In the middle of Mongolia’s vast Gobi Desert, a team of scientists has made an exciting discovery: the fossil of a never-before-seen mammal species that lived alongside dinosaurs.
The fossil was found in ancient rock layers dating back to the Late Cretaceous period, around 100 to 66 million years ago.
The newly discovered animal, about the size of a mouse, has been named Ravjaa ishiii.
Its name honors Dulduityn Danzanravjaa, a famous 19th-century Buddhist monk, and Kenichi Ishii, a key figure in building scientific ties between Mongolia and Japan.
The discovery was made by a joint team from Okayama University of Science in Japan and the Institute of Paleontology and Geology at the Mongolian Academy of Sciences.
Their findings have been published in the scientific journal Acta Palaeontologica Polonica.
The fossil itself is a tiny jawbone just one centimeter long, but it carries big scientific importance.
It was unearthed during a 2019 expedition to the Baynshire Formation, a fossil-rich area in the Gobi Desert.
At first, researchers believed the jaw belonged to a member of a known mammal family from the Cretaceous period called Zhelestidae.
However, the unique shape of the jaw and its tall molars set it apart from any other species previously found.
As a result, the scientists concluded it represents an entirely new genus and species—the first of its kind found in Mongolia.
Until now, fossils from the Zhelestidae family were mostly found near what would have been ancient coastlines.
But this new find shows that these early mammals also lived deep inland, offering fresh insight into how they spread across different environments.
The fossil’s teeth also offer clues about what this small mammal might have eaten.
Its strong molars are similar to those of animals that eat seeds and fruits, suggesting it may have fed on the early flowering plants (angiosperms) that were just beginning to spread across the planet during this time.
Tsukasa Okoshi, the study’s lead author and a doctoral student at Okayama University of Science, said that although the COVID-19 pandemic delayed the publication of their research, they are thrilled to finally share this important find.
He hopes it will lead to more studies of small fossils from the same region and time period.
Professor Mototaka Saneyoshi, also part of the team, described the discovery of such a tiny fossil in the enormous Gobi Desert as nothing short of a miracle—“a gift from the Gobi Desert.”
