Ceratopsians: my week long research and my life long love

Ceratopsians

I spent all day curled up in my recliner reading and browsing through websites, learning whatever I could. Since I was sick today, I was chair bound and not really going to get much housework done anyway. I figured the best way to spend a sick day is to learn about something amazing.

I don’t know why I suddenly became overcome with wanting to research into this group of dinosaurs, but the journey has been pretty damn entertaining. To be honest, I only knew very basic information about this species when I started, probably about the same as any dinosaur fan when they first get into a species they really like. I knew and adored the common rock stars, Triceratops, Styracosaurus and Torosaurus, but didn’t know a lot of the scientific details about them.

I wanted to know about the classification process, what they knew about the uniquely ceratopsian features of horns and frills, and what they knew so far about the evolutionary process for these animals. I was really amazed to find out the extent in which is known about these creatures, and what is still being heavily debated.

These animals have been one of my favorites since I was a little kid, so getting to dive off into the deep end of the research pool was a blast. I feel like I've had a chance to revisit an old friend as a grown up and have a whole new appreciation for these amazing dinosaurs. I've learned so much, so I hope I get a chance to share with you something you may not have known before.

Off on a side note, I will say that reading through scientific literature has made me realize how much I’ve slipped in my education. I guess spending several years away from universities and being immersed in academic studies has made my brain a little mushy.

I could tell you all about the last episode of Adventure Time I watched, but was stumped when it came to what which order “clade” fit in the classification order. Since I was having such a hard time with some of these terms, or had to have a refresher on some of them, I decided to put in a vocabulary section to help incase any of you were in the same boat as me. If not, don’t tell me, just humor me by smiling and nodding, please.

I will also admit that I used two books for this research but a lot of quick references through the internet. The bulk of what I looked into I read from the books I had at my disposal, but for general questions I used Wikipedia, which I know isn’t always the best. I tried to use information from universities if they were available, but honestly Wiki is the best for when you get stumped on what a species is called or something simple like that.

• Terms/Vocabulary -- I learned a bunch of new terms and words I had never heard before while diving into some of the more scientifically heavy reading.
• Monophyletic: In common cladistic usage, a monophyletic group is a taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants.
• Marginocephalia: a clade, or group, with thick skulls made up of Ceratopsians and Pachycephalosauria.
• Jugles: term used for dinosaurs, birds, crocodiles and lizards for their cheekbones.
• Epoccipitas: spikes along the frill.
• Sexual Dimorphism: The physical differences in species based on their sex. i.e. color, size and shape.

• What makes a dinosaur a “Ceratopsian” dinosaur?

Ceratopsian dinosaurs are herbivorous, quadrupedal animals (walked on four legs) with large face horns and large cranial frills coming from the back of the skull. These guys are known as “thick skulled” or Marginocephalia, which is actually the same classification as the Pachycephalosaurus, or the dudes with the dome head who people usually imagine slamming their heads into each other like bulls. I don’t honestly know if they actually do that, so I’ll have to do some research on that topic. I want to say the last thing I had read was that this behavior is still widely debated.

Back to the horn-faces.

Each species looks a little different in either the shape of their frill or horns, but all of them have those defining characteristics along with a beak and “exaggerated jugles”, or weird looking cheekbones. They most likely had rough, pebble skin without feathers or hair and wide feet with digits and padding. We know about their skin because of fossilized skin impressions that show how their what the skin’s texture was.

When I looked into how fast they could move, the most common answer I could find was they were faster an an elephant for sure, and probably about the same as a rhino. Rhinos, fun fact, run about 35MPH, so that’s pretty nightmarish.

Diabloceratops saying "Eeey"
Art by Ramon Garcia

So, why a beak?

Other than the horns and frills, the Ceratopsians having a beak is also pretty unique, but not entirely exclusive. According to what I read in The Dinosauria, these beaky horn-faces had a pretty impressive dental battery and a powerful bite force, which means they could much down on really anything they could find. With them being such large animals, finding enough food to sustain them must have been tough, so adapting to be able to get nutrients from anything they could is a great advantage.

The beak was most likely used to grab strongly onto plants and break them loose to eat, which makes sense since a lot of ancient plants were thick and tough.

• Ceratopsians are broken down into groups:

• Two Groups
• Centrosaurinae: no brow horns but one big nose horn and long or exaggerated frill spikes or “epoccipitas”. Examples: Centrosaurus, Styracosaurus. This group is further split into another subfamily called pachyrhinosaurini, which has the weird turkey head looking horned dinosaurs.
• Chasmosaurinae: brow horns, nose horn and sometimes long, skinny frills. Examples: Triceratops, Chamosaurus. Regaliceratops.

In each group, their defining characteristics are the shape of their frills and what kind of horns they have. The horns functionality is pretty obvious, but the purpose of their frill is really waht interested me. What is that for, exactly? And why do they look so different between species?

The reason and functionality of frills is actually still widely debated. I remember when I was a kid, I read that the frills were used to protect the neck of the animals from large theropods that are always a threat. The frills would act like a knight’s shield to block the incoming death from above as the massive jaws tried to grab onto their necks.

This doesn’t seem to be the theory so much anymore, as the recent studies of the frills show that they actually weren’t very strong and filled with lots of blood vessels. Having a pair of massive jaws clamp down on the frill would most likely break the bones and cause massive bleeding.

The more accepted theory nowadays is that the frill was probably used to warn off predators or attract mates, or both. Since the frill did have so many blood vessels in it, it most likely was able to flush with blood to display colors for these purposes. Both males and females had frills and horns, so I think it’s pretty reasonable to think that their frills had many purposes in displaying intimidation and signaling to each other.

• Sexual Dimorphism

The reason I brought up the term “sexual dimorphism” in the vocabulary, is because a big reason for the disagreement in species is over this. Every species has differences between the sexes biologically, thus making males and females look different. Sometimes this is very obvious: in deers only males have antlers, or how in certain birds the males are brightly colored, whereas in other species the differences are more subtle. The tricky thing with dinosaurs is, well, they’re aren’t any around to study while alive. Going off of just the skeleton is tough, because we don’t know which ones were male and female right away.

I dug into how paleontologists could tell the difference between sexes in dinosaurs and ended up finding a paper about it. It covers a broad range of dinosaurs, but I locked in on the clues used for specifically Ceratopsians. I got lucky in this case, because apparently the sexual dimorphism examples in this species is widely accepted, were as the ground is still pretty shaky in a lot of other species. The reason for that is because there have been so many different specimens of Ceratopsians found.

It seems that the horn morphology is what’s going to be key in figuring out if a Ceratopsian is a male or female, at least in the case with Chasmosaurine Ceratopsians, with male horns pointing up more, were females horns face more forward.

For Centrosaurine clade, the frill shape is going to be what determines more of the sex since they don’t have the brow horns. This is a bit trickier because the frill changes shape as the animal grows into adulthood. This classification seems to be still debated, because it is hard to tell the difference between smaller species of Centrosaurine and ones of the same species who just haven’t hit puberty yet.  

Ethser Van Hulsen

I had meant to get this post out much earlier, but I wanted to make sure the research I started was all fully sited and made sense. I guess I accidently fell off a science ledge on this one, because I kept coming up with more questions that needed more digging.

I hope I covered all the ground that there could possibly be about basic knowledge for Ceratopsian dinosaurs, without writing a book about them. This was a lot of fun and I enjoyed myself, so I hope it’s fun to take the journey with me as well. I think I’ll do this again with another species, maybe try Saurpods next time around. That’s another species I really adore and don’t really know a ton about.

Just in case you wanted to hear more about specific species of Ceratopsians, there’s a great podcast I listen to called I Know Dino that has “dinosaurs of the day” on each episode. Here’s a list with links to the podcasts with Ceratopsians as their stars of the show:

• I Know Dino:
• Episode 15 -- Pentaceratops
• Episode 30 -- Triceratops
• Episode 42 -- Styracosaurus
• Episode 44 -- Pachyrhinosaurus

Triceracops from Kung Fury...cause why not?

Sources:

Chapman, Ralph David Weishample, Gene Hunt, and Diego Rasskin-Gutman Sexual Dimorphism in Dinosaurs Natural Museum of Natural History, 1997

Weishampel, David, Peter Doddson, and Haszaka Osmolska Dinosauria: Second Edition. University of California press, 2004.

Prim, Keiron Dinosaurs -- The Grand Tour: Everything Worth Knowing About Dinosaurs from Aardonyx to Zuniceratops Workman Publishing Co, 2013