Your cervical ribs are (probably) non-existent

December 2, 2009

It’s a strange thing, but no-one seems to bother properly figuring their sauropods’ cervical ribs — that is, the long, thin, posteriorly directed ribs of the neck vertebrae.  I’ll be bucking that trend when the Archbishop paper comes out, but to get your mouth watering ahead of time, here is the head of the cervical rib that I have arbitrarily designated X1, the largest of those preserved in the Archbishop:

Brachiosauridae incertae sedis NHM R5937, "The Archbishop", cervical rib X1. Preserved portion is 32 cm long.

The top image shows the rib in anterior view, with dorsal pointing to the left; the middle row shows the rib with anterior pointing upwards, in (from left to right), lateral, dorsal, medial and ventral views; the bottom row shows posterior view, again with dorsal to the left.  Click through the image to see the full glory of the high-resolution version.  Remember folks: you only get this sort of high-resolution image published in PLoS journals!

As I mentioned, sauropod cervical ribs have been pretty comprehensively ignored in the literature.  I can’t offhand think of a single paper about them (unless you count Martin et al.’s (1998) proposal that they functioned in ventral compression-bracing of sauropods’ necks, and let’s not even start on that), and I am really struggling to think of paper that figures them.  Even the usually super-reliable Osborn and Mook (1921) dropped the ball here, with a single illustration (out of 127 figures) and single short paragraph of text (out of 141 pages).  Here it is:

Cervical rib of Camarasaurus supremus AMNH 5761-a/R-X-A-5, from Osborn and Mook (1921:fig. 36) and accompanying text

Janensch (1950) did discuss the cervical ribs of Giraffatitan in some detail, but his figures are not very informative.  If anyone knows of better treatments of sauropod cervical ribs in the literature, then please mention it in the comments!

Because of this poor coverage in the published record, it’s hard for me to compare the Archbishop cervical ribs with those of other taxa.  For example, the medial view of X1 (in the middle of the “cross” in the image above) shows that the internal face of the cervical rib loop, where the cervical rib reaches up to articulate with the diapophysis of its vertebra, has two parallel struts of bone extending vertically with a narrow groove between them.  Is that unusual?  I have no idea.

(I do have photos of some other Tendaguru cervical ribs, referred to Giraffatitan — although if I’m right that the Archbishop is not Giraffatitan, so that there are multiple brachiosaurs in the Tendaguru Formation, then who knows whether that referral is correct?)

Finally, we come to the matter of your cervical ribs.  I would have liked to do this post as one in the Your Noun Is Adjective series, but the brutal truth is, you don’t even have any cervical ribs — unless you are one of the lucky 0.2% that, according to the Wikipedia article, have a supernumary rib which is frankly just an additional dorsal rib (uh, thoracic rib I guess) that’s growing out of your last cervical vertebra by mistake.  (Wikipedia’s horrible humanist bias is apparent here, in that the article doesn’t even mention the fact that plenty of other animals have cervical ribs and love them.)

Anyway, here’s how human cervical ribs look, stolen from Do You Really Need Back Surgery? A Surgeon’s Guide to Neck and Back Pain and How to Choose Your Treatment:

Cervical ribs in humans

References

  • Janensch, Werner.  1950.  Die Wirbelsaule von Brachiosaurus brancai.  Palaeontographica (Suppl. 7) 3:27-93.
  • Martin, John, Valérie Martin-Rolland, and Eberhard (Dino) Frey.  1998.  Not cranes or masts, but beams: the biomechanics of sauropod necks.  Oryctos 1:113-120.
  • Osborn, Henry Fairfield, and Charles C. Mook.  1921.  Camarasaurus, Amphicoelias and other sauropods of Cope.  Memoirs of the American Museum of Natural History, n.s. 3:247-387, and plates LX-LXXXV.
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48 Responses to “Your cervical ribs are (probably) non-existent”

  1. Andy Says:

    As a matter of precision, humans do have cervical ribs – they’re just not separate elements. The embryonic costal process elongates into ribs in the thoracic region, but just turns into the boundaries of the transverse foramina in the cervical region.

    As an interesting aside, it was recently proposed (back in 2005) that the elongate cervical ribs on the protosaurus Dinocephalosaurus were an adaptation for suction feeding. Now *there’s* a hypothesis I’d like to see applied to sauropods!

  2. Nima Says:

    Well at least humanocentric-biased Wikipedia tells us one good thing about cervical ribs; apparently judging by their last tidbit of info in that article, sauropods didn’t get cancer! LOL ^_^

  3. Nathan Myers Says:

    Nima: No, it suggests that what with all those supernumerary ribs, cancer is what wiped out the sauropods well before K-T. So much for my “wrapped in bacon” hypothesis.

    Ought we to guess that each cervical rib ran in or alongside a corresponding muscle?

  4. William Miller Says:

    What is the function of sauropods’ super-long cervical ribs? It seems that they would make the neck less flexible; did the advantage of this in helping hold up a long neck outweigh the loss of neck mobility?

  5. Andy Farke Says:

    It would be interesting to do an allometric study of cervical ribs in general. . .long-necked vs. short-necked theropods, sauropods, accounting for phylogeny, etc. I.e., are the super long cervical ribs of sauropods any longer than what we would expect for an archosaur that size? Why do birds not get longer cervical ribs, when some of their non-avian theropod ancestors had perfectly nice, long cervical ribs? Is it really an ultra-long rib, or is it just extra ossification of some ligament or tendon at the end of an otherwise short process? What do cervical ribs and the structures associated with them do in modern birds and crocs (and I’m talking real research with live-muscle EMG, not some crummy equations and hand-waving)? Loads of questions to unpack here (and sadly, there are probably very few specimens that are prepared adequately to answer this!). . .

    Anyone looking for a dissertation idea?

  6. Nima Says:

    Nathan: are you sure about that? All jokes aside, I thought that the Hox genes that code for having cervical ribs are linked to an ABSENCE of cancer… at least that’s what it looks like when I read it… The funny thing about the bacon hypothesis is that sauropods survived right up to the KT extinction. Alamosaurus lived at the same time as T.rex, and the rexes didn’t wipe them out. LOL with a nose as powerful/sensitive as T.rex’s, burnt bacon may have actually saved the sauropods!

    Andy: you practically stole my suggestion before I could come up with it ;) It’s a great idea, I’ve always wondered about cervical ribs. One of my main questions is: Why are they so long in macronarians and so much shorter in diplodocids? Does it have anything to do with their different neck postures?

    The muscle attachment idea is interesting too…. but to my knowledge there aren’t a whole lot of birds and crocs with anything that big under their neck vertebrae. So I’m just as curious as you are.

    As for prepared specimens… Mamenchisaurus or Giraffatitan would be a great start…

  7. Andy Farke Says:

    Even if they’re not that big in extant archosaurs, the ribs are still there. And if the same types of muscles are attaching to the bones, that can likely tell us something about sauropods.

    Another question is how real the elongated cervical ribs are in Mamenchisaurus. . .I would suspect that intact, well-prepared cervical ribs are pretty rare. But, I wouldn’t mind being surprised!

  8. Matt Wedel Says:

    Andy is correct to note that humans do have bicipital (two-headed, that is, having both a capitulum and a tuberculum; if those terms are unfamiliar, go here) costal processes fused to our cervical vertebrae. In birds and other saurischians these fused ribs tend to be long and look like ribs so we call them “cervical ribs”. In mammals they tend to be short and look like perforate transverse processes (perforate because the costal process + diapophysis and parapophysis forms a bony loop, through which the vertebral artery passes), so they are usually referred to as “transverse processes”, which is a bit wonky, because evolutionary and developmentally they ARE ribs. In anthropology and medicine, “cervical rib” almost always means a segmentation error that results in an unfused, thoracic-style rib on one or more cervical vertebrae, usually C7. And the presence of these kind of large, unfused cervical ribs in humans and other mammals is correlated with nasty cancers that tend to kill kids while they’re still kids. So if you have one of those unfused cervical ribs and you’re still alive to read this, you really are lucky.

    In birds the cervical ribs serve as the attachment points of the large ventral neck muscles, particularly the longus colli ventralis and flexor colli lateralis. Most birds have fairly short cervical ribs but in big ratites the cervical ribs are often as long as the centrum. These start out short, developmentally, and get longer because the common tendon on which those large ventral neck muscles insert gets progressively ossified.

    About the long cervical ribs in Mamenchisaurus–there is one from M. sinocanadorum that is over 4m long. I have seen this rib in the flesh at the IVPP and it is all one real whole rib. We have some cervical ribs over 3m long for Sauroposeidon, which sounds more impressive than it is. The cervicals of Sauroposeidon were so long that even a 3m rib would only run under two cervicals past the one on which it originated, and would thus form part of a vertically-stacked bundle of three ribs under any given cervical. The cervicals of Mamenchisaurus were much shorter, and there is evidence for bundles of up to seven stacked cervical ribs toward the base of the neck.

    Could these bundles of ribs have served some kind of supporting function? I strongly doubt it, for reasons explained on pp 378-382 of this paper. The whole setup, with bundles of overlapping ribs and everything, is present in birds, except that the overlapping parts of the “ribs” are unossified tendons. Except for the proportional and pneumatic differences discussed in the previous post, sauropod cervicals look like bird cervicals with better ossified cervical ribs. So this is one area where I am content to be boring and conservative and argue that the cervical ribs of sauropods did not do anything radically different than those of birds.

  9. Nathan Myers Says:

    Nima: All I know is what it says on the wiki page. But didn’t sauropods peak in the late Jurassic, except in South America and Antarctica?

    If the cervical ribs were each collinear with a muscle, wouldn’t that imply something profound about the action of the muscles?

  10. Thomas Dean Says:

    If wikipedia is lacking information that may be of use to the rest of us, why not take a few moments and edit it?

    (this coming from someone who edits wikipedia from time to time)

    Wikipedia is about sharing and compiling information. It needs real people with real knowledge and insight to add information… that’s the only way real knowledge will outstrip the middle school bogus edits.

    Anyway… found your blog when trying to identify a skull I found (pig) while deer hunting. Thus far I am enjoying stretching my brain by reading your blog.

  11. Alton Dooley Says:

    A “cervical rib” on the 7th cervical vertebra also occurs fairly frequently in baleen whales, up to about 15% of the individuals in some taxa. As Matt mentions, this seems to be a segmentation error, and in these whales the 7th cervical tends to look more like the 1st thoracic vertebrae than a normal 7th cervical; essentially, those individuals only have 6 cervical vertebrae and an extra thoracic vertebra. Emily Buchholtz has done a lot of work on these HOX-related errors.

    We have a Miocene baleen whale in our collection that has such a rib, fused to the first “normal” thoracic rib. Since primitive baleen whales have distinct shafts separating the capitulum and tuberculum, this gives it the appearance of being a triple-headed rib. I figured these years ago in our museum publication, Jeffersoniana, which is in the process of going open access; unfortunately we haven’t gotten that far into the back issues yet.

    W. Turner figured ribs like these from humans and whales as early as 1871:

    Turner, W., 1871. On the so-called two-headed ribs in whales and in man. Journal of Anatomy and Physiology, 5: 348-361.

  12. Jamie Stearns Says:

    As for cervical ribs vs. neck length, I’m not sure how much of a connection can be found. While Mamenchisaurus and Omeisaurus have extremely elongated cervical ribs,those of Barosaurus are not particularly oversized compared to those of Diplodocus. In fact, I think Camarasaurus might have longer cervical ribs relative to the size of each vertebra than Barosaurus does. Spinophorosaurus also possesses elongated cervical ribs despite having a relatively short neck.

  13. Zach Miller Says:

    Potentially stupid question, here: Would elongate cervical ribs inhibit flexibility in any way? It seems like long cervical ribs would lock against each other and prohibit movement past a certain point, whereas a lack of cervical ribs, or at least very short ones, would not have such a problem.

  14. Nima Says:

    I don’t think cervical ribs have anything to do with neck length, but I’ve got a hunch they have something to do with the dynamics of neck posture. Basically Matt’s paper says that the ribs did not brace the neck against its own weight, but rather, anchored muscles that pulled it down to counterbalance the strong dorsally anchored “crane” muscles that raised it up, so that the neck would not lift too rapidly and risk snapping the joints dorsally. This way the sauropods could raise and lower their necks smoothly with muscles in equilibrium, much like ratites and other birds. At least I think that’s the gist of it.

    The neck length hyposthesis is sort of the conjoined twin of the ventral bracing hypothesis: the longer the neck, the greater the stresses on it, and the more it needs long, overlapping cervical ribs to hold it up. Unfortunately this has two problems – first of all this only works if the neck “walks the plank” and droops slightly below horizontal at all times, making it impossible to lower the head to drink, and making raising it a very risky unbalanced business.

    The second problem is that even the longest-necked diplodocids have cervical ribs barely linger than their parent vertebra, while short necked camarasaurs have very long cervical ribs… so longer ribs are obviously not necessary for supporting a longer neck (even though Euhelopodids and Brachiosaurs have both crazy long necks AND crazy long cervical ribs… my hunch is macronarians just had different neck posture and/or musculature than diplodocids – with macronarians being more vertical with stronger dorsal/spinal neck muscles, which needed stronger cervical rib muscles to calibrate their smooth movement).

    As for Nathan’s comment: While it’s commonly believed that Sauropods peaked in the Late Jurassic (and in terms of pylogemic/genetic diversity, this was almost certainly the case) I’m not so certain in other respects, since much of the non-phylogenic portion of the juice behind this tempting theory has dried up. The idea was that in the Late Jurassic, you had the most sauropods (both in terms of species and population-wise), the biggest sauropods, and the most successful sauropods.

    But back when Bakker (and others undoubtedly before him) wrote about this, there wasn’t a lot of easily accessible good research on big cretaceous sauropods, and plenty of proof of a big extinction of some sort ending the jurassic. So from circumstance and a paucity of evidence, the public often took this to mean a total absence of big sauropods and maybe a few small ones like Saltasaurus. Some less professional books (i.e. stuff you see in grade school classrooms) even claimed that there were no big sauropods, or no sauropods AT ALL, in the Cretaceous.

    Actually it’s more like no diplodocids or camarasaurids (almost, if you count Jobaria…) Otherwise, Brachiosaurs flourished in North America for at least the first half of the cretaceous, and elsewhere titanosaurs and to a lesser extent “somphospondyli” were quite common. Not just in South America where titanosaurs attained colossal proportions, but also Asia and Australia (more colossal proportions). The Nemegt formation in Mongolia has at least three, and Tarbosaurus may have hunted them judging based on its skull structure. They were in India, China, Europe, Africa and Madagascar.

    Now the problem is that these cretaceous remains are mostly not as good as the Jurassic ones. A lot more digging needs to be done to get a good idea of how common or diverse cretaceous sauropod actually were. Did they die out in places they had dominated in the Jurassic? Sure. But many other areas were more favorable to them than to cretaceous ornithischians. It’s interesting how there are no large ceratopsians known from Nemegt, or India, Europe and many other places. And only a handful of ornithopods. Had dinosaurs not become extinct, I suspect more than just Alamosaurus would have invaded North America. So while the end of the Jurassic was not the best of times for many sauropods, I don’t think it can be said conclusively yet that sauropods as a whole declined afterwards. Time and more remains will tell.


  15. I’ll echo Nima’s sentiments regarding neck length vs. cervical rib length being unrelated, as in theropods there is no connection. In theropods, it’s basically all phylogenetic. Basal theropods with long (coelophysoids, compsognathids) or short (abelisaurs, carnosaurs, tyrannosaurids) necks have long cervical ribs. Maniraptoriforms with long (ornithomimosaurs) or short (dromaeosaurids) necks have short ribs.

  16. John Scanlon Says:

    In a justly famous Nature paper on the developmental basis of limbless and axial patterning in snakes, Cohn and Tickle (1999) argued (inter alia) that snakes have essentially no neck because their articulated ribs start on about the 3rd vertebra. They must have forgotten to check the condition in any lizards or other appropriate outgroups, just assuming that mammals are ‘standard’. The fact that this got past any reviewers confirms that cervical ribs have been widely underappreciated.


  17. Hmm, another comment didn’t get through (but it did have a link in it). Hoping it’s recoverable, I won’t repeat the point here.

  18. William Miller Says:

    I added a brief section to the Wikipedia article on cervical ribs in nonmammals.

  19. Graham King Says:

    For part of our 10th anniversary outing, Bev and I visited again the wonderful Bell Pettigrew collection (links here and here).

    Bev asked ‘why are they called cervical ribs?’ Of course, outside zoology, cervix and cervical occur in a gynecological context – at the opposite end of the vertebral column.
    Latin cervix=neck (hence, in female anatomy, cervix as neck of the womb). But I wondered why Latin collum=neck too is not used; it occurs in specific names (both animal and plant) as ‘longicollis’ meaning long-necked. Are cervix and collum neck in slightly different senses? And how often does confusion arise from the disparate anatomical uses of cervix and cervical? I wonder..

    A Scottish health advert refers to serv-I-cal screening (long i, stress on middle syllable). But I’ve always pronounced it SERV-i-cal (short i, stress on first syllable). Whuh?

  20. Mike Taylor Says:

    SER-vikkal vs. ser-VYE-kal seems to one of those You Say Di-PLOD-uh-kuss, I Say Diplo-DOH-kuss things.

  21. Uros Says:

    Is it possible, those ribs developed different orientation in some longer neck sauropods? If they were orinented more in upwards direction (and therefore make neck wider in vertical direction), they might enable muscles to have longer handles. Such arrangment would decrease the needs for muscle strenght, size and neck weight for holding and lifting those enormous necks.

  22. Uros Says:

    Talking about cervicals and cervical ribs, easy brings out the question, why did sauropods need their long necks? By answering that question, we might see their anatomy in different perspective. I smply don’t believe, these necks were used for easier access to high grown tree branches or accessing larger area of lower located plants without the need to move.
    Such strategy is sensible for lighter and smaller sauropods, but a 60 ton sauroposeidon or 80 to 100 ton argentino- or puertasaurus could just lean on and trample to the ground parctically any tree. For the animal of this mass it seems much more logical for the evolution to favour stockier built animals, that would uproot trees and eat whats edible through larger jaws and shorter necks.
    But we now, that the largest and heaviest sauropods had almost proportionaly long necks as their lighter relatives. Cervicals are very often among the best perserved perserved parts of the largest beasts. So, for 100 ton monsters longer neck was still an advantage for some reason. And this advantage was obviously more important than its drawbacks (blood pressure problems, vulnerability to predation due to having upper necks and heads of bite size proportions for the largest predators, …).
    I think that the best explanation is, that we are missing something about sauropod diet and/or their eating habits. I find it highly possible, that sauropods didn’t only eat plants, but also some prey, that was way easier to catch, by following it with a neck, that enabled them to cover around 6000 m^3 without a need to make a single step. Such diet with a way higher energy value than conifers, would also enable them to eat less – current estimates show, that most sauropods needed to eat enormous amounts of plant food, which would consume too much time calculating in their small heads. There are some possible sources of food that sauropods could eat in this way (probably in addition to plants).
    1. Swarms of insects (some teeth appear as if they could be used as traps – similarly to whales and krill)
    2. Marine food – sauropod standing near the shore could observe a large area of a river, lake or sea and pick out crabs, fish and other animals.
    3. Larger animals – animals not large enough to seriously attack sauropod head could neither fend off sauropod attack, nor run away when chased by a head on a 10m long neck. Just to put the perspective: I believe that even animals larger than humans fall into this category. But from what I know about the sauropod teeth, such food would have to be swallowed as whole.

  23. DD Says:

    I never thought of a carnivorous sauropod, but since there was an herbivorous theropod, why not?

    Alton Dooley Says: December 3, 2009 at 1:40 pm
    “A “cervical rib” on the 7th cervical vertebra also occurs fairly frequently in baleen whales, up to about 15% of the individuals in some taxa.”

    vertebrae of estuarine boto dolphin: “Cervical ribs occur in 22.5% of the samples. The metapophyses start from the fourth thoracic vertebra, and the zigapophyses start at the cervical level, being observed up to T11. The inclination of the transverse processes and neurapophyses is most reduced around L5 or L6. Transverse processes on caudal vertebrae disappear between Ca9 and Ca13. The neurapophyses, neural arches and metapophyses are observed up to Ca13 or Ca15. Caudal foramina appear between Ca3 and Ca6. The height of the vertebral body increases up to Ca13, then starts to decrease. The maximum width is found around Ca6, where the vertebral body becomes laterally compressed. The length of the vertebral body increases from the last cervical to T7andthen remains constant up to Ca13, decreasing from then on.”

    de Castro Fettuccia, D. and P.C. Simoes Lopes (2004)
    The vertebral morphology of the estuarine dolphin, Sotalia guianensis (Cetacea, Delphinidae)]. Biotemas 17(2): 125-148.

  24. Mike Taylor Says:

    Uros, I am confident that cervical ribs did not project vertically (either upwards or downwards) on any cervical vertebrae of any sauropod. First, every CR that is fused to its centrum is oriented parallel to the centrum; second, sauropod CRs are homologous to tendons in birds that run along the neck; third, CRs are too flimsy to anchor muscles that would pull at right angles to them.

    (Exception: the very most posterior cervical ribs are often somewhat posteroventrally inclined, as they start to grade into the ventrally directed dorsal ribs of the torso.)

    Uros, the advantages and disadvantages of sauropods’ long necks are still very much up for discussion. But I don’t think that interpreting them as a predatory adaptation is going to fly. Sauropod heads could not deal with large prey; to capture small prey effectively, you need to be quick and manoeuverable — not really terms that you’d use of a multi-tonne neck. Add to that the unsuitability of sauropod teeth for carnivory, and it looks very unlikely.

  25. Uros Says:

    I didn’t actually mean a very active predation. But for the major part just picking easily avilable food, that isn’t really able to run, like swarms of insects in the air, bugs worms, etc in soft earth, different animals in shallow water. I agree, that catching a fast modern mammal or its mezozoic equivalent could be difficult or even dangerous feat for sauropod with neck that heavy. But in modern world we have plenty of larger animals (sloths, koalas, etc), that could be easily picked and eaten by a sauropod. I’know those animals didn’t exist then, but some smaller animals were almost certainly around, that based their survival not on speed and agility, but on their ability to stand still and hide.
    About the teeth. I completely agree, that sauropod teeth don’t resemble anything from the carnivorous world. But diplodocus teeth for instance could also easily be used to strip insects of the branches of a tree and not only leaves. It is common belief, sauropods just swalloved their food without chewing it. That’s probably true even if they didn’t have vegetarian diet.
    Also if I try to look at dinosaur closest relatives (reptiles and birds) the ony only group I know of that restricts itself to plant food are hummingbirds, everything else seems to enjoy and sometimes tries to catch something.

  26. William Miller Says:

    Hummingbirds don’t feed *only* on nectar, they eat insects for the protein content too.

    However, there are much truer herbivores (nectarivory is really very different from ordinary herbivory) within reptiles and birds. The Green Iguana is herbivorous; yes, it’s been recorded (occasionally) eating bugs etc, but this is true of the staunchest mammal herbivores as well. IIRC there were a couple Tetrapod Zoology posts about meat-eating in bovids etc. at one point. The hoatzin is a herbivore. Some geese are pretty herbivorous as well.

    Anyway, sauropods seem to have had giant fermenting guts and massive gizzards (with big gastroliths) — they were herbivores. I doubt they ever ate animal food except by accident (insects on leaves etc).

  27. Mike Taylor Says:

    No gastroliths, though. Oliver Wings has convincingly refuted this popular factoid. We should cover that some time.

  28. Nathan Myers Says:

    Wow, no kidding?

    http://evomech1.blogspot.com/2006/12/dinosaur-gastroliths-stones-did-not.html

    Complicated guts, evidently, then.

  29. William Miller Says:

    So they did swallow stones … but the stones didn’t help grind food? Weird…

  30. Uros Says:

    Would it be better to move diet/guts debate to another thread and stick to cervical ribs here?

  31. Michael O. Erickson Says:

    “No gastroliths, though. Oliver Wings has convincingly refuted this popular factoid. We should cover that some time.”

    But Oliver Wings basically rejected sauropod stones as being gastroliths because ostritch gastroliths never get a high polish like the sopposed sauropod gastroliths, and instead become dull and pitted. He COMPLETELY ignored the fact that there is a bird – the extinct moa(s) of New Zealand – whose gastroliths are very highly polished, just like sauropod gastroliths. With all (very, very much due) respect to Oliver, I don’t quite consider a paper in which important data is totally disregarded and not even touched upon “convincing”.

    Just my two cents.

  32. Michael O. Erickson Says:

    I hope that didn’t come off too harsh – it may well be that Oliver is simply unaware that moa gastroliths posess a high polish. I’m just trying to make a point.

  33. Uros Says:

    Are there any other birds with polished gastrolits? It would be interesting to find out what causes these diferencies … diet, size, stone-type, some post-mortem processes or something completelly diferent.

  34. DD Says:

    If ostriches spend more time walking at a higher speed on plains than large moas did, moas might be more representative of sauropods, with (herbivorous) theropods more representative of ostriches?

  35. William Miller Says:

    Also ostriches are omnivores – they eat bugs, seeds, etc. as well, which are much more nutrient-dense than foliage. Ostrich mouths are also smaller than sauropod mouths – sauropods were a lot more likely to swallow twigs, big cycad fronds, etc. And cycads etc. are nasty tough plants … sauropod gastroliths would get a MUCH bigger workout than ostrich gastroliths (especially if sauropod gizzard muscles were much stronger, as they probably were to deal with tough food).

    I’m not sure ostriches are a good analogue.

  36. Uros Says:

    Were in Oliver Wingses experiment gastroliths taken out immediatelly or left inside for some time. Acids and other liquids could also affect gastrolith apperance post-mortem.

  37. David Marjanović Says:

    Cohn and Tickle (1999) argued (inter alia) that snakes have essentially no neck because their articulated ribs start on about the 3rd vertebra.

    Thanks for the link! At long last I get to read this paper! :-) They also make the ornithological mistake of mentioning “lumbar vertebrae” in chickens (in a figure). Those are the dorsosacrals.

    Are cervix and collum neck in slightly different senses?

    I think cervix is the back of the neck; will try to look it up later today.

    Maybe the words were already confused in Classical Latin. That kind of thing happens. The German word Nacken clearly shares a common ancestor with neck, but it means “back of the neck”; “neck as a whole” is Hals.


  38. I am an illustrator, researching dinosaur anatomy for a project, and I am having the darnedest time finding reference of sauropod neck and chest muscles from a frontal perspective. I even consulted James Gurney, author’illustrator of Dinotopia, and one of the premier dinosaur illustrators of thw world – he says he has not found much in the way of dinosaur musculature himself. I have found much reference on dinosaurs from the side point of view, but so far, this article has been my best lead… any help would be greatly appreciated!

  39. Dan Says:

    Hello:
    I have a set of cervical ribs. I’m 53 now and have had high blood pressure my whole life. If the cervical rib presses on my subclavian artery would that cause an abnormal blood pressure in my arms?
    Thanks
    Dale


  40. […] cervical ribs of the Archbishop when I finally get around to finishing that paper, and I included a sneak preview of the rib that I’ve arbitrarily designated X1 a while back.  It’s instructive to compare that illustration with this one.  In fact, here […]


  41. […] any descriptive papers to PE, because when I prepare a 4100×3966 pixel figure like the one above [cervical rib "X1" of the Archbishop], I can’t tolerate having it shrunk to 711×688 to fit PE’s 711-pixel width limit […]


  42. […] including all dinosaurs, the cervical vertebrae have backward-pointing ribs; these are called the cervical ribs.  Birds have these (in reduced form) and so do crocs and mammals, but they are absent in at least […]

  43. Ridhi Ranka Says:

    U people actually do not know how much pain can a pair of cervical ribs give I am just 14 years old I face many problem since I was just 7 years old. I can not study properly my limb pains as worse like I fractured my limb it very awe full many people can not even survive as this leads to cancer to all by the age of 20.

  44. Tiffany Carlson Says:

    I don’t really care about birds and dinosaurs or other mammals with this condition. I have it, bilaterally, and my left cervical rib is fused into my first real rib. It hurts like hell! My scalene muscles look like they’ve gone through a shredder. I have debilitating headaches often and its all coupled with a heaping dose of Thoracic Outlet Syndrome. Nothing better to interrupt a good nights sleep than tingling, numbness and burning sensations ripping through both arms. As for your comment, “(Wikipedia’s horrible humanist bias is apparent here, in that the article doesn’t even mention the fact that plenty of other animals have cervical ribs and love them.)” let’s have those animals have my cervical ribs for a day and see how much “love” they have for them then. Comparing a disorder in humans to a common occurrence in other species is completely unfair.

  45. Brad Lichtenstein Says:

    Maybe this was covered already in a paper or later blog post and associated comments, in which case I apologise for being an ignorant outsider, but I’d like to politely, by question, make a few points in support of Matt, Mike, and/or other blog owners:

    1. So I’m convinced, mainly by your pics of ratite neck dissection in a ¿later? post, that sauropod C-“ribs” are homologous to birds’ tendon sheaths. Can we go ahead and call them ossified tendons instead of ribs? The homology with birds seems obvious, and birds don’t need as much ossification because they’re small: the neck muscle forces are simply small compared to tendon elasticity. I know, that’s the hand waving that an earlier poster asked us to avoid.

    2. And if birds don’t ossify them much, and titanosaurs are more derived, and therefore “better adapted to being a sauropod” than chronologically more basal diplodocoids… Isn’t it possible the short “ribs” of the diplodocoids may be simple fossilization bias? Surely their tendons ran the same length, but for whatever reason, only ossified near the attach points. And/or, MAYBE they still had more muscle “anteriorly” in the neck (hence (MAYBE) their long-term inefficiency) – but, for whatever reason.

    3. Is there evidence for any other lateral musculature? From a simple math/physics/engineering point of view, the triangular vertebrate cross section allows 3-dimensional neck movement with just 3 bundles of _tissue_: even though the massive dorsal “crane” must be at least slightly bilaterally split, it’s functionally one erector because it’s not spread far apart like the C ribs and associated musculature – which power both ventral and lateral movements. This arrangement lets the erector bundles be huge and focused only on “gross motor” oomph, with fine coordination of its movement restricted to one dimension at most, and any side to side fine movements be done with the smaller “rib” muscles. And if the “ribs” work together to pull down against a more constant-force “crane” “ligament”, then said ligament need be barely muscular or finely coordinated at all, and 2 actual muscle groups would then be all you need to move the head in 3D…

    4. …I don’t know much about how ostriches use their neck, but can the neck be seen functionally as just an organ that positions and perhaps orients the head in space? It would seem to me, as a previous poster pointed out, that bundling the “ribs” (especially ossified ones) inside a muscle sheath, would tend to inhibit a lot of fine control, perhaps disallowing the wild as curves you see in shish-kebab swans and flamingos, and maybe like how modern birds raise the neck to give a high visual vantage point, then twist ¿mostly just? the skull to look around from there – or maybe you take the moment-of-inertia hit by having a few small skull-attach muscles for that effect? Point being, especially under those force loads, it seems preferable that the sauropods’ necks just arced along their full length to put the head where it wanted, with just maybe a bit of S curving, so they don’t have to step back to rake in food, nor bend just the skull-C1 joint to aim the head straight ahead parallel to, but to the side of, the main body axis. Or maybe not.

    And by now, I’ve forgotten if I even had a 5th point – but thanks to everyone involved here (ALL commenters included) for a fascinating look at a group of creatures you guys (among others obviously) are turning into …fascinating creatures. And thanks to Steven Bellettini at The Geek Group for shaming me into actually following the external links in his videos to find this! Please keep up the good work, part time or full!!

  46. Mike Taylor Says:

    Hi, Brad, good to hear from you.

    1. So I’m convinced, mainly by your pics of ratite neck dissection in a ¿later? post, that sauropod C-“ribs” are homologous to birds’ tendon sheaths. Can we go ahead and call them ossified tendons instead of ribs?

    That wouldn’t be helpful. The bones are bones; ossified tendons are just how they came to be that way. After all, your femur is ossified cartilage, but we still call it bone.

    And if birds don’t ossify them much, and titanosaurs are more derived, and therefore “better adapted to being a sauropod” than chronologically more basal diplodocoids…

    … I’m not sure I buy that. but let it pass …

    Isn’t it possible the short “ribs” of the diplodocoids may be simple fossilization bias? Surely their tendons ran the same length, but for whatever reason, only ossified near the attach points.

    Yes, that is almost certainly true — as with birds.

    And/or, MAYBE they still had more muscle “anteriorly” in the neck (hence (MAYBE) their long-term inefficiency) – but, for whatever reason.

    Almost certainly not. The short ossified cervical ribs of diplodocoids are not inherited from a primitive ancestor, but an evolutionary novelty, since more primnitive sauropods such as mamenchisaurs had longer cervical ribs.

    3. Is there evidence for any other lateral musculature? From a simple math/physics/engineering point of view, the triangular vertebrate cross section allows 3-dimensional neck movement with just 3 bundles of _tissue_

    From a simplified engineering perspective you’re right; but animals are always more complex than that. Sauropods, like birds, had a whole swathe of neck muscles. Matt explained all this nicely in a 2002 paper, and we discuss it more in our 2013 PeerJ paper.

    It would seem to me, as a previous poster pointed out, that bundling the “ribs” (especially ossified ones) inside a muscle sheath, would tend to inhibit a lot of fine control, perhaps disallowing the wild as curves you see in shish-kebab swans and flamingos

    Maybe. Matt and I have a looong-running project (which we thought would be published in 2006) about the bending of cervical ribs as sauropods moved their necks. Hopefully it will come to completion some day!

    it seems preferable that the sauropods’ necks just arced along their full length to put the head where it wanted, with just maybe a bit of S curving, so they don’t have to step back to rake in food, nor bend just the skull-C1 joint to aim the head straight ahead parallel to, but to the side of, the main body axis. Or maybe not.

    That’s not how animals behave in practice. See our 2009 paper on this.

    And by now, I’ve forgotten if I even had a 5th point – but thanks to everyone involved here (ALL commenters included) for a fascinating look at a group of creatures you guys (among others obviously) are turning into …fascinating creatures.

    Our pleasure!

  47. Brad Lichtenstein Says:

    Thanks for your time, especially in the middle of an awesome trip! …which was thoughtless of me, I’ll delay trying to continue my barrage of noob Qs and remarks until somewhat after you’re done, because I don’t want to detract from your posting of more field trip candids for us all to enjoy! And it’ll give me time to read the research you point to. Would you prefer I either shut up totally, or take it to email instead of a comment thread?

  48. Mike Taylor Says:

    Hey, Brad, comment all you want! We’ll respond when we have time and energy.


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