Abstracts, XIV OPTIMA Meeting, Palermo (Italy) , 9-15

XIV OPTIMA Meeting, Palermo (Italy), 9-15 September 2013
Asymmetrical speciation patterns among Mediterranean and Macaronesian
Cheirolophus (Asteraceae)
VITALES D. 1 , GARCÍA-FERNÁNDEZ A. 2,4 , VALLÈS J. 1 , PELLICER J. 3 , GARCIA S. 1 , HIDALGO O. 1 , MARTÍN J. 1 ,
GARNATJE T. 2
1 Lab. de Botànica, Fac. de Farmàcia, Univ. de Barcelona, Barcelona, Catalonia, Spain. E-mail: dvitales@gmail.com
2 Institut Botànic de Barcelona (IBB-CSIC-ICUB), Barcelona, Catalonia, Spain.
3 Jodrell Laboratory, Royal Botanic Gardens, Kew, United Kingdom.
4 Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles (Madrid), Spain.
The genus Cheirolophus Cass. (Asteraceae) comprises ≈ 30 species mainly distributed along the
Western Mediterranean Basin and Macaronesia. Ten of them are currently recognized in the IUCN Red
List as vulnerable, endangered or critically endangered. Previous phylogenetic studies support the existence
of two main clades in the genus: a Macaronesian group composed by 20 species inhabiting
Canary Islands and Madeira, and a less diversified Mediterranean clade which groups most of the
North-African and Iberian species. Our main aim is to unravel Cheirolophus diversification using
recent advances in the field of phylogeny, biogeography and population genetics. Specifically, we
focus on the similarities and differences in the radiation process among Macaronesian and
Mediterranean clades.
Our results suggest a simultaneous pattern of diversification in Mediterranean and Macaronesian lineages,
coinciding with the onset of the Pleistocene climatic oscillations and the establishment of
Mediterranean climate. However, the radiation within the Macaronesian lineage derived in considerably
much more species than in the Mediterranean clade. Our analyses detected an increase of diversification
rate in the Macaronesian lineage, giving rise to one of the fastest plant radiations observed
to date. To explain the explosive diversification of Cheirolophus in the Macaronesia, some interrelated
factors may play relevant roles. Population genetic analyses -DNA sequencing and AFLP- suggest
the importance of insularity, geological history, habitat isolation and plant features in generating current
species diversity. In contrast, Mediterranean clade resulted in few species, some of them showing
wide distribution areas. In a population genetic study of Ch. intybaceus -one of these widely distributed
species, displaying a considerable morphological and ecological inter-population variability-, the
analyses reported evidences of continuum gene flow. Taking together, these results suggest that the
machinery to generate diversity may be powerful and ready-to-used in the whole genus. However,
while in continent the gene flow has limited population divergence and restrained the diversification
to the intra-specific level, the characteristics of Macaronesian archipelagos may have fueled the speciation
engines in Cheirolophus.
81