Phylogenomics and the rise of the angiosperms

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

The conservation imperative and setting plant taxonomic research priorities in South Africa

For more than a decade it has been internationally recognised that efforts should be made to remedy the concern that taxonomy is an endangered discipline in the grips of rapid decline. In acknowledgement of the perceived continuing marginalisation of taxonomy, the Darwin Declaration recognised the need to enhance the taxonomic capacity of members who are party to the CBD, and beyond. South Africa is one of the most biodiversity rich countries globally, and the unique and rich flora of the country brings with it a significant conservation imperative. Although the country, and southern African sub-region for that matter, has a strong history of taxonomic endeavour, stretching back for over a century, it also suffers from a lack of human and other resources to adequately address its taxonomic needs. This inevitably calls for a process of priority-setting to ensure the wise use of available funding. As one example, it is shown that 1,009 indigenous South African plant taxa are regarded as Data Deficient for taxonomic reasons, following the completion of a recent comprehensive Red Listing exercise. Although not the only criterion to be considered when prioritising taxonomic research, efforts focused on these groups represent a significant opportunity for taxonomists to align their work with national priorities.http://www.springerlink.com/content/0960-3115