'Most complete specimen' of giant dinosaur discovered in US state

A team of scientists has revealed that a dinosaur fossil described as the "most complete ever" in the US state of Mississippi is still 85% buried since its discovery in 2007.

Paleontologists have confirmed that the specimen is a hadrosaur, a family of herbivorous duck-billed dinosaurs that existed more than 82 million years ago.

Hadrosaurs are a large family of giant herbivores, including about 61 identified individual species, and possibly hundreds of unique species that once roamed the Earth, according to experts.

Scientists have recovered pieces of the specimen's spine, parts of its feet and pelvic bones, but other remains from its site outside Booneville in northeastern Mississippi are extremely difficult to uncover.

In this regard, Derek Hoffman, a graduate student in geology at the University of Southern Mississippi (USM), is now analyzing the hadrosaur remains using a 3D method, known in many scientific disciplines as “geometric morphometry,” which takes the approach of shape analysis.

The main features or "landmarks" of a given bone sample and their distances are identified, and the ratios of those distances are then compared through complex statistical models to confirm differences and similarities with known bones.

This method has proven effective in anthropology, as well as in studies of human evolution, including comparisons of the brain cavities of modern humans and ancestors.

But Hoffman's search for answers about this hadrosaur fossil has been made more difficult by the fact that some pieces of the creature are in the hands of private collectors.

Hoffman's work focuses primarily on bones held at the Mississippi Museum of Natural Sciences, but the skull is largely missing from the site.

Hoffman focused on the dinosaur's pubis, a bone from the front of the pelvis, as the best choice for identifying the fossil.

While the differences between the pubic bones of hadrosaur species are subtle, often too subtle for the naked human eye, subtle differences can be detected through geometric morphometric methods.

While researchers believe the hadrosaur lineage began in North America, it migrated across the world, with fossils discovered in Asia, South America, Europe and North Africa.

It is noteworthy that many species of hadrosaurs lived about 75 to 65 million years ago in the late Cretaceous period.