Two New Species of Primula Sect. Auganthus From Sichuan, China

In groups undergoing rapid radiations, species delimitation among phylogenetically close sister lineages has long been a challenge. During plant surveys in northwestern Sichuan, we unexpectedly discovered two putative new species of Primula that are morphologically similar yet distinct from each other. These species resemble P. xingshanensis, which has been assigned to sect. Auganthus based on morphological characters. To clarify the precise phylogenetic positions of the two putative new species and P. xingshanensis, we sampled related taxa and conducted phylogenetic analyses using chloroplast genomes and nuclear SNPs. The results showed that the two putative new species form sister clades and are closely related to P. sinensis, while P. xingshanensis is sister to P. rupestris. All belong to the sect. Auganthus. Based on population genetic structure, morphological statistics, and artificial hybridization experiments, both putative new species should be accepted as distinct species, herein formally described as P. rongrong sp. nov. and P. fujiangensis sp. nov. Based on our field surveys and in accordance with the IUCN criteria, we assess the conservation status of P. rongrong as least concern (LC) and P. fujiangensis as critically endangered (CR).