Discovered in the Tiaojishan rock formations of Liaoning, China, it is the first known example of an opposable thumb . The new species of arboreal flying reptile lived in China 160 million years ago and has been dubbed ‘monodactyl ‘.
The small Jurassic pterosaur had a wingspan of 85 cm and this feature of the opposable thumb can be found in mammals and some tree frogs but, with the exception of the chameleon, it is rare to find it among reptiles. It is a unique dinosaur, as it is the first time that an opposable thumb has been found in a flying reptile and it has not been seen before in pterosaurs.
“The ‘Monkeydactyl’ (monodactyl) fingers are small and partially embedded in the slab,” says Fion Waisum Ma, study co-author and PhD researcher at the University of Birmingham in the journal Current Biology that publishes the study. “ Thanks to the micro-CT scan , we were able to see through the rocks, create digital models and tell how the opposable thumb articulated with the other bones of the fingers. This is an interesting discovery. It provides the earliest evidence for a true opposable thumb, and it is from a pterosaur, which was not known to have it. “
Adapting to life in the trees
The new species has been officially baptized as Kunpengopterus antipollicatus and thanks to its fossils, images were obtained through computerized micro-tomography with which an international team of researchers could better understand its structure.
The study researchers claim that this dinosaur lurked in the treetops about 160 million years ago , likely as a living arboreal pterosaur in the Jurassic. It is a small member of the darwinopterus pterosaurs (named after naturalist Charles Darwin who detailed how evolution shaped pterosaur anatomy over time).
However, it is clear that the most curious detail is that at the end of its wings is a rather sophisticated piece for a pterosaur: an opposable thumb.
Let us remember that these flying reptiles dominated the sky in the age of the dinosaurs (between 220 and 65 million years ago) and according to the analysis of the fossilized bones, this characteristic of the opposable thumb indicates that they could have been used to catch food, but also to clinging to tree branches, suggesting that it probably adapted to arboreal life.
“The Tiaojishan palaeforest is home to many organisms, including three genera of darwinopterus pterosaurs. Our results show that K. antipollicatus has occupied a different niche than Darwinopterus and Wukongopterus , probably minimizing competition between these pterosaurs,” says Xuanyu Zhou, from China University of Geosciences and team leader.
Referencia: Xuanyu Zhou, Rodrigo V. Pêgas, Waisum Ma, Gang Han, Xingsheng Jin, Maria Eduarda C. Leal, Niels Bonde, Yoshitsugu Kobayashi, Stephan Lautenschlager, Xuefang Wei, Caizhi Shen, Shu’an Ji. A new darwinopteran pterosaur reveals arborealism and an opposed thumb. Current Biology, 2021 DOI: 10.1016/j.cub.2021.03.030
