Episode 30 is all about Triceratops, a ceratopsian with three horns on its face.

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In this episode, we discuss:

• The dinosaur of the day: Triceratops, a dinosaur that appeared in Jurassic World, whose name means “Three-Horn Face”
• Have mentioned Triceratops before, about  Triceratops v Torosaurus (Episode 21, with paleo-artist Josh Cotton)
• Two species types: Triceratops horridus and Triceratops prorsus
• Charles Marsh named Triceratops in 1889
• Quadrupedal (walked on four legs), herbivore, large skull (about a third of the length of its body)
• Grouped as a chasmosaurine because of the brow horns (a subfamily of ceratopsid)
• Lived in Cretaceous; one of the last dinosaurs to go extinct
• Found in USA,‭ ‬Colorado,‭ ‬Montana,‭ ‬South Dakota,‭ ‬Wyoming.‭ ‬Canada,‭ ‬Alberta,‭ ‬Saskatchewan
• About 30 feet (9 m) and weighed over 11,000 pounds (5,000 kg), though some weighed 15,750 pounds
• Skull had a short neck frill, and three horns
• Two biggest horns above the eyes, up to 1 m long, and a smaller nose horn on the snout
• Dominant herbivore in North America in late Cretaceous (lots of Triceratops remains)
• Triceratops is one of the most popular dinosaurs (but lots of misconceptions and controversy)
• In the 1900s a lot of Triceratops fossils were found, though the skulls varied a lot. As a result, a lot of Triceratops species were named. But in 1986 paleontologists Ostrom and Wellnhofer wrote that only the type species, Triceratops horridus, was real (variation in skulls were a mix of individual variation and fossils being distorted over time)
• Triceratops horridus means “rough”, for the rough texture of bones
• 16 Triceratops species proposed since Triceratops was discovered, but only 2 are widely considered valid. Triceratops horridus probably evolved into Triceratops prorsus over 1-2 million years, according to a 2014 study in the Proceedings of the National Academy of Sciences journal (study examined fossils from the Hell Creek Formation, with lower, middle and upper geological subdivisions (middle subdivision fossils had a combo of features found in the lower and upper subdivisions)
• Catherine Forster wrote in a later study about a difference between Triceratops horridus, Triceratops prorsus, and Triceratops hatcheri (named as a new genus, Nedoceratops hatcheri); they were found in different levels of strata, which means they were active at different times
• Dubious species: T.‭ ‬albertensis,‭ ‬T.‭ ‬alticornis,‭ ‬T.‭ ‬eurycephalus,‭ ‬T.‭ ‬galeus,‭ ‬T.‭ ‬hatcheri,‭ ‬T.‭ ‬ingens,‭ ‬T.‭ ‬maximus,‭ ‬T.‭ ‬sulcatus.
• Debate over Triceratops v. Torosaurus
• John Scanella theorized in 2009 that Triceratops was the same as Torosaurus (co-authored by Jack Horner). They said they lived at the same time, and fossils were found in the same places, and that Triceratops was a juvenile version of Torosaurus. They said that Triceratops had a short frill, and Torosaurus had a longer frill with holes to reduce the weight. Also said that Nedoceratops was a growth stage in between Triceratops and Torosaurus. Evidence to support the theory is that some ceratopsians juvenile and adult specimens have juveniles with short frills and adults with longer frills.
• Theory was very controversial
• In 2011 Andrew Farke said Nedoceratops was in its own genus, and there was too much change required for a Triceratops skull to change to a Torosaurus skull
• In 2012 Daniel Field and Nicholas Longrich, from Yale University studied 35 specimens and said there were skulls of juvenile Torosaurus and adult Triceratops. Also in some locations only Triceratops or only Torosaurus was found.
• Scanella responded that some of the fossils Field and Longrich studied could be transitional
• Either way, Torosaurus was named in 1891, and Triceratops in 1889, which means Triceratops will keep its name, no matter what
• Triceratops fossil was found in Wyoming in the 1880s and shipped to the Smithsonian museum in D.C. (on display since 1905; first mounted Triceratops in the world. Original display had “skeletal elements from over a dozen different individual Triceratops, some of which weren’t the same size and gave us bones that were too small for the skeleton” according to the website, and had “several sculpted elements that technicians made by hand, and the foot bones of a different dinosaur, a duckbill dinosaur, to replace missing Triceratops bones.” Unveiled a new mount in 2001 that was more accurate (nicknamed “Hatcher”)
• Scientists used to think Triceratops walked with its two front legs sprawled out, to support its weight. But nowadays scientists think that Triceratops walked upright, with elbows bowed out to the sides (like a rhino)
• Had hoof-like claws; thick, bumpy hide; large brows
• 2006 study in journal Proceedings of the Roayl Society found that Triceratops brow horns twisted and lengthened with age (started off stubby, then curved backward, then pointed in the opposite direction)
• Scientists have discovered a Triceratops skin impression, which has bristle-like fibers (around the tail)
• Triceratops toes on the front two feet pointed to the sides, and not forwards (like stegosaurs, ankylosaurs and sauropods). This is considered to be a primitive trait, and it shows that ceratopsian’s direct ancestors were bipedal (used hands for grasping and support, instead of supporting weight)
• May have charged at predators, like a rhino
• Large enough that only large predators could attack (Tyrannosaurus and Albertosaurus)
• Many Triceratops bones were damaged by fighting with predators
• Evidence that Triceratops and T-rex fought. One Triceratops had healed T-rex tooth marks on brow horn, bitten horn was broken and had new bone growth after the break (Triceratops may have had the advantage in the fight because of sharp horns)
• The frill protected its neck from T-rex and other predators
• Horns and frill may have been defensive weapons, though not all scientists agree that this was the sole or main reason for them (ceratopsians as a group have very different looking frills and horns, and the argument is they would have evolved to become the same, and be most effective)
• Horns and frill may have been used for display (identify its own species); frills also have been found with blood vessel impressions to “produce vivid color displays”
• Large frill may have regulated body temperature (possibly)
• Some Triceratops have been found with holes in the frills, possibly caused by combat among Triceratops
• A new chasmosaurine called Regaliceratops peterhewsi was discovered and published about in Current Biology on June 15. New dinosaur had a crown of plates around its head and have features it independently evolved (convergent evolution), which may show similar behaviors in other chasmosaurines, like fighting styles (modern mammals with similar shaped horns act similarly with horn locking or head butting)
• Often thought of as a herding animal, but no definitive evidence for this. Many Triceratops fossils found as individuals
• Other horned dinosaurs known to live in herds (found bonebeds with 2 to hundreds or thousands of individuals)
• Triceratops needed a lot of food to survive, which would be hard to consume as a large herd
• However, Triceratops may have lived in small groups (one male and multiple females); males may have fought each other for dominance (idea based on modern animals)
• Three juvenile Triceratops found in southeastern Montana; in 2012 another group of 3 Triceratops found (small juvenile and adult) in Wyoming–may have been a family, also signs of a T-rex scavenging, puncture wounds from teeth in the largest Triceratops‘ front limbs
• Unclear how Triceratops raised its young
• Ate low growing vegetation, but may have taken down larger plants to get to food it could not reach with just its teeth
• Had a parrot-like beak, and battery of teeth (many molars and pre-molars stacked tightly together and used for grinding leaves) at back of the mouth (continually replaced teeth)
• A new study in the journal Science Advances found that Triceratops had teeth that could slice through dense material (more varied diet than modern reptiles). Professor Erickson and colleagues studied Triceratops teeth from museums around North America. They found Triceratops teeth had five layers of tissue (compared to horse and bison, which have 4 layers, and crocodiles that have 2)
• Probably couldn’t move too fast, and spent lots of time grazing (like a rhino)
• Easy to find Triceratops fossils (47 skulls found in Hell Creek between 2000-2010)
• In 1889, a rancher in Wyoming found a strange skull on his property and tried to lasso its horns to haul it off (the horn snapped off)
• Triceratops fossils are in high demand. In 1997, an average skull cost $2500. In 2008 someone purchased a Triceratops for $1 million and donated it to the Boston Museum of Science
• Triceratops is the offical state fossil of South Dakota and is also Wyoming’s state dinosaur
• Ancestors may have been Zuniceratops (earliest known ceratopsian with brow horns) and Yinlong, first known ceratopsian from Jurassic era
• Pentaceratops aquilonius may also be an ancestor (from episode 15)
• Ceratopsians were ornithiscians
• Lived in North America and Asia
• They had beaks and cheek teeth to eat fiberous vegetation
• Also had a frill (used for defense, regulating body temperature, attracting mates, or signaling danger)
• Probably traveled in herds and could then stampede if threatened
• Chasmosaurinae is a subfamily of ceratopsid
• Chasmosaurinae had large brow horns and long frills (compared to centrosaurines, another subfamily of ceratopsid, which had short brow horns and shorter frills with long spines coming out of the frills)
• Chasmosaurine fossils have been found in western Canada, the western United States, and northern Mexico.
• Fun Fact: Dinosaurs had two ovaries (laid 2 eggs), but birds evolved to have only one ovary, to help with flight.