This is the fourth in a series of posts in which I review the Apatosaurus maquette from Sideshow Collectibles. Other posts in the series are:

• Part 1: intro
• Part 2: the head
• Part 3: the neck
• Part 5: posture
• Part 6: texture and color
• Part 7: verdict

A long-running theme here at SV-POW! is that the torsos of most sauropods were not just deep and slab-sided, they were unusually deep and slab-sided, more so than in most other tetrapods (see this and this, and for a more pessimistic take, this). This is something that is easy to get wrong; we are used to seeing round mammalian torsos and a lot of toy sauropods have nearly circular cross-sections. A lot of sculptors of collectible dinos do get the torso cross-section right, though, and the folks who made this Apatosaurus are no exception.

Next item: there’s an upward kink at the base of the tail, as there should be. Gilmore was the first to point this out, in his 1932 paper on the mounting of the Smithsonian Diplodocus (that’s plate 6 from that paper above; the skeleton on the bottom is the more correct one). This came up in the comment thread of the first post in this series, and since I haven’t had any deeper thoughts on the issue in the past week, I’m just going to copy and paste what I wrote then:

The upkink at the base of the tail is unavoidable; the sacrum is shaped like an inverted keystone and there’s no way to get the proximal caudals to do anything but angle upward without disarticulating them…. The reverse keystoning of sauropod sacra is weird. And it’s in every sauropod sacrum I can remember seeing with my own eyes, including Brachiosaurus altithorax. And yet the only authors I can think of off the top of my head who have discussed it seriously are Gilmore (1932), Greg Paul (2010, maybe a magazine article or two I haven’t seen), maybe Jim Jensen (1988), and IIRC Salgado et al. (1997). If there are more, please let me know–this is something I’m very curious about.

The back is gently arched, with the highest point about midway between the shoulder and hip joints. Where the highest point in the back falls depends on a host of factors, including the relative lengths of the forelimb and hindlimb bones, the amount of cartilage on the ends of those bones, the position and angle of the scapula on the ribcage, and the intrinsic curvature, if any, of the articulated series of dorsal vertebrae, which were themselves separated by an unknown amount of cartilage. Opinions are all over the map on most of these issues, particularly scapular orientation. As a scientist, I am agnostic on most of these points; I don’t think that they’re beyond being sorted out, but there’s a lot of work in progress right now and I haven’t seen evidence that would definitely convince me one way or another. So in lieu of saying that Apatosaurus must have had this scapular orientation and that dorsal curvature and so on, I’ll just note that the maquette has been a dominant feature in my office for a few weeks now and nothing about the body profile, shoulder position, or limb length has ever struck me as odd or worthy of comment. It looks like Apatosaurus to me. Moving on…

In the last post I talked about the visible bulges in the neck that allow one to count the cervical vertebrae. The maquette also has low bumps along the back that mark the neural spines of the dorsal vertebrae. This doesn’t strike me as unreasonable. Attachment scars for interspinous ligaments run all the way up to the tips of the neural spines in most sauropods, so the entire height of one neural spine was often webbed to the next by a continuous ligamentous sheet, as Janensch (1929: plate 4) drew for Dicraeosaurus in the illustration above (isp.L). I don’t think those ligaments would have prevented the bony tips of the vertebrae from being visible, necessarily, and the epaxial muscles should have been on either side of the interspinous ligaments and in the triangular spaces between the spine tips and the transverse processes.

What might have smoothed out the dorsal body profile are supraspinous ligaments (ssp.L in the plate above). These are present in crocs (Frey 1988: figs. 14, 16, 17) but apparently absent in most birds; at least, I haven’t seen any myself, and the Nomina Anatomica Avium does not mention any (Baumel et al. 1993: 156-157). So on phylogenetic grounds their presence in sauropods is equivocal. That said, the tips of the neural spines in most sauropods are fairly rugose. Does that mean that they were webbed one to the next by interspinous ligaments only, or that they were embedded in supraspinous ligaments as well? I don’t know the answer, and I don’t know if anyone else does, either. The whole issue of intervertebral ligaments in sauropods has received too little attention to date. In the absence of better data, I’ll just say that although I wouldn’t put any money on the proposition that the spines made externally visible bumps in life, neither does it offend me.

There is one fairly nit-picky point that I am honor-bound to mention. Because the dorsal neural spines make bumps, it is possible to count the dorsals, just like the cervicals last time. And this count doesn’t work out quite as well. Apatosaurus should have 10 dorsal vertebrae, but try as I might I can’t see more than 8 bumps along the back, and that’s generously assuming that c14’s spine is pretty well ahead of its rib. Is this pathologically anal to complain about? Quite possibly. On the other hand, by sculpting in those details the artists were basically begging geeks like me to come along and count vertebrae just because we could.

The tail is pretty cool. It is appropriately massive where it leaves the body, and has a visible bulge for the caudofemoralis muscle, which originated in the tail and inserted on the fourth trochanter of the femur. The caudofemoralis is the major femur retractor in lizards and crocs and in most non-avian dinosaurs, and rather than go on about it I’ll just point you to Heinrich Mallison’s awesome post about dinosaur butts. The tail of the maquette also has an awesome whiplash. I could say a ton more about the hypothesized uses of whiplash tails in diplodocids and other sauropods, but I don’t feel like climbing that hill just now. Suffice it to say that the maquette’s whiplash is pretty sweet, and avoids the “scale is too small so I just stuck in a piece of wire” mode of making whiplashes that I’ve seen in other, smaller diplodocid sculpts.

The tail has a row of little spines running down the dorsal midline, which have been de rigeur for life restorations of diplodocids and many other sauropods (ahem) since they were first reported by Czerkas (1993). AFAIK, such spines have only been found preserved in the tail region of diplodocids. That’s not to say that they weren’t present in the neck or the back of diplodocids, or in other sauropod taxa, just that the only good fossil traces of them to date have been from the tails of diplodocids, and maybe just one or two tails. So the presence of little spines in the tail of the maquette and not the back or the neck is perfectly–one might even say slavishly–consistent with the fossil evidence. I’ll discuss the flamboyancy or lack thereof in the maquette in another post, so I’ll say no more about this design choice for now.

The limbs are mostly good. The muscles under the skin look plausible, with one exception. As noted before in this series, Apatosaurus was a freakishly robust critter, and the limbs look appropriately sturdy and well-muscled, except where the thigh meets the hip. There is a visible bulge for the ilium, and the anterior margin of the thigh should converge with the most forward point on the ilium. That’s what the preacetabular blade of the ilium is for: to anchor thigh muscles (discussed here, and also nicely illustrated here). Unless the animal had some kind of wasting disease, there was no bone sticking out beyond the muscle, and so the anterior-most point of the ilium has to be the start of the anterior margin of the thigh.

On the positive side, there’s a little ridge running down from the anterior arm onto the forearm for the biceps tendon, which is a nice touch. The manus shows the short, solid arc of metacarpals typical for diplodocids, and an inward-curving thumb claw. The hind feet have the big laterally-curving claws on the first three digits that one expects.

In a way that is difficult to describe in words, the feet really look they are bearing a lot of weight, and this impression of solidity helps to ground the whole maquette. It doesn’t look like a sauropod-shaped balloon that just happens to be poling itself along with limbs that barely touch the ground–an impression that I have gotten occasionally from some other sculptures with overly skinny limbs and too-small feet. This critter looks big, heavy, and powerful, and those are exactly the adjectives one wants to come to mind when looking at Apatosaurus. (I do wonder if doing a Diplodocus in the same scale would be more difficult. How do you convey ‘multi-ton animal’ and ‘gracile’ at the same time?)

To sum up, in the trunk, tail, and limbs I find much to like and little to criticize. The only noteworthy problems are the insufficient dorsal count and the mismatch between the ilium and anterior thigh profile. On one hand these are puzzling goofs, given the overall attention to detail and the numerous points at which the sculpt is not just good but surprisingly good. On the other hand, I didn’t notice the dorsal thing until I bothered to count, and I didn’t notice the thigh thing until the other day when I was writing the first draft of this post, so both problems went unnoticed for weeks and are probably below the threshold of perception for the vast majority of people. The accuracy of the sculpt is so high that my approach to its problems has not been, “Where do I begin?” but rather, “What is keeping this thing from being perfect?” And the answer is, not very much.

Headless sauropod. NOW it's perfect.

The base is nice. It’s not just a generic slab of earth, it’s a muddy surface marked with the tracks of other dinosaurs, including a couple of theropods. The base sits nice and flat, and the Apatosaurus sits nice and flat on it, with no rocking at either point of contact. Not only do the feet of the Apatosaurus fit neatly into the sculpted footprints, one of the hindfeet has a little metal rod that slots into a socket in one of the hindfoot prints, to keep the maquette firmly on the base. That means that if you want to display the maquette off the base, you’ll have to either cut off the rod or make sure that your alternative surface will accommodate it.

The skull is…less satisfying. It’s a nice enough rendition of an Apatosaurus skull, and if it had come by itself I would have been very happy with it. The trouble is that the maquette is considerably more detailed, so when the skull sits next to the maquette it suffers by comparison. But what else are you going to do with it? Make a separate shrine to Apatosaurus somewhere else?

The difference in sculpt quality between the maquette and base on one hand and the skull on the other is apparent even on casual inspection. My copies are sitting on a bookcase adjacent to my office door. Sometimes people walking down the hall pop their heads in, and so far the most common comments are that the maquette is “awesome” and that the base is “cool”. People have been genuinely impressed that the base is a realistically detailed chunk of the environment and not just a flat slab. The only people who have commented on the skull have said that it seems “lame” compared to the maquette.

The base is included in the basic package with the maquette, in a limited edition of 500, which as of this writing goes for $289.99 (here). The package with the skull accessory is in an edition of 100, and goes for $299.99 (here). So the skull is only $10 more, and although it is not quite as nice as the maquette, I think it’s a steal at the price. Mine is certainly not going anywhere.

So much for the gross anatomy. You probably noticed that I haven’t said anything about how the maquette is posed or textured or colored. Those will all be topics for next time.

References

• Baumel, J.J., King, A.S., Breazile, J.E., Evans, H.E., and Vanden Berge, J.C. (eds.) 1993. Handbook of Avian Anatomy: Nomina Anatomica Avium, 2nd ed. Publications of the Nuttall Ornithological Club, No. 23. Cambridge, Massachusetts, 779 pp.
• Czerkas, S.A. 1993. Discovery of dermal spines reveals a new look for sauropod dinosaurs. Geology 20:1068–1070.
• Frey, E. 1988. Anatomie des Körperstammes von Alligator mississippiensis Daudin.
• Gilmore, C. W. 1932. On a newly mounted skeleton of Diplodocus in the United States National Museum. Proceedings of the United States National Museum 81:1-21.
• Janensch, W. 1929. Die Wirbelsäule der Gattung Dicraeosaurus. Palaeontographica Suppl. 7(1), 3(2), 37-133.
• Jensen, J.A. 1988. A fourth new sauropod dinosaur from the Upper Jurassic of the Colorado Plateau and sauropod bipedalism. Great Basin Naturalist 48(2):121-145.
• Paul, G.S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press, 320 pp.
• Salgado, L., R.A. Coria, and J.O. Calvo. 1997. Evolution of titanosaurid sauropods. I: Phylogenetic analysis based on the postcranial evidence. Ameghiniana 34:3-32.