Giant Rodent Weighing 66 Pounds Once Roamed Thailand, Fossilized Teeth Reveal, CBS News Reports

Two Teeth Identify a Species

The fossils were a molar and an incisor found in 2004 at a coal mine in southern Thailand’s Krabi province. Scientists later used them to identify a species that had not previously been known.

The findings appeared Wednesday in Scientific Reports. The Krabi basin has also produced fossils of ancient primates, carnivores and hoofed mammals.

Research Took Years

When the teeth were first discovered, the research team did not have enough evidence or technology to determine the species. Pannipa, 51, recalled initially mistaking one fossil for a bone.

Pannipa told AFP that her supervisor recognized it as a giant rat’s tooth. The animal’s weight was estimated at around 30 kilograms, or 66 pounds.

An Extinct Rodent Family

Although its size was compared with that of a large capybara, the ancient animal was not part of the capybara’s South American family. It belonged instead to Ischyromyidae, an extinct family among the earliest major groups of rodents.

The species was named Yakamys sirindhornae in honor of Princess Sirindhorn, who supports scientific and paleontological research. Pannipa said the find illustrates the range of life that existed in the past and raised the possibility that ancient rodents evolved in what is now Thailand before spreading elsewhere.

Other Giant Rodent Fossil

In 2008, scientists in Uruguay reported fossil evidence of a rodent weighing one ton. They said it lived in wooded parts of South America around 4 million years ago.