Hypsibema missouriensis facts for kids
Quick facts for kids Hypsibema missouriensis |
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| Assigned vertebra, North Carolina Museum of Natural Sciences | |
| Scientific classification (Nomen oblitum) |
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| Genus: |
Hypsibema
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| Species: |
missouriensis
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Hypsibema missouriensis (pronounced Hip-see-BEE-ma miss-oo-ree-EN-sis) is a fascinating plant-eating dinosaur. It is also known as Missouri's official state dinosaur! This ancient creature lived during the Late Cretaceous period, a very long time ago. Its bones were first found in Missouri in 1942, making it the first dinosaur discovery in the state.
At first, scientists thought Hypsibema missouriensis was a type of long-necked dinosaur called a sauropod. But later studies showed it was actually a hadrosaur, often called a "duck-billed" dinosaur. This is because their snouts looked a bit like a duck's bill. Some of the original bones found are now kept at the famous Smithsonian Institution in Washington, D.C.
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Discovering Missouri's Dinosaur
The story of Hypsibema missouriensis's discovery began in Bollinger County, Missouri. In 1942, the Chronister family was digging a cistern (a large tank for collecting rainwater) when they found some unusual bones.
A geologist named Dan Stewart from the Missouri Geological Survey was studying clay nearby. A boy led him to the Chronister family, who showed him the bones. Lulu Chronister, the property owner, had saved several "unusual" bones. They were found about 8 feet (2.4 meters) deep in their well, buried in dark, soft clay.
Stewart reported his exciting find to the Smithsonian Institution. The Smithsonian bought thirteen tail bones from Ms. Chronister for $50. She used the money to buy a cow! Two other bones were also found, and one more tail bone had been given to a friend. Scientists at the Smithsonian studied the bones, but they didn't quite get the identification right at first.
For many years, the dig site wasn't explored much. But in the 1970s and 1990s, new excavations began. Scientists found bones from other dinosaurs, fish, turtles, and plants there. They even found teeth from a tyrannosaur and bone fragments from a dromaeosaur (a type of raptor). These many different animal remains suggest that a large body of water, like a lake or a coastal area, was once close to the site.
The Geology of the Dig Site
Finding dinosaur bones in Missouri is quite rare. Most of the state's soft soil causes ancient remains to break down over time. That's why one paleontologist called the discovery "pretty much a miracle." However, some of the bones found were still damaged by natural processes like erosion.
Most of Missouri has very old rocks from the Paleozoic or Precambrian eras. But the Chronister site sits on younger rocks from the Mesozoic era, the time of dinosaurs. Geologist Dan Stewart realized that this part of Missouri had deposits from the Late Cretaceous period, even though much of it had worn away.
The Chronister family dug their well on top of limestone near their farmhouse. The dinosaur bones were found in a thick layer of clay, about 9 feet (2.7 meters) deep. This clay was beneath layers of yellow-brown clay and gravel. Scientists now believe the area was once a coastal plain with a lake, not just a small hole in the ground.
How the Dinosaur Got Its Name
When the bones first arrived at the Smithsonian, paleontologist Charles Whitney Gilmore and geologist Dan Stewart studied them. In 1945, they first described the species as a sauropod (a long-necked dinosaur). This was a mistake, as they didn't have strong proof. Gilmore decided it was a sauropod mainly by ruling out other options.
The species was first named Neosaurus missouriensis. But later that same year, Gilmore and Stewart changed the name to Parrosaurus missouriensis. This was because the name "Neosaurus" was already being used for another animal. Sadly, Gilmore passed away soon after, and the bones were not studied much for several decades.
In 1979, scientists Donald Baird and John R. Horner moved Parrosaurus missouriensis into the genus Hypsibema. This is how it got its current main name. Later, in the 1980s, geologist Bruce L. Stinchcomb bought the Chronister property. He and other researchers, David Parris and Barbara Grandstaff, did more digging. They finally confirmed that H. missouriensis was indeed a hadrosaur, not a sauropod! Some paleontologists have suggested going back to the name Parrosaurus for this species, and in 2018, some even decided Parrosaurus was a valid dinosaur genus.
New Discoveries of Hypsibema Bones
In 2011, paleontologist Guy Darrough found the remains of a young Hypsibema dinosaur at a secret location. Then, in 2016 and 2017, four more new specimens of Hypsibema missouriensis were found. Guy Darrough and staff from the Field Museum of Natural History, including Peter Makovicky, helped dig them up. The adult dinosaur bones went to the Field Museum in Chicago. The juvenile (young) dinosaur went to the Sainte Genevieve Museum Learning Center in Ste. Genevieve, where Darrough works as a curator. A new exhibit there now proudly displays the young dinosaur.
What Hypsibema missouriensis Looked Like
Imagine a dinosaur as big as an elephant! Hypsibema missouriensis weighed about 3 to 4 short tons (around 2,700 to 3,600 kilograms). It stood about 10 feet (3 meters) tall at its back and stretched about 30 to 35 feet (9 to 10.7 meters) from its head to its tail.
This dinosaur was a plant-eater, meaning it only ate plants. It had about 1,000 small teeth! Interestingly, its teeth were more serrated (like a saw blade) than other hadrosaurs. This suggests that the plants in Missouri during the Late Cretaceous period were very tough and needed strong teeth to chew.
In their 1945 report, Gilmore and Stewart described the tail bones. They noted that the tail bones were longer than they were wide. They also had concave (curved inward) areas with ridges and depressions, and special spots for chevron bones (small bones under the tail vertebrae).
Missouri's State Dinosaur
How Hypsibema Became Official
On January 21, 2004, a special bill was introduced in the Missouri House of Representatives. State Representatives Rod Jetton and Jason Crowell wanted to make a hadrosaur the state dinosaur. After some discussion, the committee decided on Hypsibema missouriensis specifically.
The bill then went through the Missouri General Assembly. It passed the House of Representatives on March 8, 2004, with a strong vote of 147 to 4. It then passed the Missouri Senate on May 14, 2004, with a unanimous vote of 34 to 0. Finally, then-Governor Bob Holden approved the bill on July 9, 2004. The law officially took effect on August 28, 2004. Missouri became the sixth U.S. state to have its own official state dinosaur!
Local Impact and Tourism
In 2005, local businesses and government officials in Bollinger County met. They wanted to use the dinosaur discovery to attract more visitors and boost the local economy. They created a tourism campaign focused on the dinosaur. Some businesses even helped pay for a billboard along Interstate 55 that proudly announced, "Bollinger County, Home of the Missouri Dinosaur."
The Bollinger County Museum of Natural History, which displayed some of the original bones, saw a huge increase in visitors. The museum reported that the designation of H. missouriensis as the state dinosaur tripled their visitor numbers! However, the Bollinger County Museum of Natural History permanently closed on December 31, 2021.
In March 2008, a full-size model of H. missouriensis was finished and put on display at the museum. Rod Jetton, who was then the Speaker of the Missouri House of Representatives, even sponsored a dinner to celebrate the exhibit's opening. Guy Darrough, who also led excavations at the Chronister site, directed this two-year project. This exhibit was the only permanent one to feature the species. At the opening, Jetton expressed his hope that the dig site might one day become a state park.
Today, the Missouri Ozark Dinosaur Project continues to excavate the Chronister dig site. The site is covered to protect the valuable fossil material from water. This private property, owned by Bruce Stinchcomb, remains the only place in Missouri where dinosaur bones have been found.
See also
- Timeline of hadrosaur research
