title: Beyond aridification: multiple explanations for the elevated diversification of cacti in the New World Succulent Biome.
abstract: Succulent plants are widely distributed, reaching their highest diversity in arid and semi-arid regions. Their origin and diversification is thought to be associated with a global expansion of aridity. We test this hypothesis by investigating the tempo and pattern of Cactaceae diversification. Our results contribute to the understanding of the evolution of New World Succulent Biomes. We use the most taxonomically complete dataset currently available for Cactaceae. We estimate divergence times and utilize Bayesian and maximum likelihood methods that account for nonrandom taxonomic sampling, possible extinction scenarios and phylogenetic uncertainty to analyze diversification rates, and evolution of growth form and pollination syndrome. Cactaceae originated shortly after the Eocene-Oligocene global drop in CO2 , and radiation of its richest genera coincided with the expansion of aridity in North America during the late Miocene. A significant correlation between growth form and pollination syndrome was found, as well as a clear state dependence between diversification rate, and pollination and growth-form evolution. This study suggests a complex picture underlying the diversification of Cactaceae. It not only responded to the availability of new niches resulting from aridification, but also to the correlated evolution of novel growth forms and reproductive strategies.
authors.affiliation: Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito de Ciudad Universitaria, Del. Coyoacán, México D.F, 04510, México.
authors.forename: Tania
authors.initials: T
authors.lastname: Hernández-Hernández
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI, 48109-1048, USA.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Brown
authors.affiliation: Herrenhausen Gardens, Hannover, Germany.
authors.forename: Boris O
authors.initials: BO
authors.lastname: Schlumpberger
authors.affiliation: Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, 3er Circuito de Ciudad Universitaria, Del. Coyoacán, México D.F, 04510, México.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Eguiarte
authors.affiliation: Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito de Ciudad Universitaria, Del. Coyoacán, México D.F, 04510, México.
authors.forename: Susana
authors.initials: S
authors.lastname: Magallón
mesh_terms: D044822:Biodiversity; D005075:Biological Evolution; D029421:Cactaceae / Q000235:genetics* / Q000502:physiology; D010802:Phylogeny
keywords: BEAST; BiSSE; Cactaceae; MEDUSA; Succulent Biome; adaptive radiation; diversification rates; pollination syndromes