Format: ORAL

Yanan Zhao

Institute of Systematics, Evolution and Biodiversity, Muséum national d’Histoire naturelle, Sorbonne Université, CNRS, EPHE-PSL, UA, Paris, France

Hymenophyllaceae, encompassing over 600 recognized species, are useful as indicators of the threatened humid forest environments at a pantropical scale. Emerging at least in the early Triassic and maybe in the Paleozoic, the family has ancient origins and displays a worldwide distribution resulting from significant diversifications and potential vicariance events since the Mesozoic. The taxonomic stabilization at family level is necessary and a prerequisite for biogeographic research, providing insights into its evolutionary history, including diversification patterns and processes. With nearly 1/3 of the worlds species, Asia would likely be the origin area of certain lineages. Furthermore, China would host approximately 70 species of Hymenophyllaceae, representing over 10% of the total family diversity, making it a potential key area for biogeographic studies at an Asian and global scale. Therefore, an updated revision of Hymenophyllaceae diversity and taxonomy in China appeared essential and has yet to be conducted. For this purpose, a first step was to revise the list of names, descriptions and a representative sample of specimens in the collections, including types, with the aim to provide an updated list of valid Chinese taxa and their verified synonyms, and to generate an online identification key. In a second step, we acquired DNA sequences for many Chinese specimens, used rbcLto reconstruct phylogenies for Trichomanoideae (6 genera in China: Abrodictyum, Callistopteris, Cephalomanes, Crepidomanes, Didymoglossum, Vandenboschia), and rbcLcombined with rbcL-accDand rps4-trnSfor the genus Hymenophyllum. With these datasets and by conducting dating and biogeographical analyses, we tested species hypotheses, and the role of China in the assembly of the family biodiversity, especially in Asia, was explored and is discussed. Hymenophyllaceae are emblematic and indicators of fragile and threatened wet habitats. This taxonomy work is thus integral to a conservation and decision support perspective.