Dated Phylogeny of Banisteriopsis (Malpighiaceae) Suggests an Ancient Colonization of the Cerrado and No Evidence of Human Manipulation in the Origin of B. caapi

<i>Banisteriopsis</i> is a genus in the Malpighiaceae family with 61 species, notable for including ritualistic taxa such as <i>B. caapi</i> (Spruce ex Griseb.) C.V. Morton, one of the main components of Ayahuasca tea. We analyzed 38 <i>Banisteriopsis</i> species, representing more than 60% of the genus, to investigate its geographical origin, diversification period, and colonization routes in the Neotropics. Plastid genes (<i>mat</i>K, <i>ndh</i>F, and <i>rbc</i>L) and nuclear regions (ETS, ITS, and <i>PHYC</i>) were used in our analyses. Divergence time analyses were performed using Bayesian inference with a relaxed molecular clock and ancestral area reconstruction. Our results show that <i>Banisteriopsis</i> originated in the Miocene approximately 22 million years ago, and its diversification coincides with the expansion of dry areas in South America. <i>Banisteriopsis</i> began colonizing the Cerrado earlier than most other plants, and the history of the genus reveals that the biome served as a source of species for Neotropical rainforests. Our results also indicate a probable ancient origin for <i>B. caapi</i>, with no evidence of human manipulation in its diversification, and they reinforce archaeological evidence of a millennia-old exchange of uses among Amazonian peoples.