A six-meter-long reptile once lurked in the water in southern China: Researchers have identified a previously unknown species of crocodile that was apparently exterminated by humans over the past 3,000 years. This is evident from the study of remains of the animals from the Bronze Age, as well as from historical records. Traces on one of the specimens suggest that it was ritually beheaded. The newly discovered species also sheds light on the evolutionary history of the Gavial crocodile family, say the researchers.
Prehistoric creatures with sharp teeth: There was once a great variety among the representatives of the crocodiles (Crocodylia), as is known from fossil finds. Today, only 25 species of crocodiles lurk in the water in different parts of the world for prey. They are assigned to three families: the so-called real crocodiles, the alligators and the gavials. The latter include only two species – the Ganges Gharial (Gavialis gangeticus) and the Sundagharial (Tomistoma schlegelii), which occurs in the south of the Malay Peninsula, as well as on Borneo and Sumatra. It was assumed, however, that the range of the Sungavial, which can be up to five meters long, could once have extended to southern China.
A special representative of the gavial
In fact, a separate, previously unknown large crocodile species apparently existed there, as the study by researchers led by Masaya Iijima from the Japanese University of Nagoya shows. The findings are based on examining remains found at various sites in south China’s Guangdong province. They cover much of the reptile’s skeleton. The investigations focused in particular on two particularly well-preserved specimens.
As the researchers report, their analyzes showed that it was a previously unknown species from the group of gavials, which reached a length of six meters. The animal had a comparatively slim snout, as is typical for this family. They named the new representative Hanyusuchus sinensis. “The exciting thing is that the species also shares some important skull features with the rest of the crocodiles,” says Iijima. “This is of great importance, as the finding could shed light on the previously unclear question of how, when and in what way the crocodiles evolved into the three families that still live on Earth today,” says the scientist.
Ritually decapitated?
But there is also another exciting component: the radiocarbon dating and analysis of the bones showed that the two specimens lived around 3000 years ago – they apparently only became extinct at the hands of humans. The remains show numerous hack marks, the researchers report. One of the animals was probably even deliberately beheaded, with a bronze blade. They see the use of this special tool as an indication that the “decapitation” could have taken place as part of a ritual. For their study, the scientists therefore also carried out extensive research in historical records. As they report, they came across numerous indications that could refer to Hanyusuchus and not to the Chinese alligator (Alligator sinensis), which still exists today and is only about two meters long.
In particular, the scientists highlight a story from the 9th century AD. It also formed the basis for naming the species Hanyusuchus, after government official Han Yu. The lore tells of a crocodile problem that plagued residents of a river delta in Guangdong Province. It is said that the reptiles ate livestock there and also attacked humans. Han Yu is said to have ritually warned the crocodiles and asked them to leave the area. It is said that he sacrificed a pig and a goat. Since the warning was probably unsuccessful, it can be assumed that the animals were being pursued. However, as evidenced by findings on specimens that are around 1000 years older, this was also common before.
Biological and historical importance
“Given that the two specimens we have were killed by humans, the species is no longer extant, and there is historical evidence of systematic crocodile eradication in the region, it is reasonable to conclude that humans were responsible for the disappearance of Hanyusuchus sinensis.” , says co-author Minoru Yoneda from the University of Tokyo. When exactly the last animals disappeared remains unclear – according to indications, however, the species could have existed until a few hundred years ago. “It’s also possible that these animals left cultural imprints in ancient Chinese civilization,” says Yoneda. “Perhaps even myths about dragons could have been influenced by him. Because it would have been the only reptile in ancient China that also ate humans,” says the scientist.
The University of Tokyo concludes that Hanyusuchus sinensis will continue to be in the researchers’ sights because of its importance for the development of the crocodiles: They are currently trying to elicit genetic material from the remains. If this succeeds, comparisons could clarify exactly how the animal is to be classified in the family tree of the crocodiles.
Source: University of Tokyo, professional article: Proceedings of the Royal Society B., doi: 10.1098/rspb.2022.0085