Assembled bones are stabilized in casts. These are pelvic bones of the allosaurus. Vertebrae (backbones) discovered so far would lead from these bones to the neck. A partial skull has also been found but not completely excavated.
Dinosaur diggers are giving up their desert solitude for a few days to give the public a glimpse of "death elevated." In other words, to see how they are unearthing the long-dead fossils of their latest dinosaur discovery in the San Rafael Swell.
The College of Eastern Utah Prehistoric Museum and Bureau of Land Management decided that since the find is significant and access is easy, there is an opportunity to let people watch and learn about the painstaking process of paleontology. The so-called Gooseneck Site is about nine miles east of Castle Dale on graded dirt road and an easy walk from the road (maps are available at the Prehistoric Museum between 9 a.m. and 6 p.m.) The site will be open during the days through Saturday.
Paleontologists and volunteers are excavating a young allosaurus-a meat-eater that hunted in this region during the Jurassic Period at least 140 million years ago. John Bird, the museum's Paleontology Lab Manager, said that the find is unusual because the spinal bones they have discovered are articulated. That means they are arranged together as they were in life. Flowing water or scavengers often tore apart dead dinosaurs before they could be buried and fossilized.
In all, there are 27 articulated vertebrae identified so far. Also on display at the site are three pelvic bones. The arrangement of the neck bones gave rise to the site name. They are curled like a goose neck.
The find was "a surprise, like they all are," Bird said. He and fellow explorer Bill Heffner had been searching the area for exposed fossils in late November 2009. This section of the San Rafael has exposures of the Morrison Formation, a series of strata known to be rich in Jurassic fossils. They found a few lumps extending from the rock that looked like bone, and after some careful chipping away at surrounding rock, identified vertebrae. They found six before the end of the year and decided there could be more.
They were right.
It will take further excavation and research at the museum to identify the species of allosaur. Partial remains of a skull should help.
Visitors will be able to understand just how labor-intensive a dinosaur dig can be. Diggers have to sift dirt and gravel through sieves so they don't miss any fossil fragment. Tools can include small spades, whisk brooms, sometimes tooth brushes. Often geologic forces over millions of years can break the bones into tiny pieces, so the process can become like assembling a jigsaw puzzle. There is always glue on hand to hold things together.
Laboratory preparation will also be open to the public later on.
The also appears to be a larger, plant-eating dinosaur buried with the allosaurus. Understanding how they came to be together in death will take some paleontological detective work. The allosaurus could have been eating the other dinosaur, or they both could have died separately somewhere else and their corpses drifted together in a slow moving stream. The rocks and bones can tell a lot to an expert.
The museum reminds visitors - and anyone else who finds dinosaur fossils - to leave them where they are and hide the bones if possible. Take a GPS reading or leave a marker of some sort so the site can be found later.
Visitors should pack water into the desert site. The stream that may have deposited the dinosaurs millions of years ago is long gone.
Disclosure: "Death Elevated" is the slogan on the museum's letterhead.