The story of Allosaurus X begins in the summer of 2012. After a couple weeks of serious ground-pounding with hammers and chisels, we had found many loose bones and some teeth from Jurassic dinosaurs such as Camarasaurus, Camptosaurus, Allosaurus and Torvosaurus.
Key areas of the digsite - where near-complete dinosaur skeletons had been deposited during high energy flood events and quickly buried - had been well-explored over the past four years. In 2012, we were hoping that there might be other good bone zones yet to be found in this big, ancient, meandering river system.
Late into the dig season, we began to find accumulations of nice bones (we called them “islands”) that were embedded in very hard matrix or rock. We would delineate shapes that suggested tentative IDs, such as vertebrae, ribs or chevrons but we couldn’t be sure of the species or whether the bones were from the same dinosaur.
That changed when we found a Theropod pelvic section in among the unidentifiable bones. With this discovery, the shapes began to take on more meaning. The size of the bones and bone ‘blobs’ told us that we might be working on a single dinosaur, and not a pile of bones from multiple dinosaurs. As we carefully continued digging, we excavated large blocks of rock that contained bones that we hoped to identify back home in the prep labs.
And, sometimes it’s better to be lucky than smart. Friends joined us on the dig for a couple days and late in the second day when everyone was hot, tired and hungry, one of the guys accidentally stepped on one of the excavated blocks and broke off a section of protective rock. The break exposed four perfect, knife-shaped teeth in a row in a piece of bone. Closer inspection showed this to be an Allosaurus pre-maxilla or upper jaw bone (the snout) of the dinosaur.
In a flash, we realized that a number of the hard to identify bones in the matrix were additional Allosaurus skull elements – and we now had at least the skull, pelvic section, ribs and some vertebrae of this dinosaur. Since this was near the end of the dig season, we covered bones left in the ground with plaster jackets and hoped we would find more of this Allosaurus in 2013.
And we did! Since early June 2013, we have unearthed and excavated close to 70% of the Allosaurus specimen. We hope to find more of this Jurassic Theropod as we widen the digging area in 2014 in search of more of the Allosaurus we have named Al-X.