Evolución, biogeografía y sistemática del género cymbalaria hill

Resumen

Since ancient times the diversity of life forms has fascinated and intrigued humanity. How do species originate? How did they achieve their present geographic distributions? In the last decades, the progress of molecular systematics tools has allowed for successfully answering these questions. In this thesis, we perform a systematic study of the genus Cymbalaria, a group of rupicolous plants endemic to the Mediterranean Basin. Mainly, we used phylogenetic and phylogeographic methods and morphological analyses to infer their evolution and biogeographic history, and to propose a new taxonomic classification from the perspective of integrative taxonomy. Our results show that Cymbalaria originated ca. 4 million years ago and diversified during and after the establishment of Mediterranean type climate, through allopatric, sympatric and polyploid speciation. At least, two long-distance dispersal events from Corsica-Sardinia to the Balearic Islands occurred, although no apparent adaptations for dispersal exist in this case. Marine barriers successfully interrupted gene flow and allowed allopatric speciation to take place in some cases, while, in others, species successfully maintained gene flow between populations separated by the sea. Pleistocene sea-level fluctuations could have contributed to the present distribution of taxa and triggered speciation. By combining molecular and morphological data, we bring the classification of Cymbalaria closer to the integrative taxonomy concept and identify valuable diagnostic morphological characters. Here, we propose a new circumscription of C. fragilis to include specimens misidentified as C. aequitriloba due to the variability of seed ornamentation. Also, we describe the new paraphyletic subspecies C. muelleri subsp. villosa, from which C. muelleri subsp. muelleri originated through anacladogenetic speciation. Thus, we discuss the need for recognizing non-monophyletic taxa, since evolution does not always result in purely dichotomous branching patterns. Finally we suggest a new taxonomic treatment for the eastern Mediterranean species, in which we split C. microcalyx into four species, describe the new species C. spetae and propose two new combinations.