J Syst Evol ›› 2018, Vol. 56 ›› Issue (2): 81-91.DOI: 10.1111/jse.12288

• Research Articles • Previous Articles     Next Articles

Paleogene fossil fruits of Stephania (Menispermaceae) from North America and East Asia

Meng Han1,2, Steven R. Manchester2, Qiong-Yao Fu1, Jian-Hua Jin1, and Cheng Quan3*   

  1. 1State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China

    2Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA  
    3Research Center of Palaeontology and Stratigraphy, Jilin University, Changchun 130026, China
  • Received:2017-06-29 Published:2018-03-01

Abstract: Stephania Loureiro is a large genus within Menispermaceae, with approximately 60 extant species naturally distributed in tropical to subtropical areas in Asia and Africa, and a few in Oceania. This genus possesses highly characteristic endocarps that facilitate identification of extant and fossil specimens. Here, we report some well-preserved fossil fruits of Stephania from North America and East Asia. The specimens indicate the endocarps were bony or woody with an obovate to obovate-rotund outline and a horseshoe-shaped locule. The endocarp length varies from 4.7 to 8.3 mm, and width from 3.7 to 7.0 mm. The endocarp has a clear foramen in the central area and is surrounded by a keel with ribs running along the dorsal surface. Only one lateral crest develops on each side of the endocarp. Two new species are recognized: Stephania wilfii Han & Manchester sp. nov. from the Paleocene to Eocene of Wyoming (USA), and Stephania jacquesii Han & Manchester sp. nov. disjunct between the late Eocene of Oregon (USA) and the late Oligocene of Guangxi Province (China). In addition, on the basis of more detailed morphological comparative analyses, we transfer the fossils formerly treated as Diploclisia auriformis (Hollick) Manchester from the early Eocene of London Clay, and the middle Eocene of Alaska and Oregon to Stephania auriformis (Hollick) Han & Manchester comb. nov. These fossil materials indicate a broader biogeographic distribution for the ancestors of extant Stephania lineages. This finding enhances our knowledge of the taxonomic and morphological diversity of Stephania and provides new evidence concerning its phytogeographic history.

Key words: East Asia, endocarps, North America, Paleogene, Stephania