AND IF ENGLER WAS NOT COMPLETELY WRONG? EVIDENCE FOR MULTIPLE EVOLUTIONARY ORIGINS IN THE MOSS FLORA OF MACARONESIA |
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Authors: | Delphine A Aigoin Nicolas Devos Sanna Huttunen Michael S Ignatov Juana M Gonzalez‐Mancebo Alain Vanderpoorten |
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Institution: | 1. Institute of Botany, University of Liège, 27 Blvd du Rectorat, B22, Sart Tilman, 4000 Liège, Belgium;2. E‐mail: Delphine.Aigoin@ulg.ac.be;3. Institute of Evolutionary Sciences, University of Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France;4. E‐mail: ndevos@ulg.ac.be;5. Laboratory of Genetics, Department of Biology, University of Turku, 20014 Turku, Finland;6. E‐mail: shuttu@utu.fi;7. Main Botanical Garden of Russian Academy of Sciences, Botanicheskaya 4, 127276 Moscow, Russia;8. E‐mail: misha_ignatov@list.ru;9. Department of Botany, University of La Laguna, 38271 La Laguna, Tenerife, Canary Islands, Spain;10. E‐mail: jglezm@ull.es;11. E‐mail: A.Vanderpoorten@ulg.ac.be |
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Abstract: | 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 either employing fossil evidence or using an Monte Carlo Markov Chain (MCMC) to sample absolute rates of nucleotide substitution from a prior distribution encompassing a wide range of rates documented across land plants. Both analyses suggest that the monotypic Madeiran endemic genus Hedenasiastrum diverged of other Helicodontioideae about 40 million years, that is, well before Macaronesian archipelagos actually emerged, in agreement with the relict hypothesis. Hedenasiastrum is characterized by a plesiomorphic morphology, which is suggestive of a complete morphological stasis over 40 million years. Macaronesian endemic Rhynchostegiella species, whose polyphyletic origin involves multiple colonization events, evolved much more recently, and yet accumulated many more morphological novelties than H. percurrens. The Macaronesian moss flora thus appears as a complex mix of ancient relicts and more recently dispersed, fast‐evolving taxa. |
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Keywords: | Bryophytes fossils macronesian endemism molecular dating morphological evolution |
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