A new study of 160-million year old fossilized remains found in China was published in Science, revealing new details on mammals and their relationship to Earth's history.
According to the report, Multituberculates were a group of rodent-like creatures that came around and flourished during the Jurassic period. Like current rodents (e.g. rats, squirrels, beavers), these prehistoric creatures were able to adapt to a multitude of environments; from living up in the tree canopy to burrowing deep below the earth to jumping from location to location.
For 120 million years these rat-like creatures survived in the land of dinosaurs; eventually, in the Oligocene epoch of 35 million years ago, the Multituberculates were forced into extinction by more competitive direct descendents of the modern rodent. This event coincided with the expansion of grasslands throughout the palent and the subsequent proliferation of larger and faster land mammals, such as the rhinoceros and the horse.
For much mammal life, the ancient Multituberculates set the table evolutionarily. Their teeth allowed the creatures to eat both plant and animal matter (i.e. omnivorous), an evolutionary characteristic that likely contributed to the creature's resiliency through the ages. According to researchers, the fossilized super rat (scientifically referred to as Rugosodon eurasiaticus) is similar to other remains found in Portugal, suggesting that the animal was able to thrive throughout the Eurasian continent.
The name comes from the Latin "rugosus" for wrinkles and "odon" for tooth, because of its bumpy molar surface and "eurasiaticus" for its distribution across the large land mass. Researchers estimate that the creature weighed between 65 and 80 grams. As a point of comparison, the common house mouse weighs approximately 10-25 grams. The common rat is considerably larger, weighing 250-350 grams.
The 120 million years the multituberculates roamed the earth is an impressive number; by contrast, bipedal primates (i.e. two-legged apes) have only been around for 3.5-3.7 million years, thus far. The dinosaurs walked the earth for 165 million years.