A large species of gharial, an animal closely related to crocodiles, roamed China 3000 years ago, but was probably driven extinct by humans
An unknown crocodile-like animal probably lived in China until just a few hundred years ago. The creature may have been more than 6 metres long and its discovery helps make sense of the evolution of crocodiles and their relatives.
Chinese researchers discovered the animal’s bones in the 1960s and 1970s, but they were misidentified as a living species and ignored, says Masaya Iijima at Clemson University in South Carolina. Iijima and his colleagues have now studied four of the specimens, which include skulls and other parts of the body.
The creature was a gharial, an animal closely related to crocodiles and alligators, but with a much thinner snout. Today, there are only two gharial species: one from India and neighbouring countries, and one from Malaysia and Indonesia.
All the specimens of the new extinct gharial come from south-east China. The team named it Hanyusuchus sinensis, after a Chinese politician and poet called Han Yu (AD 768-824). Confronted with crocodiles that were attacking humans and livestock, Han Yu issued a proclamation instructing the animals to leave or be killed.
Three of the specimens have been carbon-dated. They lived around 3000 years ago during the Chinese Bronze Age. However, historical accounts of dangerous gharial-like animals are known from as recently as 500 years ago, so Iijima thinks Chinese gharials survived “until at least 300 years ago”. One of the skulls has 17 chop marks on it, suggesting people cut it up using heavy bronze weapons.
Humans probably drove the Chinese gharial to extinction, says Minoru Yoneda at the University of Tokyo, who also worked on the study. “It’s not easy to say that direct attack by humans is the main cause of extinction,” he says, because rice farming probably cut into its habitat, but either way humans are probably responsible.
The Chinese gharial clarifies a mystery about crocodilians, the group that includes crocodiles, alligators and gharials. Genetic evidence shows that alligators were the first group to split from the others, and crocodiles and gharials separated from each other later. That is odd because, among previously known species, crocodiles and alligators more closely resemble one another than gharials. But the Chinese gharial is intermediate in body shape between gharials and the other two groups.
“There was a huge gap between the gharial and the rest of the crocodilians,” says Iijima. “Our specimens fit in the gap.”
Journal reference: Proceedings of the Royal Society B, DOI: 10.1098/rspb.2022.0085
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