It came from my desk

March 8, 2012

I was putting a new card in my camera and needed some test photos, so I shot what was on my desk: some random doodles from discussions with various folks, and an ostrich cervical.

I love my job.

Bonus SV-POW!bucks to the first person to decipher the diagram on the lower left.

This is the final post reviewing the Apatosaurus maquette from Sideshow Collectibles. Previous posts in the series are:

First, the objective verdict.

PROS

The head has the right shape, shows some underlying structure without being shrink-wrapped, has plenty of soft tissue without being a meat bullet, and is nicely detailed. The same comments apply for the rest of the sculpt, except as noted below. There are lots of nice little touches that show careful attention to the evidence we have for the life appearance of sauropods, as detailed in the previous posts. The base is cool.

CONS

The problems are few, and most will escape the attention of all but the most hardcore dino anatomy fiends (OTOH, the most hardcore dino anatomy fiends are probably a big chunk of the target market). The lips or marginal scales covering the teeth are not supported by our current understanding of the available evidence. The number of visible bumps for vertebrae does not add up to the correct presacral count for Apatosaurus–it’s off by probably 2, out of a presacral count of 25. The anterior margin of the thigh does not blend with the ilium as it should. The flipped-back forefoot bothers some paleobiologists but not all. The pose is otherwise fairly orthodox–which might be pro or a con, depending on your point of view. The skull accessory is not as detailed as the maquette and suffers from the comparison, but it’s still decent and a good value for the small additional outlay.

VERDICT

I’ve seen a lot of dinosaur sculptures advertised as ‘museum quality’. This one actually is. In fact–and I am being completely honest here, as I have been throughout–I doubt if I’ve ever seen a scale model of a dinosaur in a museum that could compare to this. My compliments to the artists, sculptor Jorge Blanco and painter Steve Riojas, for an amazing job.

I remember when I first saw Jurassic Park thinking, “Okay, that whole pesky restoring T. rex problem is licked. This is what they looked like.” Eighteen years later–can it really be that long?–I still feel that way. Sure, it’s cool to dress up a rex in wattles and feathers and what have you, maybe tack on a fatter tail, but any such bodywork had better start from the chassis of a JP-style rex. Because the JP rex is built on the real bones, especially the skull. I am familiar with those bones and those skulls, from a lifetime of dino-geekery in general, and six years in the Valley Life Sciences Building at Berkeley in particular. So the JP rexes look like T. rex to me, and all other rexes just look less…real.

In the same way that Jurassic Park fixed my idea of what T. rex looked like, this sculpture crystalizes Apatosaurus for me. As far as I’m concerned, and aside from the relatively minor and unintrusive problems listed above, this is what Apatosaurus looked like, and this maquette is the Apatosaurus representation by which all others should be judged.

Want more opinions? There is a thoughtful review of this maquette at the Dinosaur Toy Blog, with a comment from Mike that was probably the genesis of this whole saga.

CLOSING THOUGHTS

Have you ever wished you could give yourself a limited memory wipe and see your favorite movie again for the first time? Or read your favorite book? We value that frisson of surprise so much that we have a word for anything that preempts it: spoiler. It would be nice to be able to revisit some of our favorite things again for the first time, unspoiled.

I have been working on sauropods for a decade and a half. I am still blown away when I stand in front of a big mounted skeleton and think about what such an animal must have been like in life. I cannot help but visualize the organs that filled those immense torsos, and the muscles, vessels, and nerves that moved, plumbed, and wired their bodies. That has not ceased to be a moving experience. But I thought was beyond being surprised by the gross form of sauropods, by their bauplan. I am surrounded by sauropod representations, both 2D and 3D, including those made by others and a few that I have generated myself. How could I possibly be surprised anymore?

And yet, when I look at this sculpture, I am forcibly struck by just how friggin’ weird sauropods are. Mostly it’s the long, fat neck and tiny head, which I know are maximally exaggerated in Apatosaurus. But it just looks wrong. Some primitive mammalian circuit in me rebels at the idea that any animal could need such an immense tube of flesh to serve such a ridiculously small head. I think part of it is the faint ribbing created by the cervical ribs; it makes me think of tentacles, leeches, elephant trunks. I have to consciously remind myself that it was the neck–the neck, with vertebrae and muscles and diverticula and the rest–of a real animal, and not something outlandish invented by a sci-fi author, or moviemaker, or other artist.

And then I think, this must be what other people feel like all the time. And probably how I felt when I was four or five and really grokking sauropods for the first time. I didn’t think I’d feel anything like that about sauropods ever again. So it’s hard for me to be objective about this maquette, because it has reconnected me with the great love of my scientific life, in the most delightfully unexpected way.

I love it. I’m keeping it. Go get your own!

This is the sixth installment in a series on the Apatosaurus maquette from Sideshow Collectibles. Other posts in the series are:

Texture and color deserve discussion on two levels: biological plausibility, and level of execution.

The skin texture is wrinkled, with a few scattered warts or tubercles. The tail is crowned with a line of low spines, as previously discussed here. We know from skin impressions that sauropods had naked skin, with non-overlapping, generally hexagonal scales ranging from 1-4 cm in diameter (Czerkas 1994, Platt and Hasiotis 2006).

Would the individual scales be visible at the scale of this sculpture? The maquette is 1.1 meters long in a straight line from the right side of the mouth to the tip of the tail, and I measure it as 1.27 meters along the dorsal body margin. Most mounted apatosaurs are in the neighborhood of 70 feet long (21 meters), and the monster at the OMNH is 92 feet (28 meters). The maquette is therefore between 1/16 and 1/22 scale, depending on how big an animal it is supposed to represent (I almost wrote, “assuming it is an adult”, but most mounted sauropods are demonstrably subadult; even the monster apatosaur from Oklahoma has some elements unfused). An unusual but not unheard-of scale for dinosaur figures is 1/18, so that may have been the goal here, for a “in life” length of 75.5 feet (23 meters).

Back to the epidermal, as opposed to proportional, scales. A 4-cm scale on a real Apatosaurus would be about 2 mm on the maquette, and the more common 1-cm scales would be about 0.5 mm. Those would be pretty darned difficult to sculpt and cast in any way would that make them recognizable, so I think we can safely overlook the absence of visible scales on the maquette (warts excepted). Would scaly skin bunch and fold like the skin on the maquette? Beats me. From my experiences with turtles, some of which are pretty darned wrinkly, I wouldn’t rule it out. So I judge the texture plausible. And the level of detail in the execution is phenomenal. I said in the head post that the level of detail you see there is perpetuated through the entire sculpt, and I stand by that. The maquette invites–and withstands–close scrutiny.

The color of the maquette is interesting without being vibrant: olive green above, shading into a tannish-yellow below, with stripes on the tail and faint dark freckles on the neck, body, and limbs. The freckles remind me of the scattered dark spots sometimes seen on the skin of elephants, so that may be a deliberate homage. Finally, the dorsal surfaces of the neck, body, and proximal tail are mottled with off-white or grayish splotches that recall the spotting on some deer.

Now, I am typically an ardent proponent of flamboyant dinosaurs (see here and here). If someone had asked me to design an Apatosaurus maquette, I would have done things differently. I would have slapped on the spines and dewlaps and inflatable display sacs until this thing looked like the three-way love child of Todd Marshall’s Spinosaurus, a bird-of-paradise, and the 80s hair metal band of your choice.

That’s what I would have done, if someone asked me to design an Apatosaurus maquette. But now that I see the one that was actually produced, I would change almost nothing. Because the underlying anatomy would get lost, and the thing would become just a billboard for all the flamboyant gloop (just like some real animals). And because not every animal is a head-to-toe wack job; for every Golden Pheasant there are roughly a thousand little brown passerines.

So the color is good. Great, even. It’s really hard to convey how lifelike this thing looks, as if at any moment it might just stroll right off the end of my bookcase. Heck, I’ve seen lots of real animals that looked less alive that this maquette (some lizards, many amphibians). That the overall design and level of detail can inspire that reaction in anyone is a big win. That it can make me feel that way, when I should be maximally on guard against any mistakes, is even better.

But now I’m starting to break the bounds of objectivity, so I’ll stop here. I’ll provide a final objective verdict, and also give my subjective impressions, in the next, and final, post.

References

  • Czerkas, S. 1994. The history and interpretation of sauropod skin impressions. GAIA 10: 173-182.
  • Platt, B.F., and Hasiotis, S.T. 2006. Newly discovered sauropod dinosaur tracks with skin and foot-pad impressions from the Upper Jurassic Morrison Formation, Bighorn Basin, Wyoming. Palaios 21: 249-261.

This  is the fifth in a series of posts reviewing the Apatosaurus maquette from Sideshow Collectibles. Other posts in the series are:

There are really only a couple of interesting points to discuss for posture: the neck and the feet.

The neck posture is fine. Easy to say, but since I’m one of the “sauropods held their necks erect” guys, it might need some unpacking.

On one hand, animals really do use stereotyped postures, especially for the neck and head (Vidal et al. 1986, Graf et al. 1995, van der Leeuw et al. 2001). The leading hypothesis about why animals do this is that the number of joints and muscle slips involved in the craniocervical system permits an almost limitless array of possible postures, and that having a handful of stereotyped postures cuts down on the amount of neural processing required to keep everything going. That doesn’t mean that animals only use stereotyped postures, just that they do so most of the time, when there’s no need to deviate.

This might work something like the central pattern generators in your nervous system. When you’re walking down the sidewalk thinking about other things or talking with a friend, a lot of the control of your walk cycle is handled by your spinal cord, not your brain. Your brain is providing a direction and a speed, but the individual muscles are being controlled from the spinal cord. Key quote from the Wikipedia article: “As early as 1911, it was recognized, by the experiments of T. Graham Brown, that the basic pattern of stepping can be produced by the spinal cord without the need of descending commands from the cortex.”

But then you see a puddle or some dog doo and have to place your foot just so, and your brain takes over for a bit to coordinate that complex, ad hoc action. After the special circumstance is past, you go back to thinking about whatever and your spinal cord is back in charge of putting one foot in front of the other. This is the biological basis of the proverbial chicken running around with its head cut off: thanks to the spinal cord, the chicken can still run, but without a brain it doesn’t have anywhere to go (I have witnessed this, by the way–one of the numerous benefits to the future biologist of growing up on a farm).

Similarly, if the craniocervical system has a handful of regular postures–alert, feeding, drinking, locomoting, and so on–it lightens the load on the brain, which doesn’t have to figure out how to fire every muscle slip inserting on every cervical vertebra and on the skull to orient the head just so in three-dimensional space. That doesn’t mean that the brain doesn’t occasionally step in and do that, just like it takes over for the spinal cord when you place your feet carefully. But it doesn’t have to do it all the time.

van der Leeuw et al. (2001) took this a step further and showed that birds not only hold their heads and necks in stereotyped postures, they move between stereotyped postures in very predictable ways, and those movement patterns differ among clades (fig. 7 from that paper is above). There is a lot of stuff worth thinking about in that paper, and I highly recommend it, along with Vidal et al. (1986) and Graf et al. (1995), to anyone who is interested in how animals hold their heads and necks, and why.

So, on one hand, its wrong to argue that stereotyped postures are meaningless. But it’s also wrong to infer that animals only use stereotyped postures–a point we were careful to make in Taylor et al. (2009). And it’s especially wrong to infer that paleoartists only show animals doing familiar, usual things–I wrote the last post partly so I could make that point in this one.

For example, I think it would be a mistake to look at Brian Engh’s inflatable Sauroposeidon duo and infer that he accepts a raised alert neck posture for sauropods. He might or might not–the point is that the sauropods in the picture aren’t doing alert, they’re doing “I’m going to make myself maximally impressive so I can save myself the wear and tear of kicking this guy’s arse”. The only way the posture part of that painting can be inaccurate is if you think Sauroposeidon was physically incapable of raising its neck that high, even briefly (the inflatable throat sacs and vibrant colors obviously involve another level of speculation).

Similarly, the Sideshow Apatosaurus has its neck in the near-horizontal pose that is more or less standard for depictions of diplodocids (at least prior to 2009, and not without periodic dissenters). But it doesn’t come with a certificate that says that it is in an alert posture or that it couldn’t raise its neck higher–and even if it did, we would be free to ignore it. Would it have been cool to see a more erect-necked apatosaur? Sure, but that’s not a new idea, either, and there are other restorations out there that do that, and in putting this apatosaur in any one particular pose the artists were forced to exclude an almost limitless array of alternatives, and they had to do something. (Also, more practically, a more erect neck would have meant a larger box and heftier shipping charges.)

So the neck posture is fine. Cool, even, in that the slight ribbing along the neck created by the big cervical ribs (previously discussed here) gives you a sense of how the posture is achieved. Visible anatomy is fun to look at, which I suspect is one of the drivers behind shrink-wrapped dinosaur syndrome–even though it’s usually incorrect, and this maquette doesn’t suffer from it anyway.

Next item: the famous–or perhaps infamous–flipped-back forefoot. I have no idea who first introduced this in skeletal reconstructions and life restorations of sauropods, but it was certainly popularized by Greg Paul. It’s a pretty straightforward idea: elephants do this, why not sauropods?

Turns out there are good reasons to suspect that sauropods couldn’t do this–and also good reasons to think that they could. This already got some air-time in the comments thread on the previous review post, and I’m going to start here by just copying and pasting the relevant bits from that discussion, so you can see four sauropod paleobiologists politely disagreeing about it. I interspersed the images where they’re appropriate, not because there were any in the original thread.

Mike Taylor: the GSP-compliant strong flexion of the wrist always look wrong to me. Yes, I know elephants do this — see Muybridge’s sequence [above] — but as John H. keeps reminding us all, sauropods were not elephants, and one might think that in a clade optimsied for size above all else, wrist flexibility would not be retained without a very good reason.

Adam Yates: Yes I agree with Mike here, the Paulian, elephant-mimicking hyperflexion of the wrist is something that bugs me. Sauropod wrist elements are rather simple flat structures that show no special adaptation to achieve this degree of flexion. [Lourina sauropod right manus below, borrowed from here.]

Heinrich Mallison: Hm, I am not too sure what I think of wrist flexion. Sure it looks odd, but if you think it through the very reasons elephant have it is likely true in sauropods. And given the huge amount of cartilage mossing on the bones AND the missing (thus shape unknown) carpals I can well imagine that sauropods were capable of large excursions in the wrist.

 Mike: What are those reasons?

Heinrich: Mike, long humeri, very straight posture – try getting up from resting with weak flexion at the wrist. Or clearing an obstacle when walking. I can’t say too much, since this afternoon this has become a paper-to-be.

Mike: OK, Heinrich, but the Muybridge photos (and many others, including one on John H.’s homepage) show that elephants habitually flex the wrist in normal locomotion, not just when gwetting up from resting or when avoiding obstacles. Why?

The interesting thing here is that this is evidence of how flawed our (or maybe just my) intuition is: looking at an elephant skeleton, I don’t think I would ever have guessed that it would walk that way. (That said, the sauropod wrist skeleton does look much less flexible than that of the elephant.)

Matt: (why elephants flex their wrists) Possibly for simple energetics. If the limb is not to hit the ground during the swing phase, it has to be shortened relative to the stance limb. So it has to be bent. Bending the limb at the more proximal joints means lifting more weight against gravity. Flexing the wrist more might be a way to flex the elbow less.

(sauropod wrists look less flexible) Right, but from the texture of the ends of the bones we already suspect that sauropods had thicker articular cartilage caps than do mammals. And remember the Dread Olecranon of Kentrosaurus (i.e., Mallison 2010:fig. 3).

Mike: No doubt, but that doesn’t change the fact that elephant wrists have about half a dozen more discrete segments.

Matt: Most of which are very tightly bound together. The major flexion happens between the radius and ulna, on one hand, and the carpal block on the other, just as in humans. Elephants may have more mobile wrists than sauropods did–although that is far from demonstrated–but if so, it’s nothing to do with the number of bony elements. [Loxodonta skeleton below from Wikipedia, discovered here, arrow added by me.]

(Aside: check out the hump-backed profile of the Asian Elephas skeleton shown previously with the sway-backed profile of the African Loxodonta just above–even though the thoracic vertebrae have similar, gentle dorsal arches in both mounts. I remember learning about this from the wonderful How to Draw Animals, by Jack Hamm, when I was about 10. That book has loads of great mammal anatomy, and is happily still in print.)

And that’s as far as the discussion has gotten. The Dread Olecranon of Kentrosaurus is something Heinrich pointed out in the second of his excellent Plateosaurus papers (Mallison 2010: fig. 3).

Heinrich’s thoughts on articular cartilage in dinosaurs are well worth reading, so once again I’m going to quote extensively (Mallison 2010: p. 439):

Cartilaginous tissues are rarely preserved on fossils, so the thickness of cartilage caps in dinosaurs is unclear. Often, it is claimed that even large dinosaurs had only thin layers of articular cartilage, as seen in extant large mammals, because layers proportional to extant birds would have been too thick to be effectively supplied with nutrients from the synovial fluid. This argument is fallacious, because it assumes that a thick cartilage cap on a dinosaur long bone would have the same internal composition as the thin cap on a mammalian long bone. Mammals have a thin layer of hyaline cartilage only, but in birds the structure is more complex, with the hyaline cartilage underlain by thicker fibrous cartilage pervaded by numerous blood vessels (Graf et al. 1993: 114, fig. 2), so that nutrient transport is effected through blood vessels, not diffusion. This tissue can be scaled up to a thickness of several centimeters without problems.

An impressive example for the size of cartilaginous structures in dinosaurs is the olecranon process in the stegosaur Kentrosaurus aethiopicus Hennig, 1915. In the original description a left ulna (MB.R.4800.33, field number St 461) is figured (Hennig 1915: fig. 5) that shows a large proximal process. However, other ulnae of the same species lack this process, and are thus far less distinct from other dinosaurian ulnae (Fig. 3B, C). The process on MB.R.4800.33 and other parts of its surface have a surface texture that can also be found on other bones of the same individual, and may indicate some form of hyperostosis or another condition that leads to ossification of cartilaginous tissues. Fig. 3B–D compares MB.R.4800.33 and two other ulnae of K. aethiopicus from the IFGT skeletal mount. It is immediately obvious that the normally not fossilized cartilaginous process has a significant influence on the ability to hyperextend the elbow, because it forms a stop to extension. Similarly large cartilaginous structures may have been present on a plethora of bones in any number of dinosaur taxa, so that range of motion analyses like the one presented here are at best cautious approximations.

One of the crucial points to take away from all of this is that thick cartilage caps did not only expand or only limit the ranges of motions of different joints. The mistake is to think that soft tissues always do one or the other. The big olecranon in Kentrosaurus probably limited the ROM of the elbow, by banging into the humerus in extension. In contrast, thick articular cartilage at the wrist probably expanded the ROM and may have allowed the strong wrist flexion that some artists have restored for sauropods. I’m not arguing that it must have done so, just that I don’t think we can rule out the possibility that it may have. And so the flipped-back wrist in the Sideshow Apatosaurus does not bother me–but not everyone is convinced. Welcome to science!

I can’t finish without quoting a comment Mike left on Matt Bonnan’s blog a little over a year ago:

Ever since I saw Jensen’s (1987) paper about how mammals are so much better than dinosaurs because their limb-bones articulate properly, I’ve been fuming on and off about this — the notion that the clearly unfinished ends we see are what was operating in life. No.

This is a pretty fair summary of Jensen’s position. Of course, thanks to Heinrich, now we know why dinosaurs had such crap distal limb articulations: they weren’t mammals (part 1part 2part 3).

Finally, interest in articular cartilage is booming right now, as Mike blogged about here. In addition to the Dread Olecranon of Kentrosaurus, see the Dread Elbow Condyle-Thingy of Alligator from Casey Holliday’s 2001 SVP talk, and of course the culmination of that project in Holliday et al. (2010), and, for a more optimistic take on inferring the shapes of articular surfaces from bare bones, read Bonnan et al. (2010).

Next time: texture and color.

References

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:

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.

This is the third in a series of posts on the Apatosaurus maquette produced by Sideshow Collectibles. The rest of the series:

It is probably no surprise, given my proclivities, that I have more to say about the neck than about anything else. So unless I develop an abnormal curiosity about and mastery of, say, sauropod foot anatomy in the next few days, this will be the longest post in the series.

As with the head, the neck of the Apatosaurus maquette illustrates a lot of interesting anatomy. Some of this is unique to Apatosaurus and some of it is characteristic of sauropods in general. I’ll start with the general and move toward the specific.

As we’ve discussed before, the necks of most sauropods were not round in cross section (see here and here). The cervical ribs stuck out far enough ventrolaterally that even with a lot of muscle, the neck would have been fairly flat across the ventral surface, and in many taxa it would have been wider ventrally than dorsally.

The non-circular cross section would have been exaggerated in Apatosaurus, which had simply ridiculous cervical ribs (photo above is from this post). The widely bifurcated neural spines would also have created a broad and probably flattish surface on the dorsal aspect of the neck. The extreme width of the vertebrae and the cervical ribs created a very broad neck base. As in Camarasaurus, the base of the neck was a substantial fraction of the width of the thorax (discussed here). Consequently, the cervico-thoracic junction probably appeared more abrupt in narrow-necked taxa like Diplodocus and Giraffatitan, and more smoothly blended in Apatosaurus and Camarasaurus.

All of these features–the non-circular cross-section, the flattish dorsal and ventral surfaces, the wide neck base blending smoothly into the thorax–are captured in the Apatosaurus maquette.

The ventrolateral ‘corners’ of the neck have a ribbed appearance created by, well, ribs. Cervical ribs, that is, and big ones. In contrast to most other sauropods, which had long, overlapping cervical ribs, diplodocoids had short cervical ribs that did not overlap. But in Apatosaurus they were immense, proportionally larger than in any other sauropod and probably larger than in any other tetrapod. What Apatosaurus was doing with those immense ribs is beyond me. Some people have suggested combat, akin to the necking behavior of giraffes, and although I haven’t seen any evidence to support that hypothesis over others, neither does it strike me as far-fetched (an important nuance: giraffes use their heads as clubs, clearly not an option for the small-headed and fragile-skulled sauropods). Whatever the reason, the cervical ribs of Apatosaurus were amazingly large, and may well have been visible from the outside.

Mounted skeleton of Apatosaurus louisae in the Carnegie Museum, from Wikipedia.

Now this brings me to a something that, although not universal, has at least become fairly common in paleoart. This is the tendency by some artists to render (in 2D, 3D, or virtually) sauropods with dished-in areas along the neck, between the bony loops where the cervical ribs fuse to the centra. I am going to be as diplomatic as I can, since some of the people who have used this style of restoration are good friends of mine. But it’s a fine example of shrink-wrapped dinosaur syndrome, and it simply cannot be correct.

Adjacent cervical ribs loops in sauropods would have been spanned by intertransversarii muscles, as they are in all extant tetrapods. And outside of those single-segment muscles were long belts of flexor colli lateralis and cervicalis ascendens, which are also anchored by the cervical rib loops. All of these muscles are present in birds, and only vary in their degree of development in different parts of the neck and in different taxa. The spaces between adjacent cervical rib loops are not only not dished-in, they actually bulge outward, as in the turkey neck above.

And we’re still not done; running up through the cervical rib loops, underneath all of those muscles, were pneumatic diverticula. Not just any diverticula, but the big lateral diverticula that carried the air up the neck from the cervical air sacs at the base of the neck to the vertebrae near the head end (diverticula are reconstructed here in a cervical vertebra of Brachiosaurus, from Wedel 2005: fig. 7.2). Now, it’s unlikely that the diverticula exerted any outward pressure on the lateral neck muscles, but they were still there, occupying space (except when the muscles bulged inward and impinged on them during contraction), and with the muscles they would have prevented the neck from having visible indentations between the cervical rib loops of adjacent vertebrae.

Okay, so sauropod necks shouldn’t be dished in. But might the cervical ribs have stuck out? It might seem like the same question, only seen from the other side, but it’s not. We’ve established that adjacent cervical rib loops supported bands of single-segment muscles that spanned from one vertebra to the next, and longer, multi-segment muscles that crossed many vertebrae. But could the bony eminences of the cervical ribs have projected outward, through the muscle, and made bumps visible through the skin? The idea has some precedent in the literature; in his 1988 paper on Giraffatitan, Greg Paul (p. 9) argued that,

The intensely pneumatic and very bird-like neck vertebrae of sauropods were much lighter in life than they look as mineralized fossils, and the skulls they supported were small. This suggests that the cervical musculature was also light and rather bird-like, just sufficient to properly operate the head-neck system. The bulge of each neck vertebra was probably visible in life, as is the case in large ground birds, camels, and giraffes.

Paul has illustrated this in various iterations of his Tendaguru Giraffatitan scene; the one below is from The Princeton Field Guide to Dinosaurs (Paul 2010) and is borrowed from the Princeton University Press blog.

There is much to discuss here. First, I have no qualms about being able to see individual vertebrae in the necks of camels and giraffes, and it’s not hard to find photos that show these. It makes sense: these are stinkin’ mammals with the usual seven cervical vertebrae, so the verts have to be longer, proportionally, and bend farther at each joint than in other long-necked animals. I’m more skeptical about the claim that individual vertebrae can be seen in the necks of large ground birds. I’ve dissected the necks of an ostrich, an emu, and a rhea, and it seems to me that the neck muscles are just too thick to allow the individual vertebrae to be picked out. In a flamingo, certainly–see the sharp bends in the cranial half of the neck in the photo below–but flamingos have freakishly skinny necks even for birds, and their cervicals are proportionally much longer, relative to their width, than those of even ostriches.

What about sauropods? As discussed in this post, sauropod cervicals were almost certainly proportionally closer to the surface of the neck than in birds, which would tend to make them more likely to be visible as bulges. However, the long bony rods of the cervical ribs in most sauropods would have kept the ventral profile of the neck fairly smooth. The ossified cervical ribs of sauropods ran in bundles, just like the unossified hypaxial tendons in birds (that’s Vanessa Graff dissecting the neck of Rhea americana below), and whereas the latter are free to bend sharply around the ventral prominences of each vertebra, the former were probably not.

All of which applies to sauropods with long, overlapping cervical ribs, which is most of them. But as mentioned above, diplodocoids had short cervical ribs. Presumably they had long hypaxial tendons that looked very much like the cervical ribs of sauropods but just weren’t ossified. Whether the vertebrae could have bent enough at each segment to create bulges, and whether the overlying muscles were thin enough to allow those bends to be seen, are difficult questions. No-one actually knows how much muscle there was on sauropod necks, not even within a factor of two.  There has been no realistic attempt, even, to publish on this. Published works on sauropod neck muscles (Wedel and Sanders 2002, Schwarz et al. 2007) have focused on their topology, not their cross-sectional area or bulk.

But then there’s Apatosaurus (AMNH mount shown here). If any sauropod had a chance of having its cervical vertebrae visible from the outside, surely it was Apatosaurus. And in fact I am not opposed to the idea. The cervical ribs of Apatosaurus are unusual not only in being large and robust, but also in curving dorsally toward their tips. If one accepts that the cervical ribs of sauropods are ossified hypaxial tendons–which seems almost unarguable, given that the cervical ribs in both crocs and birds anchor converging V-shaped wedges of muscle–then the ossified portion of each cervical rib must point back along the direction taken by the unossified portion of the tendon. In which case, the upwardly-curving cervical ribs in Apatosaurus suggest that the muscles inserting on them were doing so at least partially from above. So maybe the most ventrolateral portion of each rib did stick out enough to make an externally visible bulge.

Maybe. Many Apatosaurus cervical ribs also have bony bumps at their ventrolateral margins–the ‘ventrolateral processes’ or VLPs illustrated by Wedel and Sander (2002: fig. 3). If these processes anchored neck muscles, as seems likely, then even the immense cervical ribs of Apatosaurus might have been jacketed in enough muscle to prevent them from showing through on the outside.

Still. It’s Apatosaurus. It’s simply a ridiculous animal–a sauropod among sauropods. If this were a model of Mamenchisaurus and it had visible bulges for the cervical rib loops, I’d be deeply skeptical. For Apatosaurus, it’s at least plausible.

Because the cervical ribs are visible in the maquette as distinct bulges, it’s possible to count the cervical vertebrae. Apatosaurus has 15 cervicals, and that seems about right for the maquette. The neck bumps reveal 11 cervicals, but they don’t run up all the way to the head. This is realistic: the most anterior cervicals anchored muscles that supported and moved the head, and these overlie the segmental muscles and cervical ribs in extant tetrapods. The most anterior part of the neck in the maquette, with no cervical rib bumps, looks about the right length to contain C1-C3. Plus the 11 vertebrae visible from their bumps, that makes 14 cervicals, and the 15th was probably buried in the anterior body wall.

One last thing: because the cervical ribs are huge, the neck of Apatosaurus was fat. To the point that the head looks almost comically tiny, even though it’s about the right size for a sauropod head. I first got a visceral appreciation for this when I was making my own skeletal reconstruction of Apatosaurus, for a project that eventually evaporated into limbo. Once you draw an outline of flesh around the vertebrae, the weirdness of the massive neck of Apatosaurus is thrown into stark relief. Apatosaurus is robust all over, but even on such a massive animal the neck seems anomalous. I don’t know what Apatosaurus was doing with its neck, but it’s hard not to think that it must have been doing something. Anyway, I bring this up because the maquette captures the neck-fatness very well. So much so that when I sit back from the computer and my eyes roam around the office and fall on the maquette, I can’t help thinking, for the thousandth time, “Damn, that’s weird.”

In sum, the neck of the Sideshow Apatosaurus maquette gets the non-circular cross-section right, appears to have the correct number of cervical vertebrae, and looks weirdly fat, which turns out to be just right for Apatosaurus. The bumps for the individual vertebrae are plausible, and the maquette correctly avoids the dished-in, emaciated appearance–cocaine chic for sauropods–that has become popular in recent years. It manages to be eye-catching and even mildly disturbing, even for a jaded sauropodologist like yours truly, in that it confronts me with the essential weirdness of sauropods in general, and of Apatosaurus in particular. These are all very good things.

Next time: as much of the rest of the body as I can fit into one post (all of it, it turned out).

References

This is the second in a series of posts in which I review the Sideshow Collectibles Apatosaurus maquette. The rest of the series:

First, a note on the photos. There a few minute white flecks on the head in the pictures. These are near-microscopic pieces of styrofoam packing material, which I only discovered after I’d shot the photos–they are, seriously, too small to be noticed otherwise. Just be aware that they are not flaws in the paint. The whole head, from external ear to snout tip, is 35 mm long, which gives you some idea of the quality of the sculpting and painting. The entire maquette is detailed to the same degree.

The general form and proportions are a good match for the skull of Apatosaurus. In particular, the head is roughly rectangular in dorsal view, with a very squared-off snout. Among extant animals, square snouts are typically found among grazers, and grazing on low-growing vegetation has been suggested for diplodocids as well (Stevens and Parrish 1999, Whitlock 2011). It is worth keeping mind, however, that anatomy is not destiny (Smith and Redford 1990); the behavior of living animals is often more varied than their skeletal form might suggest, and in some cases morphological specialization can lead to ecological generalization.

In a paper with direct relevance to grazing and browsing, Feranec (2003: 230) analyzed the diet of the Pleistocene camel Hemiauchenia. He found that “hypsodonty is not strictly associated with obligate grazing; instead it may, in this case, represent an adaptation to widen niche breadth that allowed grazing as well as browsing.” In other words, the tall, long-wearing (hypsodont) teeth necessary for eating tough grass do not prevent hypsodont herbivores from browsing on softer vegetation as well, whereas committed browsers with lower tooth crowns would have a harder time dealing with tough, abrasive grasses.

Sauropods didn’t chew their food, so tall grinding molars are beside the point, but snout shape is not. It is possible that a broad snout widened the niche breadth of diplodocids to allow both grazing and browsing, whereas a narrow-snouted sauropod like Camarasaurus would probably have made a poor grazer. I’m not discounting the hypothesis that diplodocids were partially or even predominantly grazing animals–in particular, it would help make sense of Nigersaurus, which seems to have taken the grazing adaptations seen in other diplodocoids to an extreme. Just pointing out that certain kinds of morphological specializations broaden, rather than narrow, the ecological opportunities of the animals that bear them. I should also point out that Whitlock’s (2011) analysis did not rely on muzzle shape alone but also on some interesting tooth microwear data. That paper is well worth reading, and happily it’s free, so go read it if you haven’t.

Back to the maquette. Several issues of the soft tissues of the head deserve comment.

The nostrils are down near the end of the snout, as predicted by Witmer’s (2001) work on nostril position in extant vertebrates. I know that some people are skeptical about the nostril position in dinosaurs hypothesized by Witmer, but it makes good sense to me. First, in formulating the hypothesis, Witmer did something that none of his critics have done, which is actually establish the nostril position in a wide range of extant animals. By itself, this doesn’t show what the nostril position in dinosaurs must have been, but it establishes a null hypothesis, which should only be discarded if there is compelling evidence to the contrary. And the scarcity of counterexamples among extant vertebrates constitutes a second, normative argument: if the default nostril position was an easy constraint to break, we’d expect to see more taxa that have broken it. (Both of these arguments also apply to the alert neck posture of tetrapods, by the way.)

Second, Witmer’s hypothesis has explanatory power: it makes sense of the troughs and tracks in front of the nostrils in sauropods with retracted nares. These tracks are most clearly expressed in the skull of Giraffatitan (see, e.g., the images at the top of this post), but they are present in other sauropods as well, like the Denver museum Brachiosaurus sp. skull shown above. Witmer’s hypothesis of nostril position made good sense to me because of my experience working on postcranial pneumaticity in sauropods. External pneumatic traces on sauropod vertebrae often consist of pneumatic foramina set inside larger pneumatic fossae (see, for example, this, from here). Similarly, the bony nares of sauropods can be thought of as pneumatic foramina set at the posterior end of the pneumatic fossae formed by the troughs and tracks on the snouts.

One last thing on nostril position in dinosaurs. I’ve seen people argue that terminal nostrils would have been bad for dinosaurs (especially carnivores) because they would have gotten poked by vegetation or fouled with food. To which I can only say, good people, stop trying to figure out dinosaurs from first principles and just look at live animals.

Next item: the teeth are covered by fleshy lips. The hypothesis that some dinosaurs had lips is not new, but it hadn’t received much technical attention until recently. Enter Ashley Morhardt (research page, blog). For her MS work under Matt Bonnan (research page, blog) at Western Illinois University, she did something that no one had done before: she counted nutrient foramina (blood vessel holes) in the jawbones of extant vertebrates and related foramina counts to the kinds of soft tissues the jaws supported: marginal scales, muscular lips, beaks, and so on. Then she looked at dinosaurs and applied what she’d learned. That work is still on the road to publication, so I won’t give away the game. But I did ask Ashley specifically about the plausibility of the lips in the Apatosaurus maquette, and she was kind enough to share her thoughts. She writes (with permission to cite):

The foramina present at the margin of Apatosaurus‘ mouth are more similar in relative size, shape, and distribution to those of crocodylians than those of mammals. … A conservative EPB approach would shy away from reconstruction that might include any type of fleshy seal at the oral margin.  This would leave the teeth bare and the posterior margin of the mouth covered in skin without any overhanging scales. … The current maquette is gorgeous, but potentially incorrect.

Ashley is now working on her PhD with Larry Witmer (research page, blog) at the University of Ohio, and we can surely expect more cool science from her in the future. Please also note that the question of dinosaur lips was recently the subject of a long, thoughtful post by Jaime Headden.

Since this post involves soft tissues of sauropod heads, I’m contractually obligated to point out that, like the maquette, real sauropods didn’t have trunks.

Finally, I’m happy to say that the head avoids shrink-wrapped dinosaur syndrome. There’s enough underlying anatomy to show that It’s built up from the skull of Apatosaurus, but you can’t see every little ridge and divot in the skull (nor should you). And the soft tissues are plausible and detailed, so the head doesn’t just look like a smooth bullet of meat. And the sculpting itself is detailed enough to support close examination. All of these are big pluses, even if the lips are a (small) step beyond what our current understanding will support.

Next time we’ll look at the real business end of a sauropod: the neck.

References

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