This Horned Dino Was Actually TWO?!

Added: 2026-06-02

[00:00:03]Horned dinosaurs are super cool. As you get to understand them more and more, you might find that there is too much going on. The mascots of the horned dinosaurs are Centrasaurus, the major face of the Centasaurs. Casmosaurus, the major face of the Casmosaurus, and Triceratops, the last and biggest of the horn dinosaurs. These dinosaurs have become waste baskets for paleontologists to throw new species into. And one that has been sitting around in the cosmosaurus bin for almost 100 years has finally got the boot. Let's look at the fossil proof and see what it says.

[00:00:52]Special thanks goes to paleontologist Danny Baretta Gua for helping me out with this video.

[00:00:58]Hello, I've turned myself into primordial.

[00:01:02]I thought it would be a fun way to transition between my voice, liveaction footage of myself, and cute little characters that fit the theme of the videos. I can use this talisman here stuck in my goo body to transform into any one of the edge totem animals.

[00:01:18]Tyrannosaurus, elephant, and hot man.

[00:01:20]Maybe down the road and if you like them, I can find out how to transform into even more critters.

[00:01:28]Paleontologists from half a century to over a century ago were doing things a little differently to how they are done today. Not really. When it comes to finding and collecting fossils, though paleontologists are a lot more thorough and delicate today, they've gotten away from using dynamite, for example. But when it comes to the actual science part, though, lots of things have changed. Most paleontologists today try not to slap scientific genus and species names on specimens that are so fragmentaryary that they can only tell you that a certain group of animals were around at a certain time and place. For example, dinosaur teeth are generally only able to tell you that spinosaurs, tyrannosaurs, or sereratopsians were around, but they don't hold enough information to name a new species off of all that. Mammal teeth are a bit different because mammals only have two or three pairs of teeth for their entire lives. So, their teeth are less adaptable over very short periods of time and can help identify species. When the tooth shape changes, it usually means the species changed as well. For the last century, paleontologists have also been arguing over two schools of thought. Lumping versus splitting.

[00:02:42]Lumping is the act of combining specimens into known species based on shared traits. While splitting is separating specimens from species they have been applied to based on differences. This is much stronger of a process today than it was even 15 years ago. And you can see lots of work done to name new animals from well-known specimens that have been resting in known species for a long time. Thanks to the fossil records bias, there tends to be a larger number of fossils that scientists are not confident about putting a label on, but are somewhat confident they probably belong to a known genus or species. These are bits and pieces or relatively nice specimens, but they are missing the parts of their anatomy used to tell species apart. more quantitatively.

[00:03:29]For example, the horned dinosaurs or sereratopsians have bones in their frills that can help describe and identify species. This is because it seems that the frills of these dinosaurs evolved faster and were more genetically plastic than the rest of their bodies.

[00:03:47]One possible explanation for this is that the frill was used in socioexual behavior and changed pretty quickly to go along with behavioral and environmental changes like the feathers of living dinosaurs.

[00:04:00]As such, the sereratopsian dinosaurs have a long connected history with the lumping versus splitting thing. For an example of lumping, over the last 140 years, as many as 18 species have been named for the Triceratops genus. Only two have survived to this day. And for splitting, you are now seeing lots of things that used to be lumped into the Centrasaurus, Straosaurus, Penteratops, and Casmosaurus genera split out into new genera. One such splitting was finally published by Robert Holmes and colleagues in the Canadian Journal of Earth Sciences in March of 2026.

[00:04:43]Kasmosaurus is one of the archetypical sereratopsian dinosaurs. It lends its name to its entire group, the Casmosaurin, to which such famous faces as Taosaurus and Triceratops belong.

[00:04:57]Like many dinosaurs found and named at the end of the 19th and start of the 20th centuries, it is known from dozens of specimens ranging from worldclass to pitiful eroded mush. The very first remains that would go on to be called Casmosaurus were found by Lawrence Lamb of Lambiosaurus fame in 1898 near Berry Creek, Alberta. This specimen was crappy by today's standards, just the bar that separates the two holes puncturing the frill that rudely breaches the back of the sereratopsian skull and a little bit of the border of the middle part of said frill. This specimen would become the holotype or namebearing specimen used to describe a species of monoconius belli.

[00:05:43]Monoconius is a convoluted dubious waste basket name with an extremely long history inappropriate for this video.

[00:05:50]Suffice it to say, the name didn't stick. And around 20 years later, paleontologist Charles H. Sternberg and his sons would find many more skulls in Alberta with striking similarities to the original material. enough to pull it out of the then valid monoconius genus and into a new one. Their first idea was to go with protoosaurus in reference to the giant toosaurus of the US southwest. But the name was taken by an arosaur from the perian that used the root words to mean early reptile rather than before toosaurus. I mean hey that just means protoosaurus or archoaurus are still available. They went with kasmosaurus, which means opening reptile, because of them big old holes.

[00:06:38]Over the next 80 years, scientists found dozens of specimens from Canada that look quite a bit like the ones used to name Kasmosaurus Belli, with some sporting all manner of minor or major differences that have had these scientists coming up with all sorts of nifty names and analyses for these names. One of these was a second species of Casmosaurus that has been around nearly 90 years only to be finally slain in a completely satisfactory manner.

[00:07:07]That second species is called Kasmosaurus Russelli in honor of the guy who found it in 1936, Loris Russell. It was described by Charles M. Sternberg in 1940 in the Journal of Paleontology using a single moderately wellpreserved skull as a holotype. a skull missing a frill for the parype, a crappy frill border, and then one other specimen for good measure. The holotype CMN or CMN FV8800 is nearly an entire skull missing only the jaw and half of the frill. It was found by Russell while doing geological survey work for the Geological Survey of Canada in the many berries area of Alberta, specifically near the former 14 research station.

[00:07:52]The holotype skull is the only one here that contains enough information for a species or genus level description scientifically. Anyways, the others lack the important parts of the frill that can help distinguish between species.

[00:08:07]For the next half century, scientists would place a whole bunch of other cosmosur specimens into the species. So much so that other named species of kasmosaurus would get lumped into it or split out of it.

[00:08:24]Kasmosaurus Kaiseni was named based on a nice skull with a rather long brow horns which was taken out and used to name Moeratops before being sunk into Casmosaurus Russelli once again. Funnily enough, the species Casmosaurus Canadensis was implied to belong to the Mohoeratops genus before it got sunk back into Casmosaurus belly.

[00:08:47]Plenty other specimens that have been placed into either Casmosaurus Belli or Russelli have had researchers questioning their validity for decades.

[00:08:56]There have been a few teams to re-evaluate what has been deemed Casmosaurus, especially with the new discoveries along the Rocky Mountains from Canada down to New Mexico. Plus, the giant penteratops and its many relatives throw a bunch more chaos into the mix.

[00:09:12]Paleontologist David Evans and colleagues rediscovered the quarry site where the holotype of Casmosaurus Russelli was found. In doing so, they found that the rock deposits that let go of the skull belonged to the upper portion of the dinosaur park formation, meaning the skull was from the Campanian age of the late Cretaceous, which is slightly different than the horizons from which all other specimens referred to Casmosaurus Russelli or even Kasmosaurus itself are from.

[00:09:43]See this diagram here? This is a rough estimate of where a bunch of casmosaur skulls have been found in relation to one another and within the dinosaur park formation.

[00:09:54]Specimen CMN2280 a reported kasmosaurus russeli is at the bottom followed by tmp 1979.011.0147 tmp 1981.019.0 0175, UALVP 40, and CMN8801.

[00:10:17]Skulls that seem to belong to the Casmosaurus genus, but of an unknown or indeterminate species.

[00:10:24]Then there's YPM 2016 and ROM843, Casmosaurus belly, followed by ROM839, an unknown species of Kasmosaurus.

[00:10:36]CMN2245 Casmosaurus Belli.

[00:10:40]Then there are four specimens much closer to one another in time and space than the others. TMP 1993.082.00001, an unknown Casmosaurus species. TMP 2011.053.0046, a specimen of Vegaeratops, which was considered a species of Casmosaurus for a long time.

[00:11:04]CMN8800, the holotype of Kasmosaurus Russelli and the topic of this video, and then TMP 1987.045.001, another specimen of Vagoseratops.

[00:11:17]To the upper left of the diagram, you will also see CMN4137, the holotype of Vegaeratops, and TMP 1998.102.008, another possible Vegaeratops specimen.

[00:11:32]This segregation of casmosaur specimens in time and strategraphy throughout the dinosaur park formation means that the holotype of kasmosaurus russeli cmn8800 is separated from all other specimens applied to the kasmosaurus russeli species by as much as a million years.

[00:11:51]Enough to question whether they would all be the same species.

[00:11:57]Hey, um mind if I just butt in real quick? Just uh throwing out a little reminder to subscribe and like this video. Share it around as much as you can. The more eyes the better.

[00:12:12]So, Robert Holmes, Jordan Malone, Michael Ryan, and David Evans all took another close look at the original skull to see if it really can be considered a casmosaurus.

[00:12:23]This involved turning all its anatomical features into data to put into software that compares that data to the data collected for a bunch of other critters that have already been collected or are used from other researchers. In this case, the team used the data set from Mark Loen and team's description of the asymmetrically frilled Lokiatops from 2024 to see where the holotype specimen of Casmosaurus Russelli would fit.

[00:12:50]Phogenetic analysis can spit out a few different results depending on how you weigh each trait, how many traits you use, how many other critters you compare, and so much more that we don't necessarily need to get into it right here. Suffice it to say, the Holmes team got three major results. One had Casmosaurus Russelli most closely related to the Penteratops part of the tree. One had it most closely related to the Casmosaurus part of the tree. and one was ambiguous and unable to commit to either part of the tree. This looked to the team like enough to justify pulling Kasmosaurus Russelli out of the Casmosaurus genus and into a new one.

[00:13:30]So, they came up with Kryparus or hidden arch.

[00:13:39]Okay, that's neat. But what about all the other specimens that were considered part of Casmosaurus Russelli? Well, since the team renamed the holotype of Casmosaurus Russelli, and since it turned out that the most important anatomical traits of that holotype were distinct from many of the specimens put into the species, the rest are now temporarily indeterminate casaurs of some type. Many of them were indistinct enough to already be casaurs of some type, but others are distinct enough with enough information preserved to potentially be reassigned to a new genus or species down the road.

[00:14:16]Interestingly, in their quest to redescribe and rename specimen CMN8800, the team found another specimen with the same type of information preserved to identify it as part of the new genus.

[00:14:28]Specimen TMP 2013.019.0038.

[00:14:33]This thing is pretty dang fragmentaryary. It's just the bar that goes in between the holes of the frill with a little bit of the top margin, but it matches the same bone in the Cryparus skull. It was found in Dinosaur Park Formation Horizons in the 14 area by Wendy Sabota, namesake of Wendyeratops in 2013 on the Sage Creek Reserve about 5.7 km east of the spot where the holotype skull was found. That's cool.

[00:15:01]We have a new sereratopsian. And it was hidden in plain sight.

[00:15:06]I don't want you to take away from this that paleontologists of the past were stupid, ignorant, and didn't know what the hell they were doing. They did. But more data is more data. There are now three to four times more sereratopsian dinosaurs known to science than there were when they named this thing Casmosaurus Russelli. Plus, now we have rather advanced computer hardware and software. We can reveal anatomical structures that were never observed with the naked eye that can help to place a critter more accurately into an evolutionary context. All good stuff really. There was even a more recent example of this. Another species of Kasmosaurus was named in 2001, Kasmosaurus Irvineis. It wouldn't be until 2010 that it was found to be too distinct and renamed Vegaeratops Irvineis.

[00:15:53]There is plenty of individual variation among dinosaur species, and scientists will continue to get to the bottom of what exactly constitutes this individual variation versus interpacific variation.

[00:16:06]So, what does this all mean for the new dinosaur? Well, not much. Since this thing is very similar to Casmosaurus and has been a species of Casmosaurus for so long, not much changes on a practical down and dirty level. The major change is in how the critter is used in hard quantitative studies. But it also helps to broaden the understanding of dinosaur communities during the late Cretaceous as well as how these critters evolved.

[00:16:31]Kryparus rivals the largest known skulls of Casmosaurus, so it probably got to a similar size. Let me bring in Mr. Man from >> Animal Planets the most extreme >> to show you really quick.

[00:16:47]Cosmosaurus has been estimated to be around 4.8 m 15.7 ft in length and around 2 tons. So Kryptorus would have been rather similar here. This is considered midsize foreratopsian with the biggest members Triceratops, Torosaurus, and Penteratops.

[00:17:04]Thanks, Mr. Man.

[00:17:11]Cryptoarcus would have had a long lowprofiled skull with narrower jaws than the centsaur part of the sereratopsian tree. This was not much changed from kasmosaurus and both animals had much shorter brow and nose horns than other more famous sereratopsians.

[00:17:27]The biggest difference is in the frills.

[00:17:30]CMN 2280. This guy right here was originally put into the Casmosaurus Russelli species. It's now an indeterminate species of Casmosaurus and technically the oldest form of the genus known. It had three lumps of triangular bone per half of the frill. Those lumps are called eposipitals.

[00:17:48]The frill is sort of shaped like a flattened cartoon heart.

[00:17:53]Room 843, a definitive member of Casmosaur's Belli, has a much more V-shaped frill with as many as four epicipitals, including a very fused one close to the center of the frill.

[00:18:06]This one, CMN 2245, has a much more square shaped frill with two big pointy epicipitals sticking out of the corners of the frill.

[00:18:15]If we take a look at a few different frills really quick, you will see a good comparison of shapes. Here's a guaceratops, Utaheratops, pentaceratops, a potential penttoeratops, cmn 2280, rom 843, and our kryptonarcus frills. As you can see, the cryptoarcus frills seems most like utriceratops and penteratops. It even has some epicipitals folding in towards the middle of the frill. Perhaps a detail missing in some of the paleo art of this animal, but it might reflect a change in how these animals evolved.

[00:18:52]Another interesting thing is that the Casmosaurus lineage/claid has a nose horn roughly in the middle of the snout. Kryparus has a nose horn position closer to the brow horns, serendipitously like that of Utaher.

[00:19:07]Something that kept Kryptonarcus hidden for so many years is the level of resorption of its horns. Where the bony core of the horns is absorbed, gnarly, stumpy horn cores replaced it. The brow horns are resorbed, and so is the nose horn to a certain degree. This isn't something that every cryptocarcus would have had, but rather something this individual presented.

[00:19:31]Resorption usually occurs in older sereratopsids.

[00:19:35]When you consider the Penttoeratops lineage, one might think of long brow horns. And when you consider the Casmosaurus lineage, you might think of short stubby brow horns. And so did paleontologists for decades. Due to the short resorbed, almost missing brow horns of CMN 8800. People attributed it to Casmosaurus. However, with new discoveries such as Utriceratops, an older member of the Pentaceratops lineage with short brow horns, it's now understood that members of the Penteratops lineage around 76 million years ago, had short stubby brow horns as seen in both Cryptoarcus and Utriceratops.

[00:20:13]By the time of Penteratops, long brow horns were all the rage in Casmosaurine fashion and would stay as a staple of this group till its end with Triceratops.

[00:20:27]Let's take a quick trip back in time to the 2024 Danny Barrera Gua LE paper that reassessed the geological formation that the Mexican Goiliceratops belong to. I made a video about this paper, so you should just go watch it before continuing this video. Link in the description and comment section below or watch it after this video. In that paper, the team hypothesized a paleobiogeographic evolutionary scenario for Laramidian North American Xeratopsians.

[00:20:55]This author team included CMN8800 in this scenario back when it was named Casmosaurus Russelli.

[00:21:03]The scenario shows a contiguous sereratopsian population around 81.5 million years ago along the coast of the western interior seaway which gets separated by the transgression of the sea by 81 million years ago. These separated populations became distinct by 80.5 million years ago. The sea regresses allowing the two populations to coingle represented here at 76.5 million years ago by Vegaeratops and Kryptorus.

[00:21:31]This intermingling produces new forms by 76 million years ago. Like Cosmoseratops in the north and Utriceratops in the south now walking across North America now that the seaway has receded.

[00:21:43]explaining the 2025 report of cosmoseratops found in Wyoming, which has still yet to see any official scientific publication. The northern cosmoseratops lineage goes extinct by 74 million years ago, leaving only the penteratops lineage, with Kryparus and Vegaeratops possibly the earliest member of this lineage. By 73 million years ago, we start to see the Penticeratops lineage make its way further north as the sea regresses, only to be cut in two again by the transgression of the sea, eventually resulting in the Ankiseratops lineage in the north and the Triceratopsin lineage in the south. With that southern lineage allowed northward as the sea regresses again, it pushes out the northern lineage with Regaleratops, the last known example by 68.5 million years ago.

[00:22:31]This scenario is not actively contradicted by the Kryparus team, but they offer up a different scenario that does not see anesenesis of a bunch of American Southwesterians as part of the pentaceratops lineage. Instead, they posit that all of these animals are splits or branches of the same tree. In other words, perhaps Scryparus is part of the Casmosaurus group that convergently evolved Penttoeratops-like features. Only more specimens that help fill in more gaps will help clear the situation more. Or maybe they will make things even more complicated.

[00:23:07]With the evolutionary parts out of the way, what could we expect Kryparus to have seen when it was alive? Since Kryparus comes from the top of the dinosaur park formation, it may have been living alongside dinosaurs such as Skolasaurus Thronis, Straosaurus, Vegaeratops, Lambiosaurus, Proerolophus, Spheratholus, and Desptoosaurus, Wilsoni, plus all sorts of other critters like Ashtaritasaurus, mini mammals, too many turtles, possibly freshwater plesiosaurs, bunch of crocs, fish, amphibians, invertebrates, and much more. It was potentially the standout of the penteratops lineage accompanied by the centsaurs and the cosmoseratops-like casmosaurs like veereratops.

[00:23:54]Hopefully more of this animal is found someday whether in the field or under our noses.

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