Format: ORAL

Renato Goldenberg1 Bruno Bastos1 Lucas F. Bacci1,2 Thuane Bochorny3 Marcelo Reginato4 Fabian A. Michelangeli5

1 Universidade Federal do Paraná, Curitiba, Brazil 2 Universidade Federal de Santa Catarina, Florianópolis, Brazil 3 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Brazil 4 Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil 5 Institute of Systematic Botany, The New York Botanical Garden, USA

Asymmetric patterns in species richness are a notable feature across different lineages and geographic regions. While some lineages are rich, diverse and widely distributed, the depauperons are phylogenetically isolated, with only one or a few narrowly distributed species. Recent phylogenetic studies of Melastomataceae resulted in a new classification with both megadiverse lineages, such as tribes Miconieae (1900 species), Sonerileae (1100) and Melastomateae (820) and groups with few species, such as Lithobieae (1), Rupestreeae (2), Stanmarkieae (4), and Eriocnemeae (7) in the Neotropics, and Dinophoreae (8) and Feliciadameae (1) in Africa. These depauperon tribes have been very recently described, with their taxa traditionally placed in bigger tribes, even though they presented features uncommon for those groups or even the whole family. Three of these groups are restricted to Eastern South America: Lithobieae grows on rock crevices, and is sister to Pantropical Henrietteae+Astronieae (250 spp); Rupestreae grows in “campos rupestres”, and is nested in Pantropical Melastomataeae+Dinophoreae+Rhexieae (850); Eriocnemeae’s 3 genera grow in rainforest, iron ore outcrops, and montane vegetation, and are sister to Neotropical Miconieae (1900). The recognition and inclusion of these depauperons in phylogenetic analyses is critical to the study of biogeography, character evolution and ecology of their speciose sister groups. The different patterns found for depauperons and their relatives may be explained by different speciation/extinction rates, but also by other traits. Overall, the species in these groups have limited dispersal ability, dependency on water for dispersal, and restricted niches. Climatic niche spaces of the depauperons are limited but included within the niche space of the sister tribes. The threat level for them can be exacerbated by climate change, mainly due to their inability to spread over long distances, restricted niches and increased habitat fragmentation. Future conservational actions should prioritize these unique taxa in Melastomataceae, especially under a phylogenetic diversity perspective.