A trip of a bamboo lifetime: tracing the origin and evolution of Chusquea (Poaceae, Bambusoideae, Bambuseae) in Patagonia, southernmost South America

Abstract

We performed a phylogenetic analysis with estimated clade ages and an ancestral-range estimation focused on the Patagonian species of Chusquea, i.e. the Chusquea culeou clade, to unravel their biogeographical history. Phylogenetic analyses were conducted with sequence data from four plastid markers, using maximum parsimony and Bayesian inference approaches. The complete sampling and addition of the Patagonian Chusquea species into a phylogenetic framework revealed the most likely origin and evolutionary history of the Chusquea culeou clade. The Patagonian Chusquea originated roughly 11.35 Mya, most likely from a common ancestor from the Atlantic Forest region, when this lineage underwent in situ diversification and its species evolved sympatrically. All the extant species have arisen in the last 8 Myr. Moreover, according to the present sampling, the most recent common ancestor of subtribe Chusqueinae originated in the Northern Andes, which is also the most common source area of the estimated dispersal events. Some other preliminary insights on the biogeographic history of the genus are included.