Rapid Eocene diversification of spiny plants in subtropical woodlands of central Tibet

Xinwen Zhang (1, 2) , Uriel Gélin (1) , Robert A Spicer (1, 3) , Feixiang Wu (4) , Alexander Farnsworth (5, 4) , Peirong Chen (1, 2) , Cédric del Rio (6, 1) , Shufeng Li (1, 2) , Jia Liu (1) , Jian Huang (1) , Teresa E V Spicer (1) , Kyle W Tomlinson (1) , Paul J Valdes (5) , Xiaoting Xu (1, 2) , Shitao Zhang (7) , Tao Deng (4) , Zhekun Zhou (1) , Tao Su (1, 2)

1 Xishuangbanna Tropical Botanical Garden
2 UCAS - University of Chinese Academy of Sciences [Beijing]
3 OU - The Open University [Milton Keynes]
4 CAS - Chinese Academy of Sciences [Beijing]
5 University of Bristol [Bristol]
6 CR2P - Centre de Recherche en Paléontologie - Paris
7 KMUST - Kunming University of Science and Technology

Spinescence is an important functional trait possessed by many plant species for physical defence against mammalian herbivores. The development of spinescence must have been closely associated with both biotic and abiotic factors in the geological past, but knowledge of spinescence evolution suffers from a dearth of fossil records, with most studies focusing on spatial patterns and spinescence-herbivore interactions in modern ecosystems. Numerous well-preserved Eocene (~39 Ma) plant fossils exhibiting seven different spine morphologies discovered recently in the central Tibetan Plateau, combined with molecular phylogenetic character reconstruction, point not only to the presence of a diversity of spiny plants in Eocene central Tibet but a rapid diversification of spiny plants in Eurasia around that time. These spiny plants occupied an open woodland landscape, indicated by numerous megafossils and grass phytoliths found in the same deposits, as well as numerical climate and vegetation modelling. Our study shows that regional aridification and expansion of herbivorous mammals may have driven the diversification of functional spinescence in central Tibetan woodlands, ~24 million years earlier than similar transformations in Africa.

Mots clés: Eocene; Tibet

Domaines: Paléontologie; Botanique; Evolution [q-bio.PE]

Xinwen Zhang, Uriel Gélin, Robert A Spicer, Feixiang Wu, Alexander Farnsworth, et al.. Rapid Eocene diversification of spiny plants in subtropical woodlands of central Tibet. Nature Communications, 2022, 13, pp.3787. ⟨10.1038/s41467-022-31512-z⟩. ⟨hal-03711562⟩