J Syst Evol ›› 2012, Vol. 50 ›› Issue (6): 540-549.DOI: 10.1111/j.1759-6831.2012.00219.x

• Research Articles • Previous Articles     Next Articles

A new euphyllophyte Kunia venusta gen. et sp. nov. from the Middle Devonian of Yunnan, South China

1Cong‐Hui XIONG 1De‐Ming WANG* 2Qi WANG 1Mei‐Cen MENG   

  1. 1(Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, Department of Geology, Peking University, Beijing 100871, China)
    2(State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China)
  • Received:2011-11-14 Published:2012-08-29

Abstract: Kunia venusta gen. et sp. nov. is reported from the late Middle Devonian (Givetian) Haikou Formation near Kunming City, Yunnan Province, China. This plant has three orders of naked axes that divide pseudomonopodially. The second- and third-order axes occur in a helix. Fertile appendages are distantly spaced and helically inserted to the third-order axis; they comprise equally dichotomous branches terminated by two clusters of paired and fusiform sporangia. Sterile appendages are dichotomous and distally recurved. A comparison is made with the basal euphyllophytes including the trimerophytes, cladoxylopsids, zygopterids, stauropterids, and some relevant genera of uncertain affinity. The new plant resembles them in dichotomous appendages with terminal elongated sporangia, but differs mainly in the three orders of pseudomonopodial axes bearing helical laterals. It is thus placed in the Euphyllophytina as incertae sedis. It is suggested that an evolutionary divergence in the branching pattern and appendage morphology might have occurred in the Middle Devonian euphyllophytes, that is, maintaining three dimensions versus yielding more or less planation.

Key words: basal euphyllophytes, Kunia venusta, Middle Devonian, South China.