Revision on a fossil species of Late Miocene polypodiaceae from Lin-cang, Yunnan Province, and its biological significance

Yunnan Province is rich in resources of modern ferns. Understanding the origin and the diversity history of Yunnan ferns must learn from fossil records. Some new materials including one sterile frond and two humus fronds of the genus Drynaria were found in recent collections. These new specimens allow us to revise the previous fossil species Drynaria propinqua Wen et al., 2013, and provide supplementary characteristics of sterile and humus fronds for this species. On the basis of detailed morphological compari-son of fossils with extant species of Drynaria, the authors identified this species as Drynariacf. propinqua. The occurrence of Drynariacf. propinqua indicates that the Late Miocene climate of Lincang in Yunnan was similar to that of Southwest China today, being warm and humid. The epiphytic habit of its extant relative species implies that the complex hierarchical forest ecosystem of Lincang in Yunnan had been established at least in Late Miocene.