Millions of years ago, a biped dinosaur with knives for the fingers have surveyed the shores of the Asian continent. But these Edward Scissorhands-like weapons were used to cut vegetation rather than gut animal prey, according to a new study.
The dinosaur belonged to a group known as the therizinosaurs – bipedal, mostly herbivorous three-toed dinosaurs that lived during the Cretaceous Period, around 145 to 66 million years ago. Recently, researchers from Japan and the United States described the youngest therizinosaurus fossil ever found in Japan; this fossil also happens to be the first found in Asia in marine sediments.
This fossil represents a newly described species, which the researchers named Paralitherizinosaurus japonicus. The genus, which was already known to science, means “reptile by the sea” in Greek and Latin; the species name pays homage to Japan, where the specimen was unearthed.
The hook-shaped fossil, which includes a partial vertebra and a partial wrist and forefoot, was discovered by another team of researchers in 2008; since then it has been kept in the collections of the Nakagawa Museum of Natural History in Hokkaido, Japan.
Japanese scientists found the specimen in Nakagawa, a district of Hokkaido located in the far north of Japan’s main islands, a place known for its rich fossil deposits. The fossil was encased in a concretion – a hardened mineral deposit – and at the time of its discovery, paleontologists said it “was thought to belong to a therizinosaurus”, although due to a lack of comparative data to the at the time, early researchers were unable to draw firm conclusions, Hokkaido University officials said in a press release (opens in a new tab).
Related: How did ‘Prehistoric Planet’ create such incredible dinosaurs? Find out in a behind-the-scenes look.
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However, new data from many other fossils that were discovered and described in the years that followed helped classify the fossil based on the shape of the forefoot claw. This prompted a new team of paleontologists to revisit the specimen for definitive answers.
Based on their analysis, the authors of the new study concluded that the fossil, which measures just under 4 inches (10 centimeters) long, belonged to a therizinosaurus that lived around 80 to 82 million years ago. years. The fossilized foot bone once contained the dinosaur’s sword-like claw, which it used to comb through vegetation for plants to feed on. Because the researchers suspect the animal used its claws for a specific purpose, they determined the specimen to be a derived therizinosaurus – one that evolved later in the line of the group – rather than a basal or early therizinosaur, with claws “generalized and not intended for any specific use”, according to the statement.
“[This dinosaur] used its claws as foraging tools, rather than tools of aggression, to bring shrubs and trees closer to its mouth to eat them,” study co-author Anthony Fiorillo, research professor in the Department of Earth sciences Roy M. Huffington at Southern Methodist University (SMU) in Dallas, told Live Science, “We believe he died on land and washed out to sea.”
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According to the study, therizinosaur fossils have been found throughout Asia as well as North America (particularly in what is now Denali National Park and Preserve in Alaska), and that over Over time, animals have adapted to life in coastal environments. Two other suspected therizinosaur fossils have already been discovered in Japan, but have yet to be described.
Based on this one specimen, it’s impossible to know for sure how big the therizinosaurus was, Fiorillo told Live Science. What scientists can say with certainty is that the dinosaur was “large”, possibly as large as a hadrosaur or a duck-billed dinosaur, which could reach 30 feet in length (9 meters) and weigh up to 3 tons (2.7 metric tons). ), according to the University of California Museum of Paleontology (opens in a new tab). The fossil is so well preserved that “we might find more of the animal if we revisit the original site,” Fiorillo said.
“We remain cautiously optimistic, and it’s on our radar,” added Fiorillo, who is also curator emeritus at the Perot Museum of Nature and Science in Dallas.
The results were published online May 3 in the journal Scientific reports (opens in a new tab).
Originally posted on Live Science