Hello! I am an artist working on a new video game whose principle character is an apatosaurus. In my consultation of sources, I have come across a great deal of variation and so want to let the scientific community add its two cents. You can look at images of the character so far at this link.

Based on what is there now, I have a few main questions:

1. This was based primarily on Apatosaurus ajax:
http://6ixsetstudios.com/drop/apatosaurus/apat_skel1.jpg
I have another image from The Scientific American Book of Dinosaurs (Ed. Paul, Gregory S., 2000) with a much thicker overall build, longer neural spines, and a more elevated neck position:
http://6ixsetstudios.com/drop/apatosaurus/apat_skel2.jpg.
Since this one is, comparatively, less clearly labeled than the other (i.e. where it is coming from), I opted for the former. Can anyone identify the specimen in the Paul book and attest to its accuracy?

2. The skeleton has about as much detail as I can afford based on the technical limitations of what we are doing, but I can make some minor adjustments without too much trouble. In the game, the skeleton appears in a sort of x-ray view rather than as a solid shaded object. I want to make sure, however, that my geometry is accurate enough for the level of detail we can support. The main things I had difficulty finding good reference for were:
* the shape of the cervical vertebrae
* bone markings (i.e. tuberosities, etc.) on the humerus and femur
* the orientation and proportions of the radius/ulna and tibia/fibula pairs (i.e. which is medial/lateral, how they should be rotated in this position, etc.)
* imagery of how the knees and elbows more generally ought to articulate (i.e. should there by epicondyles, an olecranon process, a patella, etc. like on a human)

3. With the actual body, I am mostly interested in the accuracy of the proportions and forms. I will be adding more detail for surface anatomy, color, scales, and so forth. With that in mind, I am also looking for pointers to move ahead on that. I have seen a range of surface anatomy representations ranging from pretty dumpy to stocky to lean. Does anything in this image look particularly correct?
http://6ixsetstudios.com/drop/apatosaurus/apatosaurus.jpg
Artistically, number 3 is the most interesting I think, but does it have any noticeable problems to the trained eye?

4. Finally, I am having difficulty locating information on superficial details. An article by Paul in the Scientific American text describes most scales as being "nonbony, flat, mosaic-patterned and never overlapping, and semi-hexagonal in shape. In general, large scales are surrounded by a hexagonal ring of smaller scales, forming rosettes that are themselves set in a sea of small scales. The size of the scales ranges from a substantial fraction of an inch to an inch or two across. In some dinosaurs, subconical scales an inch or two across projected from the skin. ...[Yet] little is know about the skin on dinosaur heads" (Paul 2000: 87-88). Based on that description, I thought this seemed to be a fair representation (though certainly with plenty of folds and variations throughout the body):
http://6ixsetstudios.com/drop/apatosaurus/apat_head.jpg

Please let me know if there are any other considerations you think I ought to keep in mind. I appreciate your time in helping us out!

Hi, Adam.  Your question is waaay longer and more detailed than what this site is set up to deal with you.  Luckily for you, though, I am a sauropod nut, and will happily talk about them forever :-)  Good job you're not doing a game about ornithopods!

First of all, congratulations on your work so far.  Your models look superb, and are certainly on course to be the most accurate sauropods I've ever seen in a computer game.  Your attention to detail and quest for accuracy are laudable, and the results are looking wonderful.

Second, the Greg Paul skeeletal reconstruction is taken from his 1998 paper "Terramegathermy and Cope's Rule in the Land of Titans", where it is part of FIGURE 1(b).  There is a scan of all of FIGURE 1(b), if you're interested, on the SV-POW! web-site (Sauropod Vertebra Picture of the Week) at http://svpow.wordpress.com/2007/11/18/x … ig-was-it/
According to the caption in the paper, this is the skeleton of Apatosaurus louisae CM 3018, with skull CM 11162 scaled to fit.  Yes, it is a scientifically rigorous reconstruction, and would make a fine basis for your work.  By the way, I can send you a PDF of the paper if that would be helpful.  Contact me on dino@miketaylor.org.uk

Third, among all sauropods, Apatosaurus is very much one of the more heavily built, rivalled in that respect only by some of the titanosaurs.  As Matt Wedel has rather picturesquely expressed it, "Apatosaurus sort of looks like a pro wrestler when most of the other sauropods tend to look like ballerinas".  No doubt there was some interspecific variation, but to my mind Greg Paul's A. louisae captures the spirit of apatosaurosity rather better then Scott Hartman's A. ajax.  That is not a comment on the accuracy of Hartman's work, just an aesthetic judgement: that animal looks closer to how we would normally think of Diplodocus in terms of skeletal robustness.

Fourth, you asked about the shape of cervical vertebrae, the tuberosities on the humerus and femur, and proportions of radius/ulna and tibia/fibula.  By far the best way to get this information is from the primary literature: luckily for you, Apatosaurus is one of the most comprehensively described of all sauropods, and most of the important detailed descriptions are available as PDFs.  Email me and I'll send you the necessary material.  Even if you don't know enough science to understand the papers, you'll find that the lavish illustrations give you plenty to go on.  For the record, your cervical are OK but not really extreme enough.  Apatosaurus cervicals are among the most bizarrely shaped objects in the known universe, and by they way raise all sorts of mechanical questions which I won't go into here.

Fifth, orientation of the leg bones.  Hind limb is simple, the fibula is directly lateral to (i.e. outside of) the tibia, which is the main weight-bearing bone of the lower leg.  In the lower forelimb, the ulna is the main weight-bearing bone, and is roughly triangular in cross-section, one side of the triangle being slightly concave and the radius fitting into that concavity.  The exact orientation is still slightly controversial, but consensus is that the radius should be anterior and slightly lateral to the ulna.  No patella in reptiles!  Other orientation questions are, again, best resolved by reference to the primary literature.

Sixth, your gallery of alternative skins.  These are too small to assess in detail, but from what I can make out, 1, 4 and 6 are all pretty much old-school fatso renditions with little respect for bony anatomy.  2, 3 and 5 all look rather better, although 5 has a rather odd interpretation where the neural spines project above the surface of the torso: that's unlikely, and in any case the shoulder region of this one is completely wrong since at that point of the vertebral column, the neural spines are widely bifurcated.  (You have them coalescing too early in the column in your model).  In terms of how stocky or lean you want your restored model to be, the best way to go is to actually sketch muscles onto the skeleton, connecting where they would in real life (e.g. thigh muscles extending to the front and back of the ilium) and follow the outlines they give you.  IIRC, Greg Paul's article in that Scientific American book has some advice on how to do that.

Your favourite, number 3 looks pretty good to me in thumbnail version at least, and I like the visibility of the scapula beneath the skin.  As to its accuracy, the only thing that immediately strikes me as wrong is that the tail narrows too quickly: the caudal vertebrae should have tall spins further back than they do here.

Seventh (and last!) superficial details: your mockup of the head and anterior neck looks like a good representation of Paul's description, but I have to say that the only sauropod skin I've ever seen doesn't look much like that.  I've posted a photo of it for you at http://www.miketaylor.org.uk/tmp/peloro … -skin.jpeg
This is from the elbow region of "Pelorosaurus" becklesii, an English titanosaur from the Early Cretaceous.  It's not particularly closely related to Apatosaurus, but it's all I have and it is at least a real fossil.  Hope that helps.

(The skin photo was taken at the Natural History Musuem in London.  As it is their specimen, the terms under which I took the photograph mean that they hold copyright on it.  Just saying.)

I think that's everything.  If you have more questions, you can either post them here (if you think they're of general interest) or just email me.

Mike, just so as you know, Adam contacted me independently, and rather than just answer him directly, I though it would be good if we got a few good questions out of it on AAB and I knew you and Darren would want to pitch in. Enjoy! ;-)

Everyone loves sauropod anatomy questions!  Plus I got to plug SV-POW! -- everyone wins.