Professor Matthew Bennett and Dr Xavier Velay, Bournemouth University.
Professor David Huddart and Dr Silvia Gonzalez, Liverpool John Moores University.
Dr Tom Higham and Dr Jean-Luc Schwenninger, University of Oxford.
Professor Rainer Grun, The Australian National University.
Human footprints found in Mexico could challenge the current consensus about how and when humans first arrived in the Americas. The team from Bournemouth and Liverpool John Moores Universities that discovered the footprints believes that they are 40,000 years old, which would be some 28,500 years older than previous human finds from this region. 'Accounting for the origin of these footprints would require a complete rethink on the timing, route and origin of the first colonisation of the Americas', says Matthew Bennett, one of the team that found the prints on a former lake shore south of Puebla, Central Mexico.
Matthew and his colleagues were in Mexico to establish the precise age range of what are known as the 'Valsequillo Gravels' sediments associated with a range of human artefacts and animal remains. The sediments were deposited thousands of years ago in a lava-dammed lake which filled the Valsequillo Basin. It was entirely by chance that the team found the human footprints in a layer of volcanic ash deposited in the former lake below the Valsequillo Gravels. 'Luckily, we knew what we were looking at, as my co-workers have worked on footprints on the saltmarshes of the northwest coast of the UK', says Matthew.
Over 250 footprints were found. The majority were human; the rest belonged to dogs, big cats and animals with cloven feet. The human footprints suggest that these people had heights of 117 190cm. But the key finding was the age of the footprints. Prior to these footprints, the oldest directly dated human find from Mexico was part of a human skull thought to be 11,500 years old. A variety of dating techniques on the volcanic ash containing the footprints and on fossils within the overlying sediments, led the team to the conclusion that this new find could be at least 40,000 years old.