Abstract:
The genus Dalbergia L.f. comprises ca. 270 species, and particularly known for its high valuable rosewoods. Previous studies poorly resolved the intrageneric phylogenetic relationships within the genus due to sparse taxon sampling and limited molecular data, which hindered the ability to address targeted evolutionary questions. In this study, we reconstructed the phylogeny of Dalbergia using concatenated and coalescent approaches based on 89 captured nuclear genes from 98 Dalbergia species, which covered the entire distribution range and all recognized clades of the genus. We identified six strongly supported clades within Dalbergia, including the newly identified subclade D1 and clade E, comprising species from Africa and Africa–Madagascar, respectively, which had not been sampled in previous studies. Additionally, we suggested to expand Dalbergia sect. Ecastaphyllum by including a few African species. Topological discordance has been detected between the concatenated and coalescent trees, along with low levels of gene tree conflict and reticulate evolution within the genus, likely due to hybridization and incomplete lineage sorting (ILS). Ancestral area reconstruction analyses indicated a Neotropical origin at ca. 39 Ma (middle Eocene) for Dalbergia, with its lineages subsequently dispersing into other regions, and likely facilitated by long-distance dispersals through ocean currents. Dispersal, habits, biomes diversity, and climatic events that occurred during the Eocene–Miocene period may have shaped the diversification pattern of the genus. Overall, our study provides the first well-resolved phylogeny of Dalbergia and suggests that geographical shifts and climatic changes may have played important roles in driving species diversification in pantropical regions.
Speaker: Dr. Fabien R. Rahaingoson
Affiliation: Kunming Institute of Zoology, Chinese Academy of Sciences
Time: 16:30 PM, Tuesday, Jan. 16, 2024
Venue: Tencent Meeting ID：823-833-779
https://meeting.tencent.com/dm/HnCbrsD3y5pL
