Authorities in Morocco said Monday they doubt the authenticity of an alleged dinosaur tail sold in Mexico, after launching a probe to see if it had been illegally exported from the North African country.

The purported four-metre-long (13-foot) fragment of an "Atlasaurus tail from the Jurassic period" was sold on Tuesday for 1.8 million pesos (78,000 euros, $96,000), according to Mexican auctions website Morton.

But Morocco's mines ministry said preliminary investigations showed the supposed dinosaur tail was likely "restored from an assembly of vertebrae found isolated, not emanating from the same species."

The ministry said it had not issued any export permit for the "vertebrae".

A skeleton of an Atlasaurus, a species which dates back 160 million years and is estimated to have measured 18 metres in length and 10 metres in height, is on display at the in the Moroccan capital Rabat.

Last April, Morocco secured the return of the bones of an aquatic dinosaur which was withdrawn from an auction in Paris.

With its land mass partly submerged by the sea around 500 million years ago, Morocco is rich in palaeontological treasures, minerals and .