Therizinosaurs!

Therizinosaurs are some of the creepiest dinosaurs I can think of. Our dinosaur this week, Falcarius (One species: Falcarius utahensis), is considered a valuable transitional discovery between other theropods and true therizinosaurs. Study of this Utah discovery in conjunction with the recently discovered Beipiaosaurus from China have allowed researchers to discover a lot more and draw a lot more logical conclusions about the evolution of the family of therizinosaurs. Falcarius, meaning "sickle" in Latin, was named for its high curvature claws present on its hands. A fairly long dinosaur, Falcarius has quite a stretch at the neck as well as quite a reach with its forelimbs. Typical therizinosaurs are assumed to be some of the only theropods that are obligate herbivores; ornithomimids are the other major family of theropods thought to be partially herbivorous but are proposed to have been much more omnivorous in nature. Falcarius was discovered by Larry Walker in 1999 in the Crystal Geyser Quarry of eastern Utah. James Kirkland, who we mention a lot in Utah related paleontology, was called in to head the geological survey team in 2001 that began to recover the bones of this dinosaur from the quarry. By 2005 a couple of thousand specimens had been recovered comprising the total remains of at least 300 individuals. Since that time the number of specimens has increased to over 3000 in the original quarry and a second quarry has been discovered to also contain specimens of this animal. The name was officially given to the dinosaur in May 2005's publication of Nature by Kirkland et al., which we will visit later in the week.

Picture by Paul Fisk. Mounted at the Utah Museum of Natural History.