New giant rodent fossil found in Thailand dates to 34 million years ago
Two fossil teeth from Thailand point to a previously unknown rodent that may have been far larger than its contemporaries.
Key points
- Researchers identified a new extinct rodent species, Yakamys sirindhornae, from two fossil teeth.
- The animal lived about 34 million years ago, in the middle of the Paleogene period.
- The specimens came from a pit within a lignite mine in Thailand's Krabi Province.
- Size estimates suggest a body mass of about 30 kilograms, though the figure is only approximate.
- The find suggests Southeast Asia played a larger early role in the evolution of giant rodents.
According to ScienceDaily, scientists have identified a previously unknown rodent species from roughly 34 million years ago. The animal has been named Yakamys sirindhornae, and it is known so far only from a pair of fossil teeth. The remains comprise one lower molar of the second position and one lower front tooth.
The specimens came out of the Bang Mark Pit, located within a lignite mine in Thailand’s Krabi Province. The animal lived during the middle of the Paleogene period. The teeth are described as unusually large for a rodent of that age.
A Rodent Estimated at About 30 Kilograms
To approximate the animal’s body size, the research team relied on seven accepted techniques that use dimensions of the teeth. Their calculations point to a weight of around 30 kilograms. That is roughly double the weight of Hulgana and other rodents known from the same era.
The researchers stress that this figure is a rough estimate. Working out the weight of an extinct animal from only a few teeth carries a great deal of uncertainty. The limited material also makes it hard to say how the species evolved or what its daily life looked like.
Why the Find Matters
Virginie Millien, a biology professor at McGill University and a co-author of the study, said very large rodents existed long before modern times. The capybara holds the title of largest rodent alive today. Earlier giant rodents appeared several times in the group’s history, mostly in South America.
The new fossil suggests that Southeast Asia also played a significant part in the early history of large rodents. Scientists had not fully recognised this role before. The discovery widens the picture of where and when rodent gigantism first appeared.
How the Name and the Research Came About
The name merges a Thai term for giant with a Greek root meaning mouse or rat. The second part pays tribute to Princess Maha Chakri Sirindhorn. Millien said the honour recognises her long-standing backing of science and palaeontological research in Thailand.
The fossils were identified through an ongoing international project studying ancient mammals in the Krabi Basin. The team brings together researchers from McGill University, the Thai Department of Mineral Resources, and French bodies such as CNRS and Université de Poitiers. Several institutions, including Université de Montpellier and McGill University, also backed the research.
Further fossil finds will be needed to clarify the animal’s physical features, its ecological role, and its links to other rodents. Until then, the two teeth remain the only evidence of this species.
Frequently asked questions
What is Yakamys sirindhornae?
It is a previously unknown extinct rodent species identified from two fossil teeth. The animal lived about 34 million years ago in what is now Thailand.
How big was the rodent?
Researchers estimate it weighed about 30 kilograms, based on seven tooth-based methods. They say the figure is only a rough estimate because of the limited fossil evidence.
Where were the fossils found?
The teeth came from the Bang Mark Pit, which is part of a lignite mine in Thailandu0026#039;s Krabi Province.
Sources
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