Kathleen

Even though we have a soft spot for Dippy (Diplodocus carnegii) here at the Carnegie Museum of Natural History, Tyrannosaurus rex—the “king of the tyrant lizards”—is arguably the most famous dinosaur of all. T. rex was a fearsome theropod that weighed up to 9 tons, had a mouth full of razor-sharp, serrated teeth, and dominated what is now western North America during the Cretaceous period about 68 million years ago. But for all these ferocious credentials, T. rex’s closest living relative may surprise you. Take a moment or two to think about it. I’ll give you a hint, you may have eaten one of these in its nugget form at some point in your life. That’s right, the common chicken (gallus gallus domesticus), a slightly less intimidating animal! Was that your first guess?

Not only do T. rex and other dinosaurs share anatomical characteristics with birds—the wishbone, or furcula, for instance—but scientists in the twenty-first century have found molecular evidence to support the relationship, specifically from collagen proteins extracted from T. rex fossils, proteins that are strikingly similar to those found in modern birds. Scientists have also discovered through expressing the gene for feathers in embryonic alligator skin that feathers are highly modified scales. “It tastes like chicken,” the saying goes. But what does chicken taste like you ask? Perhaps a little like dinosaur.

While T. rex is a part of a fascinating evolutionary web that includes the birds we see today, the history of how T. rex got the name T. rex in the first place is no less fascinating. It all began in 1900, when the famous paleontologist Barnum Brown was quarrying in Wyoming for the American Museum of Natural History. Brown was looking for a triceratops skull to wow patrons back in New York City. Spoiler alert: he did not find the triceratops skull of his dreams. What he did find that autumn in Wyoming were the fossil remains of an enormous carnivore. Brown sent this new discovery back to the American Museum of Natural History where curator of vertebrate paleontology Henry Fairfield Osborn analyzed the unknown specimen, finally naming it Dynamosaurus imperiosus (literally, dynamic imperial lizard)—quite a tongue-twister.

Two years later, in 1902, Barnum Brown found another impressive cache of fossilized carnivore bones, this time in Montana. Osborn believed this second find to be a separate species from the first and called it Tyrannosaurs rex. Osborn published a scientific paper in 1905 officially naming and describing both theropods. However, after spending another year studying the two specimens, he came to the startling conclusion that they were one and the same species! Even legendary scientists have face-palm moments. Convention in the field of paleontology states that in such cases the first name sticks—but, lo and behold, Osborn had mentioned T. rex first in his 1905 paper. So, because of this seemingly small technicality, T. rex is T. rex…and not D. imperiosus. T. rex may be the most famous of the dinosaurs, but to this day it keeps its share surprises, both scientific and historical.

I remember visiting the museum often as a child. My favorite gallery was always Dinosaur Hall, now called Dinosaurs in Their Time. The gallery has changed a lot since I was a kid with specimens being displayed in ways that we now know to be scientifically accurate and even some specimens finally being displayed as free-standing mounts.

If you are exploring Dinosaurs in Their Time, as you pass underneath  Dippy’s (Diplodocus carnegii) tail you will spot a relatively small and seemingly unassuming dinosaur, Camptosaurus. While Camptosaurus  may not have the grand presence of Dippy or T. rex or the cuteness of baby Apatosaurus or Protoceratops it is still a remarkable specimen, with an interesting history.

Our specimen of Camptosaurus was discovered in 1922. It was on display for over 60 years, half embedded in the rock in which it was discovered. In 2005-2006, during renovations of the dinosaur exhibit, it was decided that Camptosaurus would be freed from the rock and turned into a free-standing mount. At that time, it was discovered that our Camptosaurus specimen was not Camptosaurus dispar like we thought. It was actually a species that had never been discovered before! Our specimen, described in 2008 by Kenneth Carpenter and Yvonne Wilson, is Camptosaurus aphanoecetes and it is the holotype, or the specimen that defines this species.  Its new scientific name is accurate- Camptosaurus means “flexible lizard” and aphanoecetes means “hiding in plain sight.”

Camptosaurus lived in the late Jurassic period, about 150 million years ago. It was an herbivore, or plant eating dinosaur. The wear on its teeth shows that it likely ate tough vegetation. It was originally thought to walk on all four limbs, but now we know that was able to walk on its hind limbs or all four limbs as needed. Camptosaurus  was the ancestor to later dinosaurs like iguanodonts and duck-billed dinosaurs.

Camptosaurus is a great demonstration of the fact that scientists are always learning. Paleontology, despite being the science of studying animals that existed long ago, is constantly changing and evolving. We discover new ancient species, sometimes hiding in plain sight, all the time.

Soaring high over the tallest of treetops, snatching up an unlucky land-dweller for lunch, and emitting long screeches that echoed far and wide— these are a few of the images one could imagine when asked to think about pterosaurs. And, for some, this might be correct; smaller species of pterosaurs were easily capable of flight, hunting or even scavenging in many different ways. But for other species, an air of mystery remains. Pterosaurs tend to be far more complex than people think at first— for one, they aren’t even considered dinosaurs, despite living alongside them throughout the Mesozoic. For another, pterosaurs likely could have varied drastically in how they lived. We still have a long way to go before we figure out these winged reptiles, and perhaps none of them are as awe-inspiring as Quetzalcoatlus northropi, often considered one of the largest flying animals that ever existed.

Living throughout the late Cretaceous, Quetzalcoatlus northropi could grow to have a wingspan of up to 36 feet— about the size of a standard city bus. Early scientists estimated that this species of pterosaur may have weighed anywhere from 200 to 500 pounds. Like today’s birds, pterosaurs had hollow bones, which made them light enough to fly.

Scientists, however, are not sure if Quetzalcoatlus could take to the skies like its cousins. Even with special bones, a reptile as big as Quetzalcoatlus may have had a hard time getting up into the air. It isn’t always easy for us to know how an ancient animal might have lived during its time, but a Paleontologist can make educated guesses based on the bones that they study. Sometimes, the best clues lie in the animals that we have today; by comparing some of the features of Quetzalcoatlus to modern-day birds, Paleontologists have proposed a few different theories as to how one of the largest pterosaurs lived.

Quetzalcoatlus had a very long, sharp beak similar to the storks that we know today. Based on this observation, it is commonly thought that this pterosaur may have hunted small animals on the ground, similar to storks or hornbills. Supporting this hypothesis is the front and back limbs, which suggests to many modern scientists that Quetzalcoatlus may have been more suited to walking on land than we would expect. However, this alone does not rule out flight. A more recent study, aided in part by Chatham University’s Mike Habib, revealed through a computer model that Quetzalcoatlus could have been capable of flight, and likely flew in short bursts. This likely was used by Quetzalcoatlus before soaring, much like today’s vultures.

Even with modern technology, what we know about creatures like Quetzalcoatlus northropi still leaves plenty of mystery around the winged giant. Able to fly or not, there is no question that this pterosaur is a breathtaking reminder of the complex nature of the Mesozoic era.

Let’s go on a trip! We’ll have to travel about 1,000 miles and roughly 66 million years to arrive on the rocky beach of the Western Interior Sea of Kansas. There is lush plant life with ancient birds and bugs buzzing around the water – we might feel as though we’ve been transported to the land of Oz! Better stop Toto before he leaps in for a swim though, it’s full of dangerous creatures!

One of the creatures in these waters were the Mosasaurs. These animals evolved from the same ancestor as today’s monitor lizards like Komodo Dragons and Water Monitors. Feeling the predation pressure from larger dinosaurs, this little lizard adapted to life in the water and soon became fully suited for life in the oceans as they developed the ability to give birth to live young, eliminating the need to lay eggs on land.

The mightiest of all the mosasaurs was Tylosaurus. They grew more than 45 feet long, making them the largest. Mosasaurs had a long and muscular tail that was vertically flattened, like a shark, that powered Tylosaurus through the water. This allowed them to ambush its prey with rapid bursts of acceleration. Paddle-like limbs helped steer their slim body, covered in lizard-like scales, through the water. (Image 1- illustration of blue Tylosaurus)

Tylosaurus was the deadliest hunter of the ancient seas, ready to seize and kill just about any smaller creature that crossed its path using jaws that were lined on each side with two rows of pointy, cone-shaped teeth. This reptile used its snout to locate prey, which, once inside the mosasaur’s jaws, was swallowed whole. When the sea monster opened wide for the final gulp, two extra rows of teeth on the roof of its mouth started digestion by shredding the prey as it was being swallowed.

Though not a dinosaur, Tylosaurus lived alongside them and went extinct around the same time. Many Tylosaurus remains have been found near the Great Plains in Nebraska and Kansas, which was once covered by a large ocean we went to visit. Don’t be fooled, we couldn’t swim in this ocean like we can in today’s waters