Falcarius was a 12 foot long theropod dinosaur which lived in Utah during the early Cretaceous Period, approximately 139 to 136 million years ago. It was a very primitive therizinosaur – so primitive that it still bears a close resemblance to the coelurosaurs that it likely evolved from. It was almost certainly feathered, although the extent of how much of its body was covered in feathers is still unknown.

Falcarius’ fossils were found within the lower part of the Yellow Cat Member of the Cedar Mountain Formation at a place called Crystal Geyser Quarry. During this time, Utah was much more verdant and fertile than it is now, with evidence of rich soil, forests, and a much higher rainfall. Falcarius shared its habitat with the turiasaurian sauropod Mierasaurus, the iguanodont Iguanacolossus, and the primitive raptors Geminiraptor and Yurgovuchia. Other creatures who inhabited the landscape which have not yet been named include a large allosauroidean theropod similar to Acrocanthosaurus, an ankylosaurian similar to Gastonia except it was much larger, and another iguanodont ornithopod.

It’s possible that the genus Falcarius is divided into two species. One of them is F. utahensis, named in 2005. However, in 2014, a short abstract was published in the Journal of Vertebrate Paleontology which hinted that a second primitive therizinosaur had been found which was very similar to F. utahensis. The fossils were discovered at a place called “the Suarez Site”, located approximately 800 meters northwest of Crystal Geyser Quarry – both sites are from the lower Yellow Cat Member. The specimens found at the Suarez Site, which may come from at least twenty-five individuals, seem to be more derived than F. utahensis and therefore might represent a second Falcarius species. However, it hasn’t been officially named or described yet.

Below is a drawing that I made of Falcarius utahensis. This drawing was made with No.2 pencil, No.3 pencil, and Crayola and Prismacolor colored pencils on printer paper, and measures 12 inches long from nose to tail (1/12 scale). The color pattern was based upon the Eastern Milk Snake (Lampropeltis triangulum triangulum) and a few species of rattlesnakes with similar color patterns.

Falcarius utahensis. © Jason R. Abdale (July 17, 2022)

Keep your pencils sharp, everyone.

Sources (listed in order of publication)

Kirkland, James I.; Zanno, Lindsay E.; Sampson, Scott D.; Clark, James M.; DeBlieux, Donald D. (2005). “A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah”. Nature, volume 435, issue 7038 (2005), pages 84-87.

Utah’s Dinosaur Graveyard. The Science Channel, 2007.

Zanno, Lindsay E.; Kirkland, James I.; Herzog, Lisa L. (2014). “Second therizinosaurian mass death locality in the Lower Cretaceous Cedar Mountain Formation yields a new taxon”. Journal of Vertebrate Paleontology, Abstracts and Programs, 74th Annual Meeting (Berlin, Germany) (November 5-8, 2014), page 260.

Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 101-228.

Categories: Paleontology, Uncategorized

Tags: , , , , , , , , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: