Bollinger County Museum of Natural History
the Missouri Dinosaur

Hypsibema missouriense - the Missouri Dinosaur!

The history of the Missouri Dinosaur

by Mike Fix

In 1942, a geologist named Dan Stewart, who worked for the Missouri Geologic Survey, was doing field exploration for clay deposits in Bollinger County near the town of Glen Allen. One day he was examining an outcrop of clay in a creek bank when a young boy poked his head over the top of the bank and asked what Dan was doing. When the boy heard that Dan was looking for clay, he told him that his family had found some in the process of digging a cistern. So Dan followed the boy to investigate.

Dan Stewart

Much to his surprise, the boy's mother showed him some large bones that they had found in the clay. Dan searched the other piles of clay further and found more bones. A total of 14 tail bones (vertebrae) were found, as well as a few other bone fragments. Dan asked Mrs. Chronister if he could take the bones to have them examined by experts, and she agreed. Later the Smithsonian Institution paid her a tidy sum of 50 dollars for the bones and she used the money to buy a cow.


Eventually, the bones were sent to the Smithsonian where Dr. Charles Gilmore, a dinosaur expert, identified them as belonging to a dinosaur which he believed was new to science. In 1945, a paper was published in the Journal of Paleontology by Gilmore and Stewart in which this dinosaur was named Neosaurus missouriensis, and described as probably being a sauropod - a large, plant-eating dinosaur with a long neck, small head, massive body, and long tail - such as Brontosaurus (Apatosaurus) or Diplodocus.

Shortly after the paper was published, it was discovered that the name Neosaurus had previously been assigned to another animal by a Russian paleontologist, and therefore could not be used for the Missouri genus. Gilmore changed the name to Parrosaurus missouriensis in 1945. He unfortunately died shortly afterward and did not get a chance to visit the site for further study.


In the late 1970's, two dinosaur experts, D. Baird and J.R. Horner, examined the Missouri dinosaur fossils in the Smithsonian, and decided that they were from the same kind of animal as a dinosaur called "Hypsibema crassicauda," described by E.D. Cope in the late 1800's from bones found in North Carolina. They kept the species name that Gilmore had assigned and agreed with him that it was probably a sauropod. They published their conclusions in a 1979 paper entitled "Cretaceous Dinosaurs of North Carolina," and so Hypsibema missouriense became the new name for this enigmatic beast.

Hypsibema missouriense

Then in the 1980's, Dr. Bruce Stinchcomb, with assistance from Dr. David Parris and Dr. Barbara Grandstaff of the New Jersey State Museum, conducted a series of test excavations to determine if more dinosaur material was present and the extent of the clay. A number of dinosaur bones were recovered, as well as fossils of turtles, crocodiles, and fish. These new fossils made it possible for Dr. Parris and Dr. Grandstaff to determine that Hypsibema is not a sauropod after all, but rather a hadrosaur. Hadrosaurs are also called "duck-billed" dinosaurs because their snout superficially resembles a duck's bill.

In 1989, Guy Darrough and Michael Fix obtained permission from Dr. Stinchcomb to conduct an excavation within a protective enclosure. The enclosure was necessary because the clay deposit holds water. In 1990, under the guidance of Dr. Parris an excavation was conducted by an all volunteer crew. More bones of Hypsibema were recovered including vertebrae, and fragments of the pelvis. Also, fossils of two other types of dinosaurs were found at the site. One of these is a relative of Tyrannosaurus rex, and the other is related to velociraptor.


In 1999, a 20 ft. by 36-1/2 ft. greenhouse was erected over the dig site, which allowed for year-round excavation. This enclosure was equipped with a hanging grid of square meters for precise mapping. Since that time many fossils have been found and prepared at the Bollinger County Museum of Natural History. One of the more important finds is a section of the upper jaw of Hypsibema missouriense.

The greenhouse worked great until 2010, when an unusually bad ice storm damaged the structure. Fundraising for a new greenhouse installation is planned for the summer of 2015 so the excavations can continue. For now, discoveries continue being made at the museum where a large 900-pound block of clay from the site is being examined. Visitors can view the process as the bones are uncovered and prepped for exhibit. The Chronister site has a history of significant discoveries and will yield fossils for years to come.

dig tent


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