Phylogenomics, Biogeography and Evolution of the Hemicryptophytes Species of Dalechampia L. (Euphorbiaceae)

• Grant number: 24/22275-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2025
• End date: October 31, 2028
• Field of knowledge: Biological Sciences - Botany - Plant Taxonomy
• Principal Investigator: Otávio Luis Marques da Silva
• Grantee: Luiza Oliveira Brigato
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Dalechampia is a pantropical genus comprising approximately 130 species, with its highest diversity found in the Neotropical region (ca. 90). Among the species of the genus, those belonging to D. subsects. Humiles and Brevipedes are notable for their hemicryptophytic growth form and are primarily found in the Cerrado. The only phylogenies conducted to date are based on a limited number of loci (trnK, matK, ETS, and ITS) and indicate that the current infrageneric classification requires revisions. Furthermore, species within D. subsect. Humiles do not form a monophyletic group, while D. subsect. Brevipedes has never been sampled in these studies. In this project, we propose to infer the phylogenetic relationships among species of Dalechampia, focusing on D. subsects. Humiles and Brevipedes, and to consistently evaluate the current infrageneric classification through a robust phylogeny using high-throughput sequencing (HTS) data with the Angiosperms353 probe kit and extensive species sampling. This approach aims to investigate the biogeographic history of the species and the evolution of key morphological traits. The primary hypotheses of the project are: (i) D. subsects. Humiles and Brevipedes are not monophyletic; (ii) the hemicryptophytic growth form evolved independently in multiple Dalechampia lineages; (iii) these lineages diversified recently, associated with the emergence of Cerrado grassland formations; and (iv) Dalechampia originated in the Amazon and spread to the Old World via GAARLandia and boreotropical forests. The project aims to clarify infrageneric relationships using phylogenomic data, advancing the understanding of the evolutionary history of the genus, particularly the hemicryptophytic lineages and their connections to Cerrado savannas. This research will also contribute to the systematics of Dalechampia and Euphorbiaceae, as well as to biogeographical studies of the Cerrado.