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Abstract Detail



Macroevolution

Chang, Hsuan [1], Xu, Wei-Bin [2], Liu, Yan [2], Peng, Ching-I [3], Chung, Kuo-Fang [1].

Convergent plant evolution in the twilight zone of limestone caves.

Caves and associated subterranean hydrological systems are conspicuous features of limestone karst landscapes worldwide. Because of their darkness and lack of daily and seasonal cycles, these simple and yet extreme habitats are often regarded as natural ecological and evolutionary laboratories, dwelled by animals featured by peculiar convergent ‘regressive’ traits: the absence of eyes and lack of body pigment. These ‘troglomorphic’ organisms, also known as Darwin’s ‘wrecks of ancient life’, are often referred as evidence of adaptation via natural selection, resulting from strong convergent evolution to the similar cave environment. Despite the wealthy of evolutionary research into cave fauna, however, how these extreme environments have affected the evolution of plants restricted to the twilight zone of cave entrances are largely neglected. Characterized by small and white flowers, Chiritopsis is a cave-specific gesnerid genus of ca. 15 described species restricted to caves of the Sino-Vietnamese limestone karst. Previous phylogenetic analyses, however, showed that Chiritopsis is polyphyletic and nested within the re-circumscribed Primulina, indicating that the characteristic floral traits of the former have been evolved multiple times from within the latter. Based on phylogenetic analyses of increased sampling and character state reconstruction of Primulina, we show that the Chiritopsis-like species have evolved independently more than 10 times and their floral traits, coupled with self-pollination, are closely associated with cave environments. We propose that the small and white flowers of Chiritopsis-like Primulina are equivalent to the troglomorphic traits of cave fauna, resulting from adaptation to the twilight zone of cave entrances that are devoid of light and pollinators.


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1 - National Taiwan University, School of Forestry and Resource Conservation, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
2 - Guangxi Institute of Botany, Chinese Academy of Sciences, Guilin, Guangxi Zhuangzu Autonomous Region, 541006, China
3 - Academia Sinica, Herbarium (HAST), Biodiversity Research Center, Taipei, 11529, Taiwan

Keywords:
ancestral states reconstruction
Chiritopsis
Gesneriaceae
Primulina
Sino-Vietnamese limestone flora
troglomorphism.

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: Salon 3/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 11:00 AM
Number: 3012
Abstract ID:657
Candidate for Awards:None


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