Diodonopteris virgulata sp. nov., a climbing fern from the early Permian Wuda Tuff Flora and its paleoecology

Botryopteridaceae, characterized by an omega-shaped foliar trace, is one of the best known late Paleozoic fern families with frequent occurrence in the Carboniferous of Euramerica and recent recognition in Permian deposits of Gondwana and Cathaysia. Diodonopteris is a recently established botryopterid genus based on coal-ball material from the lower Permian Taiyuan Formation of Shanxi Province, China. Here, a new species of Diodonopteris is described based on an anatomically preserved specimen from the well-known early Permian Wuda Tuff Flora in the Wuda Coalfield of Inner Mongolia, China. Diodonopteris virgulata sp. nov. is similar to the type species D. gracilis in the marginal position of protoxylem groups but differs from the latter in having a simpler cortex and a more expanded xylem strand. The two known Diodonopteris species share several characteristics considered ancestral among botryopterids, including strand shape, mode of pinna trace divergence, weak pinnule lamination, and a laminar wing on the rachis, as is consistent with Diodonopteris sitting outside any of the derived sublineages within Botryopteris. D. virgulata is confirmed to be a climber by direct preservation with the host. Moreover, the host plant is also evidenced to be a climber. The repeated preservation of the dual-climbing phenomenon in this swamp forest signals the complexity of early Permian ecosystems. (c) 2022 Published by Elsevier B.V.

Automated summary

A new species of the botryopterid genus Diodonopteris, Diodonopteris virgulata, is described based on a well-preserved specimen from the early Permian Wuda Tuff Flora in Inner Mongolia, China. The new species shares similarities with the type species, D. gracilis, but differs in cortex structure and xylem strand morphology. Both D. virgulata and its host plant are confirmed as climbers, suggesting the complexity of early Permian ecosystems.