New Tyrannosauroid Species Offers Clues to Dino Evolution

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A species of tyrannosauroid was discovered among fossils excavated from Late Cretaceous rock layers in Mongolia. The fossil dates back approximately 90 million years. The international research team behind the discovery included researchers from Hokkaido University, the University of Calgary in Canada, and other institutions.

They named the species Khankhuuluu mongoliensis and published their findings in the June 12 issue of the British scientific journal Nature. This discovery offers a new perspective on the origin and evolution of tyrannosaurs.

The team explained that this new species was actually discovered among fossils collected around 50 years ago in Mongolia's Gobi Desert. Khankhuuluu had a slender body, similar to juvenile tyrannosaurs, and weighed less than 500 kilograms (1102 lbs). Its leg shape and other features were distinct enough from known tyrannosaurs to classify it as a new species.

Tyrannosaur Origins

Until the discovery of Khankhuuluu, it was believed that tyrannosaurs originated in North America. However, the new evidence suggests their ancestors first appeared in Asia and later migrated back and forth between Asia and North America, evolving into larger forms over time.

Moreover, Khankhuuluu is thought to be the common ancestor not only of large tyrannosaurs but also of Alioramus, a related species weighing around 750 kilograms, offering important clues about their evolution.

Professor Kaiji Kobayashi from the Hokkaido University Museum, part of the research team, said, "The discovery of Khankhuuluu has clarified the origin and evolutionary process of large tyrannosaurs. We plan to continue our research to better understand the migration routes tyrannosaurs took between Asia and North America."

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Author: The Sankei Shimbun

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