Format: ORAL

Pablo Garca-Moro,1 Tamara Villaverde2, Mara Sanz-Arnal1, Jos Ignacio Mrquez-Corro3, Paulo Muoz-Schler4, Kerry Ford5, Karen Wilson6, Germinal Rouhan7, Mnica Mguez1, Santiago Martn-Bravo1 Pedro Jimnez-Mejas1

1 Universidad Pablo de Olavide, Seville, Spain 2 Universidad Rey Juan Carlos, Madrid, Spain 3 Royal Botanic Garden, Kew, United Kingdom 4 Universidad de Concepción, Concepción, Chile 5 Royal Botanic Gardens, Sydney, Australia 6 Manaaki Whenua – Landcare Research, New Zealand 7 Muséum National d’Histoire Naturelle, Paris, France

Carex sect. Uncinia with c. 70 species is the most diverse lineage of subgenus Uncinia and displays a remarkable disjunct distribution in the Southern Hemisphere. It had its ancestral area in South America, where it originated 15 million years ago, but it is also present in the Pacific-Southwest Region (Australia-New Zealand), as well as in some Pacific Islands and circum-Antarctic archipelagos. The colonization of these regions was likely facilitated by the presence of an exserted hooked rachilla, which is a syndrome for long-distance dispersal (epizoochory) exclusive of sect. Uncinia. A large proportion of the species richness is roughly halved between South America and New Zealand, which have been related to putative evolutionary radiations, especially in the later. Previous phylogenetic reconstructions based on standard DNA barcoding markers failed to disentangle relationships at shallow evolutionary level. We have enhanced phylogenetic resolution within this section by using Hyb-Seq genomic data for an almost complete species sampling. We tried to further studied the evolution within this lineage by obtaining genome size data and by conducting morphometric analyses for shallow species complex with disjunct trans-oceanic distributions (C. austrocompacta s.l., C. brevicaulis s.l.) biogeographic patterns. Genome size reconstruction analysis reveals that several species of sect. Uncinia could be polyploid, as they exceed the average size of the genus. This increase in genome size could be associated to its colonization ability in new ecological niches as previously seen in other Cyperaceae. The dispersal routes of sect. Uncinia through the Oceans can be appreciated in some of its species complex as those of the circum-Antarctic archipelagos: Carex austrocompacta s.l. describes a Stepping-Stone pattern from New Zealand in an East-to-West direction. Carex brevicaulis s.l., on the other hand, seems to have colonized Pacific, Atlantic and circum-Antarctic islands through several, independent LDD events from South America.