A new fossil record of Thyrsopteridaceae (Cyatheales) from the mid-Cretaceous amber of Myanmar

Paleopalynology evidence and megafossil records indicated that tree fern order Cyatheales, played an important role in Mesozoic terrestrial ecosystem. Few fossil records of the family Thyrsopteridaceae have been reported so far. In the present study, we describe a distinctive fertile pinnule segment of a fern plant preserved in a mid-Cretaceous amber from Myanmar. The well-preserved fertile pinnule is identified as a new species of the extant tree fern genus Thyrsopteris (Thyrsopteridaceae): Thyrsopteris cyathindusia n. sp. It represents the second fossil species of Thyrsopteridaceae found in the mid-Cretaceous amber from Myanmar. The new species shows distinctive characteristics of the sporophyll that are considered paleoecologically/paleobiogeographically significant for evolution of the Thyrsopteridaceae.