In the northern Mexican state of Coahuila, archaeologists have made an extraordinary discovery --- a reward for all of their hard work under the sun.

The massive tail from a dinosaur that experts believe could be 72 million years old.

A team of excavators have been painstakingly brushing away millennia worth of sand and gravel to reveal this remarkable tail, five meters long - that's 16 feet.

It's a first such find for Mexico -- and one of only a few of its kind in the world, says palaeontologist Rene Hernandez.

SOUNDBITE: Palaeontologist, Rene Hernandez saying (Spanish):

"Discovering these pieces is not easy because there needs to be a series of conditions that allow for the organism to preserve itself. Like here, where you can see the sequence of the vertebras from the sacrum to where it ends at the point of the neck. Also, it is together with other skeletal elements."

Archaeologists believe the rest of the dinosaur's body may be buried even deep