Diversity variation and tempo-spatial distributions of the Dipteridaceae ferns in the Mesozoic of China

The extant family Dipteridaceae is a remarkable leptosporangiate fern because it includes only one genus with a restricted distribution to tropical regions. The fossil record of this family has been widely reported from the Mesozoic strata in Eurasia, America, Australia, and Greenland. In China, numerous fossils of the Dipteridaceae have been documented, in total, about 74 species of 6 genera. Geographically, they are distributed both in the Southern and Northern Floristic Provinces, and were particularly well developed in the Southern Floristic Province during the Late Triassic and the Early Jurassic intervals. Fossil diversity of Dipteridaceae varies in the different episodes of the Mesozoic in China. It is shown that Dipteridaceae has undergone a diversity development process and a distinct turnover during the Mesozoic. They appear to have diversified in the warm and humid Late Triassic–Early Jurassic, but declined sharply as aridity developed in the Middle Jurassic, and became extinct at the end of the Early Cretaceous. The diversity variation and tempo-spatial distribution pattern is suggested to be linked with paleoclimatic variations during the Mesozoic.