A dinosaur hunter from Manchester has found what may be a Tyrannosaurus rex footprint.
Dr Phil Manning, from the University of Manchester, UK, found the 76-centimetre-long specimen last year in the western USA and has studied it to find out whether it belongs to the one of the largest carnivores ever to live on Earth.
Rocks in the Hell Creek area where the specimen was found date from 65-70 million years ago, the time when T.rex and other large dinosaurs lived.
There are only two large dinosaur discoveries from the Hell Creek region, T.rex and Nanotyrannus. Dr Manning believes the track could be from one of these large therapods (meat-eating dinosaurs) or possibly from another unknown species.
Finding such a specimen is the Holy Grail of palaeontology. However, this is not the first such find as Natural History Museum dinosaur expert, Angela Milner explains.
'It will be interesting to compare the footprint found by Dr Manning with one that was discovered in New Mexico in 1993. It was published in a scientific paper in 1994 where it was given the name Tyrannosauripus pillmorei , after Charles Pillmore who discovered it'.
'That print was about 4cm longer than the one discovered by Dr Manning and is also thought to have been made by a T.rex .'
T.rex was a huge fierce carnivore that grew to up to 12m in length. It had one of the strongest bites of any animal with 60 sharp teeth, some of which were up to 20cm long. T.rex lived 67-65 million years ago at the end of the Cretaceous Period. Its name means tyrant lizard king.
About fifty T.rex specimens have been found in Canada and the USA and there have been just three complete skulls found.
'It is never possible to be certain of the identity of an animal that made fossil footprints as they do not die conveniently at the end of their tracks!' says Milner.
'However both these prints occur in rocks of the right age, they definitely were made by large carnivorous dinosaurs - and the only one that was large enough to leave such a huge footprint was Tyrannosaurus rex - unless it was made by another big meat-eater whose remains have yet to be discovered.'
Dr Manning's research will be published as a scientific paper shortly allowing other scientists to study the findings too.
You can follow Dr Manning's discovery in the BBC TV series Inside Out North West tonight at 19.30.