New Record of the Hueberia from the Posongchong Formation, Pragian Stage, Lower Devonian Series in the Bainiuchang Area, Southeastern Yunnan, China

The Posongchong Flora is an important window for understanding early vascular plant evolution. During a recent investigation of the Feigucun Section in the Bainiuchang area, Southeastern Yunnan, the author’s team discovered a large number of plant fossils from the Posongchong Formation of the Pragian Stage, Lower Devonian Series. Among the fossils collected in this investigation, there are six morphologically distinct drepanophycalean fossils, characterized by irregular dichotomous branching forming clustered stems, with the surface of the stems densely covered with spirally arranged falcate leaves. After comparing with coeval plant fossil records, it was found that the above characteristics are consistent with the generic characteristics of Hueberia fossils found in the Posongchong flora, indicating that these specimens should be assigned to the genus Hueberia. The team compared the newly discovered Hueberia fossils with the previously described Hueberia zhichangensis. The comparison revealed that the Hueberia specimens collected in the Bainiuchang area have thicker stems, longer intervals between successive branchings, and certain differences in leaf morphology from Hueberia zhichangensis. Therefore, the team considers that there are significant differences between it and Hueberia zhichangensis in morphology, geographical distribution, and other aspects, and there is sufficient reason to erect a new species, Hueberia bainiuchangensis sp. nov. The discovery of this species enriches our understanding of the species diversity of the genus Hueberia, expands the geographical distribution range of the Posongchong Flora, further corroborates that the Southeastern Yunnan region had extremely high biodiversity during the Pragian Age of the Early Devonian, and provides new clues for the study of Early Devonian plant evolution.