Bryological and Lichenological Section/ABLS
Vanderpoorten, Alain , Aigoin, Delphine , Devos, Nicolas , Huttunen, Sanna , Ignatov, Michael .
And if Engler was not completely wrong? Evidence for a mixture of neo- and paleoendemism in the moss flora of Macaronesia.
The Macaronesian endemic flora has traditionally been interpreted as a relict of a subtropical element that spanned across Europe in the Tertiary. This hypothesis is revisited in the moss subfamily Helicodontioideae based on molecular divergence estimates derived from two independent calibration techniques. The analyses employing a fossil calibration on the one hand, and using of a MCMC to sample absolute rates of nucleotide substitution from a prior distribution encompassing a wide range of rates documented across land plants on the other, both converged towards a unique scenario, wherein the Madeiran endemic Brachythecium percurrens diverged about 40 mya, i.e., well before Macaronesian archipelagos actually emerged. In the absence of any fossil evidence, this unambiguously points to a relictual origin of the species. Brachythecium percurrens further exhibits the remarkable feature of a complete morphological stasis over 40 myrs, since all its traits, for which significant reconstructions of ancestral states could be achieved at the most recent common ancestor of the Helicodontioideae, are shared with the latter. Macaronesian endemic Rhynchostegiella species, by contrast, evolved much more recently, and their polyphyletic origin suggests multiple colonization events. The Macaronesian moss flora thus appears as a complex mix of ancient relicts and more recently dispersed taxa.
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1 - University of Liege, Institute of Botany, B22 Sart Tilman, Liege, 4000, Belgium
2 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
3 - University of Turku, Biology, Laboratory of Genetics, Turku, 20014, Finland
4 - Main Botanical Garden of Russian Academy of Sciences, Botanicheskaya 4, Moscow, 127276, Russia
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie B/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 10:45 AM