A new species Lepidopteris baodensis sp.nov.belonging to the family Peltaspermaceae and represented by two ultimate pinnae in the collection under study,was recently discovered at the Baijiagou of Baode,Shanxi,China,from the Upper Permian Sunjiagou Formation.The lower surface of the ultimate rachis,the midrib and secondary veins is covered with triangular,trapezoid,rounded,or ligulate subepidermal swellings,which show different natures from intercalary pinnules.Lepidopteris is one of typical elements of the Late Permian Euramerican flora.Since Schimper erected the genus Lepidopteris in 1869,the entire epidermal structure of subepidermal swellings had been unclear.The new species L.baodensis clearly showing the distinguished epidermal structure of subepidermal swellings,not only enlarges and supplements our knowledge in biology and taxonomy of Lepidopteris as well as the Upper Permian stratigraphy of China,but also provides an opportunity to understand the relationship between Euramerican floras and Cathaysian floras in paleoclimatic,paleoenvironmental and paleogeographic context.
Phymatopteris Pic.Serm.,a derived polypodiaceous fern,is one of the many fern genera that still suffer from nomenclatural confusion.Its generic circumscription and phylogenetic relationships with other selligueoid ferns have been controversial,and its geographic origin,whether in the Himalayan region of continental Asia or in Malay Archipelago,is still unknown.A phylogeny of all selligueoid ferns based on 4 cpDNA(rbcL,trnL-F,rps4 and rps4-trnS) regions indicates that Phymatopteris is not monophyletic.Phymatopteris species are distributed in 5 well-supported clades that can be distinguished with frond-shape and frond-margin characters.All early-divergent species are from the Malaysian Archipelago,while the remaining species are all from the Himalayan region and form a recently diverged group that is largely unresolved,most likely having resulted from an explosive radiation.Divergence-time estimation suggests that the first diversification of selligueoid ferns occurred at ca.27 Ma in the Malaysian Archipelago,followed by migration into the Himalayan region around 20 Ma.The radiation of the Himalayan species occurred mostly within the last 20 million years,within the period of recent major uplifts of the Qinghai-Tibetan Plateau(between the early Miocene and the Pleistocene) and late-Cenozoic global cooling.Our evidence leads us to propose that the Malaysian Archipelago is the ancestral area for Phymatopteris.
LI ChunXiangLU ShuGangMA JunYeSUN XiaoYanGAI YongHuaBARRINGTON David SYANG Qun
