“One hundred and twenty-five million years ago, amidst a landscape of springs and greenery, hundreds of feathered dinosaurs met their doom and were entombed together in a single grave. Now a barren wasteland in the heart of the Utah desert, a rust-colored hilltop dotted with bones is the only testament to their tragic demise. This is the burial site of Falcarius utahensis—one of the oldest bird-like dinosaurs and home to what may be the largest graveyard of feathered dinosaurs anywhere in the world.”
We are living through the most exciting period in the history of dinosaur paleontology. More than half of all known dinosaur species were discovered within the past 25 years, including nearly all of the remarkable feathered dinosaur specimens. One of the hottest areas for dinosaur discovery in North America is the Cedar Mountain Formation of eastern Utah, where new dinosaurs are being discovered and described at a phenomenal rate. These fossil beds span the last 25-30 million years of the Early Cretaceous, a time when North America was undergoing a period of climate change that resulted in localized extinction events and invasive dinosaur species.
Our team returns to Utah every year to hunt for new dinosaurs. In 2012 we resumed excavations at an unprecedented dinosaur burial ground in the Cedar Mountain Formation known as the Crystal Geyser Quarry (CGQ). The CGQ is a mass mortality site entombing the rare feathered dinosaur dubbed Falcarius utahensis. One hundred and twenty-five million years ago an estimated 300 Falcarius individuals ranging in age from hatchlings to 4-meter long adults died and were buried here under mysterious conditions. This extraordinary phenomenon makes the CGQ one of the largest feathered dinosaur graveyard known anywhere in the world.
99% of all the bones buried at the CGQ belong to Falcarius utahensis. Falcarius is the most primitive member of an extremely bizarre dinosaur group known as Therizinosauria—notable for having tiny beaks, potbellies, and enormous claws up to 5 feet in length!
Why is Falcarius important? As the most primitive therizinosaur, Falcarius acts as a missing link, recording the earliest transition of these massive, lumbering, and freakish vegetarians from their agile, carnivorous, raptor-like ancestors. Although the transition from meat eating to plant-eating has occurred several times in the evolutionary history of dinosaurs, Falcarius is one of a handful of transitional dinosaurs recording this complex and poorly understood evolutionary process.
Although rare, the remains of other extinct animals are preserved at the CGQ. These include a new undescribed rhino-sized ankylosaur (armored dinosaur), a new sauropod (long-neck dinosaur), a large, meat eating, sickle-clawed dinosaur closely related to Utahraptor, as well as turtles and crocodiles. So far, we have not collected enough bones of these species to be able to name them, but each year we collect additional bones of these new taxa.
Although, much of the skeleton of Falcarius is known, many of the bones are still missing including most of the skull. We have hopes of finding more skull material because skull bones are critical for linking Falcarius to its closest relatives in the dinosaur family tree. Even more exciting is the potential to ask questions about how Falcarius grew, what its population structure and longevity were like, and whether there were skeletal differences between males and females. These questions are typically unanswerable for dinosaurs because of the sheer rarity of this type of mass death assemblage. One major goal for recent expeditions is to collect more bones from Falcarius babies so that we can better understand how their skeleton changed as they grew up.