Publications (Showing 5 of 5)

Generic delimitation of Turraea (Meliaceae–Turraeeae) and allied genera in continental Africa and Madagascar

Botanical Journal of the Linnean Society
2026
We investigated here speciation and diversification mechanisms in Turraea and allied genera (Meliaceae-Turraeeae) from Madagascar and continental Africa, as well as their generic delimitations. Our goal was to contribute to an improved understanding of the origin and diversification of the Malagasy and African floras. Using target-enrichment sequencing, we assembled a nuclear dataset comprising 64 taxa (75% of the group’s species diversity) to reconstruct phylogenetic relationships within the group. We estimated divergence times and diversification rate shifts and assessed the prevalence of incomplete lineage sorting and introgression/hybridization. The group appears to have originated in the Eocene, probably in southern Africa, with a diversification rate shift occurring in the Miocene coinciding with the colonization of Madagascar. This shift, associated with incomplete lineage sorting and introgression/hybridization, suggests a rapid diversification linked to the onset of the Indian Monsoon. We propose a revised generic classification, including a new key and synoptic descriptions of the genera, to accommodate the polyphyly of Turraea. In this context, we place the endemic Malagasy genera Humbertioturraea and Calodecaryia in synonymy under Turraea, and resurrect the South African genus Nurmonia and the Angolan and Indian genus Naregamia. We therefore publish the necessary new combinations in Nurmonia and Turraea.

DOI:

10.1093/botlinnean/boag026

View Publication

Phylogenomics and the rise of the angiosperms

Nature
2024

Vol. 629, Issue 8013

pp. 843-850

Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5–7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.

DOI:

10.1038/s41586-024-07324-0

View Publication

Phylogenomic analyses of Sapindales support new family relationships, rapid Mid-Cretaceous Hothouse diversification, and heterogeneous histories of gene duplication

Frontiers in Plant Science
2023

Vol. 14

Sapindales is an angiosperm order of high economic and ecological value comprising nine families, c. 479 genera, and c. 6570 species. However, family and subfamily relationships in Sapindales remain unclear, making reconstruction of the order’s spatio-temporal and morphological evolution difficult. In this study, we used Angiosperms353 target capture data to generate the most densely sampled phylogenetic trees of Sapindales to date, with 448 samples and c. 85% of genera represented. The percentage of paralogous loci and allele divergence was characterized across the phylogeny, which was time-calibrated using 29 rigorously assessed fossil calibrations. All families were supported as monophyletic. Two core family clades subdivide the order, the first comprising Kirkiaceae, Burseraceae, and Anacardiaceae, the second comprising Simaroubaceae, Meliaceae, and Rutaceae. Kirkiaceae is sister to Burseraceae and Anacardiaceae, and, contrary to current understanding, Simaroubaceae is sister to Meliaceae and Rutaceae. Sapindaceae is placed with Nitrariaceae and Biebersteiniaceae as sister to the core Sapindales families, but the relationships between these families remain unclear, likely due to their rapid and ancient diversification. Sapindales families emerged in rapid succession, coincident with the climatic change of the Mid-Cretaceous Hothouse event. Subfamily and tribal relationships within the major families need revision, particularly in Sapindaceae, Rutaceae and Meliaceae. Much of the difficulty in reconstructing relationships at this level may be caused by the prevalence of paralogous loci, particularly in Meliaceae and Rutaceae, that are likely indicative of ancient gene duplication events such as hybridization and polyploidization playing a role in the evolutionary history of these families. This study provides key insights into factors that may affect phylogenetic reconstructions in Sapindales across multiple scales, and provides a state-of-the-art phylogenetic framework for further research.

DOI:

10.3389/fpls.2023.1063174

View Publication

Flora of Singapore: Checklist and bibliography

Gardens' Bulletin Singapore
2022

Vol. 74, Issue (suppl.1)

pp. 3-860

A checklist of all species of bryophytes, lycophytes, ferns, gymnosperms and angiosperms that are found in the wild (native, naturalised and casual) in Singapore is presented. We have attempted to account for all names of species and infraspecific taxa that have ever been recorded for Singapore, along with the pertinent publications that reported each of these names. For each currently accepted name, the synonyms of relevance for Singapore are included. The native or non-native status for all taxa is given, along with the most recent national conservation assessment applied to each native taxon. If we were aware that the most recent assessment required an update, the taxon is newly assessed here. The checklist includes 2654 native taxa, 479 naturalised/casual taxa and 101 cryptogenic taxa.

DOI:

10.26492/gbs74(suppl.1).2022-01

View Publication

New Guinea has the world’s richest island flora

Nature
2020

Vol. 584, Issue 7822

pp. 579-583

New Guinea is the world’s largest tropical island and has fascinated naturalists for centuries. Home to some of the best-preserved ecosystems on the planet and to intact ecological gradients—from mangroves to tropical alpine grasslands—that are unmatched in the Asia-Pacific region, it is a globally recognized centre of biological and cultural diversity. So far, however, there has been no attempt to critically catalogue the entire vascular plant diversity of New Guinea. Here we present the first, to our knowledge, expert-verified checklist of the vascular plants of mainland New Guinea and surrounding islands. Our publicly available checklist includes 13,634 species (68% endemic), 1,742 genera and 264 families—suggesting that New Guinea is the most floristically diverse island in the world. Expert knowledge is essential for building checklists in the digital era: reliance on online taxonomic resources alone would have inflated species counts by 22%. Species discovery shows no sign of levelling off, and we discuss steps to accelerate botanical research in the ‘Last Unknown’.

DOI:

10.1038/s41586-020-2549-5

View Publication
Martin Cheek | Flora of the World