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Description
Stegosaurus stenops
The Jurassic Period was the apex of the dinosaurs’ reign on the planet. Among the most iconic dinosaurs that arose during the time were the thyreophoran dinosaurs. A broad and diverse group that included the armored dinosaurs such as the ankylosaurs and of course, the stegosaurs. And none would have been more iconic than the type genus, Stegosaurus.
History of Discovery and Naming:
In 1877, fossils of a dinosaur were discovered north of Morrison, Colorado. What was found was partially tail, hips and a single plate. Given its fragmentary nature, Marsh thought this was a shell fragment and thus named it “Stegosaurus armatus” derived from the Greek meaning armored roof lizard. In the following year, he found and named a second species, “Stegosaurus ungulatus” meaning ungulate roofed lizard. Throughout the 1880s, he named a variety of species of Stegosaurus. Due to the nature of the Bone Wars between him and Edward Drinker Cope, many species that were named were named just to one up the other. Some were named by Cope, others by Marsh.
Species History:
The originally named species, Stegosaurus armatus, is now believed to be dubious. Given the fragmentary nature of the type specimen consisting only of partial tail bones, hips, and leg, parts of some back vertebrae, and a fragmentary plate.
With the original specimen now dubious, how did the animal featured in this profile become the type species? In 1891, Marsh described a relatively complete and partially articulated “roadkill specimen” of Stegosaurus, and allowed an actual look at the plate orientation. Marsh described the specimen as having plates not on the back as armor but facing upwards. Furthermore, the skull was described and seen as kind of narrow. Thus, Marsh named the species, Stegosaurus stenops, meaning the species named derived from the Latin, and meaning in full, “Narrow Faced Roof Lizard”. In 2013, re-examination of the S. armatus specimen was conducted and the International Commission on Zoological Nomenclature (ICZN) concluded that there was not enough material to justify the existence of the type species. Thus, the type species moniker was assigned to Stegosaurus stenops.
Stegosaurus ungulatus the second named species, the ungulate roofed lizard, was described as such since the feet of this dinosaur was described and Marsh likened them to resemble more like ungulate-like toes on the forefeet (hands). A big difference it had were its more triangular shaped plates, which were relatively smaller than S.stenops. However, the biggest and most apparent difference was its size. Reaching 30ft long, 8-9ft tall (excluding the plates) and 7-8 tons in weight, this was the largest stegosaurian known.
Finally, there’s Stegosaurus sulcatus. Roughly the same size as Stegosaurus stenops, it had one unique feature, Marsh described the specimen as having shoulder spikes. This species could have been a questionable dinosaur in that it may have been a distinctive genus of dinosaur separate from Stegosaurus.
Description:
Stegosaurus was the largest genera of stegosauria itself. The type species, S.stenops was slightly above average for most other stegosaurian species. Its cousin, S.ungulatus took the cake in terms of size. Roughly the size of an avg. elephant at around 6-7ft tall (excluding the plates), 22-26ft long and weighted approximately 5-6.5 tons.
As characteristic of all stegosauria, were the plates for which Stegosaurus is especially famous. Which were modified Osteoderms that grew to much larger sizes and embedded from the neck, all along the back in a staggered, alternating placement. Ranging from about 4-5 inches tall and the same diameter wide to about 2ft tall and wide.
Probably even more famous than the plates were the spikes on the tail. These are called thagomizers. The term isn’t actually derived from any language. It was actually coined by cartoonist Gary Larson in 1982 in a small illustration where a caveman was pointed at the tail of a Stegosaurus. In 1993, paleontologist Dr.Ken Carpenter put it in a study, and the term stuck. At 2-3ft long, these were unquestionably for defensive protection from predation and perhaps for combat between rivals, although the latter has not been proven.
A find from the Morrison formation show an Allosaurus vertebra that had a massive wound in the side of the tail. Based on a growth of bone, the injury healed and the predator survived.
Plate Orientation and Function:
Early on when Stegosaurus was first discovered, Marsh theorized a variety of layouts for the plates. Some had them in line all the way down the back in a single-filed position. Another paired together down the back, and most bizarre of all, would be laying over the back giving it armor reminiscent of a pangolin. The lattermost description is where it derives its name.
Articulated specimens indicate Stegosaurus had a staggered alternating placement of plates down the back. Starting from the neck and increasing in size down the length of the back and going about a third of the way down the tail.
The function of these plates has long puzzled paleontologists. Many think they were for defense, which is possible, but more likely they were used for display and maybe for the thermoregulation of the animal. One function that was popular in the 90s and through the 2000s (and featured in Walking With Dinosaurs) was that the plates could have been covered in skin and used to flush blood into the plates to create a display of color to ward off predators or attract mates. However, recent finds from a related (and more derived) genera, Hesperosaurus, indicate that stegosaurs’ plates were covered in keratin, which both would have hampered the thermoregulation and made the color changing plates impossible. Although, thermoregulation cannot be ruled out for even keratinous horns on various species of cattle use their horns to flush off heat.
A Stego Named Sophie:
In 2003, a juvenile specimen of Stegosaurus was found in Wyoming at the Red Canyon Ranch dig site. Being a private dig site, all specimens are owned by the owner of the ranch. Ultimately, the specimen went in storage, and wasn’t until the 2010s where the Natural History Museum in London was able to acquire it through the contribution from a wealthy donor. While its look surely surprised the avg. laymen, to many stegosaurian experts, it wasn’t as surprising.
Throughout the 20th century, even during the dinosaur renaissance, the appearance of Stegosaurus was relatively the same as when it had been first discovered, aside from the necessary tweaks such as a tail being raised high off the ground and not dragging it, erect, pillar-like legs, among other corrections. Sophie amends that in that it helped bring Stegosaurus itself more in-line with a lot more animals within the stegosaurian family. A longer neck, a more compressed body, slightly longer forelimbs, and a longer tail with the thagomizer section downturned.
It's thanks to this find that we finally have a proper image of Stegosaurus itself.
Brain:
Stegosaurus famously has a very small brain, around the size of a dog’s or more famously repeated, “the size of a walnut”. The braincase of Stegosaurus was what started this trend, described by March in the 1880s, made many paleontologists wonder how such a brain could power this animal.
Early on, there was a theory they had a “second brain” near the tail. Based on features found near the base of the tail, would have helped it be more alert and power its massive tail in case of predation. Today, this is now believed to be an antiquated view of dinosaurian physiology. Furthermore, compared to other dinosaurs, by no means, does it have the smallest brain to body mass ratio. Sauropods, their cousins, Ankylosaurs have far reduced brains and show no evidence of a supposed “second brain”.
Diet:
The diet of these dinosaurs was unquestionably herbivorous. Based on comparisons of skull build and bite force, it’s believed that this dinosaur had a bite force similar to basal therizinosaurs as well as basal sauropodomorphs. So, it probably fed upon cycad and woodier plants.
Habitat:
Stegosaurus lived in North America and resided in the Morrison Formation from around 155-145,000,000 years ago. The environment it resided in was savannah-like, but no grass existed at the time. Only horsetail and ferns populated the prairies of the Morrison. There were pronounced wet and dry seasons where it varied from lush floodplains to arid semi-desert environments. Tall conifer trees like Monkey Puzzle and Sequoia trees surrounded these prairies. Taphonomic studies suggests that these dinosaurs lived in drier settings than other animals.
It lived alongside many sauropod dinosaurs like Apatosaurus, Brontosaurus, and Diplodocus. Smaller ornithopods, like Camptosaurus, Dryosaurus, and Nanosaurus lived in the environment as well.
The most common apex predator was Allosaurus, and Stegosaurus was likely preyed upon by these carnosaurs. A Stegosaurus plate was shown to be bitten off by Allosaurus and as previously mentioned, the vertebra shows that conflict was inevitable between these to iconic animals. Ceratosaurus, Marshosaurus, and Stokesosaurus filled the smaller carnivore niche.
Extinction:
At the end of the Jurassic, Stegosaurus would vanish. Climate change is largely believed to be why these animals vanished. Some paleontologists think the reason why Stegosaurs would not survive to the end of the Mesozoic is probably because angiosperms arose and became common in the Cretaceous. The last stegosaur, Wuerhosaurus from China, another large animal died out during the cretaceous about 113,000,000 years ago.
Stegosaurus itself, however, is an icon of the Jurassic. The history of it being portrayed from a pangolin turtle beast to an iconic dinosaur of the dinosaur renaissance, and now a textbook example as to how the progress of paleontology updates these awe-inspiring animals.
___________________________________________________________________________________________
Okay, here's another remake of an old profile. I thought about doing something different for this weekend, but a few weeks back, I went to the Field Museum and saw the outdated depiction of Stegosaurus and it ate away at me so much, I had to remake it. Plus, it's one of my favorite dinosaurs and an animal I've always wanted to redo and bring up to modern standards.

Here in this profile, yeah it's cliché, BUT, c'mon, it's Allosaurus and Stegosaurus, I had to show it. Here, it's just two adolescent Allosaurus targeting a bull Stegosaurus.

Yeah, it's in PMP, but, I largely depicted it under the old depiction of Stegosaurus. I probably will go back and remake the scenes at the end of the series. In fact, I probably will re-write them and put them on here. Why? Mainly because there's some really inaccurate anatomic details and some plot details make no sense.

For Past Meets Present:
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original model and skin by Tyranachu modified by me:
Stegosaurus (Tyranachu) | ZT2 Download Library Wiki | Fandom

Description
Stegosaurus stenops
The Jurassic Period was the apex of the dinosaurs’ reign on the planet. Among the most iconic dinosaurs that arose during the time were the thyreophoran dinosaurs. A broad and diverse group that included the armored dinosaurs such as the ankylosaurs and of course, the stegosaurs. And none would have been more iconic than the type genus, Stegosaurus.
History of Discovery and Naming:
In 1877, fossils of a dinosaur were discovered north of Morrison, Colorado. What was found was partially tail, hips and a single plate. Given its fragmentary nature, Marsh thought this was a shell fragment and thus named it “Stegosaurus armatus” derived from the Greek meaning armored roof lizard. In the following year, he found and named a second species, “Stegosaurus ungulatus” meaning ungulate roofed lizard. Throughout the 1880s, he named a variety of species of Stegosaurus. Due to the nature of the Bone Wars between him and Edward Drinker Cope, many species that were named were named just to one up the other. Some were named by Cope, others by Marsh.
Species History:
The originally named species, Stegosaurus armatus, is now believed to be dubious. Given the fragmentary nature of the type specimen consisting only of partial tail bones, hips, and leg, parts of some back vertebrae, and a fragmentary plate.
With the original specimen now dubious, how did the animal featured in this profile become the type species? In 1891, Marsh described a relatively complete and partially articulated “roadkill specimen” of Stegosaurus, and allowed an actual look at the plate orientation. Marsh described the specimen as having plates not on the back as armor but facing upwards. Furthermore, the skull was described and seen as kind of narrow. Thus, Marsh named the species, Stegosaurus stenops, meaning the species named derived from the Latin, and meaning in full, “Narrow Faced Roof Lizard”. In 2013, re-examination of the S. armatus specimen was conducted and the International Commission on Zoological Nomenclature (ICZN) concluded that there was not enough material to justify the existence of the type species. Thus, the type species moniker was assigned to Stegosaurus stenops.
Stegosaurus ungulatus the second named species, the ungulate roofed lizard, was described as such since the feet of this dinosaur was described and Marsh likened them to resemble more like ungulate-like toes on the forefeet (hands). A big difference it had were its more triangular shaped plates, which were relatively smaller than S.stenops. However, the biggest and most apparent difference was its size. Reaching 30ft long, 8-9ft tall (excluding the plates) and 7-8 tons in weight, this was the largest stegosaurian known.
Finally, there’s Stegosaurus sulcatus. Roughly the same size as Stegosaurus stenops, it had one unique feature, Marsh described the specimen as having shoulder spikes. This species could have been a questionable dinosaur in that it may have been a distinctive genus of dinosaur separate from Stegosaurus.
Description:
Stegosaurus was the largest genera of stegosauria itself. The type species, S.stenops was slightly above average for most other stegosaurian species. Its cousin, S.ungulatus took the cake in terms of size. Roughly the size of an avg. elephant at around 6-7ft tall (excluding the plates), 22-26ft long and weighted approximately 5-6.5 tons.
As characteristic of all stegosauria, were the plates for which Stegosaurus is especially famous. Which were modified Osteoderms that grew to much larger sizes and embedded from the neck, all along the back in a staggered, alternating placement. Ranging from about 4-5 inches tall and the same diameter wide to about 2ft tall and wide.
Probably even more famous than the plates were the spikes on the tail. These are called thagomizers. The term isn’t actually derived from any language. It was actually coined by cartoonist Gary Larson in 1982 in a small illustration where a caveman was pointed at the tail of a Stegosaurus. In 1993, paleontologist Dr.Ken Carpenter put it in a study, and the term stuck. At 2-3ft long, these were unquestionably for defensive protection from predation and perhaps for combat between rivals, although the latter has not been proven.
A find from the Morrison formation show an Allosaurus vertebra that had a massive wound in the side of the tail. Based on a growth of bone, the injury healed and the predator survived.
Plate Orientation and Function:
Early on when Stegosaurus was first discovered, Marsh theorized a variety of layouts for the plates. Some had them in line all the way down the back in a single-filed position. Another paired together down the back, and most bizarre of all, would be laying over the back giving it armor reminiscent of a pangolin. The lattermost description is where it derives its name.
Articulated specimens indicate Stegosaurus had a staggered alternating placement of plates down the back. Starting from the neck and increasing in size down the length of the back and going about a third of the way down the tail.
The function of these plates has long puzzled paleontologists. Many think they were for defense, which is possible, but more likely they were used for display and maybe for the thermoregulation of the animal. One function that was popular in the 90s and through the 2000s (and featured in Walking With Dinosaurs) was that the plates could have been covered in skin and used to flush blood into the plates to create a display of color to ward off predators or attract mates. However, recent finds from a related (and more derived) genera, Hesperosaurus, indicate that stegosaurs’ plates were covered in keratin, which both would have hampered the thermoregulation and made the color changing plates impossible. Although, thermoregulation cannot be ruled out for even keratinous horns on various species of cattle use their horns to flush off heat.
A Stego Named Sophie:
In 2003, a juvenile specimen of Stegosaurus was found in Wyoming at the Red Canyon Ranch dig site. Being a private dig site, all specimens are owned by the owner of the ranch. Ultimately, the specimen went in storage, and wasn’t until the 2010s where the Natural History Museum in London was able to acquire it through the contribution from a wealthy donor. While its look surely surprised the avg. laymen, to many stegosaurian experts, it wasn’t as surprising.
Throughout the 20th century, even during the dinosaur renaissance, the appearance of Stegosaurus was relatively the same as when it had been first discovered, aside from the necessary tweaks such as a tail being raised high off the ground and not dragging it, erect, pillar-like legs, among other corrections. Sophie amends that in that it helped bring Stegosaurus itself more in-line with a lot more animals within the stegosaurian family. A longer neck, a more compressed body, slightly longer forelimbs, and a longer tail with the thagomizer section downturned.
It's thanks to this find that we finally have a proper image of Stegosaurus itself.
Brain:
Stegosaurus famously has a very small brain, around the size of a dog’s or more famously repeated, “the size of a walnut”. The braincase of Stegosaurus was what started this trend, described by March in the 1880s, made many paleontologists wonder how such a brain could power this animal.
Early on, there was a theory they had a “second brain” near the tail. Based on features found near the base of the tail, would have helped it be more alert and power its massive tail in case of predation. Today, this is now believed to be an antiquated view of dinosaurian physiology. Furthermore, compared to other dinosaurs, by no means, does it have the smallest brain to body mass ratio. Sauropods, their cousins, Ankylosaurs have far reduced brains and show no evidence of a supposed “second brain”.
Diet:
The diet of these dinosaurs was unquestionably herbivorous. Based on comparisons of skull build and bite force, it’s believed that this dinosaur had a bite force similar to basal therizinosaurs as well as basal sauropodomorphs. So, it probably fed upon cycad and woodier plants.
Habitat:
Stegosaurus lived in North America and resided in the Morrison Formation from around 155-145,000,000 years ago. The environment it resided in was savannah-like, but no grass existed at the time. Only horsetail and ferns populated the prairies of the Morrison. There were pronounced wet and dry seasons where it varied from lush floodplains to arid semi-desert environments. Tall conifer trees like Monkey Puzzle and Sequoia trees surrounded these prairies. Taphonomic studies suggests that these dinosaurs lived in drier settings than other animals.
It lived alongside many sauropod dinosaurs like Apatosaurus, Brontosaurus, and Diplodocus. Smaller ornithopods, like Camptosaurus, Dryosaurus, and Nanosaurus lived in the environment as well.
The most common apex predator was Allosaurus, and Stegosaurus was likely preyed upon by these carnosaurs. A Stegosaurus plate was shown to be bitten off by Allosaurus and as previously mentioned, the vertebra shows that conflict was inevitable between these to iconic animals. Ceratosaurus, Marshosaurus, and Stokesosaurus filled the smaller carnivore niche.
Extinction:
At the end of the Jurassic, Stegosaurus would vanish. Climate change is largely believed to be why these animals vanished. Some paleontologists think the reason why Stegosaurs would not survive to the end of the Mesozoic is probably because angiosperms arose and became common in the Cretaceous. The last stegosaur, Wuerhosaurus from China, another large animal died out during the cretaceous about 113,000,000 years ago.
Stegosaurus itself, however, is an icon of the Jurassic. The history of it being portrayed from a pangolin turtle beast to an iconic dinosaur of the dinosaur renaissance, and now a textbook example as to how the progress of paleontology updates these awe-inspiring animals.
___________________________________________________________________________________________
Okay, here's another remake of an old profile. I thought about doing something different for this weekend, but a few weeks back, I went to the Field Museum and saw the outdated depiction of Stegosaurus and it ate away at me so much, I had to remake it. Plus, it's one of my favorite dinosaurs and an animal I've always wanted to redo and bring up to modern standards.

Here in this profile, yeah it's cliché, BUT, c'mon, it's Allosaurus and Stegosaurus, I had to show it. Here, it's just two adolescent Allosaurus targeting a bull Stegosaurus.

Yeah, it's in PMP, but, I largely depicted it under the old depiction of Stegosaurus. I probably will go back and remake the scenes at the end of the series. In fact, I probably will re-write them and put them on here. Why? Mainly because there's some really inaccurate anatomic details and some plot details make no sense.

For Past Meets Present:
Past Meets Present (Pt4 is Up) - The ZT2 Round Table

Original model and skin by Tyranachu modified by me:
Stegosaurus (Tyranachu) | ZT2 Download Library Wiki | Fandom