants - data sets - dna - winteraceae - takhtajania - perspective
    The congenital fusion of carpels, or syncarpy, is considered a key innovation as it is found in more than 80% of angiosperms. Within the magnoliids however, syncarpy has rarely evolved. Two alternative evolutionary origins of syncarpy were suggested in order to explain the evolution of this feature: multiplication of a single carpel vs. fusion of a moderate number of carpels. The magnoliid family Annonaceae provides an ideal situation to test these hypotheses as two African genera, Isolona and Monodora, are syncarpous in an otherwise apocarpous family with multicarpellate and unicarpellate genera. In addition to syncarpy, the evolution of six other morphological characters was studied. Well-supported phylogenetic relationships of African Annonaceae and in particular those of Isolona and Monodora were reconstructed. Six plastid regions were sequenced and analyzed using maximum parsimony and Bayesian inference methods. The Bayesian posterior mapping approach to study character evolution was used as it accounts for both mapping and phylogenetic uncertainty, and also allows multiple state changes along the branches. Our phylogenetic analyses recovered a fully resolved clade comprising twelve genera endemic to Africa, including Isolona and Monodora, which was nested within the so-called long-branch clade. This is the largest and most species-rich clade of African genera identified to date within Annonaceae. The two syncarpous genera were inferred with maximum support to be sister to a clade characterized by genera with multicarpellate apocarpous gynoecia, supporting the hypothesis that syncarpy arose by fusion of a moderate number of carpels. This hypothesis was also favoured when studying the floral anatomy of both genera. Annonaceae provide the only case of a clear evolution of syncarpy within an otherwise apocarpous magnoliid family. The results presented here offer a better understanding of the evolution of syncarpy in Annonaceae and within angiosperms in general.
    Revealing the secrets of African annonaceae : systematics, evolution and biogeography of the syncarpous genera Isolona and Monodora
    Couvreur, T.L.P. - \ 2008
    Wageningen University. Promotor(en): Marc Sosef, co-promotor(en): J.E. Richardson; Lars Chatrou. - [S.l.] : S.n. - ISBN 9789085049241 - 296
    annonaceae - isolona - monodora - evolutie - taxonomie - plantengeografie - biogeografie - klassen - moleculaire taxonomie - taxonomische revisies - soorten - determinatietabellen - identificatie - afrika - annonaceae - isolona - monodora - evolution - taxonomy - phytogeography - biogeography - genera - molecular taxonomy - taxonomic revisions - species - keys - identification - africa
    The goal of this PhD project was to study the evolution, systematics and biogeography of two African genera from the pan-tropical Annonaceae family: Isolona and Monodora. Both genera are unique within the family in that the female reproductive parts (or carpels) are fused into a single unit. All other Annonaceae have freely arranged carpels. We investigated the phylogenetic relationships of Isolona and Monodora at the intra-familial and intra-generic levels.
    In Chapter 2, we explore the influence of priors when using the novel Bayesian based posterior mapping to study the evolution of morphological characters. Up to now, it was unclear if these priors had any influence on the results. Using a family level molecular phylogeny of the Annonaceae, we study the evolution of two morphological characters under different prior values. We show that different prior values will return different results. Thus, inadequate prior values can lead to erroneous conclusions over the evolution of the studied morphological characters. We also indicate a practical way to choose the prior values when using the posterior mapping approach to study morphological character evolution.
    In Chapter 3, using the posterior mapping approach, we study the evolutionary origins of syncarpy in Annonaceae. The closest relatives of Isolona and Monodora are elucidated. We generate a well resolved phylogeny which included for the first time the majority of African Annonaceae genera. We also study additional morphological and palynological characters relevant to Annonaceae classification in general. Our phylogenetic analyses recover a fully resolved clade comprising twelve endemic African genera, including Isolona and Monodora, which was nested within the so-called long-branch clade. This is the largest and most species-rich clade of African genera identified to date within Annonaceae. Our results indicate that syncarpy arose by fusion of a moderate number of carpels. The alternative hypothesis that syncarpy arose by multiplication of an initial single carpel receives no support.
    In Chapter 4 we use African Annonaceae as a model family to study the biogeographical aspects of the evolutionary origins of African rain forests. It is generally thought that the large West-Central rain forest blocks was continuous during the Eocene with the now fragmented and smaller forests of East Africa, explaining the strong floristic affinities between both areas. Using dated molecular phylogenies we provide evidence of the recurring break-up and reconnection of this pan-African rain forest during the Oligocene and Miocene. The reconnections allowed for biotic exchange while the break-ups induced speciation enhancing the levels of endemicity, thus providing an explanation for present-day patterns in the distribution and diversity of plants in African rain forests.
    In Chapter 5, we perform a detailed analysis of pollen morphology within a strongly supported monophyletic group of five African genera, including Isolona and Monodora. We specifically assess if pollen characters are useful for classification purposes within Isolona and Monodora using a species-level molecular phylogeny. The results show a wide pollen morphological diversity. The pollen types defined within Isolona and Monodora provide little taxonomic information for major clades within both genera. However, pollen variation proves useful as a support of phylogenetic relatedness between groups of closely related species.
    Finally in Chapter 6, a monographic revision of both Isolona and Monodora is presented. Isolona consists of 20 species with five endemic to Madagascar and one newly described species. Monodora has a total of 14 species, three of which were described during this PhD project from Tanzania. Detailed descriptions as well as keys are provided. The conservation status of each species is assessed following the IUCN recommendations. Just under half of the total number of species from both genera is assigned to some level of threat (12 species or 60% in Isolona and four species or 28% in Monodora).
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