The Neogene rise of the tropical Andes facilitated diversification of wax palms (Ceroxylon: Arecaceae) through geographical colonization and climatic niche separation MAR  IA J. SAN  IN 1 *, W. DANIEL KISSLING 2 , CHRISTINE D. BACON 3 , FINN BORCHSENIUS 4 , GLORIA GALEANO 5 , JENS-CHRISTIAN SVENNING 6 , JOS  E OLIVERA 7 , RINA RAM  IREZ 7 , PHILIP TR  ENEL 8 and JEAN-CHRISTOPHE PINTAUD 9† 1 Department of Biology, Universidad CES, Medellín, Colombia 2 Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, the Netherlands 3 Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden 4 Science Museums, Aarhus University, Ole Worms Allé 1, Building 1137, DK-8000, Aarhus C, Denmark 5 Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogota, Colombia 6 Section for Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Aarhus, Denmark 7 Universidad Nacional Mayor de San Marcos, Lima, Peru 8 AgroTech a/S, Aarhus, Denmark 9 Institut de Recherche pour le Développement, Montpellier, France Received 4 November 2015; revised 20 February 2016; accepted for publication 27 February 2016 The tropical Andes are a biodiversity hotspot, partly due to their rich and complex floristic composition. A fundamental question regarding this outstanding biodiversity is what role the Andean orogeny has played in species diversification. Ceroxylon is a genus of endemic Andean palms that stands out in the palm family (Arecaceae) due to its adaptation to cold, mountainous environments. Here, we reconstruct the biogeography and climatic preference of this lineage to test the hypothesis that Andean uplift allowed diversification by providing suitable habitats along climatic and elevational gradients. Ancestral areas were reconstructed under a model allowing for founder-event speciation and climatic niches were inferred from climatic variables at present-day occurrences of all species. Niche evolution in a phylogenetic framework was evaluated by testing differences between the climatic niches of clades. Our analyses identified four main clades, with a general pattern of diversification through geographical colonization from south to north after the Pliocene uplift of the northern Andes. Adaptation to low temperatures was conserved at the generic level, with climatic niche differentiation among clades along elevational temperature gradients. We conclude that the Neogene Andean uplift has facilitated the diversification of this iconic plant group via opportunities for geographical migration and separation within its climatic niche. © 2016 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 182, 303–317 ADDITIONAL KEYWORDS: cold adaptation – Miocene – Neotropics – niche shift – phylogenetic niche conservatism – range expansion. INTRODUCTION The tropical Andes is the most species-rich biodiver- sity hotspot on a global scale harbouring almost *Corresponding author. E-mail: msanin@ces.edu.co †In memoriam. 303 © 2016 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 182, 303–317 Botanical Journal of the Linnean Society, 2016, 182, 303–317. With 3 figures Downloaded from https://academic.oup.com/botlinnean/article-abstract/182/2/303/2707818 by guest on 22 May 2020