Anything Psittacosaurus

[wings]

Yeah I was hesitant to include prosauropods but sure I guess we can consider some of them obligatory bipeds too.  A while back I was working on an illustration of plateosaurus and didn't know whether or not to depict the female on all fours or standing on her hind legs.  I asked around and actually conversed with Heinrich Mallison via interwebs.  Here is what he had to say.

"Chris,
this is a tricky question, because it depends on how you use the term "prosauropods". Let's use it in the classic sense: covering all the basal sauropodomorphs. In that case, the answer is "some could, some could not".

The "Prosauropoda" is a fairly varied group, and if you just look at Plateosaurus and Riojasaurus in comparison it's fairly obvious that they have a high overall similarity, but quite different limb and body proportions. Plateosaurus was, as Bonnan and Senter (2007) and a certain German biomech guy showed, incapable of pronating its hands, had very short front limbs, with a very limited range of motion (Mallison 2010a, b, c). Add to that a short trunk, and you get an animal that is well balanced over the hind limbs.
Riojasaurus, in contrast, has a much longer upper arm, very likely (working off drawings here, have not seen the specimens) a differnetly arranged shoulder girdle and thus more motion range in the shoulder, and a longer trunk. That's a quadruped we're seeing. I made a nice comparative figure for Mallison (2010d), which I now uploaded here on my blog:
http://dinosaurpalaeo.files.wordpress.c ... plateo.jpg
That's the skeleton of Plateosaurus, with the arms scaled to the proportions of Riojasaurus. Note that I did not even scale the trunk!

So were prosauropods bipedal? Some of them were, some were not, and some certainly were capable of changing from bipedal to quadrupedal.

There is also a very nice paper by Jeff Wilson and colleagues (2009) on a trackway of an ornithiopod that might interest you: the animal was crossing a slippery slope, and changed from a bipedal, narrow-gauge walk to a quadrupedal, wide-gauge crawl! The feet even left drag marks from protraction! A threopod crsooing the same terrain simply dug in its claws, but otherwise didn't change its behavior much.

References

Bonnan, M.F. and Senter, P. 2007. Were the basal sauropodomorph dinosaurs Plateosaurus and Massospondylus habitual quadrupeds? In: P.M. Barrett and D.J. Batten (eds.), Evolution and Palaeobiology of Early Sauropodomorph Dinosaurs. Special Papers in Palaeontology 77: 139–155

Mallison, H. (2010a). The digital Plateosaurus I: body mass, mass distribution and posture assessed using CAD and CAE on a digitally mounted complete skeleton. Palaeontologia Electronica 13.2.8A (open access: HTML, PDF) FOR 533

Mallison, H. (2010b). The digital Plateosaurus II: an assessment of the range of motion of the limbs and vertebral column and of previous reconstructions using a digital skeletal mount. Acta Palaeontologica Polonica 55(3): 433-458; doi:10.4202/app.2009.0075 (open access: access to PDF) FOR 533

Mallison, H. (2011). Plateosaurus in 3D: how CAD models and kinetic-dynamic modeling bring an extinct animal to life. Pp. 219-236 in Klein, N., Remes, K., Gee, C. & Sander M. (eds): Biology of the Sauropod Dinosaurs: Understanding the life of giants. Life of the Past (series ed. Farlow, J.) Indiana University Press.

Mallison, H. (2011). Digitizing methods for paleontology – applications, benefits and limitations. Pp. 7-44 in Elewa, A.M.T. (ed.): Computational Paleontology. Springer.

Wilson JA, Marsicano CA, Smith RMH (2009) Dynamic Locomotor Capabilities Revealed by Early Dinosaur Trackmakers from Southern Africa. PLoS ONE 4(10): e7331. doi:10.1371/journal.pone.0007331"

I later found out from other sources that a few seemingly bipedal prosauropods were at least able to rest on all fours.  There are tracks from plateosaurus that show it resting its hands on the ground.  At the museum I used to illustrate for in NJ there was a trackway that included a resting prosauropod as well (hands on the ground beside the body, palms facing inward). 

Since my illustration was of plateosaurus I decided to let her hands touch the ground.  Doesn't mean she could walk that way though.  Does that make it an obligatory biped still?  I dunno haha.

So your answer is still some were and don't, right? I don't see how this is different to what has been said so far. My answer was always some do and some don't anyway (...There is evidence that shows some prosauropods are also obligate bipeds...). Are you also implying that being able to walk rest on all four indicates an animal to be "facultative biped" (Gryphoceratops:"...I later found out from other sources that a few seemingly bipedal prosauropods were at least able to rest on all fours.  There are tracks from plateosaurus that show it resting its hands on the ground...")? If that is the case then we also have crouching/resting theropod tracks as well but I kind of doubt that animal which made the track is an facultative biped... 

[Gryphoceratops]

Just adding to what was already said!  Thought an explanation as to why I didn't mention prosauropods with some nice information from a credible source would be welcomed no?  No need to argue

[wings]

I find all the help and suggestions most useful. I had posed the question earlier in this thread and will again...what else have I missed about this dinosaur? Is anything else incorrect or missing? Thoughts and suggestions would be appreciated. I had already pointed out the processes are missing for the verts. The coracoids were not preserved either. The pubic bone, as with most psittacosaurus mounts is not there either. I also made note the actual ankle bones were not intact. The ribs are of course replicas made from resin.Other than that, the fossil should be entirely original or at least genuine fossil. I believe there are some elements composited. The skull suffers from serious compression that collapsed the side and rear of the skull and had to be repaired. (lower orbital fenestrae) This makes the skull look asymetrical in top view. There are some teeth present in the jaws, however the mouth was fossilized shut and to attempt to open it would destroy the teeth present. The skull fossilized in a gorgeous purplish lavendar tint, making the teeth appear bright purple. The dinosaur is 25 inches long. I counted 67 verts down his back. Anything else? thoughts, suggestions?

The vertebral count for psittacosaurs is quite uniformal, they all seem to have able 70 odd number of vertebrae (8 or 9 from the neck and 13 or 12 on the body, 6 at the hip and about 45 on the tail) so 67 is very close. Well, this part is more speculative. I think the articulation of some of the ribs at the front should probably be sloping backward slightly rather than going straight up and down (as in Paul's 1987 paper http://gspauldino.com/Howto.pdf). His reasoning was that unlike mammals, most archosaurs have their anterior (front) ribs sweeping backward. I'm not sure whether this is a good enough reason to do so but for me I think that in most if not all of the well articulated Psittacosaurus specimens the front ribs were never found sweeping forward (if these ribs are attaching in a straight up and down fashion then you would expect to find that some of these (front) ribs would be preserved pointing forward and some of them would be sweeping to the back, but that's not really the case here). As in these examples:

http://earthlingnature.files.wordpress.com/2012/03/psittacosaurus_mongoliensis.jpg
http://www.dinocasts.com/images/products/Psittacosaurus%20sinensis64.jpg
http://upload.wikimedia.org/wikipedia/commons/0/0d/Psittacosaurus_gastroliths.jpg
http://upload.wikimedia.org/wikipedia/commons/3/3c/Psittacosaurus_holotype.jpg
http://skywalker.cochise.edu/wellerr/fossil/reptile/6dinosaur-Psittacosaurus-meileyingensis-kikkos328.jpg
http://upload.wikimedia.org/wikipedia/commons/e/e1/Machurochelys_liaoxiensis_and_Psittacosaurus.jpg

However, the problem in this is that it's going to be a bit tricky to make estimates when your specimen seems to lack the spines and transverse processes (as this is the part where one of the heads of the ribs attach to.
From the top, the ilia blades seems to be pinched a bit too close together as well. Maybe that area was forced together from compression of the surrounding sediments. 

[wings]

Just adding to what was already said!  Thought an explanation as to why I didn't mention prosauropods with some nice information from a credible source would be welcomed no?  No need to argue

I found that reply a little strange when you've mentioned "...Since my illustration was of plateosaurus I decided to let her hands touch the ground... Does that make it an obligatory biped still?  I dunno haha...", which could be misinterpreted as you are still thinking that none of the prosauropods could possibly be obligatory bipeds. Since that is not what you are saying as you stated from the last comment then good, I suppose we are not debating about this anyway.

[Gryphoceratops]

Just adding to what was already said!  Thought an explanation as to why I didn't mention prosauropods with some nice information from a credible source would be welcomed no?  No need to argue

I found that reply a little strange when you've mentioned "...Since my illustration was of plateosaurus I decided to let her hands touch the ground... Does that make it an obligatory biped still?  I dunno haha...", which could be misinterpreted as you are still thinking that none of the prosauropods could possibly be obligatory bipeds. Since that is not what you are saying as you stated from the last comment then good, I suppose we are not debating about this anyway.

I don't see how what i said is strange.  It means what I said it means.  There is evidence for it according to what some of their anatomies suggest but we also have tracks of them using their front legs at least to stand up.  When did I imply that i thought none could possibly be obligatory bipeds?  I put her on all fours because there are trackways of it.  Can't argue with that.    I thought including that nice blurb he sent me as well as a link to a paper would be cool to share.  It was never a debate.

[wings]

Just adding to what was already said!  Thought an explanation as to why I didn't mention prosauropods with some nice information from a credible source would be welcomed no?  No need to argue

I found that reply a little strange when you've mentioned "...Since my illustration was of plateosaurus I decided to let her hands touch the ground... Does that make it an obligatory biped still?  I dunno haha...", which could be misinterpreted as you are still thinking that none of the prosauropods could possibly be obligatory bipeds. Since that is not what you are saying as you stated from the last comment then good, I suppose we are not debating about this anyway.

I don't see how what i said is strange.  It means what I said it means.  There is evidence for it according to what some of their anatomies suggest but we also have tracks of them using their front legs at least to stand up.  When did I imply that i thought none could possibly be obligatory bipeds?  I put her on all fours because there are trackways of it.  Can't argue with that.    I thought including that nice blurb he sent me as well as a link to a paper would be cool to share.  It was never a debate.

Ichnotaxonomy is often quite tricky, we have the trackways but I don't know whether there is actually a paper where the author would make a definitive identification of the track maker. The prints that you've mentioned (I assume, since I've never seen these particular prints, not sure if they are in  a sequence or just resting since that wasn't in your description) would probably be make by a prosasauropod grade animal. Could this be made by Melanorosauridae grade animal or could this be made by Plateosauridae grade animal? Maybe it is actually from a Plateosaurus, perhaps?
I won't repeat on quotes again about what you said, since this is a thread on Psittacosaurus. I think arguing about this is meaningless and non-productive. So I'll drop this now.

[amargasaurus cazaui]

The vertebral count for psittacosaurs is quite uniformal, they all seem to have able 70 odd number of vertebrae (8 or 9 from the neck and 13 or 12 on the body, 6 at the hip and about 45 on the tail) so 67 is very close. Well, this part is more speculative. I think the articulation of some of the ribs at the front should probably be sloping backward slightly rather than going straight up and down (as in Paul's 1987 paper http://gspauldino.com/Howto.pdf). His reasoning was that unlike mammals, most archosaurs have their anterior (front) ribs sweeping backward. I'm not sure whether this is a good enough reason to do so but for me I think that in most if not all of the well articulated Psittacosaurus specimens the front ribs were never found sweeping forward (if these ribs are attaching in a straight up and down fashion then you would expect to find that some of these (front) ribs would be preserved pointing forward and some of them would be sweeping to the back, but that's not really the case here). As in these examples:

http://earthlingnature.files.wordpress.com/2012/03/psittacosaurus_mongoliensis.jpg
http://www.dinocasts.com/images/products/Psittacosaurus%20sinensis64.jpg
http://upload.wikimedia.org/wikipedia/commons/0/0d/Psittacosaurus_gastroliths.jpg
http://upload.wikimedia.org/wikipedia/commons/3/3c/Psittacosaurus_holotype.jpg
http://skywalker.cochise.edu/wellerr/fossil/reptile/6dinosaur-Psittacosaurus-meileyingensis-kikkos328.jpg
http://upload.wikimedia.org/wikipedia/commons/e/e1/Machurochelys_liaoxiensis_and_Psittacosaurus.jpg

However, the problem in this is that it's going to be a bit tricky to make estimates when your specimen seems to lack the spines and transverse processes (as this is the part where one of the heads of the ribs attach to.
From the top, the ilia blades seems to be pinched a bit too close together as well. Maybe that area was forced together from compression of the surrounding sediments.

The ribs might be a tricky fix. While they are slanted slightly backwards, they are more oriented up and down than slanted. The main problem I see with adjusting them is the way the scapula are attached to them, as it would require removing the scapula, slanting the ribs and then replacing the scapula over the angled pieces.
   The illium blades are not fossilized as a single piece, and could easily be removed (I think) and perhaps spaced wider . If I were to do this, is it far off or does it look close...meaning perhaps an inch space or two? I cannot see much more width being possible without adding a bar or something crossways to maintain the gapping. Finally thanks for the help and suggestions from ALL, I think these little guys are fascinating creatures and old enough they ask us alot of questions.

[wings]

The ribs might be a tricky fix. While they are slanted slightly backwards, they are more oriented up and down than slanted. The main problem I see with adjusting them is the way the scapula are attached to them, as it would require removing the scapula, slanting the ribs and then replacing the scapula over the angled pieces.
   The illium blades are not fossilized as a single piece, and could easily be removed (I think) and perhaps spaced wider . If I were to do this, is it far off or does it look close...meaning perhaps an inch space or two? I cannot see much more width being possible without adding a bar or something crossways to maintain the gapping. Finally thanks for the help and suggestions from ALL, I think these little guys are fascinating creatures and old enough they ask us alot of questions.

Ah, I see, it's a very time consuming fix, so just ignore my comments on the ribs. As for the ilia, it's more about the orientation of the blades. As you can see from these examples (http://rickgross.com/Psittacosaurus_files/image014.jpg, http://www.dinocasts.com/images/products/psittacosaurs2_640.jpg, http://1.bp.blogspot.com/-vU4AujstWWI/TWKcpNTe4iI/AAAAAAAAARU/7FhYCEvnmq4/s1600/Psittacosaurus+family.jpg and http://gastondesign.com/07galleries/dinoskels/p7hg_img_1/fullsize/psittacosaurus_fs.jpg), the ilia don't really slant toward the top and they probably run parallel with each other. Some of the articulated examples from my previous comment seems to be compressed dorsoventrally (top and bottom) which forces the ilia to rotate and gives the illusion of these elements (ilia) being slanting dorsally. I have no idea on how easy or hard it is to make this adjustment, I hope this is not as time consuming as my comments on the ribs. It's interesting to see someone who would actually purchase and mount a complete skeleton at home.

[amargasaurus cazaui]

I purchased the dinosaur, in an unmounted and mostly semi prepped state, and somewhat determined and decided how he would be posed and so forth. A lab in England did the actual mount and final prep, including the rib recreations, the cleaning of the skull from matrix,and subsequent repair to the skull, as well as fortifying the entire specimen with condolidant to make it much more durable. In addition I believe some of the verts and smaller digits of one hand are composited from another similar sized dinosaur. I chose the pose, a running pose, myself. The other option offered was a four feet down, racoon type pose I just was not that enamored with. In additon the dinosaur was mounted as a form of model, meaning he is made of nine pieces that can be taken apart, and packed, taken to a presentation or class, then rebuilt within a matter of a few minutes. Truly a dinosaur on the move........
  While not perfectly complete, I think it a nice dinosaur and not something every dinosaur buff has in their living room. I consider it somwhat a pet almost...although he does not tend to eat just a whole lot.

[postsaurischian]

I was thinking of this thread when I took these pics at the Aathal Museum in Zürich .

Psittacosaurus neimongoliensis (juvenile)

[amargasaurus cazaui]

Thanks for sharing the little guy !!! I like the way they cleaned the skull and did not mount the rest of the skeleton, so that it is just as they found it. It does not seemingly appear to even have elements repositioned. I noticed the same somewhat pinkish purple coloration to my own dinosaurs skull. It is subtle but definitely there.Very awesome find, and such a great addition to the forum, thanks so much.

[postsaurischian]

   Found this, also in Zürich:

[amargasaurus cazaui]

Ha and a face only a mother could love . Thanks for sharing him Helge...I like the eyes especially. Lets hope noone notices the extra claw on each hand or that the hands are fully pronated! I would still love to have that piece in my living room .

[amargasaurus cazaui]

I have decided to proceed in sculping the missing few bones from my mount. The three areas I am for now focused on are the small bones above the feet bones, that are the actual ankle bones. These seldom preserve in Psittacosaur fossils. The coracoids, are another. The third bone is the actual pubic bone itself. I explained earlier in the thread what becomes of this bone normally.I intend to sculpt these bones in a darker color than the actual mount so they can be easily recognized as restorations.(per Seijun suggestion)  If anyone has any up close drawings, or pictures that clearly detail these actual bones from various angles, and so forth it would be useful. I know the general shapes, but am looking for small details like surface texture, and so forth..so anything would be useful. thanks

[amargasaurus cazaui]

Another quilled , beaked early dinosaur !! He isnt a true Psittacosaurus, but I bet the Psittacosaur family could call this a distant ancestor .


http://news.yahoo.com/tiny-african-dinosaur-species-unveiled-011448836.html

[attachment msg=20516][/attachment]

[wings]

Not sure whether you've seen this or not but here is the actual paper (http://www.pensoft.net/journals/zookeys/article/2840/taxonomy-morphology-masticatory-function-and-phylogeny-of-heterodontosaurid-dinosaurs), I think you can probably download it from the site (I think it's the 112M pdf file). I wasn't able to because I have very slow internet connection at home... .

[Balaur]

Another quilled , beaked early dinosaur !! He isnt a true Psittacosaurus, but I bet the Psittacosaur family could call this a distant ancestor .


http://news.yahoo.com/tiny-african-dinosaur-species-unveiled-011448836.html

Wow! I have a new favourite dinosaur from this year! 

[Gryphoceratops]

Another quilled , beaked early dinosaur !! He isnt a true Psittacosaurus, but I bet the Psittacosaur family could call this a distant ancestor .


http://news.yahoo.com/tiny-african-dinosaur-species-unveiled-011448836.html

There was no evidence of quills on that particular fossil just so you know. 

[amargasaurus cazaui]

Another quilled , beaked early dinosaur !! He isnt a true Psittacosaurus, but I bet the Psittacosaur family could call this a distant ancestor .


http://news.yahoo.com/tiny-african-dinosaur-species-unveiled-011448836.html

There was no evidence of quills on that particular fossil just so you know.

I would assume Sereno had Some reason for reconstructing it that way? .Sereno himself stated it was ...."part vampire and part porcupine" which suggests he had solid evidence to suggest that reconstruction. Or is he just speculating based on Tianyulong? Here is the actual fossil, from Sereno's paper...notice the lines radiating from the fossil....The lighter ones appear to be from the fossil prepping, but what about those really dark deep ones towards the upper part of the picture? Quills or just patterning in the matrix?

[attachment msg=20606][/attachment]

[amargasaurus cazaui]

Not sure whether you've seen this or not but here is the actual paper (http://www.pensoft.net/journals/zookeys/article/2840/taxonomy-morphology-masticatory-function-and-phylogeny-of-heterodontosaurid-dinosaurs), I think you can probably download it from the site (I think it's the 112M pdf file). I wasn't able to because I have very slow internet connection at home... .

Had forgotten to say thanks for sharing the paper Wings, you are always so helpful. I read them all and save them once I figure out how to download them as well so thanks again .