生物多样性 ›› 2022, Vol. 30 ›› Issue (11): 22348.  DOI: 10.17520/biods.2022348

所属专题: 青藏高原生物多样性与生态安全

• 中国南方新生代植物多样性演化专题 • 上一篇    下一篇

我国西南植物区系的分异: 椿榆属和臭椿属化石的启示

贾林波1,2,*(), 苏涛3,*(), 李伟成3, 李树峰3, 黄永江1, 周浙昆3   

  1. 1.中国科学院昆明植物研究所中国科学院东亚植物多样性与生物地理学重点实验室, 昆明 650201
    2.现代古生物学和地层学国家重点实验室(中国科学院南京地质古生物研究所), 南京 210008
    3.中国科学院西双版纳热带植物园热带森林生态学重点实验室, 云南勐腊 666303
  • 接受日期:2022-09-05 出版日期:2022-11-20 发布日期:2022-10-13
  • 通讯作者: 贾林波,苏涛
  • 作者简介:sutao@xtbg.org.cn
    E-mail: jialinbo@mail.kib.ac.cn;
  • 基金资助:
    国家自然科学基金(31900194);现代古生物学和地层学国家重点实验室(中国科学院南京地质古生物研究所)开放项目(183112);云南省科技厅项目(202101AT070163);云南省科技厅项目(202001AU070058);中国科学院“西部之光”计划

The floristic differentiation of Southwest China: Insights from Cedrelospermum and Ailanthus fossils

Linbo Jia1,2,*(), Tao Su3,*(), Weicheng Li3, Shufeng Li3, Yongjiang Huang1, Zhekun Zhou3   

  1. 1. CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201
    2. State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology, CAS), Nanjing 210008
    3. Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303
  • Accepted:2022-09-05 Online:2022-11-20 Published:2022-10-13
  • Contact: Linbo Jia,Tao Su

摘要:

滇西北‒西藏和滇东南‒桂西是我国西南植物区系中两个面貌和谱系年龄差异最为鲜明的区域, 分别以区系年轻、草本植物和区系古老、木本植物为特征。其中一个饶为有趣的问题是这两个地区的区系分异现象是如何演变形成的? 古植物学研究能为回答这一问题提供重要证据。本文报道分别发现于滇西北‒西藏和滇东南‒桂西的椿榆属(Cedrelospermum)和臭椿属(Ailanthus)化石新纪录。结合已有研究, 这两个类群在我国西南的化石历史为: 椿榆属见于西藏中始新世至晚渐新世(西藏椿榆C. tibetica)及滇东南晚始新世(亚洲椿榆C. asiaticum)地层, 而臭椿属化石见于西藏中始新世至晚始新世(大果臭椿A. maximus)及滇东南晚始新世至早渐新世(古臭椿A. confucii)地层。以上古近纪滇西北‒西藏和滇东南‒桂西植物区系在属级水平上的相似性表明这两个地区之间曾经存在区系交流、类群组成相近。然而, 在种级水平上, 自晚始新世以来其椿榆属和臭椿属植物又各不相同, 暗示着以上两个区系可能在晚始新世或更早已经由于环境分异等因素而向着不同的方向发展。现在椿榆属和臭椿属都已经从西藏消失了, 取而代之的是总体上更为年轻的草本植物区系。与此不同, 臭椿属在滇东南‒桂西延续到了现在, 体现了该地区区系的古老性。本研究为滇西北‒西藏和滇东南‒桂西植物区系在地质历史时期的相似性及其分异的形成提供了化石证据。

关键词: 中国西南, 古近纪, 植物区系演化, 榆科, 苦木科

Abstract

Aims: Northwest Yunnan-Xizang and Southeast Yunnan-West Guangxi are two regions with distinct differences in pedigree age and appearance in southwestern China. The two regions are characterized by young flora dominated by herbaceous plants and ancient flora dominated by woody plants, respectively. It is unknown how the floristic differentiation of these two regions has formed.

Methods: We report new fossil records of Cedrelospermum and Ailanthus from the two study regions. We also review the fossil history of the two genera, particularly those in Southwest China.

Results: The fossil history of the two genera in Southwest China is as follows: Cedrelospermum occurred in the middle Eocene to late Oligocene of Xizang (C. tibetica) and the late Eocene of Southeast Yunnan (C. asiaticum). Ailanthus appeared in the middle Eocene to late Oligocene of Xizang (A. maximus) and the late Eocene of Southeast Yunnan (A. confucii). Our results show that both Northwest Yunnan-Xizang and Southeast Yunnan-West Guangxi floras grew Cedrelospermum and Ailanthus in the Paleogene, but the species are different since the late Eocene.

Conclusion: The genus level similarity of Northwest Yunnan-Xizang and Southeast Yunnan-West Guangxi floras support the hypothesis that floristic exchanges have occurred between the two regions. However, the difference in species indicates that the two floras have separated from each other since or before the late Eocene due to environmental differentiation. The woody Cedrelospermum and Ailanthus have disappeared from Xizang, and have been replaced by a generally younger herbaceous flora. In contrast, Ailanthus occurs presently in Southeast Yunnan, providing evidence for the archaic nature of the flora. Our study provides fossil evidence for the similarity and differentiation of the floras of Northwest Yunnan-Xizang and Southeast Yunnan-West Guangxi in the geological past.

Key words: Southwest China, Paleogene, floristic evolution, Ulmaceae, Simaroubacea