Fun Hesperosaurus Facts For Kids

The Hesperosaurus, which means "western lizard" is a plant-eating stegosaur closely related to the Dacentrurus, also a stegosaur. The specimen of this species indicates that it lived during the Kimmeridgian to the Tithonian age of the Jurassic epoch. The remains of these stegosaurs were discovered by Patrick McSherry with help from Jeff Parker and Ronald G. Mjos from the Western Paleontological Laboratories, Inc.

The fossils of the Hesperosaurus were found in the Morrison Formation of Montana and Wyoming in the United States of America. The type species, H. mjosi, was described and named by Clifford Miles, Kenneth Carpenter, and Karen Cloward, in 2001. In a published study of 2008, Susannah Maidment and team claimed that the Hesperosaurus was derived form of the Stegosaurus and the Wuerhosaurus, and proposed that it should be a species of Stegosaurus by renaming it Stegosaurus mjosi.

However, Carpenter rejected this theory, and later in 2017, Maidment accepted the Hesperosaurs as a distinct genus from the Stegosaurus. Apart from this, the Hesperosaurus skeleton specimen proved it had several differences from the Stegosaurus such as the 13 neck vertebrae instead of 10, 13 back vertebrae instead of seven, and 20 maxillary teeth on each side, which is less than the Stegosaurus.

If you want to read about more dinosaurs, check out the Chungkingosaurus and the Sauropelta facts.

How do you pronounce 'Hesperosaurus'? 

The Hesperosaurs name is pronounced as Hes-per-o-sore-us.

What type of dinosaur was a Hesperosaurus?

The Hesperosuarus was a plant-eating stegosaur species.

In which geological period did the Hesperosaurus roam the earth?

These dinosaurs found in the Morrison Formation lived between the Kimmeridgian and the Tithonian age of the Late Jurassic epoch.

When did the Hesperosaurus become extinct?

Based on the specimen, these stegosaurs would have gone extinct about 156 million years ago.

Where did a Hesperosaurus live? 

Fossils of these stegosaur dinosaurs have been found in North America among the older region of the Morrison Formation in the western USA, specifically Wyoming and Montana, which also means that it is older than other stegosaurs from the Morrison Formation.

What was a Hesperosaurus' habitat? 

This plant-eating dinosaur found in the Morrison formations seems to have preferred terrestrial climates in densely vegetated forests, especially near river channels

Who did a Hesperosaurus live with?

Although not much is known about the living patterns of this dinosaur, several specimens of stegosaurs have indicated that they were either solitary or could have lived in a small group alongside other dinosaurs.

How long did a Hesperosaurus live?

The lifespan of this species has not been analyzed based on these stegosaur specimens.

How did they reproduce?

Not much is known about the reproduction system in this dinosaur, except that they were oviparous and mated through copulation with the eggs fertilized inside the body of the female.

What did a Hesperosaurus look like?

This was a large-size stegosaur dinosaur, with a specimen that displays the first-ever impression of horn sheath on the backplate. They had two rows of alternating plates on the back which were bigger on the back and become smaller towards the tail. The plate shape resembled an angled oval with the tapering end towards the top. These plates along with their scaly bodies and the spines at the base of their tails were used for protection as well as thermoregulation of their bodies. Since Maidment wanted to group the H. mjosi with the S. stenops, Carpenter suggested a list of characteristic features that confirm why these species must belong to two separate genera. He explained that the antorbital fenestra of the stegosaurus dinosaur was much smaller and the maxilla is longer with a height of around one thirds the length. He also mentioned that the stegosaurus had lesser neck vertebrae and more dorsal vertebrae than the Hesperosaurus. Even the plates on the base of the tail and hip were more oval in Hesperosaurus as compared to the higher, triangular ones of the stegosaurus. He also claimed that the Hesperosaurus had twenty maxillary teeth on each side, while the S. stenos had a lesser number. Apart from these, he pointed out several intricate anatomical aspects that thoroughly differentiate the two genera.

*We've been unable to source an image of Hesperosaurus and have used an image of Stegosaurus instead. If you are able to provide us with a royalty-free image of Hesperosaurus, we would be happy to credit you. Please contact us at [email protected]

How many bones did a Hesperosaurus have?

Although almost the entire skeleton, apart from the limbs, of this dinosaur was discovered, the number of bones in its body has not been identified. HMNS 14, the holotype found in the lower Morrison Formation displayed a complete skull, a hyoid, and back lower jaws. A total of 13 neck and back vertebrae each, three sacral vertebrae, 44 tail vertebrae, chevrons, left shoulder blade, neck ribs, ten neck and back plates, a complete pelvis, and dorsal ribs were also identified.

How did they communicate?

The communication pattern or behavior of this dinosaur species is unknown. Although some species of stegosaurs are known to have had sweet, song-like vocalizations, which could mean they communicate through vocal signals.

How big was a Hesperosaurus? 

This dinosaur was around 15-21 ft (4.57-6.4 m) in length, which is one-fifth the length of the blue whale. The Hesperosaurus height was measured around 6.2-9.5 ft (1.9-2.9 m), which is around half the height of a zebra.

How fast could a Hesperosaurus move?

The speed at which this dinosaur species could move is unknown.

How much did a Hesperosaurus weigh?

The Hesperosaurus size was considered large and it weighed around 1,763.7-7,716.17 lb (800-3,500 kg) around the average weight of the tiger shark.

What were the male and female names of the species?

Male and females of this species did not have separate names.

What would you call a baby Hesperosaurus?

The baby of this dinosaur can be called a juvenile.

What did they eat? 

Based on the analysis of the jaw structure and tooth surface of the Hesperosaurus, it is speculated that they fed on ferns, bushy conifers, clubmosses, horsetails, cycads. In addition, a better understanding of stegosaur dinosaurs was provided when Reichel created an identical anatomical model of the teeth in the Stegosaurus dinosaur. The first aspect that was confirmed said that stegosaurs had a weak bite, weaker than that of wolves or dogs. This suggests that would be able to feed only on leaves and small branches, but unable to bite into thick food with a diameter over 0.5 in (1.27 cm). To support this theory, an analysis of the flora present in the Morrison Formation confirmed that the plants present during the same time as stegosaur dinosaurs were of a small, seasonal, and fast-growing herbaceous type.

How aggressive were they?

Considering they were plant-eaters, these dinosaurs may not have shown much aggression, except for when defending their territory or fighting off threats.

Did you know...

The Hesperosaurus name was coined by Clifford Miles, Kenneth Carpenter, and Karen Cloward in 2001. The prefix of the name means "western lizard" in Greek and was given to this dinosaur because it was only found in the western US.

What species of Hesperosaurus is there?

There is only one known species of these dinosaurs and the type species was discovered in 1985 by Patrick McSherry, a fossil hunter, along with R. G. Mjos and Jeff Parker.

Where were the Hesperosaurus fossils found?

The fossils of this dinosaur were found in the Morrison formation of western US, specifically in Montana and Wyoming.

Here at Kidadl, we have carefully created lots of interesting family-friendly dinosaur facts for everyone to discover! For more relatable content, check out these Puertasaurus fun facts and Zigongosaurus facts pages.

You can even occupy yourself at home by coloring in one of our free printable Hesperosaurus coloring pages.