A skeleton of a new dinosaur species has been discovered in Missouri - after paleontologists spent 15 years excavating the site.
Curator Guy Darrough, 70, found the remains of the reptile at an undisclosed site earlier this year.
Experts later confirmed they were bones of a juvenile parrosaurus missouriensis - a dinosaur never to have been identified before.
Prior to Guy's crew's major discovery of almost a full dinosaur's skeletal system, they'd also found a variety of other fossils.
During their many years working on the Missouri site fossils of turtles, crocodilians and fish have been uncovered, along with the tooth of a relative of a tyrannosaurus rex.
These discoveries were little and often until Guy found a partial articulated skeleton of a juvenile dinosaur and a jaw section with a battery of teeth.
He suspected the significance of these finds and made contact with the Field Museum in Chicago, who sent Professor Pete Makovicky, 49, to investigate.
Soon after the initial discovery, the field museum brought an entire crew of scientists down to help excavate the site.
That's when they found the bones of the parrosaurus missouriensis - the first time juvenile bones from the species have been uncovered.
Guy, from Cadet, Missouri, said: "Finding this dinosaur has been one of Missouri’s most important and famous discoveries.
"Me and my amazing team had been working on the site for 15 years prior to this find.
"I had a hunch that there was more to be discovered and that a more detailed examination needed to be done.
"After finding the jaw section of the dinosaur with its gorgeous set of teeth it really felt like we were on to something.
"With the help of Pete and his team we kept digging and digging and sure enough we hit the jackpot."
After months of carefully removing the matrix from the bones, a skull, tail section and two articulated arms complete with hands, were revealed.
An adult parrosaurus missouriensis is thought to have measured 35 feet from head to tail and weighed around four tons.
The species had unique dental features, with palaeontologists saying it is likely to have had around 1,000 small teeth.
Guy believes other bones will soon be found at the site, which is being kept secret until it can be secured.