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252 results on '"Bell, Charles D."'

5. Phylogeny and palaeoecology of Polyommatus blue butterflies show Beringia was a climate-regulated gateway to the New World

Author

Vila, Roger, Bell, Charles D, Macniven, Richard, Goldman-Huertas, Benjamin, Ree, Richard H, Marshall, Charles R, Bálint, Zsolt, Johnson, Kurt, Benyamini, Dubi, and Pierce, Naomi E

Subjects
Americas, Animal Migration, Animals, Asia, Butterflies, Climate, Ecosystem, Molecular Sequence Data, Paleontology, Phylogeny, Phylogeography, Polymerase Chain Reaction, Sequence Analysis, DNA, Beringia, biogeography, climate change, Lycaenidae, Nabokov, phylogeny, Biological Sciences, Agricultural and Veterinary Sciences, Medical and Health Sciences
Abstract

Transcontinental dispersals by organisms usually represent improbable events that constitute a major challenge for biogeographers. By integrating molecular phylogeny, historical biogeography and palaeoecology, we test a bold hypothesis proposed by Vladimir Nabokov regarding the origin of Neotropical Polyommatus blue butterflies, and show that Beringia has served as a biological corridor for the dispersal of these insects from Asia into the New World. We present a novel method to estimate ancestral temperature tolerances using distribution range limits of extant organisms, and find that climatic conditions in Beringia acted as a decisive filter in determining which taxa crossed into the New World during five separate invasions over the past 11 Myr. Our results reveal a marked effect of the Miocene-Pleistocene global cooling, and demonstrate that palaeoclimatic conditions left a strong signal on the ecology of present-day taxa in the New World. The phylogenetic conservatism in thermal tolerances that we have identified may permit the reconstruction of the palaeoecology of ancestral organisms, especially mobile taxa that can easily escape from hostile environments rather than adapt to them.

Published
2011

11. Pollen morphology of selected taxa of Valeriana (Caprifoliaceae): taxonomic and evolutionary implications

Author

Tsymbalyuk, Zoya M., Ivanova, Daniella, Bell, Charles D., and Nitsenko, Lyudmila M.

Subjects
taxonomy, Valerianaceae, Biodiversity, Plant Science, exine sculpture, pollen morphology, Ecology, Evolution, Behavior and Systematics, Eudicots, Taxonomy
Abstract

Pollen morphology of 34 herbarium specimens belonging to 17 taxa of the genus Valeriana was studied using light and scanning electron microscopy. The aim of this research was to evaluate the taxonomical value of palynomorphological data for species-specific identification. Pollen grains are monads, radially symmetrical, isopolar, tricolpate, oblate to prolate (P/E = 0.69–1.59); medium- or large-sized (P = 26.60–66.50 µm; E = 23.94–57.19 µm). Colpi are long, medium-length or short, with acute, obtuse or rounded ends. Four types and eight subtypes of exine sculpture were recognised: type I—echinate-verrucate (5 spp.), type II—echinate-nanoechinate-verrucate (10), type III—echinate-microechinate-nanoechinate-verrucate (1), type IV—echinate-microechinate-nanoechinate (1). Additional characters of taxa of Valeriana diagnostic at species level for the purposes of taxonomy are: size of pollen and colpi, exine sculpture: presence/absence of verrucae, their form, size and form of echini/microechini/nanoechini, their number, pattern of tectum in areas between echini, exine thickness in mesocolpia and apocolpia. Our palynomorphological data support the results of molecular phylogenetic studies. The close phylogenetic relationships of the species V. montana, V. tripteris, V. supina and V. pyrenaica are also supported by their palynomorphological characters, such as exine sculpture (type I). Cluster analysis mainly supports the definition of pollen types and subtypes (based on qualitative data), since species are grouped as five separate branches. The pollen grains of five taxa were analysed for the first time in the current study.

Published
2022
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24. Angiosperm phylogeny: 17 genes, 640 taxa

Author

Soltis, Douglas E., Smith, Stephen A., Cellinese, Nico, Wurdack, Kenneth J., Tank, David C., Brockington, Samuel F., Refulio-Rodriguez, Nancy F., Walker, Jay B., Moore, Michael J., Carlsward, Barbara S., Bell, Charles D., Latvis, Maribeth, Crawley, Sunny, Black, Chelsea, Diouf, Diaga, Xi, Zhenxiang, Rushworth, Catherine A., Gitzendanner, Matthew A., Sytsma, Kenneth J., Qiu, Yin-long, Hilu, Khidir W., Davis, Charles C., Sanderson, Michael J., Beaman, Reed S., Olmstead, Richard G., Judd, Walter S., Donoghue, Michael J., and Soltis, Pamela S.

Published
2011
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32. Polyploidy and angiosperm diversification

Author

Soltis, Douglas E., Albert, Victor A., Leebens-Mack, Jim, Bell, Charles D., Paterson, Andrew H., Zheng, Chunfang, Sankoff, David, dePamphilis, Claude W., Wall, P. Kerr, and Soltis, Pamela S.

Published
2009

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