Search for: All records

Abstract— Artocarpus bergii , named for the late C. C. Berg, is from Halmahera in the Moluccas, and is a close ally of breadfruit ( A. altilis ). The species resembles the Micronesian A. mariannensis but with generally smaller parts. Because it is known from only a small area and the type locality is a potential mining site, A. bergii is likely of conservation concern, particularly given its status as a crop wild relative. 

Recent taxonomic work on Artoarpus has revealed two undescribed species from Thailand and Vietnam. Artocarpus rubrosoccatus, endemic to peninsular Thailand, resembles A. lacucha but is distinguished by its deep red clavate staminate inflorescences. Artocarpus montanus is found in the montane regions of southern and central Vietnam, and perhaps also in Thailand. This species resembles the vegetative parts of A. lowii and A. excelsus, but A. montanus differs in its longer syncarp processes and its geographic distribution. The vast majority of Artocarpus species are found in tropical lowlands, and A. montanus, along with A. excelsus, represent the only known members of the genus that are restricted to montane habitats. The provisional conservation assessment of both new species is Near Threatened, because although their known areas of occupancy are restricted, both occur in protected areas. 

Abstract We present a 517-gene phylogenetic framework for the breadfruit genus Artocarpus (ca. 70 spp., Moraceae), making use of silica-dried leaves from recent fieldwork and herbarium specimens (some up to 106 years old) to achieve 96% taxon sampling. We explore issues relating to assembly, paralogous loci, partitions, and analysis method to reconstruct a phylogeny that is robust to variation in data and available tools. Although codon partitioning did not result in any substantial topological differences, the inclusion of flanking noncoding sequence in analyses significantly increased the resolution of gene trees. We also found that increasing the size of data sets increased convergence between analysis methods but did not reduce gene-tree conflict. We optimized the HybPiper targeted-enrichment sequence assembly pipeline for short sequences derived from degraded DNA extracted from museum specimens. Although the subgenera of Artocarpus were monophyletic, revision is required at finer scales, particularly with respect to widespread species. We expect our results to provide a basis for further studies in Artocarpus and provide guidelines for future analyses of data sets based on target enrichment data, particularly those using sequences from both fresh and museum material, counseling careful attention to the potential of off-target sequences to improve resolution. [Artocarpus; Moraceae; noncoding sequences; phylogenomics; target enrichment.] 

Abstract Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods^1,2. 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 genome^3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins^5–7. 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 studies⁹provides 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.