Phylogenomics, historical biogeography, and diversification of leaf traits in the Malagasy‐endemic genus Uncarina (Pedaliaceae)

作者：Jeffrey P. Rose, John G. Zaborsky, Nisa Karimi, Kenneth J. Sytsma · 发表于：American Journal of Botany · 年份：2025 · DOI：10.1002/ajb2.70028 · 被引用次数：2 · 研究领域：Primate Behavior and Ecology、Evolution and Paleontology Studies、Morphological variations and asymmetry

PREMISE: Uncarina contains 14 species of woody plants endemic to Madagascar. Its occurrence across dryland biomes on the island make it an interesting system to study the diversification of the flora. METHODS: Using samples of all species and 512 nuclear loci, we reconstructed phylogenetic trees to examine species relationships and assess their monophyly. We also studied the historical biogeography of the genus and combined leaf trait data derived from SEM photography of trichomes and geometric morphometric analysis of leaf shape to better understand its diversification across dryland biomes. RESULTS: Uncarina is monophyletic, and major clades showed a clear biogeographical signal. Leaf traits also corroborated relationships among major clades. Although most species are monophyletic, at least one cryptic species exists. Uncarina, like many arid-adapted plant lineages in Madagascar originated in the Miocene or Pleistocene. Geographic movement has been primarily along a south-north axis, with river basins apparently acting as barriers to gene flow. The evolution of leaf traits corroborated movement from the spiny thicket to the dry forest biome. CONCLUSIONS: As with Malagasy lemurs and other animals, riverine barriers may have been involved in the diversification of Uncarina and may apply more broadly to epizoochorous angiosperms of Madagascar. Leaf traits suggest either a loss of adaptations to extremely arid, high irradiance environments or a release from herbivores. As is li...