絶滅の危機に瀕する熱帯樹木の化石を初めて発見(First fossil evidence of endangered tropical tree discovered)

2005-05-08 ペンシルベニア州立大学(PennState)

<関連情報>

• https://www.psu.edu/news/research/story/first-fossil-evidence-endangered-tropical-tree-discovered
• https://bsapubs.onlinelibrary.wiley.com/doi/10.1002/ajb2.70036

絶滅の危機に瀕した固有種の巨大フタバガキ科樹木の化石が、ボルネオの消滅しつつある熱帯雨林への歴史的扉を開く Fossils of an endangered, endemic, giant dipterocarp species open a historical portal into Borneo’s vanishing rainforests

Teng-Xiang Wang (王腾翔), Peter Wilf, Antonino Briguglio, László Kocsis, Michael P. Donovan, Xiaoyu Zou (邹啸宇), J. W. Ferry Slik
American Journal of Botany  Published: 08 May 2025
DOI:https://doi.org/10.1002/ajb2.70036

Abstract

Premise

Asia’s wet tropical forests face a severe biodiversity crisis, but few fossils record their evolutionary history. We recently discovered in situ cuticles on fossil leaves, attributed to the giant rainforest tree Dryobalanops of the iconic Dipterocarpaceae family, from the Plio-Pleistocene of Brunei Darussalam (northern Borneo). Studying these specimens allowed us to validate the generic identification and delineate affinities to living dipterocarp species.

Methods

We compared the leaf cuticles and architecture of these fossil leaves with the seven living Dryobalanops species.

Results

The cuticular features shared between the fossils and extant Dryobalanops, including the presence of giant stomata on veins, confirm their generic placement. The leaf characters are identical to those of D. rappa, an IUCN red-listed Endangered, northern Borneo endemic. The D. rappa monodominance at the fossil site, along with Dipterocarpus spp. leaf fossils, indicates a dipterocarp-dominated forest near the mangrove-swamp depocenter, most likely in an adjacent peatland.

Conclusions

The Dryobalanops rappa fossils are the first fossil evidence of a living endangered tropical tree species and show how analysis of in situ cuticles can help illuminate the poorly known floristic history of the Asian tropics. This discovery highlights new potential for fossils to inform heritage values and paleoconservation in Southeast Asia.