Meet Horridus, the world's best-preserved and most complete Triceratops
T-rex is hacky. Velociraptors are just exaggerated movie monsters. And Brachiosaurus is pretty much just “kind of a big cow.” No, the most discerning of dinosaur-obsessed kids always knew that Triceratops was the coolest. And now, the coolest specimen of this coolest dinosaur has just gone on public display for the first time.
Meet Horridus. Named for its species epithet, Triceratops horridus, this huge skeleton stands about 2 m (6.6 ft) tall, 6 to 7 m (19.7 to 23 ft) long and weighs over a ton. And it’s the centerpiece of the new exhibition, Triceratops: Fate of the Dinosaurs, at Melbourne Museum in Australia.
Triceratops are among the most commonly found dinosaur fossils, thanks to their large bones – particularly that uniquely recognizable skull – that lend themselves well to fossilization. But even among all that competition, Horridus stands out as a specimen of international significance – with 266 bones comprising 85 percent of the total skeleton, it’s the most complete and best-preserved example of its species ever found.
New details from old bones
It’s impossible not to be awestruck by the sight of it. Triceratops is inarguably one of the most iconic dinosaurs, and to see it step out of the movies and childhood picture books and stand beside it, as a real-world animal that actually existed, is exhilarating.
Even for the scientists who study these creatures, that awe never fades – it just hits differently. The unprecedented completeness of Horridus reveals new details about one of the most well-known, well-studied dinosaurs.
“This skeleton uniquely preserves parts of this animal that don’t survive so well in the fossil record,” Tim Ziegler, Melbourne Museum’s Collection Manager of Vertebrate Paleontology, told New Atlas. “In this case, we’ve got things as precious as the entire tail of the animal for the first time, to know how long that stretches out, and to see the very last vertebra unequivocally, small enough to sit in the palm of your hand.”
When the team cracked open the rock around the animal’s front foot, they discovered a hexagonal pattern in the sediment around its toes. But on closer inspection they found it isn’t just a footprint – it’s actually the fossilized remains of the skin itself.
“Rather than an impression left behind by a handprint, that’s the last trace of the soft tissues of the animal,” said Ziegler. “It’s the organic remains of its skin underneath its last little finger.”
For very large animals, it’s not unusual for supporting tendons to harden during the animal’s life, becoming stronger, almost like bone. Some of these “ossified tendons” have been preserved and are visible along the Triceratops’s back.
Because the specimen remained largely undistorted by the pressures and temperatures of fossilization, the team was able to make an accurate cranial endocast – a 3D model of the cavity that once held Horridus’s brain, and by extension, determine the shape of the brain itself. Like most reptiles, that brain was long and cylindrical.
The shape of its inner ear is also captured in that endocast, which reveals more than you might expect. For starters, it can tell you that Triceratops specialized in hearing low-frequency sounds, such as the heavy footsteps of other large dinosaurs. As such, it probably made low, deep noises to communicate with its own kind. But the most fascinating insight is that the semicircular canals of the inner ear reveal much about the balance and posture of the animal.
“If you need to keep balance, and you have a native position in which an animal is most comfortable, then the direction and shape of those canals will reflect that resting posture,” Ziegler told us.
This informed the pose of the Triceratops on the museum floor.
“What we have is a realistic and really dynamic pose,” said Ziegler. “I think to have it in this stepping posture, moving through, lifting its toes off the ground, splaying them out, and putting weight on other limbs, this kind of evocation of the animal while it was alive is a way to really honor this individual, and pay respect to it.”
This helps to remove some of the abstraction of a museum exhibit and hammer home that this strange silhouette had parents, favorite foods, and a rich, full life.
“We don’t look at it as a static, dead animal,” said Ziegler. “You look at this skeleton and you think of Horridus when it was alive.”
Horridus lived around 67 million years ago, in what is now Montana, USA. But rather than the baking badlands that the region is today, back in the Cretaceous it was a lush, swampy forest, and this environment is key to how Horridus became so beautifully preserved.
“This Triceratops was preserved in an ancient river channel, now part of the Hell Creek Formation in the Late Cretaceous in Montana,” Ziegler explained. “And that’s a river channel that most of the time is fairly quiet. But what we see surrounding this specimen in situ was an undifferentiated, massive sand body. That’s indicative of a pulse of water and a pulse of sediment that must have covered this animal relatively soon after it had died, and certainly before it was, say, scavenged by predators.”
It doesn’t look like Horridus died in this flood, though. The dig team examined the site using a process called photogrammetry, which involves making a 3D model out of photos taken throughout the different stages of excavation. This allows the scientists to see the position that the dinosaur had been in when it was buried – a natural, resting pose.
“That was so evocative because you saw that it was not scattered bones down a riverbed,” said Ziegler. “It’s not abstracted in the way that a disarticulated skeleton might be. But instead it was like this poor old beast that had just laid down and gone to sleep.”
This sudden burial so soon after death is why we see so much of Horridus today. Between death, burial, deep burial, fossilization, uplift, erosion, and then discovery and collection, there are a lot of steps for bones to go missing. Tens of millions of years of wind, water, animals and bad luck mean that most fossil skeletons are frustratingly incomplete.
Horridus may be the most complete example of its species, but of course even it wasn’t immune to these effects. Some of the smallest pieces are missing, particularly the intricate bones of the feet and underside of the tail. These, Ziegler says, are the most vulnerable to being swept away in rushing waters or carried off by scavengers.
These gaps are filled in with models molded from other specimens or, in the case of the rear left foot bones, mirror images of Horridus’ more complete right foot. Rather than the earth tones of the original fossil bones, these replacement pieces are a dull grey and clearly artificial. Leaving these fillers uncolored was a deliberate choice, serving to highlight just how complete Horridus is.
Horridus may be the star attraction, but it’s not the only Cretaceous creature on show in the exhibition. Upstairs, visitors will find cases full of small fossils – teeth, shards of armor plating, and skull fragments. While these may seem a tad underwhelming after taking in the Triceratops, they provide some insightful context.
“You’ll notice that a lot of these fossils are much less impressive than the main event, and that just serves to underline how incredibly rare finding an amazingly complete, wonderfully preserved, single individual dinosaur is,” said Hazel Richards, curatorial research assistant of paleontology at Melbourne Museum. “It’s one in a million, no exaggeration.”
These fossils also help to flesh out the world that the Triceratops lived in. They were all found in the same layer of sediment, indicating that the animals they belonged to lived at the same time, in the same place, as Horridus.
And it’s an intriguing cast of characters. Armored Ankylosaurus, thick-skulled Pachycephalosaurus, small, fleet-footed predators like Troodon, herds of grazing Edmontosaurus, and of course the fearsome Tyrannosaurus rex. Ancestors of modern animals also called this swampy landscape home, including small mammals, reptiles, amphibians, turtles and crocodiles.
“By taking all of these fossils together, we can get an idea of the diversity of animals that existed at that time,” Richards told us.
While fossil evidence of the Triceratops’s contemporaries can be seen in the displays upstairs, you’ll first meet them as soon as you walk into the exhibit. Before you even see Horridus, you walk through rooms and halls covered in floor-to-ceiling projections of prehistoric Montana, where animated likenesses of these animals roam, inviting visitors to stop and admire the scenery.
The idea, according to exhibition producer Maggie Watson, was to contrast the location’s past and present, set the scene and build suspense for Horridus itself.
“It’s about creating that visitor journey, so we really wanted to set up some anticipation before you meet the actual Triceratops,” Watson said. “We wanted to transport visitors to the place of Montana, where the fossil comes from, and invite people to step back in time into that Cretaceous world.”
Permanent public home
The universal appeal of dinosaurs means that, of course, they attract the attention of wealthy collectors – after all, who wouldn’t want a giant skeleton as a conversation starter in their parlor? But unfortunately that means that some of the most iconic and important specimens in the world are disappearing behind closed doors – in 2020, Stan the T-rex sold for US$31.8 million to an anonymous buyer, ending a several-decade public display in the Black Hills Institute Museum in South Dakota. That marks a great loss for the scientific community and general public alike.
Thankfully, Horridus has found its permanent home at Melbourne Museum, where it will remain open for all to see and study. Better yet, before it was assembled, every single bone in its body was individually documented, cataloged, and scanned in three dimensions. All of this information, as well as the digital 3D models, are publicly accessible by the worldwide scientific community, and some of the data has already been incorporated into published works.
“One of the critical things about having this in a public collection, is that now that information isn’t locked up or simply never gathered,” Ziegler told us. “As a public asset, all of that information that gets generated can be used to further scientific discovery about horned dinosaurs, and about dinosaurs [in general] and maybe even about vertebrates overall.”
But it’s not just current scientists that can benefit – Horridus could have a hand in inspiring future generations, in ways that won’t become clear for decades.
“There’s also scientific importance in having generations of five-year-old girls and boys in here, to find that first moment of engagement with natural history and science,” said Ziegler. “It’s my joy to not know what this will spark in a new visitor, to see their first dinosaur. They might become an artist, or a scientist … That’s one of the fundamental values of putting this in a state collection, is that it can now belong to everyone.”
Horridus and the Triceratops: Fate of the Dinosaurs exhibition opens to the public on March 12 at Melbourne Museum.