We’ve reached a milestone: episode 100! Thank you so much to all our patrons on Patreon! We hope you enjoy this very special episode and please keep a lookout for the extra special rewards we promised. We are so lucky to have this podcast and meet such wonderful dinosaur enthusiasts, and we owe it all to our listeners.
On that note, in our 100th episode, we had the pleasure of speaking with Dr. Emanuel Tschopp, a postdoctoral fellow at the University of Turin in Torino, Italy, as well as the author of numerous papers, one of the most well known being A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda), a study published in 2015 about 81 sauropod specimens, which found Brontosaurus to be a valid genus again. You can find more of Dr. Tschopp’s work at https://www.researchgate.net/profile/Emanuel_Tschopp.
Episode 100 is all about Brontosaurus, a sauropod whose name means “thunder lizard” and one of the earliest named dinosaurs that wasn’t considered to be a valid genus for about 100 years.
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In this episode, we discuss:
- The dinosaur of the day: Brontosaurus
- Name means “thunder lizard”
- Type species is Brontosaurus excelsus, which Marsh named in 1879
- The species name excelsus means “noble” or “high”
- Brontosaurus lived about 155 to 152 million years ago, and fossils have been found in Wyoming and Utah
- For a long time was considered a junior synonym of Apatosaurus, and the original species Brontosaurus excelsus was reclassified as Apatosaurus excelsus in 1903
- The Morrison Formation was the center of the Bone Wars, and at the time lots of dinosaur descriptions were rushed
- Marsh named Apatosaurus in a two-paragraph article for the American Journal of Science in 1877, and then wrote a more detailed article in 1879 with a sketch of Apatosaurus‘ pelvis, shoulder blade, and vertebrae
- In 1903, Elmer Riggs said Brontosaurus was too similar to Apatosaurus, and he called Brontosaurus excelsus, Apatosaurus excelsus. Apatosaurus was named first, so Brontosaurus became a synonym. However, Henry Fairfield Osborn decided to label the skeleton in the American Museum of Natural History Brontosaurus, even though he opposed Marsh and Marsh’s taxa
- The AMHN Brontosaurus skeleton is the reason for so much controversy the last 100 years or so (scientists thought it should be Apatosaurus, but the public knew about Brontosaurus)
- The skeleton was unveiled in 1905 at the AMNH and was the first mounted sauropod. It was a mostly complete specimen, but it was missing feet, lower leg, shoulder bones, and tail bones (the tail was mounted with too few vertebra, but according to what Marsh thought it should be). The skull was also based on “”the biggest, thickest, strongest skull bones, lower jaws and tooth crowns from three different quarries”, which most likely came from a Camarasaurus (only other sauropod at the time with known skull material). Adam Hermann couldn’t find any Brontosaurus skulls so he had to hand sculpt a skull to stand in. Osborn made a note in a publication that Hermann’s skull was “largely conjectural and based on that of Morosaurus” (now Camarasaurus)
- An Apatosaurus skull was found in 1909 near a skeleton that was found to be an Apatosaurus specimen. The skull was similar to Diplodocus‘ skull, and so many believed it was an Apatosaurus skull (though Osborn and others rejected this). William H. Holland, the Douglass and Carnegie museum director, believed it was an Apatosaurus skull, but he didn’t put a head on the mount at his museum, possibly because he was waiting for someone to find an articulated skull and neck. After he died in 1934, museum staff put a Camarasaurus skull on their mount
- The first Apatosaurus with an articulated skull was found in 2011
- In 1931, the Yale Peabody Museum created a unique skull, where they based the lower jaw on a Camarasaurus, and gave it forward-pointing nasals, instead of basing it solely on Camarasaurus
- In the 1970s, John Stanton McIntosh and David Berman redescribed Diplodocus and Apatosaurus skulls, and found that Holland was right, and that Apatosaurus, and Brontosaurus, had a skull similar to Diplodocus. They also reassigned many Diplodocus skulls as Apatosaurus.
- In 1979, Carnegie mounted the first Apatosaurus skull on a skeleton, then AMNH did the same in 1995 (also relabeled their skeleton Apatosaurus excelsus and corrected the tail
- British-Portuguese research team did a joint study in 2015 that found Brontosaurus was a valid genus, separate from Apatosaurus (though not all paleontologists agree)
- “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)” by Emanuel Tschopp, Octavio Mateus, and Roger B.J. Benson, published in April 2015
- The 2015 study also found that two species that used to be considered Apatosaurus and Eobrontosaurus were now Brontosaurus: Brontosaurus parvus and Brontosaurus yahnahpin
- Brontosaurus parvus was first described as Elosaurus in 1902, by Gilmore and Peterson. Then it was assigned to Apatosaurus in 1994, and then to Brontosaurus in 2015. Includes a partial juvenile skeleton, a nearly complete skeleton that’s mounted at Brigham Youn University, and another partial skeleton
- The oldest species is Brontosaurus yahnahpin, found in Wyoming in the Morrison Formation (lived about 155 million years ago). It was 69 ft (21 m) long, and described in 1994 by James Filla and Patrick Redman (who named it a species of Apatosaurus). The species name means “breast necklace” because it has pairs of sternal ribs that look like hair pipes worn by the Lakota tribe
- Bob Bakker said in 1998 that it was more primitive than originally thought, and named it Eobrontosaurus (Greek word “eos” means dawn), which again is now back to Brontosaurus, according to the 2015 study
- The original intent of the 2015 study was to revise the family tree of diplodocids
- Most diplodocid species were described in the late 1800s and early 1900s
- Many holotype specimens were incomplete and fragmentary
- The study included “81 operational taxonomic units, 49 of which belong to Diplodocidae”
- The 2015 study is almost 300 pages long, and it analyzed 477 different physical features of 81 sauropod specimens, and took 5 years to do (and visits to 20 museums in Europe and the U.S.)
- In the 2015 study, they used algorithms to compare traits, and if more than 20% of the traits were different, they classified the bones as their own genus
- Tschopp said, “The border between different species and different individuals within a species were progressively much lower,”
Tschopp said, “We were very surprised when we got these results that Brontosaurus was valid again.” And they had Roger Benson, from Oxford University, verify their results - Roger Benson said, “The differences we found between Brontosaurus and Apatosaurus were at least as numerous as the ones between other closely related genera, and much more than what you normally find between species,”
- Brontosaurus coming back has been often compared to Pluto, with many people hoping Pluto will be classified as a planet again
- “It’s a nice example of how science works. A new finding can overturn more than 100 years of beliefs,” said Emanuel Tschopp
- “We knew it would be a major finding because Brontosaurus is such a popular name,” Tschopp said. “I’m pretty sure there will be a scientific discussion around this. I hope there will be. That’s how science works.”
- Tschopp said this study could not have been done 15 years ago, but so many dinosaurs similar to Apatosaurus and Brontosaurus have been found recently, which makes it easier to reexamine
- Three valid species of Brontosaurus (according to the 2015 study): Brontosaurus excelsus, Brontosaurus parvus, Brontosaurus yahnahpin
- 2015 found that Elosaurus and Eobrontosaurus are synonymous with Brontosaurus
- 2015 study said Brontosaurus amplus was an invalid proposed species (and would become Brontosaurus excelsus)
- Marsh named Brontosaurus amplus in 1881, but it’s now considered to be a synonym of Apatosaurus excelsus (Gilmore said it in 1936, McIntosh said it in 1990 and 1995, Upchurch, Tomida & Barrett said it in 2004, though most studies also said there needed to be a more detailed assessment)
- 2015 study said that Brontosaurus had “1) a longer than wide base of posterior dorsal neural spines (279-0, unique among Apatosaurinae), (2) the area on the scapula posterior to the acromial ridge and the distal blade is excavated (365-0, unique among Apatosaurinae), (3) the acromial edge of the scapular blade bears a rounded expansion at its distal end (367-1, unique among Apatosaurinae), (4) the ratio of the proximodistal length/transverse breadth of the astragalus is 0.55 or greater (451-1, unique among Apatosaurinae).”
- 2015 study said “Brontosaurus excelsus can be diagnosed by the following autapomorphies: (1) absence of a median tubercle in posterior cervical and anterior dorsal, bifid neural spines (210-0*, unique among Diplodocidae), (2) orientation of the tuberculum of mid-dorsal ribs follows the straight direction of the rib shaft (285-1*, unique among Apatosaurinae), (3) the posterior end of mid- and posterior caudal neural spine summits lies more or less straight above the postzygapophyses (343-1*, unique among Apatosaurinae), (4) the ratio of iliac blade height above the pubic peduncle to its anteroposterior length is 0.40 or greater (405-1*, unique among Apatosaurinae), (5) the highest point on dorsal margin of the ilium lies anterior to the base of the pubic process (410-1*, unique among Apatosaurinae), (6) presence of a large nutrient foramen opening on midshaft anteriorly on the femur (434-1*, unique among Apatosaurinae), (7) absence of a laterally directed ventral shelf on the astragalus, which underlies the distal end of the fibula (455-1*, unique among Apatosaurinae).”
- According to Emanuel Tschopp, Brontosaurus has a higher, less wide neck than Apatosaurus. “So although both are very massive and robust animals, Apatosaurus is even more extreme than Brontosaurus.”
- Interesting because Brontosaurus means thunder lizard, and Apatosaurus means deceptive lizard
- Paul Barrett, from the Natural History Museum in London, said ““It’s the biggest study on this family, they marshal a lot of evidence and make a very good case” and “It’s taken us a long time to convince people that we shouldn’t be using the name ‘Brontosaurus’, Just as we’ve got to that point, it looks like we’re going to have to turn around and say ‘Actually, it’s alright again’.”
- Not everyone is fully convinced yet though. Brian Switek said the problem is there is no standard for choosing which traits are significant, so there’s still some subjectivity when classifying genera. This may not be settled until a Brontosaurus skull is found
- Kenneth Carpenter, from Utah State University’s Eastern’s Prehistoric Museum, said the fossil that Apatosaurus is based on hasn’t been described in detail, and should have been in order to be compared to Brontosaurus. He said, “So is Brontosaurus valid after all? Maybe. But I think the verdict is still out.”
Paleontologist Donald Prothero who said, “Until someone has convincingly addressed the issue, I’m going to put “Brontosaurus” in quotes and not follow the latest media fad, nor will I overrule Riggs (1903) and put the name in my books as a valid genus. - Brontosaurus was quadrupedal, with a long neck, a long, whip-like tail, and forelimbs that were a little shorter than its hindlimbs
- Originally, Brontosaurus (and other sauropods) were thought to be too heavy to walk on land, so it was thought they lived partly in water (this is not true)
- If Brontosaurus were completely submerged in water, it would not have been able to breathe, because the water pressure on its lungs would be too much
Most sauropod fossils are found in dry, inland areas - Like other sauropods, Brontosaurus had neck vertebrae that was bifurcated (had paired spines, which meant it had a wide, deep neck)
- Its neck had air sacs, to help make it lighter
- Brontosaurus also had tall spines on its vertebrae, like Apatosaurus
- Had long ribs compared to other diplodocids, so they had very deep chests
- Had stout arm bones, and a large claw on its forelimb, and three toes on each foot (each toe had a claw as well)
- Why there’s a claw on the forelimb is unclear. It may have been for defense, though it’s not the best size or shape for that. It may have been used for feeding, or used to grasp things like tree trunks when rearing
- Brontosaurus was originally thought to have a short tail
- It could crack its tail, to signal to others, show dominance, or warn predators such as Allosaurus, Torvosaurus, or Ceratosaurus
- Brontosaurus excelsus is the largest species and weighed 15 tons, and was 72 ft (22 m) long
- Adult Brontosaurus parvus is estimated to weigh 14 tons
- Sauropod trackways show that they moved as fast as 12-19 mph (20-30 kph), and moved on average 12-25 miles (20-40 km) per day
- Had a small head
- Swallowed stones to help digest
- May have reared up to reach high plants or fight for mates
- Brontosaurus may have been solitary
- Brontosaurus has been featured in film, ads, stamps, and lots of other media
- Gertie the Dinosaur, Winsor McCay’s animated film (one of the first) is a Brontosaurus
- Brontosaurus and Allosaurus battled in the 1925 silent film The Lost World
- Brontosaurus is also in the 1985 movie Baby: Secret of the Lost Legend
- Brontosaurus is also the logo of the Sinclair Oil Corporation (it’s green)
- A full sized Brontosaurus model of Sinclair’s Brontosaurus was at the 1964-65 New York World’s Fair
- In 1989 the U.S. Postal Service made four dinosaurs stamps, and one was Brontosaurus (which people complained as “fostering scientific illiteracy”). The Postal Service said in Postal Bulletin 21744, “Although now recognized by the scientific community as Apatosaurus, the name ‘Brontosaurus‘ was used for the stamp because it is more familiar to the general population.” They also said “”[s]imilarly, the term ‘dinosaur’ has been used generically to describe all the animals [i.e., all four of the animals represented in the given stamp set], even though the Pteranodon was a flying reptile [rather than a true ‘dinosaur’],” which people did not complain about. Stephen Jay Gould, a paleontologist, wrote an essary and book partly based on this (the part “Bully for Brontosaurus” says, “Touché and right on; no one bitched about Pteranodon, and that’s a real error.” (Though Gould did agree that Brontosaurus be a synonym for Apatosaurus
- Part of the family Diplodocidae (which includes Diplodocus, Supersaurus, Barosaurus)
- Also part of the subfamily Apatosaurinae (includes Apatosaurus)
- The family Diplodocidae means “double beams”
- The Diplodocidae clade has 12-15 species that lived in the Late Jurassic and Early Cretaceous
- Compared to titanosaurs and brachiosaurs, dipodocids were slender and long, with short legs, and their back legs were longer than their front legs
- Many may have had spines on its back
- Very long necks, may not have been able to lift heads as high up as other sauropods
- Had small heads and peg-like teeth
- Probably didn’t chew, but swallowed gastroliths to digest their food
- Had long, whip-like tails that they could snap
- Diplodocidae was originally known as Amphicoelidae (named by Edward Cope in 1878), but became a forgotten name; Charles Marsh also named the family Atlantosauridae back in 1877, but that also became a forgotten name (nomen oblitum)
- Fun fact: Back in January we mentioned that the “Dinosaur Genera List” listed 1007 dinosaur genera (which is at the higher end of valid genera counts) The list was just updated and now includes another 20 genera, bringing the total to 1027 (Both numbers include Brontosaurus)
This episode was brought to you by:
The Royal Tyrrell Museum. The Royal Tyrrell Museum is located in southern Alberta, Canada. One of the top paleontological research institutes in the world, the entire museum is dedicated to the science of paleontology. It’s definitely a must see for every dinosaur enthusiast. More information can be found at tyrrellmuseum.com.
For those who may prefer reading, see below for the full transcript of our interview with Dr. Emanuel Tschopp:
