Evolutionary Distribution Changes of Sichuan Golden Monkeys (Rhinopithecus roxellana) in the Quaternary

Retrospective reconstruction of animals' evolutionary development and geographic changes in recent history, as well as monitoring contemporary conservation status, are critical to amending existing conservation strategies. This study presents an innovative effort, as demonstrated by the Sichuan golden monkeys (Rhinopithecus roxellana) in China. We studied their fossil distribution patterns during the Pleistocene, explored historical distribution changes over the last 400 years, and surveyed 27 nature reserves where they dwell. The results indicate that this species successfully dispersed from Southwest China to the rest of the mainland of East Asia along the Yangtze and Pearl Rivers, reaching Taiwan during the Pleistocene, which marked the broadest geographic distribution in its evolutionary history. Unfortunately, its population began to shrink during the Holocene, leaving it currently restricted to the provinces of Sichuan, Gansu, Shaanxi, and Hubei in China. Accordingly, we proposed four conservation strategies to amend its conservation status.