Parrosaurus missouriensis


Dinosaur fossils are rare in Missouri: so rare, in fact, that only one site has ever been found. In 1942, geologist Dan R. Stewart heard of an unusual discovery near Glen Allen, Missouri on a farm belonging to the Chronister family. They were digging a new well when they stumbled upon a set of large, fossilized bones. The Missouri Geological Survey and Water Resources department sent Stewart to investigate. He saw twelve vertebrae and a few bone fragments belonging to a previously undiscovered species of dinosaur.

Stewart enlisted help from Dr. C.W. Gilmore of the U.S. Geological Survey. Together, the two published a paper in 1945 announcing the discovery. Gilmore took over the classification portion and described the dinosaur as an Upper Cretaceous sauropod. Sauropods are the largest dinosaurs and include favorites such as Brachiosaurus, Brontosaurus and Apatosaurus. Gilmore named the Missouri specimen Neosaurus missouriensis.

Over time, Missouri’s only dinosaur was reclassified as a hadrosaur, or “duck-billed dinosaur.” Its scientific name was changed to Parrosaurus missouriensis in late 1945, then Hypsibema missouriensis in 1979. Chase Brownstein reverted it back to Parrosaurus in 2018.

Not only is P. missouriensis significant because it’s Missouri’s first dinosaur, it is of huge importance to paleontologists because it is one of few species discovered that lived on the east coast of the former inland sea – the Western Interior Seaway – that broke up what is today the United States into eastern and western continents. The species became Missouri’s state dinosaur in 2004.

In January 1943, Lula Chronister sold all but one of the bones to the Smithsonian Institution for $50, which is where they remain today. (The twelfth bone has since been reunited with the others.)

On Nov. 22, 2021, Museum Curator Guy Darrough formally announced the discovery of an adult Parrosaurus missouriensis fossil at the Chronister site. Darrough, director of the dig site, said the fossil and its surrounding material weighed 2,500 pounds. The dinosaur was excavated by a team including Dr. Pete Makovicky of the University of Minnesota and Akiko Shinya of the Field Museum. The specimen was transported to the Field Museum in Chicago where it will be cleaned, studied and eventually displayed.


Revised Statutes of Missouri (RSMo)

§10.095. State dinosaur. – The Parrosaurus missouriensis dinosaur is hereby selected for, and shall be known as, the official dinosaur of the state of Missouri. (L. 2004 H.B. 1209; 2022 S.S. S.C.S. H.B. 1738)

approved 01 July 2022
effective 28 August 2022


Photo Gallery:

Click on an image below to enlarge and read a caption. This will open a new window in the Missouri State Symbols Flickr album.

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Additional Resources:

Click here to read an essay on Missouri’s state dinosaur. Essay contains many additional bibliographic references.

Click here to open a PDF of the Smithsonian Institution’s original accession paperwork and correspondence regarding these dinosaur bones. (Courtesy of the Smithsonian Institution, accession no. 164163, catalog no. 16735, 21 January 1943.)

Gilmore, Charles W., and Dan R. Stewart. “A New Sauropod Dinosaur from the Upper Cretaceous of Missouri.” Journal of Paleontology 19, no. 1 (January 1945): 23-29.

Lost World Studios, Guy Darrough’s website:

Ste. Genevieve Museum Learning Center, which includes a juvenile Parrosaurus missouriensis fossil still encased in hardened clay, a replica of an adult forelimb and multiple dinosaur models of other species presented by Lost World Studios/Guy Darrough:


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