2024-02-25 05:14:00
A fossil of the lower jaw (mandible) of a Tyrannosaurus was unearthed in Kumamoto, Japan. This is the first time that the mandible of a Tyrannosaurus, which represents not only theropods but also all dinosaurs, has been found in an archipelago.
Japan’s Amakusa City Goshoura Cretaceous Museum (GCM) introduced the mandible fossil of a Tyrannosaurus family dinosaur from the late Cretaceous period (regarding 74 million years ago) excavated from the Shimotsufukae Formation in Reihoku-cho, Amakusa-gun, Kumamoto Prefecture through its official channel on the 23rd. .
In Japan, fossil teeth of Tyrannosaurus dinosaurs have been discovered so far, and this is the first mandible fossil. Scholars welcomed it as important data for understanding the origin and habitat distribution of tyrannosaurus dinosaurs in Asia and the ecology of large theropods of the late Cretaceous period.
Left and right mandibles of a Tyrannosaurus dinosaur unearthed in Japan
A GCM official explained, “The mandible of a Tyrannosaurus-type dinosaur exists on both the left and right sides, and the remaining parts are different, so there is a slight difference in length,” adding, “The alveolar bone and teeth that make up the mandible are also partially preserved.”
This fossil was first excavated in October 2014 through a joint investigation between GCM and the Fukui Prefectural Dinosaur Museum (FPDM). Scholars thought it was a fossil of Tyrannosaurus dinosaur bones from various parts, but the existence of the mandible was later revealed during a recent investigation using CT.
A GCM official said, “The discovered fossil corresponds to the first half of the mandible and mainly consists of the alveolar bone area where the teeth are arranged. The left and right alveolar bones are incomplete, but solid and deep, and the teeth that protrude from them are very strong.”
Structure of the left mandible obtained by CT scan. Strong teeth protruded from deep within the alveolar bone.
He added, “There are 4 teeth in the left alveolar bone, and 3 teeth with damaged crowns were also confirmed,” and “5 teeth remain on the right, and you can see that solid teeth have protruded from deep in the alveolar bone.”
Tyrannosaurus is a large theropod that survived in Campania (regarding 83.6 to 72.1 million years ago) and Maastricht (regarding 72.1 to 66 million years ago) in the Late Cretaceous Period. This mandible fossil is conclusive evidence showing that tyrannosaurs lived in Japan in the past.
A GCM official said, “This fossil, which appears to be regarding 74 million years old, is an important specimen that helps in accurate classification and comparative research of theropod dinosaurs.” He added, “It is the mandible fossil of the first tyrannosaurus dinosaur in Japan, and it is the first Cretaceous theropod discovered so far. “It is valuable because it is older than the tooth fossil (regarding 80 million years ago),” he emphasized.
Reporter Lee Yoon-seo lys@sputnik.kr
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