An ancient, unique tusk from the modern elephant's cousin stegodon is claimed to have been unearthed by a team of scientists in Pakistan. The finding may shed light on the evolutionary history of the prehistoric mammal.

The stegodon tusk, which is believed to be 1.1 million years old, was excavated in the central province of Punjab.

The fossil is 96 inches in length and 8 inches in diameter, making it the largest tusk ever discovered in the country.

The stegodon tusk was discovered by scientists from the University of the Punjab's zoology department during an expedition in the Padri district.

"This discovery adds to our knowledge about the evolution of the stegodon, particularly in this region," said Professor Muhammad Akhtar, lead researcher of the excavation. Akhtar said it sheds light on what the mammal's environment was like when it was alive.

The dating of the tusk, however, needs further verification, said paleontologist Gerrit Van Den Bergh, Ph.D., of the University of Wollongong, Australia. He has conducted comprehensive research on stegodons all over the world and in Pakistan.

"If you have a complete tusk, that's quite special," said Van Den Bergh. "They are quite rare."

The age of the stegodon tusk was determined through a radioactive dating technique that involved uranium and lead, researchers said.

Stegodons are believed to have roamed the Earth about 11 million years ago until the late Pleistocene period, which ended about 11,700 years ago. The prehistoric mammal was known for its teeth that has low crown and peaked ridges, and long tusks that were nearly straight.

This indicated that stegodons were mixed feeders or browsers in a forested environment. Elephants and mammoths, on the other hand, which possessed high-crowned plated molars, were able to graze because of their tooth structure.

Stegodons were good swimmers. They were thought to have come from Africa and then quickly spread to Asia, where most fossils of the mammal were found.

Van Den Bergh said stegodons were still thriving at 1.2 million years ago. The species' extinction coincided with the emergence of modern humans, he said, but it was difficult to say for certain whether men hunted stegodons.