Format: ORAL

Fabin Augusto Aldaba Nez1, Salvador Guzmn-Daz1, Emily Veltjen2, Pieter Asselman2, Isabel Larridon3, Esteban Manuel Martnez Salas4, Marie-Stphanie Samain1,2

1 Instituto de Ecología, A.C., Pátzcuaro, Mexico 2 Ghent University, Gent, Belgium 3 Royal Botanic Gardens, Kew, United Kingdom 4 Universidad Nacional Autónoma de México, Mexico City, Mexico

The genus Magnolia includes around 390 species inhabiting the Nearctic (~10 spp.), Neotropical (~170 spp.) and Oriental and Palaearctic (~210 spp.) biogeographic regions. Although several studies have been carried out to elucidate their phylogenetic relationships, the Neotropical taxa have been underrepresented, whereas the number of Neotropical species described has doubled in recent decades. Hence, this research focused on determining the phylogenetic relationships of Neotropical Magnolia using phylogenomic procedures to understand the infrageneric classification of Neotropical clades. The study included 137 samples from 90 taxa: 75 Neotropical and 15 Nearctic and Asian, covering one-third of all Neotropical species and including related clades to maintain phylogenetic representativeness. A list of 25 macromorphological characters for Magnolia, emphasizing Neotropical species was provided to delimit lineages. Two primary clades were identified: the first grouped the Neotropical sections Talauma and Splendentes, as well as Gwillimia from Asia, while the second was composed of the Neotropical sections Macrophylla and Magnolia and the four remaining Asian and Nearctic groups. These two main clades corresponded to those found in previous studies based on plastome data. The section Talauma was divided into two geographically patterned clades: one included species from Mexico and Central America, and the other comprised species from South America and the Caribbean. The Splendentes section was also subdivided into two subclades corresponding to the former sections Cubenses and Dugandiodendron. The phylogenomic evidence showed a species complex in the Macrophylla section, where taxa intersected among lineages. Relationships within the Magnolia section were unclear due to inconsistent topologies. All recognized Neotropical clades can be diagnosed by a combination of macromorphological traits, and they were confirmed as monophyletic, while certain Nearctic or Asian groups were not.The infrageneric classification of Neotropical clades was updated basedbased on the phylogenomic evidence and a taxonomic key is provided.