paleontology – Dinosaur Lady

Death of the Dinosaurs, Part 3

We finally conclude our deep dive into the extinction event that killed the dinosaurs. We end with Robert dePalma, whose findings shaped our understanding of the asteroid.

At first it was just disappointment. Thirty-year-old graduate student, Robert dePalma, was excavating a fossil site on a ranch in North Dakota. When he began digging in 2021, he had hoped to find layers of sediment that would show the years leading up to the end of the Cretaceous Time Period. The site was a large area, covering about two acres and measuring about three-feet deep, but it was clear the entire layer had been laid down all at once by some kind of flood. There were fish fossils, but they broke apart into tiny flakes when he tried to dig them out.

North America at the End of the Cretaceous Period
Ron Blakely, Colorado Plateau Geosystems is credited for the maps, in the paper, and Terry A. Gates et al are stated to be the copyright holders for the paper and its contents, CC BY 1.0, via Wikimedia Commons

He continued to dig, though, and he found tiny, white/gray bits that looked like sand. When he looked at them under a magnifying glass, he recognized their tear-drop shape as belonging to microtektites. Tektites, as mentioned in last week’s blog, are created when rock becomes so hot that it turns to liquid. They can be formed by volcanos or by an asteroid hitting the earth. The liquid rock is flung into the air in small bits until it goes high enough the air cools them. As they fall to Earth, they form tear-shaped, glass fragments. Over millions of years, they turn to clay. The tektites he found were so small they were classified as microtektites. DePalma found millions of them. He knew the bed he was digging in was from the end of the Cretaceous Time Period. It dawned on him that the microtektites might be from the asteroid that hit the Earth then.

DePalma continued his excavation. He found an amazing number of fossils. Most of the time fossils are flat, crushed by layers and layers of rock, laid down over time. But many of these fossils were three-dimensional because they had been deposited and covered immediately, and the sediment around them acted as support.

He found new species of fish and a variety of plants, including tree trunks smeared in amber. The amber contained what appeared to be asteroid debris. He suspected that the site he was working on had been formed the very day the asteroid hit! If that was true, it was an incredible find!

Robert de Palma describing his find at NASA
NASA Goddard Photo and Video, Public domain, via Wikimedia Commons

As a child and young adult, dePalma had collected bones and fossils. He lent them to a nearby museum where he also reconstructed some dinosaur skeletons. But when the museum went bankrupt, they refused to return his collection. After that he was very careful about the fossils he excavated. In the United States, fossils belong to whoever’s property they are found on and can be sold to anyone. It is not unusual for a paleontologist or commercial fossil collector to sign a contract with a private land owner for an excavation. They usually agree to split the profit on any fossils that are found and sold. Museums and universities don’t like this arrangement because important finds can disappear into private collections.

Realizing that this site was potentially one of the most important ever found, he entered a long-term agreement with the ranch owner. The details of the agreement have been kept private.

Over the next several years, dePalma continued to excavate. He confided in only three other people what he had found, including Walter Alvarez, the man who had originally proposed the asteroid theory. DePalma did publish a paper that described a hadrosaur bone he’d found with a tyrannosaur tooth embedded in it. The bone had healed, indicating that the hadrosaur had gotten away after the attack, which dePalma said proved Tyrannosaurus hunted live prey. Scientists have long debated whether Tyrannosaurus was just a scavenger who lived by finding meals that were already dead or if it hunted live prey. DePalma’s evidence was not taken very seriously because he was just a student and a commercial fossil collector.

Continued excavation at the site revealed a paddlefish, but underneath it was a mosasaur tooth. A paddlefish is a freshwater fish, but a mosasaur is a giant, saltwater reptile. How could fossils of both be in the same site? DePalma and the others tried to come up with a theory to explain this, but they couldn’t.

Paddlefish
Raver Duane, U.S. Fish and Wildlife Service, Public domain, via Wikimedia Commons

Mosasaur
Nobu Tamura email:nobu.tamura@yahoo.com http://spinops.blogspot.com/, CC BY-SA 4.0, via Wikimedia Commons

Then he found small impact craters, about three inches across. At the bottom of each crater was a normal-sized tektite. DePalma was sure they had to be from the asteroid that ended the Cretaceous Period, even though the impact site was about 2000 miles away. He arranged to have a laboratory compare the tektites to material from the Chicxulub (CHICKS-ih-lube) Crater. They matched! The asteroid impact was so explosive that debris was thrown 2000 miles away!

For years dePalma had worked on the site in secret, sharing it with just a few others. But in 2019, he invited a reporter from New Yorker magazine to see the site and tell the world its story. When the story was published, the scientific community was skeptical. The normal procedure for announcing a significant discovery would be to submit a paper to a peer-reviewed journal where experts would evaluate the evidence before it was published, not submit it to a literary magazine. Many scientists disparaged his theories because dePalma was just a student only working on a PhD, a nobody who dug up fossils to sell rather than to study. But they sold dePalma short, as evidence he was right continued to pour in. (And he did eventually publish papers in peer-reviewed journals.)

Depiction of a Cretaceous forest of what is today the Tanis site, in North Dakota, hours after the K-Pg impact. Notice a burnt carcass of a Thescelosaurus, an impaled turtle, a small mammal and a small ornithuran avialan.
YellowPanda2001, CC0, via Wikimedia Commons

DePalma has named the site Tanis, after an ancient Egyptian city. In the late Cretaceous, a large inland sea stretched from the Gulf of Mexico to what is now the U.S./Canadian border. What is now North Dakota was subtropical. DePalma and the people he has now working with him on the site have determined that Tanis was a sandbar located between a river and a forest. They think that when the asteroid hit in the Gulf of Mexico, it created a gigantic earthquake. It took maybe ten minutes for the shock waves to reach Tanis. The disturbance caused giant waves to form on the inland sea shown in the map above. They flung sea creatures, such as the mosasaur, at Tanis, many miles away. In addition, waves were formed in the nearby river, flinging freshwater creatures onto the site. DePalma found a turtle that was flung so hard that a tree branch went right through its body.

Continued excavation has also revealed

Fish with asteroid debris clogging their gills,
Ant nests with the ants still in them and asteroid debris in their tunnels,
Large feathers that likely came from a large dinosaur,
Broken bits from almost all the dinosaurs known to have lived in that area during the late Cretaceous,
A small burrow inhabited by a small mammal,
Dinosaur eggs and hatchlings,
Pterosaur bones,
A partial mummified Thescelosaurus with its skin still intact,
And pieces of the actual asteroid preserved in amber.

*Thescelosaurus*
Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons

DePalma and his crew continue to work on the site. It will take years to explore it thoroughly. Right now, though, it’s an amazing picture of what happened the day the dinosaurs died.

Death of the Dinosaurs: Part 2

Death of the Dinosaurs: Part 1

Sources (Click Me!)

Barras, Colin. “Astonishment, Skepticism Greet Fossils Claimed to Record Dinosaur-Killing Asteroid Impact.” Science. 1 April 2019. https://www.science.org/content/article/astonishment-skepticism-greet-fossils-claimed-record-dinosaur-killing-asteroid-impact

Black, Riley. “Fossil Site May Capture the Dinosaur-Killing Impact, but It’s Only the Beginning of the Story.” Smithsonian Magazine. 3 April 2019. https://www.smithsonianmag.com/science-nature/fossil-site-captures-dinosaur-killing-impact-its-only-beginning-story-180971868/

Hunt, Katie. “Fragment of the Asteroid That Killed Off the Dinosaurs May Have Been Found.” CNN. 11 May 2022. https://www.cnn.com/2022/05/11/world/dinosaur-apocalypse-tanis-fossil-site-scn/index.html

Preston, Douglas. “The Day the Dinosaurs Died.” New Yorker. 29 March 2019. https://www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died

The Day the Dinosaurs Died, Part 1

Everyone knows an asteroid killed the dinosaurs. But is that all we know? Join me as we go down the rabbit hole of how the dinosaurs went extinct…

Sixty-six million years ago, life on Earth was very different from today. Trees, ferns, and flowering plants covered the land. There wasn’t any grass (despite what the picture below shows. I couldn’t find a free Cretaceous scene anywhere without green ground). Grass hadn’t evolved yet.

User:Debivort, CC BY-SA 3.0, via Wikimedia Commons

The only mammals were small creatures, no bigger than about three feet long. Dinosaurs dominated the planet. There were small dinosaurs, medium-sized dinosaurs and BIG dinosaurs. They lived in every part of the world. They lived in valleys and on mountains. They lived in dry places and wet places. They lived in forests and on open plains. They had ruled the Earth for 180 million years, and it seemed they would continue to do so indefinitely.

But out in space an asteroid was plunging toward Earth. It was about six miles wide and the height of Mt. Everest. When it reached the Earth’s atmosphere, it would have looked like a fireball brighter than the sun. It was seen, though, for only a few seconds before it hit the Earth because it was hurtling through the air at about 45,000 mph! It hit in the Yucatan Peninsula in Mexico, forming a crater that covers a large portion of the Gulf of Mexico. The crater has been named Chicxulub (CHICKS-ih-lube) Crater.

NASA/JPL-Caltech, modified b, Public domain, via Wikimedia Commons

The asteroid hit with a force 10 billion times larger than the atomic bomb detonated on Hiroshima, blowing a hole in the ground 120 miles wide and 18 miles deep. Imagine how loud that explosion must have been! In an instant, the intense heat of the explosion vaporized the asteroid and turned thousands of cubic miles of rock into liquid and spewed it into the air, like a colossal volcano erupting. Anything within 600 miles or more would have been instantly incinerated by the fireball. A combination of soot, sulfuric gases, and extremely fine dust was flung into the atmosphere. For the next several hours, titanic winds blew this debris around the whole Earth. They ignited a world-wide firestorm that probably killed most of life on Earth. In addition, a mega-earthquake shook all of Mexico and Central America, the southern United States, and as far south as far as Argentina. The earthquake (magnitude 13 – likely the biggest earthquake the Earth has ever felt) triggered giant tsunamis and mudslides. One-thousand-foot-high waves of water hit the coast where now Texas, Alabama, Mississippi, northern Mexico, and Cuba lie. Secondary waves traveled as far as what is now North Dakota.

Continent placement at the end of the Cretaceous Era
Merikanto, CC BY-SA 4.0, via Wikimedia Commons

Life that somehow survived this, now faced another horror. Dust and soot lingered in the atmosphere blocking most of the sunlight for at least a year. Without sunlight plants couldn’t grow and thrive. Plant eaters lost their food source and died. Meat eaters lost their food source and died. In addition, the lack of sunlight lowered the temperature on Earth by about 80° Fahrenheit.

As if this weren’t bad enough, volcanos in India had been erupting at this same time, with lava flows covering 190,000 square miles of land, killing all life in that area. The eruptions also added more toxic fumes and debris to the atmosphere.

Scientists disagree about how long it took, but about 75% of all life on earth, plant and animal, died because of the asteroid hit and the volcanos, including all the dinosaurs (except birds which most scientists believe are direct descendants of dinosaurs). Some small animals survived, including the ancestors of today’s frogs, snakes, lizards, alligators, crocodiles, a variety of insects, birds, and mammals.

How do we know all this happened? I’ll explain in my next blog.

Death of the Dinosaurs: Part 2

Death of the Dinosaurs: Part 3

Sources (Click Me!)

“Asteroid as Powerful as 10 Billion WWII Atomic Bombs May Have Wiped Out the Dinosaurs.” CNN. 10 September 2019. https://wtop.com/gallery/science/asteroid-as-powerful-as-10-billion-wwii-atomic-bombs-may-have-wiped-out-the-dinosaurs/

“Asteroid Impact that Killed Dinosaurs Triggered ‘Mega-Earthquake’ that Lasted Months.” Press Release Montclair State University. 19 October 2022. https://www.montclair.edu/newscenter/2022/10/19/asteroid-impact-killed-dinosaurs-triggered-mega-earthquake-lasted-months/

Black, Riley. “What Happened in the Seconds, Hours, Weeks After the Dino-Killing Asteroid Hit Earth?” Smithsonian Magazine. 9 August 2016. https://www.smithsonianmag.com/science-nature/what-happened-seconds-hours-weeks-after-dino-killing-asteroid-hit-earth-180960032/

Cornell, Sean, et al. “The Tsunami that Killed Dinosaurs!” InTeGrate. Pennsylvania State. n.d. https://www.e-education.psu.edu/earth107/node/1623

Kaufman, Mark. “Scientists Reveal Deadly Earth just after the Dinosaur Asteroid Hit.” 4 November 2023. Mashable. https://mashable.com/article/dinosaur-extinction-asteroid-cause

Lea, Robert. An Asteroid and Volcano ‘Double Punch’ Doomed the Dinosaurs, Study Suggests. Space.com. 21 Sept. 2022. https://www.space.com/dinosaur-extinction-volcanoes-aided-asteroid-impact

Osterloff, Emily. “How an Asteroid Ended the Age of the Dinosaurs.” Natural History Museum of London. n.d. https://www.nhm.ac.uk/discover/how-an-asteroid-caused-extinction-of-dinosaurs.html

Roden, Nathan. “How Did We Find Out that an Asteroid Killed the Dinosaurs?” ScIU Indiana University Bloomington. 8 April 2023. https://blogs.iu.edu/sciu/2023/04/08/an-asteroid-killed-the-dinosaurs/

Smith, Roff. “Here’s What Happened the Day the Dinosaurs Died.” National Geographic. 111 June 2016. https://www.nationalgeographic.com/animals/article/what-happened-day-dinosaurs-died-chicxulub-drilling-asteroid-science 

Uneasy Lies the Crown, Part 2

As I wrote a few weeks ago, there are some serious contenders for Tyrannosaurus’ crown as the biggest, fiercest land carnivore of all time. Giganotosaurus and Megaraptor could certainly give Tyrannosaurus a battle, but this week’s contenders, from Africa, are even more powerful.

Carcharodontosaurus (Kar-KAR-oh-don-toe-SAWR-us) lived in Northern Africa during the late Cretaceous Period 99 to 94 million years ago. Its name means “shark-toothed lizard,” and its long jagged-edged teeth are much like those of a shark.

https://upload.wikimedia.org/wikipedia/commons/f/f5/Carcharodontosaurus_Scale.svg

Most estimates rank Carcharodontosaurus as about three or four feet longer than Tyrannosaurus. It’s hard to tell because scientists have found only some tens of bones and a number of teeth from it.

Even if Carcharodontosaurus is slightly larger, Tyrannosaurus still has a number of advantages. Smithsonian Magazine reported that Tyrannosaurus’ bite force was almost 12,800 pounds, stronger than any other animal that ever walked on land. (Megalodon, an enormous extinct shark, does have it beat at 41,000 pounds. There was also an extinct crocodile named Purussaurus which had a bite of 15,500 pounds of force.) Tyrannosaurus’ bite was stronger than the force of an average-sized African elephant dropping on you. (I don’t want to even think what that means about Megalodon’s bite.) Tyrannosaurus’ teeth are shaped like bananas. The rounded shape is very effective at breaking bones. Carcharodontosaurus’ teeth were shaped differently. They were thinner, more like the blade of a knife. They were meant for shearing meat from bones. They might have broken if Carcharodontosaurus bit directly into thick bones.

Tyrannosaurus also had an advantage in eyesight. Its eyes were more forward looking than Carcharodontosaurus’. This gave Tyrannosaurus a wider range of sight, enabling it to see more of what was in front of it. Because of the shape of Carcharodontosaurus’ skull, it would have had to drop its head toward its chest to see any distance ahead. This likely meant it hunted its prey by ambushing them, rather than chasing after them. Regardless, if the two had ever met, it would have been a titanic battle.

Franko Fonseca from Redondo Beach, USA, CC BY-SA 2.0,via Wikimedia Commons

And then there’s the biggest of the top five, Spinosaurus. It also lived during the late Cretaceous Period and was found in North Africa. This creature was about 49 feet long and weighed just over eight tons. However, its back legs were much shorter than Tyrannosaurus’, making it about 9 feet tall at the hip compared to Tyrannosaurus’ 12-15 feet in height. However, if the sail on Spinosaurus’ back is included, then it was 15-16 feet tall.

Durbed, CC BY-SA 3.0, via Wikimedia Commons

It’s difficult to compare its power to the other three because it was shaped differently and lived a different kind of life. It was a little thinner, with a large sail on its back, a paddle-shaped tail and its jaws were long and narrow like a crocodiles’. Its teeth were like overturned ice cream cones instead of curved with jagged edges. Scientists think that it hunted at least part of the time in the water and that on land it stayed near the coast and ambushed its prey, rather than running it down. Its likely that, despite its huge size, its shorter legs would have made it less agile than Tyrannosaurus. Its tail would have been a formidable weapon for knocking other dinosaurs around, but that might not be enough.

Figure 1 (left) Spinosaurus tooth – 1 Jiří X. Doležal (about me), CC BY-SA 3.0, via via Wikimedia Commons. Figure 2 (right) Tyrannosaurus tooth

Scientists don’t know which of these dinosaurs was most powerful. Even though it’s been many years since Giganotosaurus, Megaraptor, Carcharodonotosaurus, and Spinosaurus were discovered, scientists still know very little about them. It takes a long time for fossil bones to be excavated and studied. For me, however, Tyrannosaurus still holds its crown by virtue of its long teeth, large brain, and powerful bite. But never forget that there is another alternative: any day a paleontologist might dig up a new dinosaur that could take on all of them.

What do you think?

Sources (Click Me!)

Aureliano Tito, Aline M. Ghilardi, Edson Guilherme, Jonas P. Souza-Filho, Mauro Cavalcanti, and Douglas Riff . “Morphometry, Bite-Force, and Paleobiology of the Late Miocene Caiman Purussaurus brasiliensis.” PLOS ONE. 17 Feb. 2015. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117944.

Black, Riley. “The Tyrannosaurus Rex’s Dangerous and Deadly Bite.” Smithsonian Magazine. Oct., 2012. https://www.smithsonianmag.com/science-nature/the-tyrannosaurus-rexs-dangerous-and-deadly-bite-37252918/

Currie, Philip J and Colleayn O. Mastin. The Newest and Coolest Dinosaurs. Grasshopper Books Publishing, 1998.

Gasparini, Zulma, Leonardo Salgado, and Rodolfo A. Coria (eds.). Patagonian Mesozoic Reptiles. Indianapolis: Indiana University Press, 2007.

Hecht, Jeff. “Contenders for the crown.” Earth 7.1 (Feb. 1998): 16. _Academic Search Premier_. EBSCO. Judson University Library, Elgin, IL.15 July 2009 <http://www.judsonu.edu:2048/login?url=htto://<http://www.judsonu.edu:2048/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=89601&site=ehost-live>.

Horner, John R. and Don Lessem. The Complete T-rex. New York: Simon and Schuster, 1993.

Larson, Peter and Kenneth Carpenter. Tyrannosaurus Rex: The Tyrant King. Indianapolis: Indiana University Press, 2008.

Monastersky, R. “New beast usurps T. rex as king carnivore.” Science News 148.13 (23 Sep. 1995): 199. Academic Search Premier. EBSCO. Judson University Library, Elgin, IL. 15 July 2009 <http://www.judsonu.edu:2048/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=9510094855&site=ehost-live>.

Novas, Fernando, E., Diego Pol Juan I. Canale; Juan D. Porfiri; Jorge O. Calvo. “A bizarre Cretaceous theropod dinosaur from patagonia and theevolution of Gondwanan deomaeosaurids. Proceedings: Biological Sciences, Mar2009, Vol. 276 Issue 1659, p1101-1107, 7p.

Rafferty, John P. “Megalodon.” Britannica. <https://www.britannica.com/animal/megalodon>.

Richardson, Hazel. Smithsonian Handbooks: Dinosaurs and Prehistoric Life. New York: Dorling Kindersley, 2003.

Sereno PC, Myhrvold N, Henderson DM, Fish FE, Vidal D, Baumgart SL, Keillor TM, Formoso KK, Conroy LL. “Spinosaurus is Not an Aquatic Dinosaur.” Elife. 2022 Nov 30;11:e80092. doi: 10.7554/eLife.80092. PMID: 36448670; PMCID: PMC9711522.

Smith, Nathan D., Peter J. Makovicky1, Federico L. Agnolin, Martin D. Ezcurra, Diego F. Pais3 and Steven W. Salisbury. “A Megaraptor -like theropod (Dinosauria: Tetanurae) in Australia: support for faunal exchange across eastern and western Gondwana in the Mid-Cretaceous.” Proceedings of the Royal Society. 20 May 2008.

“Spinosaurus.” Natural History Museum of London. nd. https://www.nhm.ac.uk/discover/dino-directory/spinosaurus.html

“Spinosaurus aegyptiacus.” The Sauropodomorph’s Lair. 23 Aug. 2020. <https://thesauropodomorphlair.wordpress.com/skeletal-reconstructions/dinosaurs/theropoda/spinosaurus-aegyptiacus/>

Spotts, Peter N. “Giant dinosaur fossil forces scientists to question theories.” Christian Science Monitor 03 Dec. 1997: 3. Academic Search Premier. EBSCO. Judson University Library, Elgin, IL. 15 July 2009. <http://www.judsonu.edu:2048/login? url=http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=9712050418&site=ehost-live>.

Stevens, Kent A. “Binocular vision in theropod dinosaurs.” Journal of Vertebrate Paleontology. 12 June 2006. 26 (2): 321–330. doi:10.1671/0272-4634. https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282006%2926%5B321%3ABVITD%5D2.0.CO%3B2.

Straight, Will. “Carcharodontosaurus vs. Tyrannosaurus.” 2015. https://www.dinosaurhome.com/carcharodontosaurus-vs-tyrannosaurus-685.html

“Sue at the Field Museum.” The Field Museum, Chicago, IL. 2007. 15 July 2009.

University of Queensland. “Australian Dinosaur Found To Have South American Heritage.” ScienceDaily 15 June 2008. 10 September 2009 <http://www.sciencedaily.com /releases/2008/06/080613111410.htm>.

How the Brontosaurus Lost its Name

Ever wonder how the Brontosaurus lost its name? Commonly known as the icon of Sinclair Oil, this sauropod’s history is complex and newsworthy.

The Brontosaurus is one of the most famous dinosaurs in the world. Millions of people know its name. Most can recognize its huge shape. It’s been on lunch boxes, made into countless toys, and was featured on a U.S. postage stamp. It even served as the official icon of Sinclair Oil company. However, there is one problem: there is no dinosaur named Brontosaurus.

How did this happen? When dinosaurs were first discovered in the 1820s, the idea of those huge reptiles stalking the earth caught people’s imagination. Every museum in the world wanted to display a huge skeleton of a dinosaur. But it takes many years to find dinosaur bones, dig them up and put together a dinosaur skeleton. Over the next sixty years the competition to discover dinosaur bones grew, and then it became especially fierce during the 1880s. In fact, that time is now known as the “Bone War.”

From 1877 to 1892, two paleontologists in particular, Edward Cope of the Academy of Natural Sciences in Philadelphia and Othniel C. Marsh of the Peabody Museum in Connecticut, were the fiercest competitors. They used their own money to finance expeditions and to buy dinosaur bones from other fossil hunters.

In the beginning Cope and Marsh just paid collectors to send them fossils. But this was only the start. As the rivalry intensified, each side spied on the other, stole bones when they could, bribed workers, and even blew up fossils with dynamite so that the other side couldn’t get them. As soon as either dinosaur hunter got new bones, he rushed to get a description into print. Whoever publishes a description of a new dinosaur first gets to name it, and each man wanted to be the one to name the most. In the end Cope lost. He named 56 new dinosaur species, while Marsh named 80. And by the end of the Bone Wars in 1892, both men had gone nearly bankrupt trying to be the best (or most famous) paleontologist. And the hurry of both men led to mistakes.

Tadek Kurpaski from London, Poland, CC BY 2.0, via Wikimedia Commons

In 1877 Marsh published a papernaming a new dinosaur, Apatosaurus ajax. Its name means “deceptive lizard,” which turned out to be the truth. The description was based on only a few bones. Two years later Marsh published another article describing what he thought was a different dinosaur, Brontosaurus excelsius. This description was based on one of the most complete skeletons of a long-necked dinosaur ever found. Brontosaurus means “thunder lizard,” and the catchy name became popular. The mount of that Brontosaurus skeleton in the Yale Peabody Museum of Natural History increased its popularity. Unfortunately, one of the missing pieces of the skeleton was its skull. Not to worry. Marsh just put a Camarasaurus skull on it.

But, in 1903, Chicago paleontologist Elmer Riggs took a look at both dinosaurs. He determined that the two dinosaurs were actually the same dinosaur. It was given the name Apatosaurus first, and the International Code of Zoological Nomenclature states that the oldest name has priority, so that is the name used by scientists. Brontosaurus became Apatosaurus. And in 1979 scientists finally put the right skull on the skeleton. Still, the general public didn’t let go of the name Brontosaurus until about the 1990s. It was just too cool a name to let go.

However, all is not lost. There is a movement to resurrect the name Brontosaurus. In 2015 paleontologists studied hundreds of bones from Apatosaurus and the dinosaur called Brontosaurus and found differences in the neck, back, and shoulder bones. Originally scientists thought those difference were because one of the dinosaurs was a juvenile. Now some feel these differences are enough to say Brontosaurus and Apatosaurus are different dinosaurs. But this has not gained wide acceptance. More research may resolve the problem. But a lot of people who are just dinosaur lovers would welcome the return of the “thunder lizard.”

Cover Image Source: An Errant Knight, CC BY-SA 4.0, via Wikimedia Commons