The genus Chasmosaurus encompasses a number of species of ceratopsial dinosaurs that lived in the Cretaceous Period in North America.

Although it had a size and shape similar to a rhinoceros, if we forget about the three horns it had in total and the characteristic glue of the Ceratopsians, its name comes to mean “open lizard”.

It has also been known as “the rhinoceros dinosaur” because of its resemblance to this mammal, but always with the thought that it was a dinosaur not a mammal.

In this article we will tell you all the information available about this amazing dinosaur.

Basic information about Chasmosaurus

The Chasmosaurus is a medium sized ceratopsid. Its name refers to its characteristic tail.

  • How long is it? – About 5 to 6 meters long.
  • How tall is it? – The Chasmosaurus is approximately 2 meters high.
  • What is its weight? – The average weight of this extinct animal is about 3.6 tons.
  • When did it live? – It appeared on Earth 76 million years ago and disappeared 70 million years ago (it was 6 million years on Earth).
  • What is its order? – The order of the Chasmosaurus is the Ornistichians. To be more specific, it comes from the infra-order Ceratopsia.

The taxonomy of Camptosaurus

Kingdom Animalia > Filo Chordata > Superorder Dinosauria > Class Sauropsida > Order Ornithischia > Suborder Neornithischia > Suborder Ornithopoda > Family Ceratopsidae > Subfamily Ceratopsinae > Genus Chasmosaurus

The family: ceratopsids

Chasmosaurus belongs to the ceratopsid family (Family Ceratopsidae). This family includes all dinosaurs that had horns.

This group of dinosaurs inhabited the earth during the late Cretaceous period (the last one within the era of dinosaurs).

The existence of ceratopsids was really short, even though it was a rather popular group of dinosaurs. It was quite successful as many species of this family appeared (among which are the Chasmosaurus).

The Ceratopsidae family cannot be easily divided, as most of them share characteristics with each other and there is not much to differentiate.

However, the only distinction that could be made was the size of their necklaces. The ceratopsids that have a large collar and those that have a short collar.

It seems that those with a large necklace were the next stage in the evolution of those with a short necklace. This deduction is based on the fact that the oldest ones are usually short necked while the most recent remains we have are of large necked ceratopsids.

Characteristics of ceratopsids

Absolutely all ceratopsids had horns. They had horns above the nose and above the eyes. Those that did not have horns and only had the bumps were prior to the ceratopsids. As an example we have Psittacosaurus and Protoceratops.

Also, the ceratopsids had a strong beak and crumbling teeth behind. The curved bony beak that it had on its snout allowed it to pull out branches with resistant leaves.

Description of Chasmosaurus

The Chasmosaurus were a kind of ceratopsid with a medium size. It was neither the largest nor the smallest, its size was average.

This dinosaur was approximately 2 meters high, while its length was between 5 and 6 meters. The weight that this extinct creature had is about 3600 kilograms.

It is worth mentioning that, like all ceratopsids, the Chasmosaurusson quadrupeds (they have four legs) and that they are boiling animals.

Its enormous gola covered its shoulders and also its neck. This they used to keep away their predators and in turn they used it to attract their partner.

It is a kind of frill, a bony frame with large fenestrations that were covered by skin.

It had, as described above, three horns. One of them is located on the nose (a small horn) and two others on the eyes.

Its tail and legs were very short, and it had five toes on each leg. It possessed a large muzzle but no teeth, in addition to having protuberances on its cheeks.

It is also known that the Chasmosaurus possessed osteoderms, thanks to a sample of fossilized skin that they were able to investigate. In theory, they were placed in evenly spaced rows.

Its skull was of quite large proportions, as it is a quarter of the length of its body, with 2 meters long, while the whole animal measured between 5-6 meters.

It can be said that the Chasmosaurus has one of the largest skulls known among land animals.

The necklace (flyer) we talked about before, had the shape of a heart. The structure of its bone is divided into two large lobes and a central bone.

Even though this made it look bigger and scared off predators, the truth is that its frill did not serve as a defense method. It’s just skin stretched between his bones, so it was practically very fragile.

It is also worth noting that during the mating season, the steering wheel could have become a bright color or increased in size to attract attention during the mating season.

Initially, both C.kaiseni and C.belli were considered as different species. In the case of C.kaiseni they had long forehead necks, as opposed to C.belli which had short horns. Later it was discovered that some were the males and others the females and that they belonged to the same species

Interesting details about the Chasmosaurus

In order to distinguish the types of ceratopsids, let us at first separate them by size on their horns. It follows that this classification is probably wrong and that the long horns belong to the males and the short horns to the females.

You can find a complete skeleton of Chasmosaurus on display at the Royal Tyrrell Museum. This museum is located in Alberta, Canada.

They weren’t very fast, but they didn’t need to be either. A three-year-old had the same size steering wheel as an older one.

When and where did this dinosaur live?

When did this dinosaur live? – It is strange to talk about years in these cases. You can’t really appreciate the years that have passed by other than the simple number. No one is able to get an idea of how many years have passed (the human race has “only” been on earth for 200,000 years).

The Chasmosaurus appeared on earth 76 million years ago and disappeared with the end of the dinosaurs (the meteorite that wiped out all the dinosaur species) and that was about 70 million years ago.

They lived in the late Mesozoic period in the Cretaceous period. If we want to be more specific it would be in the Upper Cretaceous Maaestrichtian. It is very probable that the meteorite that ended the Mesozoic Era (the Era of the dinosaurs) also ended the existence of the Chasmosaurus.

Where did the Chasmosaurus live? – We can only refer to the area where fossils have been found. It is possible that it would have inhabited more areas, but obviously since no fossils have been found it cannot be said for sure. The Chasmosaurus inhabited North America along the Laramidian coast.

The defense of the rhino dinosaur

It’s already becoming commonplace for boiling dinosaurs to become the prey of carnivorous dinosaurs.

It is because boiling dinosaurs are usually quieter and they don’t have claws and sharp teeth like carnivores. Therefore, it is not surprising that Chasmosaurus have enemies.

The Chasmosaurus’ trick in front of their enemies is to use their flywheel as a defense, as well as their horns to intimidate the predator. They used to live in herds and in case of an attack they would stand in a circle, creating a barrier thanks to their large fliers and horns.

This position would have helped them survive and intimidate the enemy that wanted to eat them.

What did the Chasmosaurus eat?

What do these rhinoceros dinosaurs eat? – It should be noted that these dinosaurs were not very tall, as they were only 2 meters high (an average adult is 1.75 meters).

The Chasmosaurus are heviborous animals as well as another species of dinosaur that we have recently described, the Camarasaurus. Unlike the Camarasaurus that had such long necks that they could reach high vegetation, the Chasmosaurus only reached low vegetation.

The plants it ate were very selective due to their large snout, their short stature and their toothless jaws.

Who discovered the three-horned?

Who discovered the three-horned? – As it was going to be less, this species was also discovered at the time of the Bone War. It was discovered in 1898.

Lawrence Morris Lambe was in charge of the Canadian Geological Survey. He was doing his work in the berry cove area when he found the first holotype that exists on chasmosaurus, holotype NMC 491.

Lambe was aware that his discovery was a new species, but what he didn’t expect was that it would be an entirely new genus.

Lambe believed that the discovered species would belong to a short-flying ceratopsyan genus, Monoclonius. He named his find Monoclonius belli to honor the collector who actually found it, Mr. Walter Bell.

It was not until 1913 that paleontologist Charles Hazelius Sternberg and his sons found more parts of the supposed species Monoclonius belli. These parts would be found by the Dinosaur Park Formation in the city of Alberta (Canada).

In 1914, Lambe realized that it really wasn’t a simple species but a new genus and named it Protosaurus. However, this name was being used by a reptile (found in 1836 by Meyer). So some time later Lambe found out and officially the genus Chasmosaurus was born.

From that date the description of Chasmosaurus has been completed each time thanks to new findings of remains. Several skulls have been found among other remains. And new species have been created.

In 1933, Barnum Brown named Chasmosaurus kaiseni (in homage to Peter Kaisen) after the species he had found. According to him, the difference was that it had the largest horns. He based it on AMNH 5401, a skull.

Several other species have been named over the years:

1933 – Richard Swan Luli named the species C.brevirostris
1940 – Charles Motram Sternberg added the C.russelli.
1987 – Gregory S. Paul renamed a Pentaceratops stembergii to a Chasmosaurus stembergi. However, it has not found acceptance.
1989 – Thomas Lehman describes C. mariscalensis (in Texas). He now has his own genus, Vagaceratops (since 2010).
2000 – George Olshevsky renamed Monoclonius recurvicomis (discovered by Cope in 1889) as Chasmosaurus recurvicornis.

The only species of Chasmosaurus: C.belli and C.russelli

Despite the number of species that have been named, most have been named wrongly. There are not that many species of Chasmosaurus found, there are only two: C.belli and C.ruselli.

The difference between C.belli and C.ruselli is minimal. It has slight differences in morphology and also in stratigraphy. In the case of C.ruselli, it is found in the oldest of the Dinosaur Park Formation and C.belli in the middle of the Dinosaur Park Formation.

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