Reticulate Evolution, Ancient Chloroplast Haplotypes, and Rapid Radiation of the Australian Plant Genus Adenanthos (Proteaceae)

Cytonuclear discordance, commonly detected in phylogenetic studies, is often attributed to hybridization and/or incomplete lineage sorting (ILS). New sequencing technologies and analytical approaches can provide new insights into the relative importance of these processes. Hybridization has previously been reported Australian endemic plant genus Adenanthos (Proteaceae). Like many genera, relatively ancient origin, provides an opportunity examine long-term evolutionary consequences gene flow between lineages. Using a hybrid capture approach, we assembled densely sampled low-copy nuclear plastid DNA sequences for , inferred its history, used Bayesian posterior predictive approach coalescent simulations assess contributions ILS cytonuclear discordance. Our analyses indicate that strong incongruence our phylogenies not only result ILS, but also results from extensive introgression as well recent chloroplast extant species. The deep reticulation was long-persisting haplotypes shared evolutionarily distant These may have persisted over 12 Ma localized populations across southwest Western Australia, indicating region important area old lineages accumulation species, characterized by persistence high genetic diversity. Deep coincided with rapid radiation during Miocene, time when temperate groups radiated response large-scale climatic change. This study suggests play role evolution flora more broadly.