A Mexican man has discovered dozens of dinosaur footprints dating back up to 110 million years along the banks of a dried river, scientists said on Tuesday.

Biologist Oscar Polaco said the footprints, found by a local resident in a desert region in central Mexico, belonged to three prehistoric species that came to drink water in the area, once a swampy zone close to the sea.

Polaco said more studies needed to be done to determine what species of dinosaur the fossilized prints, each one up to 60 cm (24 inches) across, belonged to.

"At the moment we can confirm these are footprints that belong to dinosaurs that lived during the early Cretaceous (period)," the scientist said.

The early Cretaceous period began about 144 million years ago and followed on from the late Jurassic period. The Cretaceous period is considered the last period before dinosaurs disappeared from earth about 65 million years ago.

The footprints are spread across land belonging to a local cooperative, whose members have built a fence round the site to protect it.

Last year scientists identified 30 other dinosaur prints in the same region, an area famous for the large numbers of fossils deposited there.

The prints found in 2006 belonged to 20-meter (66 foot)-long animal that weighed between 30 metric tons and 40 metric tons, with a small head, long neck and heavy feet.

Mexican researchers say those prints may have been made by a brontosaurus.