This flying reptile from the Jurassic period may be the oldest known animal that was able to touch the belly of the thumb with the inside of its other fingers. The so-called opposite thumb is typical today, especially for primates, and has significantly helped humans to learn to control instruments.
It has appeared several times in the history of evolution, but this case from 160 million years ago is the oldest, paleontologists have described. in the current journal Current Biology in half of April.
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The thumb allowed the “Monkeydactyl” to climb trees, perhaps feeding on insects and other prey that other lizards could not catch. The unique scientific name Kunpengopterus antipollicatus also draws attention to the uniqueness of his thumb; antipollicantus means the opposite thumb in Greek.
The fossilized remains of this creature were discovered in 2019 in northeastern China as part of a rock. Therefore, paleontologists had to use so-called microCT scanning to obtain a 3D image of the fossil. “Thanks to it, we were able to look at the fossil from any angle and prove that the bones are in the right original place,” said paleontologist Rodrigo Pêgas, who studied and described the remains.
An evolutionarily advantageous thumb
The images confirmed that the skeleton had a well-preserved opposite thumb on each hand. “Almost all modern animals with opposite toes use them to climb trees,” Pêgas described – typically primates or some species of tree frog.
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This evidence, together with the flexibility of the Monkeydactyl joints, suggests that this species has been very well adapted to climbing between tree branches – but some experts suggest that the results of this work are too hasty.
However, the ability did not evolve anywhere from Monkeydactyl – bird lizards, like their related dinosaurs, became extinct at the end of the Cretaceous in a mass extinction caused by an asteroid hitting Earth.
For other species, the opposite thumb formed again, and evolution had to try this experiment from the beginning.
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