Pagamea coriacea s.l. (Rubiaceae Juss.) e seus segredos: desvendando espécies crípticas nas campinaranas da Amazônia

Abstract

This thesis investigates the complex biodiversity within the Pagamea coriacea species complex (Rubiaceae), focusing on the identification and delimitation of cryptic species found in the Amazonian white sand ecosystems. An integrative approach was employed, combining morphological, genetic, spectral, and ecological data to delineate species boundaries. Using methods such as DNA sequencing, leaf morphometry, and near-infrared spectroscopy (NIR), the study identified four independent lineages within Pagamea coriacea species complex, which were recognized as distinct species: Pagamea m.acuta, Pagamea m.coriacea, Pagamea m.coriacearana, and Pagamea igapoana sp. nov., being the last exclusive to the Igapó forests. The new sequencing, annotation, and curation of the complete chloroplast genome of Pagamea acrensis, Pagamea m.acuta, Pagamea m.coriacea, Pagamea m.coriacearana, Pagamea igapoana sp. nov. and Pagamea plicata are provided for the first time here. We provide insights into the genome structure and organization and identify hypervariable regions useful for molecular species identification among different species of the Rubiaceae family. Furthermore, we employ phylogenetic methods to reconstruct the evolutionary relationships of the new chloroplast with respect to the other subfamilies of Rubiaceae. Furthermore, a comprehensive morphological description is provided, including diagnostic features that distinguish Pagamea igapoana sp. nov. from other species of the complex, discussing the ecological adaptations of this new species to its specific habitat and emphasizing its uniqueness and conservation status. The conservation status assessment of the new Pagamea igapoana sp. nov. is critically endangered due to its limited distribution, specific habitat requirements and single population known to date. These findings contribute to our understanding of evolutionary relationships and diversification patterns in the Pagamea coriacea species complex, as well as in the Amazonian white sand systems.