Ancient remains shed new light on crocodilian evolution

Crocodilians species such as the unique, small Chinese alligator once flourished in China. However, during the Tang Dynasty in the 9th century, people started to push out crocodilians in the Han River Delta of Guangdong province.   

A government official named Han Yu is said to have attempted to warn the crocodilians, even offering them animal sacrifices to leave the area in peace. Unfortunately, the crocodilians did not need the warning, and new evidence suggests that they were most likely wiped out by humans. 

Recently, a team of experts led by Professor Minoru Yoneda from the University of Tokyo studied two crocodilian subfossils found in the region. The animals appear to have died in the 10th and 14th centuries B.C. Although the timing means these crocodiles weren’t connected to Han Yu, the story fits with them nicely and the researchers named the croc Hanyusuchus sinensis.

Interestingly, the H. sinensis remains appear to have been beheaded as part of a ritual. Perhaps even more interestingly, the individual shares skull features both with gharials and with other crocodilians. 

“I have studied modern crocodilians for years, but even though it’s extinct, Hanyusuchus sinensis is by far the most astonishing creature I’ve ever seen,” said study co-author Professor Jun Liu from Hefei University of Technology in China.

“Everyone is familiar with sharp-nosed crocodiles and blunt-nosed alligators, but may be less familiar with a third kind of modern crocodilian called gharials that have much longer and thinner skulls. Hanyusuchus sinensis is a type of gharial, but what’s exciting is how it also shares some important skull features with the rest of the crocodilians.”

“This is significant as it could settle a decades-long debate about how, when and in what way crocodilians evolved into the three families still roaming the Earth today.”

The marks of human violence on the two subfossils indicate that they were driven to extinction by an expanding human population. The researchers believe that the crocodilians may have also left scars on the culture of China. Stories of dragons, and other cultural elements may have been inspired by the crocodilians people feared and even wiped from the Earth.  

The study is published in the journal Proceedings of the Royal Society B Biological Sciences.

—

By Zach Fitzner, Earth.com Staff Writer