Talk:Ceratosaurus/Archive 1

Unhinge its jaws like a snake?
A book I have states that the way Ceratosaurus's skull was built indicated it was probably able to unhinge its jaws like a snake, allowing it to swallow prey whole. I doubt that theory still stands, but are there any other sources discussing this? Jerkov 13:06, 14 July 2006 (UTC)
 * Bakker's Dinosaur Heresies discusses this to some extent on pages 264-266 (paperback). He talks about "how to swallow something larger than your head" and has an illustration of a Ceratosaurus gaping its jaws like a python. It never implies that it ate small animals whole, however. lawofmetal43 16:23, 20 January 2007 (UTC)


 * Hmmmmm... I've never heard that about Ceratosaurus. I really doubt it could un-hinge it's jaws.  If you look at a snakes lower jaw, it has a space that splits the jaw equally in half thus allowing it to un-hinge its jaws.  The same thing would have to present on the lower jaw of Ceratosaurus in order for it to un-hinge its jaws. Just as a reference, I compiled this from a bunch of different books and experiences. --Silverstag89 03:27, 19 November 2007 (UTC)
 * This idea was also discussed in Bakker's larger paper on how wide theropods could open their jaws. See the wide-gape illustration of Allosaurus, based on the reconstructions in that paper. I don't think the jay was 'unhinged', it just had a mechanism that allowed it to open really, really wide. Dinoguy2 (talk) 02:05, 20 November 2007 (UTC)
 * That's what I meant. Ceratosaurus was good at widening it's jaws, but not for swallowing prey whole, just for taking bigger bites out of its prey.  Most big carnivorous dinosaurs could do that like, as mentioned by Dinoguy2, Allosaurus and my favorite Tyrannosaurus Rex.  --Silverstag89 02:22, 2 December 2007 (UTC)
 * Actually I don't think T. rex had the wide-jaw adaptation. IIRC the paper only found it (or only studied) various allosaurs and ceratosaurs. Dinoguy2 03:35, 2 December 2007 (UTC)
 * What need it for after all? T. rex could cut to shish-kebab even hadrosaur bones.--Draco ignoramus sophomoricus (talk) 12:54, 29 May 2008 (UTC)


 * Snakes have the ability to laterally expand the front of the fleshy mandibula because the lower jaws are only connected in front by loose connective tissue. So both lower jaws front ends can fan out. Prey of any magnitude can thus be swallowed without any bony jaw obstruction. Note that the actual jaw joints at the back are thus not "unhinged", though the joint as a whole can be lowered due to the kinesis of the quadrate. The supposed Ceratosaurus mechanism is precisely the opposite: the lower jaw front ends would be brought more in line with each other, shortening the mandibula. The widening theropod joint is not in front but at the side of the lower jaw, allowing movement between the dentary and the surangular/angular. Both lower jaws can thus fold in, pulling the mandibula front to the rear, and the flesh of the prey with it. Perhaps also some more room for swallowing is created, though a bony size limitation continues to exist.--MWAK (talk) 10:02, 27 January 2016 (UTC)
 * I wonder whether Bakker's claims do warrant a mention, ? FunkMonk (talk) 13:52, 23 April 2018 (UTC)
 * Thanks, I forgot about that. Will see what I can add! --Jens Lallensack (talk) 18:13, 25 April 2018 (UTC)

Possibly confusing text in article
Having run through this article, there are a couple of places in which I feel the text is potentially confusing and I need help in clarifying.
 * 1. penultimate sentence of 'Discovery and species' section []: "While C. nasicornis remains the type species .......
 * 2. last three sentences of 'Paleobiology' section []: "A recent study by Bakker . confirmed that Ceratosaurs generally hunted aquatic prey, such as fish and crocodiles, although it had potential for feeding on large dinosaurs. The study also suggests that sometimes adults and juveniles ate together. This evidence is, of course, very debatable and Ceratosaurus tooth marks are very common on large, terrestrial dinosaur prey fossils."
 * - Ballista 05:19, 15 July 2006 (UTC)

What evidence?
"Evidence suggests that there may also have been a row of small spurs or even a low sail, along the spine." - Weaselly. (WP:WEASEL). What's the evidence? -- Writtenonsand 20:04, 13 September 2006 (UTC)
 * I don't know, and i'm inclined to remove it from displaying on the page until a cite is provided. I do know that osteoderms have been found, but this seems to imply Diplodocus- or iguana-style dermal spines.Dinoguy2 20:55, 13 September 2006 (UTC)

Conflicting Points
In "Discovery" it says that Ceratosaurus was larger than Allosaurus, but in Paleobiology the reverse is said. What should be done with these conflicting points? MelicansMatkin 22:30, 4 January 2007 (UTC)
 * I think that's based on an African specimen rumored to be very big. Either it wasn't really as big as claimed, or the biggest material was never published. Either way, I'll change this to reflect what's actually in the literature. Dinoguy2 00:58, 5 January 2007 (UTC)

Addition of an external link requested
I would like to add and external link  Are there any objections? Keith Irwin 15:03, 28 January 2007 (UTC)
 * The link is ok, but not for this page. As it mentions, the tracks cannot be identified to the genus level, and are Early Jurassic, making it imposible that they were made by Ceratosaurus. It does suggest there were made by Ceratosauria, i.e. some member of the larger group to which Ceratosaurus belongs, so it would be more appropriate on that page. Dinoguy2 16:05, 28 January 2007 (UTC)

scale graph
why does the scale graph for ceratosaurus make it look like its the size of Allosaurus? 24.208.55.168 18:56, 24 June 2007 (UTC)
 * Not sure actually... I remember hearing of very large Ceratosaurus remains that would indicate an animal of this size, but I'm having trouble finding sources now that I look for them. Dinoguy2 23:08, 24 June 2007 (UTC)
 * Article says 6-8m, and as best I can estimate, the image shows it about 7.2m. Debivort 23:20, 24 June 2007 (UTC)
 * I think it may be the pose and angle that's throwing me off. Just as a test I did a scale chart using the flat-on lateral view illustration. It comes out to the same length and same height if you measure them both, but it looks like a more reasonable size. Dinoguy2 00:08, 25 June 2007 (UTC)

Why was this scale graph removed from the main page?It shows a more accurate size for the average adult Ceratosaurus than the one shown now.Ever since programs like "Jurassic Fight Club",it seems to be the "in thing" for Ceratosaurus to be shown under sized while Allosaurus is sometimes exaggerated to be the size of the largest T.rex... —Preceding unsigned comment added by 69.140.198.147 (talk) 01:07, 8 February 2009 (UTC)
 * Well, the one in there now is about right for most specimens. Mine was based on a single, larger specimen so it doesn't really represent the typical size, just the known maximum. Maybe both should be included, with the caption mentioning one is average size and one is max? That said, the allosaur in that comparison is above average, looks to be about 11m long, average length for A. fragilis was 8.5m, so it's not really a fair comparison. Dinoguy2 (talk) 01:38, 8 February 2009 (UTC)
 * Animals always vary, and remember that the fossil records for most dinosaurs show the variety and various morphs of a genus over the span of a few million years, and so making pinpoint "size" estimates is an impossible science in most case. C. nasicornis, to my knowledge, is probably the most basal species and one found primarily in the Morrison arid plains alongside Allosaurs; the 6 meter/ 450 kg size estimates for it seem appropriate. C. dentisulcatus is present in both the Morrison and Portugal (a wetter, less Allosaur-dominated environment) and appears to be bigger (7-8 meters, 800-1000kg). Personally I'd vouche for showing a 6.5-7m Ceratosaur, but the current 6m does represent the best-known morph in the fossil record as of right now...I do agree, however, that the Allosaurus needs to be downsized to its relative "normal" size (8-9m). Forescore68 (talk) 22:11, 13 May 2009 (UTC)

Just something that bothers me...
I feel like I have to stand up for ol' Ceratosaurus sometimes, especially after its defamation in that bizarre Jurassic Fight Club miniseries where Ceratosaurus was too weak to compete with Allosaurus, last of its kind and dying out (?), etc....

my nitpickiness in this case is with the skeletal picture we have at the top of the article that appears- unless I'm nuts- to be those of a juvenile/ sub adult. This guy (Ceratosaurus) already gets pegged as undersized and feeble. There has to be a better fossil mount/ sketch/ life-like restoration to put as the "primary" picture here...the one we have IS good though and should be somewhere in the article.

If I'm just noticing things that don't matter, feel free to shoot me down...but that's my dinosaur improvement suggestion for the day. Forescore68 (talk) 21:36, 2 June 2009 (UTC)
 * All we have are these images: . The one with the Dryosaurus might be more impressive, but the Ceratosaurus in that image is kind of obscured. FunkMonk (talk) 22:11, 2 June 2009 (UTC)
 * Unless I get objections, I'm at least changing the lead picture caption to "juvenile Ceratosaurus...". It's definately a young individual and a good bit smaller and more gracile than the adults. Forescore68 (talk) 01:19, 11 November 2009 (UTC)
 * Have a citation for that? The thing behind it is Suchomimus, so no wonder it looks small in comparison. The largest specimen of Ceratosaurus was apparently 8 m, that's not very impressive, so let's not yearn for something that isn't there. FunkMonk (talk) 01:21, 11 November 2009 (UTC)
 * What? You act like I'm making some kind of push to turn the image into Godzilla. I don't have a source handy, but I am 100% certain that it's a juvenile specimen, no more than about 4.5-5.0m long, smaller than the type specimen, which, in turn, is one of the smaller Ceratosaurus specimens we have. The horn is undeveloped, the teeth are extrordinarily long, the arms are proportionally long, and the entire build is gracile- all indicative of a non-matured specimen. By the way, mid-shin high on a Suchomimus (which is how high the hips of the Ceratosaur are) is about 1.3m or so; an adult Ceratosaurus is a solid 2+ meters tall. I mean...look at your original photo: http://www.flickr.com/photos/puroticorico/326686264/sizes/l/ The Suchomimus would have to be Spinosaurus sized for that Cerat to be 6 meters long (note the Gallimimus/ Struthiomimus/ Ornithomimus also dwarfs it). It's a great mount but it's definately not an adult. I just don't like using juvenile mounts as lead pictures on large theropods, but as mentioned above, I feel like we owe it more to this genus than most. It's probably the best picture we have, yes, but I vote to qualify it. That's my soapbox. Forescore68 (talk) 03:38, 11 November 2009 (UTC)


 * Revisiting this, it has since occurred to me that most Ceratosaurus skeletal mounts around the world seem to be casts of that juvenile, long-toothed specimen. Is this photo of the original fossil? Apart from the holotype, the only larger specimen we have photos of is this one, which seems to be a cast of the "large" Utah Museum skeleton (note three spikes on nasal horns), but the photos aren't too great. I'm not sure what this skull is, maybe just a sculpt? Perhaps has more insights, and maybe thoughts on image selection... FunkMonk (talk) 19:53, 31 October 2017 (UTC)
 * Might be related to the attribution of adults to C. "dentisulcatus"... Lythronaxargestes (talk &#124; contribs) 20:27, 31 October 2017 (UTC)
 * Yes, that is the juvenile from Bone Cabin Quarry. I have slightly better pictures of it, will upload them soon. I also have photos of the mount in the Utah museum (and yes, User:Lythronaxargestes is right, it is indeed Ceratosaurus dentisulcatus from the Cleveland Lloyd Quarry); the mount is not entirely accurate however. And yes, that skull is a reconstruction, not a real one. Will upload everything I have as time allows! --Jens Lallensack (talk) 21:25, 31 October 2017 (UTC)
 * Ah, nice! Our sub-par image selection for this dinosaur has long irked me... FunkMonk (talk) 21:49, 31 October 2017 (UTC)
 * Here they are: . Not ideal either, but maybe a small improvement. --Jens Lallensack (talk) 12:11, 1 November 2017 (UTC)
 * Looks good, I'd say this photo of the Utah mount could be the new taxobox image, though something weird seems to be going on with the radius and ulna? FunkMonk (talk) 12:41, 1 November 2017 (UTC)
 * Yes, the forearms are quite uggly. But what I like is that one can recognize the skeleton easily even at thumb size, the background is not that distracting. As an alternative for the taxonbox, I was thinking about showing just the holotype skull (which shows the most distinctive features anyway), maybe, which certainly can be improved a lot with a bit of image editing. Perhaps we could use the lower one only. What do you think? --Jens Lallensack (talk) 16:50, 1 November 2017 (UTC)


 * Personally I think the Utah mount is good enough; though the forearm bones are weird, the hands are at least not in "bunny" pose, and the inaccuracy wouldn't even be visible at thumb size anyway (see right). The mount used in the taxobox at Baryonyx has similar problems, for example, but it looks pretty good at thumb size as well. As for the B/W picture, isn't it basically the same as this cast? That picture might look even better with a white background and better contrast... FunkMonk (talk) 20:19, 1 November 2017 (UTC)
 * Ok I will use the Utah specimen for the taxon box then! Yes, that is the cast of the holotype skull, but the B/W picture shows the original. --Jens Lallensack (talk) 20:25, 1 November 2017 (UTC)


 * First, my thanks to Jens for the new pictures! Secondly, it should be stressed that the radius runs from the outer distal condyle of the humerus, crossing over the ulna, to the inner side of the hand. So the mount correctly shows this, only the radius of the left arm has probably been axially rotated too much. Also the problem with the mount in this Triceratops picture is not that ulna and radius are crossed but that the hand is placed too pronated: Museum of Science, Boston, MA - IMG 3203.JPG


 * Many mounts incorrectly show an ulna running to the inside of the hand and a radius running to the outside.--MWAK (talk) 08:57, 2 November 2017 (UTC)
 * Yes, but a radius crossing over the ulna is only possible in mammals (and chameleons), so both mounts are incorrect in this respect. Of course, having the radius running to the fifth digit instead of the first would be much worse. --Jens Lallensack (talk) 10:19, 2 November 2017 (UTC)
 * Also, isn't the articulation with the humerus wrong in the left arm? I'd assume the ulna would articulate with the humerus below the radius, like here, but it seems the ulna has popped up somewhere behind the radius... Anyhow, I don't think it's enough of a problem, unlike in this Dilophosaurus mount, where the radius and ulna are placed too weirdly (reversed by the humerus?) to use in that article, which is annoying, since I'm about to work on it... FunkMonk (talk) 13:24, 2 November 2017 (UTC)


 * Well, the proximal end of the radius is lateral to the ulnar coronoid and the distal end of the ulna is lateral to the distal end of the radius, so the radius does cross the ulna in front view, although this is made less obvious by the olecranon. Indeed, the latter should contact the humerus below/behind the radius but it is hard to see whether it does in the Ceratosaurus image. The arm of that Allosaurus is of course much more massive. This image is also easy to misinterpret as the radius obscures the ulnar coronoid making it seem to contact, or be in line with, the inner condyle of the humerus. The Dilophosaurus picture perhaps shows the distortion resulting from trying to uncross the lower arm, resulting in an extreme pronation and the olecranon being wrenched to the wrong side ;o). Compare that to a real specimen showing a nicely crossed left arm: https://qilong.wordpress.com/2011/08/12/incredulous-teeth-i-with-twin-crests/ --MWAK (talk) 17:48, 2 November 2017 (UTC)


 * The weird thing about the Dilophosaurus mount is that the left forelimb is rotated almost 90° out of its natural position, with the palm of the hand facing to the outside rather than to the inside. The inability of active forearm pronation in dinosaurs is current consensus. The primitive condition in tetrapods is semi-supination, meaning that radius and ulna are parallel to each other, with no crossing possible. So any rotational movement of the forelimb must have come out of the shoulder, at least as long as the forelimb is held straight: if forearm and humerus are at an angle to each other, like in sprawling reptiles, it is no problem to achieve an pronated manus while retaining parallel forearm bones. This is the problem with the Dilophosaurus mount: While ulna and radius are not crossing each other (which is correct), any rotation of the forearm was very limited because the forelimb is mounted in a straight posture. --Jens Lallensack (talk) 19:26, 2 November 2017 (UTC)


 * My point is that while it is common to describe the ulna and radius as "parallel" when the proximal radius cannot rotate much in relation to the humerus, they really aren't. Even with Tiktaalik the radius is placed medial in anterior view and contacts the humeral outer epicondyle. You can always find an angle at which they cross. In various dinosaur groups, this effect is stronger. So a "crossing ulna and radius" does not necessarily imply the mount is wrong. Now, Ceratosaurus probably was pretty stiff in the elbow, to judge by the flat proximal end of its radius. I know this because I just consulted the 2016 study to confirm a nasty suspicion, which I developed when I enlarged this image:


 * On the right hand it seems that the presumed radius has a glenoid joint and a collateral ligament pit. They must have used some casts of theropod metatarsals as stand-ins! This might explain why the lower arms looked so strange.--MWAK (talk) 19:25, 3 November 2017 (UTC)

Ceratosaurus ingens
Rauhut (2011) finds ceratosaurus ingens to be a carcharodontosaurid and not a ceratosaur as hypothesized by Paul (1988). He also confirms Ceratosaurus stechowi as being ceratosaurian, even though lacks diagnostic characters to place it in Ceratosaurus.

Rauhut, Oliver W. M. (2011). "Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)". Special Papers in Palaeontology 86: 195-239. doi:10.1111/j.1475-4983.2011.01084.x.68.4.61.168 (talk) 02:27, 11 January 2012 (UTC)Vahe Demirjian
 * I have updated the article accordingly. FunkMonk (talk) 02:39, 11 January 2012 (UTC)

UUVP 81 and UUVP 56 specimens
Have they've got their names changed? I can't find them on "The Therapod Database" and they list the type specimen of C. dentisulcatus as UMNH 5278, also, Scott Hartman, in a reconstruction he made from 2010 showing the growth of Ceratosaurus mentions that his adult Ceratosaurus is the type specimen of C. dentisulcatus from UMNH. Mike.BRZ (talk) 20:53, 9 June 2012 (UTC)
 * Yes, I believe the UUVP specimens have been re-catelogued in the UMNH. Unfortunately specimen numbers change whenever they are transferred between institutions. MMartyniuk (talk) 13:46, 11 June 2012 (UTC)


 * I declare that I was a bit ignorant about the meaning of the letters so I started searching after I made the post, it just felt just too obvious!, anyway, I guess we've got to change them, though, I don't know what UUVP 81 numbers might be now.. this post on the dml kind of makes it harder, but then there's this information on dinodata:


 * Type: MWC skull & skeleton, Brushy Basin Member Morrison Formation, Fruita, Colorado.
 * Referred specimen: UUVP disarticulated skull & skeleton (UUVP 47-49, 53, 56, 66, 80-81, 83, 155, 158, 170, 173, 212, 234-236, 272, 316- 317, 327, 329, 355, 365, 375-378, 433, 438-439,531-534, 549, 562, 674, 677, 1035, 1053, 1229, 1231, 1615, 1646, 1979,2172, 3729, 5658, 5681-5683, 5911, 5959-5960, 5982, 6305, 6520, 6739, 6743,6788, 6857, 6933, 6935, 6938, 6940-6941, 6945-6949, 6951-6956, 6958, 6961-6968), Cleveland-Lloyd Quarry, Utah. The UUVP skull/skeleton are now at the Utah Museum of Natural History, catalogued as UMNH 5728.


 * Could it be that they're the same specimen? Mike.BRZ (talk) 18:39, 11 June 2012 (UTC)
 * Yup. It looks like what probably happened here is that when the UUVP had the specimen, they gave each bone a different specimen number. Then when it was given to the UMNH, that museum cataloged the whole skeleton under the single number 5728. MMartyniuk (talk) 18:51, 11 June 2012 (UTC)
 * Now the problem is that comparison image is wrong... MWC 1 is barely bigger than the holotype (like 2%) and certainly won't dwarf UMNH 5728. Mike.BRZ (talk) 21:02, 11 June 2012 (UTC)
 * There was a typo in the post from dinodata, the correct number (and what Micky Mortimer has on the Therapod database) is 5278. Mike.BRZ (talk) 20:50, 4 July 2012 (UTC)

Ceratosaurus species
I was reading Carrano et al. 2012. The phylogeny of Tetanurae. and they consider that there only exists one species of Ceratosaurus, in agreement with Carrano and Sampson, 2008. The Phylogeny of Ceratosauria. I'm now reading the 2008 paper to see how they got that conclusion. Do you think the article should be updated accordingly? Mike.BRZ (talk) 22:17, 18 December 2012 (UTC)
 * Carrano and Sampson (2008), Rauhut (2003) do not accept the species named by Madsen and Welles (2000). They argue that the anatomical differences between these species could simply be intraspecific (differences between individuals of the same species) or ontogenetic (age dependent) variations. Other studies still accept the validity of these species, though. --Jens Lallensack (talk) 22:52, 18 December 2012 (UTC)
 * In Carrano and Sampson (2008) it reads as the supposed differences are pretty much only based on size, attributing them to, like you said; individual variation and ontogeny. I don't know if there are others but including Carrano et al. (2012) there are at least 3 papers supporting the "one species" hypothesis and being phylogenetic studies I think they'll have a little more weight but I don't know... I think I understood now what you're trying to say, it won't be changed unless there's a complete consensus right? Mike.BRZ (talk) 23:12, 18 December 2012 (UTC)
 * If not removed should they be at least marked with a "?" in the taxobox? I think that and a mention of the issue on the article should be added. Mike.BRZ (talk) 00:49, 19 December 2012 (UTC)
 * I have changed the article. There may is a consensus about these species not being valid, but I do not want to decide that. In "The Dinosauria" (2004), they argue in favor of these species, contra Britt (2000) who was the first to doubt their validity. --Jens Lallensack (talk) 19:49, 19 December 2012 (UTC)

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History of discovery
In the article, the error: the holotype of ceratosaurus USNM 4735, not USNM 4737 (Anatasaurus annectens) — Preceding unsigned comment added by 188.242.60.83 (talk) 06:53, 7 April 2018 (UTC)
 * Thanks, it is fixed! --Jens Lallensack (talk) 07:10, 7 April 2018 (UTC)

predatory
Johnboddie and I are working on a TFA blurb for this one. I don't have a good feeling about "predatory". It seems a little ambiguous. Apex predator? Carnivorous? Aggressive? Also, in common speech, the word almost always means "unscrupulous" rather than "like a predator". Thoughts? - Dank (push to talk) 21:07, 5 December 2018 (UTC)
 * Well, in biology, it only has one meaning, which is this. There is even a very well-known book called "Predatory Dinosaurs of the World". But carnivorous could work, it just doesn't imply that it was hunting as well. FunkMonk (talk) 21:11, 5 December 2018 (UTC)
 * "predator" (no -y) is certainly fine, let me see if I can use that. - Dank (push to talk) 22:14, 5 December 2018 (UTC)
 * I moved "predator" down to the "deep jaws" sentence ... see if that works (User:Dank/Sandbox/3). The January TFAs will be scheduled in a few days.

There's a suggested change to the blurb at WT:Today's_featured_article/January_2019. I don't agree, but I don't feel strongly about it; whatever you guys want is fine. Are there any other problems with the blurb? Pinging the FAC nominators and supporters: Jens Lallensack, FunkMonk, Epicgenius, Casliber. - Dank (push to talk) 15:22, 6 January 2019 (UTC) Dudley Miles. - Dank (push to talk) 15:23, 6 January 2019 (UTC)
 * Can't say I have a strong opinion on commas, I'd go with whatever Jens thinks. FunkMonk (talk) 15:53, 6 January 2019 (UTC)
 * I slightly prefer the current version (because the Formation is mentioned last), although the suggestion seems also fine. --Jens Lallensack (talk) 21:42, 6 January 2019 (UTC)