A new polysporangiate land plant with novel fertile organs from the Lower Devonian of Guizhou, southwestern China

Abstract

The diversification of early land plants during the mid-Paleozoic has been considered an important event that was essential for the evolution of terrestrial ecosystems, and the plant fossils from numerous localities around the world are the key for understanding this event. Here we report a new plant, Teyoua antrorsa gen. et sp. nov., from the lower part of the Mangshan Group at a newly found locality near Baoyang Village (Baoyang section), Duyun City, Guizhou Province, southwestern China. The plant-bearing horizon at this locality is suggested to be Early Devonian in age (probably Pragian), based on the occurrence of Adoketophyton subverticillatum and Zosterophyllum australianum, two plants also occurring in the well-known Pragian-aged Posongchong Formation of Yunnan, China. The fertile axes of Teyoua gen. nov. are dichotomously divided at least five times and each of the ultimate branches terminates in a fertile organ. The fertile organs are composed of up to seven linear sporangia that share a common base and depart three-dimensionally. This plant is assigned to the polysporangiate clade, in that the whole architecture and internal anatomy remain unknown, but its similarities to some basal euphyllophytes are notable. Nevertheless, the linear sporangia of Teyoua gen. nov., and their grouping as a unique fertile organ, add to the diversity of fertile structures in early polysporangiophytes.