Ceratosaurus and Dryosaurus

I’m not quite out of Canegie photos yet, so here are the mounted Ceratosaurus and Dryosaurus. My first of either and while it is cool to see a young Ceratosaurus (I simply didn’t know there were specimens of animals this size) I must confess I had hoped to see an adult Allosaurus-sized individual. Still these are both classic Morrison taxa and added still more to my ‘first time’ list of species that I got from this trip to the U.S.

25 Responses to “Ceratosaurus and Dryosaurus”


  1. 2 reptilianmonster 10/01/2012 at 3:12 pm

    I’ve often read that Ceratosaurus had really long tooth crowns but sheesh! Those maxillary teeth look ridiculous. I can’t really tell from the photo; is that all/mostly crown action we’re looking at or are they hanging by the roots like in some casts of the Stan’s (I think) skull?

  2. 4 Bruce J. Mohn 10/01/2012 at 3:57 pm

    I’m not sure how complete the larger specimens of Ceratosaurus are. The skeleton at the Smithsonian is also rather small. What is the length and height of the Carnegie specimen?

    • 5 David Hone 10/01/2012 at 4:34 pm

      I wasn’t that close to it, but maybe 4ft high and 8 or so long. Not big at all for somthing that should get towards 30 ft.

  3. 6 220mya 10/01/2012 at 4:41 pm

    The juvenile Ceratosaurus is based on a private specimen owned by Western Paleo Labs thats on display at the North American Museum of Ancient Life in Lehi, UT. It is a very nice skull and skeleton!

    Yes – Ceratosaurus does have long maxillary teeth, but as reptilianmonster supposed, these teeth have partially fallen out of their alveoli and are hanging by their roots.

  4. 7 Zhen 10/01/2012 at 9:09 pm

    I’ve been hearing that Ceratosaurus is aquatic/semi-aquatic. Is that true? No ,matter how I look at it, I don’t see a semi-aquatic animal.

    • 8 David Hone 10/01/2012 at 10:16 pm

      News to me. I really can’t conceive where that idea came from.

      • 9 Zhen 11/01/2012 at 2:03 am

        The only reference I can find is on wikipedia. It comes from: “Gilmore, C.W. (1920). “Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus”. Bulletin of the United States National Museum 110: 1–154.”

      • 10 Bryan Riolo 11/01/2012 at 2:27 am

        Maybe the powerful tail? Would a Ceratosaurus have been a good swimmer?

      • 11 reptilianmonster 11/01/2012 at 2:51 am

        Greg Paul speculates on it in PDW, stating (along the lines of Bryan Riolo’s comment),”The tail is both broad and deep, and unusually powerful, and may have been a sculling organ for swimming.”

      • 12 David Hone 11/01/2012 at 9:05 am

        Lots of theropods have ‘deep powerful tails’ that hardly makes them semi-aquatic, or even well adapted for swimming. It that’s the limit of the evidence (and the fish noted below) then colour me unconvinced.

      • 13 Zhen 11/01/2012 at 10:49 pm

        Yeah, that’s why I asked. This theory just doesn’t make sense. The tail definitely looks like every other theropod tail out there.

  5. 14 Bryan Riolo 11/01/2012 at 12:20 am

    As always, your photos are beautiful, inspirational, and very useful! Thanks!!!

  6. 15 Pete Ross 11/01/2012 at 3:18 am

    Wasn’t there a Bakker quote somewhere or another about Ceratosaurus hunting lungfish, citing evidence of associated Ceratosaur teeth with lungfish fossils?

    I’d love to see more images of Ceratosaur fossils, I think all I’ve ever seen it the Smithsonian stuff.

    • 16 David Hone 11/01/2012 at 9:04 am

      Well hunting fish doesn’t make something semi-aquatic. Jaguars can swim well enough and often go fishing, but I doubt anyone would consider them in the same arena as say otters.

      • 17 Pete Ross 11/01/2012 at 12:05 pm

        Yes, of course. I’m not endorsing the notion of semi-aquatic Ceratosaurus, just putting a thought out on what the source of that concept might be.

      • 18 reptilianmonster 11/01/2012 at 3:09 pm

        I’m not endorsing it either way. Subsequent to Paul’s observation, I seem to recall some credible source(though I can’t remember for the life of me who) stating that the tail of Ceratosaurus probably would not have not have been terribly efficient at sculling, at least compared to the deep-tailed scullers we have today like crocs and some of the monitors, because it would not have been flexible enough to execute effective horizontal undulations.

    • 19 David Hone 11/01/2012 at 12:13 pm

      Sorry didn’t meant to imply your were, just commenting on it.

  7. 20 Thomas R. Holtz, Jr. 11/01/2012 at 2:10 pm

    Even the biggest Ceratosaurus specimen (the type of “C. dentisulcatus” isn’t tremendously big: femur length of 759 mm (compared to, for instance, the small Allosaurus fragilis at the Smithsonian, with a femur length of 850 mm).

    I do not know if there are any mounts of this specimen or of the “C. magnicornis” reconstructed skeletons anywhere. There are individual bones on display, and I’ve seen the reconstructed skull of “C. magnicornis”, but no skeletons to my knowledge.

  8. 22 Darren Naish 12/01/2012 at 10:19 am

    The swimming Ceratosaurus stuff is from Bakker & Bir’s article ‘Dinosaur crime-scene investigations: theropod behavior at Como Bluff, Wyoming, and the evolution of birdness’ in the Currie et al. Feathered Dragons volume. Therein, Ceratosaurus is actually depicted as a tail-sculling swimmer that spends its time in the water, pursuing giant lungfish. I see that this was all covered in the comments at Tet Zoo ver 2.

  9. 24 Zhen 21/01/2012 at 3:01 am

    Hey Dave, they found your 30 feet Ceratosaurus. It’s Ceratosaurus dentisulcatus.

    http://blogs.smithsonianmag.com/dinosaur/2012/01/the-largest-ceratosaurus/


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