pachycephalosaurus

[darylj]

im working on the papo pachycephalosaurus and have a question?
what was the natural position of the hands / arms?
where they the same as other theropod dinosaurs? facing in?

[Gwangi]

im working on the papo pachycephalosaurus and have a question?
what was the natural position of the hands / arms?
where they the same as other theropod dinosaurs? facing in?

Facing in would be correct but just so you know, they weren't theropods.

[darylj]

noooo i know they werent theropods, i was just implying that they had the same arms... so to speak.
anyways, thats great thanks... damn papo bunny arms!

[Gryphoceratops]

You trying to customize a papo pachy? 

[darylj]

yeah, going for a correct arms / running position... i think

[Gryphoceratops]

Cool.  If its any help the torso and tail base should be wider too if you want it to be more accurate.  I'll try and find a diagram for you if i can.   

[wings]

im working on the papo pachycephalosaurus and have a question?
what was the natural position of the hands / arms?
where they the same as other theropod dinosaurs? facing in?

Pretty much we weren't sure how much we have of this animal (Pachycephalosaurus), we have plenty of descriptions on their skulls however their postcranials (anything behind their skulls) were never "formally" described. So at this moment, we kind of not sure how much of this animal we actually have.There is a paper that talks about its (Pachycephalosauria group) general anatomy (http://www.palaeontologia.pan.pl/Archive/1974_30_45-102_22-31.pdf). You get the idea. That is why you've rarely seen skeletal illustration of Pachycephalosaurus (not fully described and published). Due to the lack of materials, from what we know, in general the Pachycephalosaurinae group tend to have quite robust radii and ulnae (http://www.angelfire.com/mi/dinosaurs/images/casts/prenocephale_1.jpg and http://skeletaldrawing.com/SDBlog/1924_gilmore_stegoceras.jpg), movement between these elements is very limited (the shape of the radial head probably doesn't allow it to rotate, it wasn't quite rounded. see the form of the radial head is rather flat (kind of ellipsoidal in shape) rather than rounded (like ours) in the Prenocephale specimen (from the first link). In the Prenocephale or the Stegoceras (Troodon in Gilmore 1924) specimen it seems when lower arm is articulated the end of the radius appears to rest on top of the ulna so the hand (don't think we have any preserved pachycepahosaurs hands yet) would be facing medially. So it is very likely "all" pachycepahosaurs have clapping hands.

[darylj]

thanks for the insight... i knew there wasnt much with regards to remains but thanks for all the info there.

also... a diagram would be great

[wings]

thanks for the insight... i knew there wasnt much with regards to remains but thanks for all the info there.

also... a diagram would be great

There was one by Paul on Pachycephalosaurus (http://press.princeton.edu/blog/wp-content/uploads/2010/09/pachycephalosaurus_wyomingensis.jpg), not sure whether there is one out there with front and top views. As for a top view of these animals in general Paul also has done one for Prenocephale with the top view (http://books.google.com.au/books?id=wdKBfB2k9asC&pg=PA243&lpg=PA243&dq=prenocephale+paul&source=bl&ots=rMstiiKZT8&sig=dnpCGS6fRERvPdr7Xvwlb9a2KcE&hl=en#v=onepage&q=prenocephale%20paul&f=false), and Hartman has done a Stegoceras (probably the same as Pauls' Prenocephale, you know how Paul's classification goes...) (http://shartman.deviantart.com/gallery/?offset=24#/d3azbbf) but only on a side view.

[darylj]

so what remains do we actually have of these guys?
is there actually any evidence that they were infact bipedal for instance? and not just, say.... ceratopsian like?

[wings]

so what remains do we actually have of these guys?
is there actually any evidence that they were infact bipedal for instance? and not just, say.... ceratopsian like?

As for confirmed materials we have one complete skull and about three skull fragments. And for the unconfirmed, we have probably quite a bit of the postcranials (Stygimoloch spinifer / Pachycephalosaurus wyomingensis collected by Triebold from the Sandy Quarry, Hell Creek Formation but it seems like none of these materials have been formally described yet. So there is no way to tell how much we have of it on this particular specimen. You probably have to email him directly to find out...) and lastly we have Dracorex (presumably a juvenile Pachycephalosaurus) which has a complete skull and a few neck vertebrae. 

For Pachycephalosaurs in general and from looking at the links that I've sent from the earlier message, if they are habitually walking on all fours then their forelimbs looked kind of short to do so (like http://3.bp.blogspot.com/-p6eZhyY7KNc/T876USH8pcI/AAAAAAAABd4/bi3pcKT5wlI/s1600/IMG_7615.JPG , I think that's the cast of the Triebold "Pachycephalosaurus"). Did someone tell you that they are ceratopsian like?

[darylj]

no, nobody told me... it was merely an example... what with the beak, head display etc...
if we only have skulls to go by, then technically they could look very different?

[wings]

no, nobody told me... it was merely an example... what with the beak, head display etc...
if we only have skulls to go by, then technically they could look very different?

That really depends on how you would define "very different"? The reason I said this is because as a group (Pachycephalosauria) there are certain combination of features that unite this group and not shared by other groups (that's pretty much how classification works, identifying these features and categorize these animals into groups).  In short for this group we can say that their size is small to medium, bipedal (very likely), heads with relatively short facial region, thickened skull roof, small leaf like teeth, bony ornamentation of varying degrees on snout and in the back of the skull... etc. You'll probably need to dig through a few literature on this because there are certainly other more technical features as well but I'm a little lazy to list the lot here (or just a bit too much for me to type here... ). Unfortunately, it's hard to pinpoint one single source that describes the anatomy of the whole animal.