Today finally sees the publication of a paper (Taylor 2022) that’s been longer in gestation than most (although, yes, all right, not as long as the Archbishop). I guess the first seeds were sown almost a full decade ago when I posted How long was the neck of Diplodocus? in May 2011, but it was submitted as a preprint in 2015. Since then it’s taken far longer than it should have done to get it across the line, and it is primarily with a feeling of relief that I see the paper now published.

Taylor (2022: figure 4). W. H. Reed’s diagram of Quarry C near Camp Carnegie on Sheep Creek, in Albany County, Wyoming. The coloured bones belong to CM 84, the holotype of Diplodocus carnegii; other bones belong to other individuals, chiefly of Brontosaurus, Camarasaurus and Stegosaurus. Modified (cropped and coloured) from Hatcher (1901: plate I). Cervical vertebrae are purple (and greatly simplified in outline by Reed), dorsals are red, the sacrum is orange, caudals are yellow, limb girdle elements are blue, and limb bones are green.

In this quarry map for the Carnegie Diplodocus, does it seem to you that the vertebrae of the neck (in purple) are drawn unconvincingly, compared with the fairly detailed drawings of the dorsals? Does that suggest that maybe Reed — who drew this diagram years after the excavation was complete — didn’t really remember how the neck was laid out? How well does the textual description of the skeleton in situ match this map? These are the kinds of questions I was asking myself as I started thinking about what has become the paper published today.

In some ways it’s a really simple paper, pretty much summarised by its title: almost all known sauropod necks are incomplete and distorted. It started out as a formalised version of three posts on this blog (How long was the neck of Diplodocus?, Measuring the elongation of vertebrae and The Field Museum’s photo-archives tumblr, featuring: airbrushing dorsals), but somewhere along the line the tale grew in the telling and it’s ended up as 35 pages of goodness. In the process of review it acquired a lot of new material, including: a discussion of how to locate the cevicodorsal junction (summary: it’s complicated); a couple of ways to numerically quantify the degree of distortion along a neck; and a brief discussion of retrodeformation (summary: it’s complicated).

Head and neck from Janensch’s (1950b: plate VI) skeletal reconstruction of Giraffatitan brancai (= “Brachiosaurusbrancai of his usage) mounted specimen based on MB.R.2181 (formerly HMN SII). The parts of the head and neck that were lost to damage are greyed out, including the first two cervicals and the neural arches and spines of all cervicals after C8. Oh, and the head.

I hope this paper will be of use, especially to people coming into the field with the same unrealistic assumptions I had back in the early 2000s. Back then, I had in mind a project to determine the thickness of intervertebral cartilage in the neck of Diplodocus by measuring the radii of curvature of the condyles and cotyles of successive vertebrae — an idea that distortion makes unrealistic. I took the DinoMorph work at face value — something that seems incredible to me knowing what know now. The paper that came out today is basically the one I wish I’d been able to read in 2000 (but updated!)

By the way, when I was fine-tooth-combing the proof PDF a few days ago, I was delighted to be reminded that I got the phrase “rigidly defined areas of doubt and uncertainty” into the paper — a reference of course, to the words of the philosopher Vroomfondel in The Hitch-Hiker’s Guide to the Galaxy. I’ll file this alongside the Monty Python reference in my history-of-sauropod-research book chapter and the Star Wars paraphrase that opens a computer-science paper I lead-authored in 2005.

References

Matt dropped me a line midweek about the catalogue of complete sauropod necks, with some interesting thoughts. He broke down the necks as listed across a basic phylogeny of sauropods, and counted the occurrences:

Simplified phylogeny of Sauropoda, showing counts of complete and near-complete necks. Captions: C, complete and described; U, complete but undescribed; –1, missing the atlas but otherwise complete; O, other near-complete necks; T, total.

Matt and I were both surprised to see that non-neosauropods are quite well represented, both inside and outside of Mamenchisauridae — although it’s a pity that two of those ten specimens are of Jobaria, for which we have next to zero information.

Diplodocoids are surprisingly poorly represented, with essentially just one each in Dicraeosauridae and Diplodocidae that are complete. And brachiosaurids are a black hole, with absolutely no representation — see the 2015 preprint for details on how unconvincing the neck of Giraffatitan is.

But camarasaurids are crushing it, probably just by being the most abundant sauropods of all time in terms of individual specimens in museums. (Of course when we say “camarasaurids”, we just mean Camarasaurus, which is the only named sauropod currently considered to belong to Camarasauridae unless you follow Mateus and Tschopp (2013) in considering Cathetosaurus to be generically distinct. But Matt and I both suspect that Camarasaurus is way over-lumped, so we’ll see how this pans out over the next decade or two.)

It’s surprising, though, that the second and third best represented sauropods in museums, Diplodocus and Apatosaurus, are both barely represented in terms of complete necks. And while it’s encouraging to see quite a few complete and nearly-complete necks among somphospondyls, including titanosaurs,it’s disappointing that about half of them are not yet described.

References

The more I look at the problem of how flexible sauropod necks were, the more I think we’re going to struggle to ever know their range of motion It’s just too dependent on soft tissue that doesn’t fossilise. Consider for example the difference between horse necks (above) and camel necks (below).

The skeletons of both consist of vertebrae that are pronouncedly opisthocoelous (convex in front and concave behind), so you might think their necks would be similarly flexible.

But the balls of horse cevicals are deeply embedded in their corresponding sockets, while those of camels have so much cartilage around and between them that the tip of the ball doesn’t even reach the rim of the socket. As a result of this (and maybe other factors), camel necks are far more flexible than those of horses.

Which do sauropod necks resemble? We don’t currently know, and we may never know. It will help if someone gets a good handle on osteological correlates of intervertebral cartilage.

 


[This post is recycled and expanded from a comment that I left on a Tetrapod Zoology post, but since Tet Zoo ate that comment it’s just as well I kept a copy.]

Since I posted my preprint “Almost all known sauropod necks are incomplete and distorted” and asked in the comments for people to let me know if I missed any good necks, the candidates have been absolutely rolling in:

I will be investigating the completeness of all of these and mentioning them as appropriate when I submit the revision of this paper. (In retrospect, I should have waited a week after posting the preprint before submitting for formal review; but I was so scared of letting it brew for years, as we’re still doing with the Barosaurus preprint to our shame, that I submitted it immediately.)

So we probably have a larger number of complete or near-complete sauropod necks than the current draft of this paper suggests. But still very few in the scheme of things, and essentially none that aren’t distorted.

So I want to consider why we have such a poor fossil record of sauropod necks. All of the problems with sauropod neck preservation arise from the nature of the animals.

First, sauropods are big. This is a recipe for incompleteness of preservation. (It’s no accident that the most completely preserved specimens are of small individuals such as CM 11338, the cow-sized juvenile Camarasaurus lentus described by Gilmore, 1925). For an organism to be fossilised, the carcass has to be swiftly buried in mud, ash or some other substrate. This can happen relatively easily to small animals, such as the many finely preserved stinkin’ theropods from the Yixian Formation in China, but it’s virtually impossible with a large animal. Except in truly exceptional circumstances, sediments simply don’t get deposited quickly enough to cover a 25 meter, 20 tonne animal before it is broken apart by scavenging, decay and water transport.

Taylor 2015: Figure 5. Quarry map of Tendaguru Site S, Tanzania, showing incomplete and jumbled skeletons of Giraffatitan brancai specimens MB.R.2180 (the lectotype, formerly HMN SI) and MB.R.2181 (the paralectotype, formerly HMN SII). Anatomical identifications of SII are underlined. Elements of SI could not be identified with certainty. From Heinrich (1999: figure 16), redrawn from an original field sketch by Werner Janensch.

Taylor 2015: Figure 5. Quarry map of Tendaguru Site S, Tanzania, showing incomplete and jumbled skeletons of Giraffatitan brancai specimens MB.R.2180 (the lectotype, formerly HMN SI) and MB.R.2181 (the paralectotype, formerly HMN SII). Anatomical identifications of SII are underlined. Elements of SI could not be identified with certainty. From Heinrich (1999: figure 16), redrawn from an original field sketch by Werner Janensch.

Secondly, even when complete sauropods are preserved, or at least complete necks, distortion of the preserved cervical vertebrae is almost inevitable because of their uniquely fragile construction. As in modern birds, the cervical vertebrae were lightened by extensive pneumatisation, so that they were more air than bone, with the air-space proportion typically in the region of 60–70% and sometimes reaching as high as 89%. While this construction enabled the vertebrae to withstand great stresses for a given mass of bone, it nevertheless left them prone to crushing, shearing and torsion when removed from their protective layer of soft tissue. For large cervicals in particular, the chance of the shape surviving through taphonomy, fossilisation and subsequent deformation would be tiny.

So I think we’re basically doomed never to have a really good sauropod neck skeleton.

One aspect of sauropod neck cartilage that’s been overlooked — and this applies to all non-avian dinosaurs, not just sauropods — is the configuration of the cartilage in their necks. It’s not widely appreciated that birds’ necks differ from those of all other animals in this respect, and we don’t yet know whether sauropods resembled birds or mammals.

Here’s a classic sagittal view of a mammal neck — in this case a human — from The Basics of MRI (Joseph P. Hornak, 1996-2013):

sagittal-neck

You can see two distinct kinds of structure alternating along the neck: the big, square ones are vertebral centra (slightly hollow at each end), and the narrower lens-shaped ones are the intervertebral discs.

In mammals, and most animals, we find this distinct fibrocartilaginous element, the disc, between the centra of consecutive vertebrae. These discs have a complex structure of their own, consisting of an annulus fibrosus (fibrous ring), made of several layers of fibrocartilage, surrounding a nucleus pulposus (pulpy centre) with the consistency of jelly.

IntervertebralDisc

But in birds, uniquely among extant animals, there is no separate cartilaginous element. Instead, the articular surfaces of the bones are covered with layers of hyaline cartilage which articulate directly with one another, and are free to slide across each other. The adjacent articular surfaces are enclosed in synovial capsules similar to those that enclose the zygapophyseal joints. You can see this in the hemisected Rhea neck from last time:

Figure 18. Cartilage in the neck of a rhea. Joint between cervicals 11 (left) and 10 (right) of a rhea, sagittally bisected. Left half of neck in medial view. The thin layers of cartilage lining the C11 condyle and C10 cotyle are clearly visible.

Taylor and Wedel (2013c: Figure 18). Cartilage in the neck of a rhea. Joint between cervicals 11 (left) and 10 (right) of a rhea, sagittally bisected. Left half of neck in medial view. The thin layers of cartilage lining the C11 condyle and C10 cotyle are clearly visible.

The difference between these two constructions is very apparent in dissection: in birds, adjacent vertebrae come apart easily once the surrounding soft tissue is removed; but in mammals, it is very difficult to separate consecutive vertebrae, as they are firmly attached to the intervening intervertebral disc.

Figure 19. Alligator head and neck. Sagittally bisected head and neck of American alligator, with the nine cervical vertebrae indicated. Inset: schematic drawing of these nine vertebrae, from ([62]: figure 1), reversed.

Taylor and Wedel (2013c: Figure 19). Alligator head and neck. Sagittally bisected head and neck of American alligator, with the nine cervical vertebrae indicated. Inset: schematic drawing of these nine vertebrae, from ([62]: figure 1), reversed.

To complicate matters further, thin articular discs occur in the necks of some birds — for example, the ostrich (see illustration below), the swan, and the king penguin. But these discs do not occur in all birds — for example, they are absent in the turkey and the rhea. When they are present, these articular discs divide the synovial cavity and prevent the (cartilage-covered) bones on either side from ever articulating directly with each other, just like the articular discs in the human temporomandibular and sternoclavicular joints. These discs are thinner than the true intervertebral discs of mammals and crocodilians; and they are different in composition, lacking the annulus/nucleus structure and consisting of a simple sheet of fibrocartilage.

Taylor and Wedel (2013: Figure 4). Intervertebral articular discs of an ostrich (not to scale). Left: first sacral vertebra in anterior view, showing articular disc of joint with the last thoracic vertebra. Right: posterior view view of a cervical vertebra, with probe inserted behind posterior articular disc. The cervical vertebra is most relevant to the present study, but the the sacral vertebra is also included as it shows the morphology more clearly. These fibrocartilaginous articular discs divide the synovial cavity, like the articular discs in the human temporomandibular and sternoclavicular joints, and should not be confused with the true intervertebral discs of mammals and other animals, which consist of a nucleus pulposus and an annulus fibrosus.

Taylor and Wedel (2013: Figure 4). Intervertebral articular discs of an ostrich (not to scale). Left: first sacral vertebra in anterior view, showing articular disc of joint with the last thoracic vertebra. Right: posterior view view of a cervical vertebra, with probe inserted behind posterior articular disc. The cervical vertebra is most relevant to the present study, but the the sacral vertebra is also included as it shows the morphology more clearly. These fibrocartilaginous articular discs divide the synovial cavity, like the articular discs in the human temporomandibular and sternoclavicular joints, and should not be confused with the true intervertebral discs of mammals and other animals, which consist of a nucleus pulposus and an annulus fibrosus.

Crucially, the extant phylogenetic bracket (EPB) does not help us to establish the nature of the intervertebral articulations in sauropods, as the two extant groups most closely related to them have different articulations. As noted, birds have synovial joints; but crocodilians, like mammals, have fibrocartilaginous intervertebral discs. So their most recent common ancestor, the ur-archosaur, could equally have had either condition, and so could its various descendants.

vertebral-joint-type-cladogram

This seems like a mystery well worth solving. For one thing,  in the wholly inadequate database that we assembled for the paper, the birds had much thinner cartilage than the other animals. Since they are also the only animals with synovial neck joints, thin cartilage correlates with this kind of joint — at least across that tiny database. Is that correlation reliable? Does it hold out across a bigger sample? Is there a causation? If so, then finding out what kind of intervertebral joints sauropods had would help us to determine how thick their cartilage was, and so what their actual neutral posture was.

But we can’t tell this directly unless we find sensationally well preserved specimens that let us see the structure of the cartilage. We might speculate that since birds have unique saddle-shaped joints and sauropods have ball-and-socket joints like those of mammals and crocs, they’d be more likely to resemble the latter in this respect, too, but that’s rather hand-wavey.

Can we do better?

If we can, it will be through osteological correlates: that is, features of the bones (which are preserved in fossils) that are consistently correlated with features of the soft tissues (which are not). We’d want to find out from analysis of extant animals what correlates might exist, then go looking for them in the bones of extinct animals.

A couple of times now, I’ve pitched this as an abstract for a Masters project, hoping someone at Bristol will work on it with me as co-supervisor, but so far no-one’s bitten. Maybe next year. It would be a very specimen-based project, which I’d think would be a plus in most people’s eyes.

Figure 8. Cervical vertebra 7 from a turkey. Anterior view on the left; dorsal, left lateral and ventral views in the middle row; and posterior on the right.

Taylor and Wedel (2013: Figure 8). Cervical vertebra 7 from a turkey. Anterior view on the left; dorsal, left lateral and ventral views in the middle row; and posterior on the right.

Anyway, the awful truth is that at the moment we know spectacularly little about the cartilage in the necks of sauropods. We don’t know whether they had true intervertebral discs. If not, we don’t know whether they had articular discs like those of ostriches. We don’t know how thick these elements, if present, were. We don’t know how thick the hyaline cartilage on the bones’ articular surfaces was, or how evenly it covered its those surfaces.

And until we know those things, we don’t really know anything about neck posture or range of movement.

There’s lots of work to be done here!

A forthcoming issue of The Journal of Zoology will contain our paper on why sexual selection was not the main driver of neck elongation in sauropods.  That journal’s “Early View” facility publishes online before print, so it’s available to the world already.

The paper

High resolution figures

You can get these from Mike’s web-site. They’re the same figures as appear in the paper, but in higher resolutions.

SV-POW! posts

Elsewhere on the Web

A couple of months ago, I asked for your help in compiling a list of all known complete sauropods necks. This has gone really well, and I want to thank everyone who chipped in, and all the various authors I have contacted for details as a result.

My next step is to take the raw data in the Google spreadsheet that I have been maintaining, and write it up as prose for the paper that I am shortly going to resubmit, having first done so back in 2015. And I thought it would make sense to draft that section here on SV-POW!, so I can get any further feedback before I finalize it for the manuscript.

Young and Zhao (1972:figure 3). Mamenchisaurus hochuanensis holotype CCG V 20401 as is occurred in the field.

So here goes: any additional comments at this stage will be welcome!


Unambiguously complete necks are known from published accounts of only a few sauropod specimens. In chronological order of description, the following specimens were found with their necks complete and articulated, and have been adequately described:

  • CM 11338, a referred specimen of Camarasaurus lentus described by Gilmore (1925). This is a juvenile specimen, and thus does not fully represent the adult morphology. (McIntosh et al. 1996:76 claim that this specimen is the holotype, but this is not correct: YPM 1910 is the holotype — see below.)
  • CM 3018, the holotype of Apatosaurus louisae, described by Gilmore (1936). The neck was separated from the torso but articulated from C1–C15, though the last three cervicals were badly crushed: see below for details.
  • CCG V 20401, the Mamenchisaurus hochuanensis holotype, described by Young and Zhao (1972). Each vertebra is broken in half at mid-length, with the posterior part of each adhering to the anterior part of the its successor; and all the vertebrae are badly crushed in an oblique plane.
  • ZDM T5402, a Shunosaurus lii referred specimen, described in Chinese by Zhang (1988), with English figure captions. Figure 22 depicts the atlas. Unlike the holotype T5401, this specimen is mature.
  • BYU 9047, the Cathetosaurus lewisi holotype, described by Jensen (1988). (Jensen incorrectly gives the specimen number as BYU 974.) This specimen was redescribed, and the species referred to Camarasaurus, by McIntosh et al. (1996). Although all 12 cervicals are present, “10–12, particularly 12, have suffered such severe damage that it is impossible to restore them” (McIntosh et al. 1996:76).
  • MACN-N 15, the holotype of Amargasaurus cazaui MACN-N 15, described by Salgado and Bonaparte (1991) who desribed “22 presacral vertebrae articulated with each other and attached to the skull and sacrum, relatively complete” (Salgado & Bonaparte 1991:335, translated.
  • ZDM 0083, the holotype of Mamenchisaurus youngi, described in Chinese by Ouyang and Ye (2002) with English figure captions. Figure 14 depicts the atlas and axis.
  • MUCPv-323, the holotype of Futalognkosaurus dukei, initially described by Calvo et al. 2007a and redescribed by Calvo et al. 2007b. The neck was found in two articulated sections which fit together without needing additional vertebrae in between (Jorge O. Calvo, pers. comm., 2021).
  • SSV12001, the holotype of Xinjiangtitan shanshanesis, described by Zhang et al. (2018). The original description of this specimen by Wu et al. 2013 included only the last two cervicals, which were the only ones that had been excavated at that time.

A few additional specimens are known to have complete and articulated necks, but have not yet been described:

  • USNM 13786, a referred subadult specimen of Camarasaurus lentus recently mounted at the Smithsonian. The specimen “was almost completely buried before the sinews had allowed the bones to separate” (letter from Earl Douglass to William J. Holland, 22 August 1918), and photographs kindly supplied by Andrew Moore show that the atlas was preserved.
  • MNBH TIG3, the holotype of Jobaria tiguidensis. Sereno et al. (1999:1343) assert that this species has 12 cervicals in all and say “One articulated neck was preserved in a fully dorsiflexed, C-shaped posture”. Sereno (pers. comm., 2021) confirms that the articulated neck is MNBH TIG3
  • SMA 002, referred to Camarasaurus sp. Tschopp et al. (2016), in a description of its feet, say that this specimen “lacks only the vomers, the splenial bones, the distal end of the tail, and one terminal phalanx of the right pes. The bones are preserved in three dimensions and in almost perfect articulation”.
  • MAU-Pv-LI-595, the “La Invernada” Titanosaur. Filippi et al. (2016) give a very brief account in an abstract. Filippi, pers. comm, 2021) says that the entire preserved specimen was articulated.
  • MAU-Pv-AC-01, an unnamed titanosaur mentioned in abstracts by Calvo et al. (1997) and Coria and Salgado (1999). The specimen was found in perfect articulation from skull down to the last caudal vertebrae (Rodolfo Coria, pers. comm., 2021).

The first cervical (the atlas) in sauropods is very different in form from the other vertebrae, and small and fragile. Consequently it is easily lost. Some further specimens have necks that are complete and articulated from C2 (the axis) backwards:

  • MB.R.4886, the holotype of Dicraeosaurus hansemanni, described by Janensch (1929), has a neck that complete and well preserved from C2 to C12 (the last cervical). Janensch referred to this as “specimen m” and writes “It was found articulated from the 19th caudal vertebra to the 9th cervical vertebra inclusive. The proximal part of the neck from the 8th cervical vertebra up to the axis was bent ventrally and lay at right angles to the distal part of the neck.” (Janensch 1929:41).
  • PMU 233, the holotype of Euhelopus zdanskyi, described by Wiman (1929) as “exemplar a” and redescribed by Wilson and Upchurch (2009).
  • ZDM T5401, the subadult holoype of Shunosaurus lii, described in Chinese by Zhang et al 1984. The quarry map (Zhang et al. 1984:figure 1) suggests that the atlas is missing.
  • MCT 1487-R, informally known as “DGM Series A”, described by Powell (2003). Gomani (2005:9) summarises as “12 cervical vertebrae, except the atlas, preserved in articulation with three proximal dorsal vertebrae”.
  • GCP-CV-4229, the holotype of Spinophorosaurus nigerensis, described by Remes et al. (2009). The specimen was found in very good condition and well articulated from C2 to C13, the last cervical. The atlas seems to be missing (Remes, pers. comm., 2021.

One other sauropod is complete from the first cervical, but probably not to the last:

  • MOZ-Pv1232, the holotype of Lavocatisaurus agrioensis, described by Canudo et al. (2018). This is complete from C1-C11. Canudo’s guess is that this is complete neck (Canudo, pers. comm, 2021), but the specimen doesn’t demand that conclusion and no known eusauropod has fewer than 12 cervicals.

Other sauropod specimens have necks that are complete and articulated from further back in the cervical sequence:

  • YPM 1910, Camarasaurus lentus, a mounted specimen described by Lull (1930). The neck is complete from C2 or C3, Lull was uncertain which.
  • SMA 0004, Kaatedocus siberi, described by Tschopp and Mateus (2012). Cervicals 3-14 are preserved.
  • AODF 888 (informally “Judy”), probably referrable to Diamantinasaurus, briefly described by Poropat et al. (2019). Preserved from C3 or maybe C4. “One posterior cervical (XIII or XIV) found several metres from articulated series, but appears to slot nicely into the gap between the articulated cervical series and the unprepared thoracic section, which might include at least one additional cervical (XIV or XV)” (Poropat, pers. comm. 2021).

Several necks are probably nearly complete, but it is not possible to knew due to their not being found in articulation:

  • CM 84, the holotype of Diplodocus carnegii, described by Hatcher (1901). C2–C15 are preserved, though not all in articulation; C11 may be an intrusion: see below for details.
  • ZDM T5701, the holotype of Omeisaurus tianfuensis, described by He et al. (1988). The neck was not articulated (He et al. 1988:figure 1), and was missing “two elements or so” (He et al. 1988:120).
  • QJGPM 1001, the holotype of Qijianglong guokr, described by Xing et al. (2015). On page 8, the authors say “The axis to the 11th cervical vertebra were fully articulated in the quarry. The atlas intercentrum and the 12th–17th cervical vertebrae were closely associated with the series.”
  • MNBH TIG9, a referred specimen of Jobaria tiguidensis. Wilson (2012:103) writes that this specimen “includes a partially articulated series of 19 vertebrae starting from the axis and extending through the mid-dorsal vertebrae.”
  • MNBH TIG6, another referred specimen of Jobaria tiguidensus, which has not been mentioned in the literature. Sereno (pers. comm., 2021) says that it is “a subadult partial skeleton with excellent neck” and that “the sequence was articulated from C2–11. Most of the ribs were attached as well.”

At the time of writing, the Paleobiology Database (https://paleobiodb.org/) lists more than 270 sauropod species. The nine unambigously complete and articulated necks therefore represent only one in 30 known sauropod species.

Note. The Jobaria tiguidensis individuals previously had specimen numbers beginning MNN, but the Musee National du Niger changed its name to Musée National Boubou Hama and the specimen numbers have changed with it.

Early in my 2015 preprint on the incompleteness of sauropod necks, I wrote “Unambiguously complete necks are known from published account of only six species of sauropod, two of which are species of the same genus”, and listed them.

Taylor 2015: Figure 3. W. H. Reed’s diagram of Quarry C near Camp Carnegie on Sheep Creek, in Albany County, Wyoming. The coloured bones belong to CM 84, the holotype of Diplodocus carnegii; other bones belong to other individuals, chiefly of Brontosaurus, Camarasaurus and Stegosaurus. Modified (cropped and coloured) from Hatcher (1901: plate I). Cervical vertebrae are purple (and greatly simplified in outline), dorsals are red, the sacrum is orange, caudals are yellow, limb girdle elements are blue, and limb bones are green.

Haha, stupid me! I had hugely under-counted. With thanks to the three peer-reviewers of the submitted manuscript and to SV-POW! commenters, I have revised this list, in preparation for forthcoming resubmission. The table as it stands currently consists of 24 candidates, not all of them very solid. Of these, 15 were found in articulation, the others mostly not — though we don’t know for sure in all cases. Not all of the necks have been properly described, and not all of the ones that have been described have been named. And other questions hang over some of them, very briefly summarised in notes.

Here is the list, sorted by date of description. If I got the Google-docs permissions right, you should be able to see it but not edit it. (If you can edit, please don’t! And let me know.)

Please let me know if you find any mistakes, or if you think I have missed anything. Everyone who contributes will get a mention in the acknowledgements.

 

Are you a lover of sauropod necks?

Do you long to demonstrate to your friends and family how much better[1] they are than the necks of other long-necked critters?

Are you crazy for the Taylor and Wedel (2013a) paper on why sauropods had long necks; and why giraffes have short necks, but disappointed that it’s not, until now, been obtainable in T-shirt form?

front

back

If so, it’s your lucky day! You can now buy a T-shirt featuring Figure 1 on the front (necks of a human, giraffe, ostrich, Paraceratherium[2], Therizinosaurus, Gigantoraptor, Arambourgiania and Tanystropheus) and Figure 3 on the back (necks of Diplodocus, Puertasaurus, Sauroposeidon, Mamenchisaurus and Supersaurus).

And here it is in real life — sorry I couldn’t get a more photogenic model at short notice.

DSCN0800-front

DSCN0796-back

And here are the original figures as they appeared in the paper. The full captions, as reproduced here, are also on the shirts — just in case you need to check details while you’re out and about.

Figure 1. Necks of long-necked non-sauropods, to scale. The giraffe and Paraceratherium are the longest necked mammals; the ostrich is the longest necked extant bird; Therizinosaurus and Gigantoraptor are the largest representatives of two long-necked theropod clades; Arambourgiania is the longest necked pterosaur; and Tanystropheus has a uniquely long neck relative to torso length. Human head modified from Gray’s Anatomy (1918 edition, fig. 602). Giraffe modified from photograph by Kevin Ryder (CC BY, http://flic.kr/p/cRvCcQ). Ostrich modified from photograph by “kei51” (CC BY, http://flic.kr/p/cowoYW). Paraceratherium modified from Osborn (1923, figure 1). Therizinosaurus modified from Nothronychus reconstruction by Scott Hartman. Gigantoraptor modified from Heyuannia reconstruction by Scott Hartman. Arambourgiania modified from Zhejiangopterus reconstruction by Witton & Naish (2008, figure 1). Tanystropheus modified from reconstruction by David Peters. Alternating blue and pink bars are 1 m tall.

Figure 1. Necks of long-necked non-sauropods, to scale. The giraffe and Paraceratherium are the longest necked mammals; the ostrich is the longest necked extant bird; Therizinosaurus and Gigantoraptor are the largest representatives of two long-necked theropod clades; Arambourgiania is the longest necked pterosaur; and Tanystropheus has a uniquely long neck relative to torso length. Human head modified from Gray’s Anatomy (1918 edition, fig. 602). Giraffe modified from photograph by Kevin Ryder (CC BY, http://flic.kr/p/cRvCcQ). Ostrich modified from photograph by “kei51” (CC BY, http://flic.kr/p/cowoYW). Paraceratherium modified from Osborn (1923, figure 1). Therizinosaurus modified from Nothronychus reconstruction by Scott Hartman. Gigantoraptor modified from Heyuannia reconstruction by Scott Hartman. Arambourgiania modified from Zhejiangopterus reconstruction by Witton & Naish (2008, figure 1). Tanystropheus modified from reconstruction by David Peters. Alternating blue and pink bars are 1 m tall.

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Figure 3. Necks of long-necked sauropods, to scale. Diplodocus, modified from elements in Hatcher (1901, plate 3), represents a “typical” long-necked sauropod, familiar from many mounted skeletons in museums. Puertasaurus, Sauroposeidon, Mamenchisaurus and Supersaurus modified from Scott Hartman’s reconstructions of Futalognkosaurus, Cedarosaurus, Mamenchisaurus and Supersaurus respectively. Alternating pink and blue bars are one meter in width. Inset shows Fig. 1 to the same scale.

No doubt these will be all the rage at SVPCA this year!

So get your T-shirts!

Update (the same evening)

As suggested by Kevin, I’ve now made the shirt available in a selection of eight versions: four men’s shirt, two women’s, and two kids. I don’t really understand what the differences are between them all, but they seemed to be the saner choices among those offered by Cafe Press. You can get any or all of them here. The shirt modelled above is the one called simple “White T-Shirt”. Please be aware that unlike all the others, the “Value T-Shirt” has no printing on the back — only Figure 1 on the front.

Notes

[1] i.e. bigger.

[2] Not to be confused with Paramecium.

References

Taylor, Michael P., and Mathew J. Wedel. 2013. Why sauropods had long necks; and why giraffes have short necks. PeerJ 1:e36. doi:10.7717/peerj.36

Why did sauropods have such long necks?

Mamenchisaus hochuanensis skeletal reconstruction (Young and Zhao 1972:fig. 4), based on the holotype

It’s the single most obvious and important question about sauropods, so it’s a bit surprising to think that we’ve never really addressed this question directly.

Maybe sauropod necks are so obvious and familiar that we just take them for granted, and move straight on to questions of how they were able to grow so long and remain workable.

Well, let’s fix that.  Let’s think about why they had such long necks.  What were they for?  What were sauropods doing with their necks that was valuable enough to justify all that investment?

Back in the good old days, everyone assumed that sauropod necks were all about high browsing.  If you have a 9.5m neck, then of course you will use it to browse high up in trees — it’s intuitively obvious.  But of course “intuitively obvious” is not the same thing as “true”.

Then John Martin (1987) proposed that the long necks were used for low browsing — not raised above shoulder level, but swept back and forth to allow food to be gathered across a wide area without all that tedious mucking about with locomotion.  This interpretation was of course endorsed by Stevens and Parrish (1999) in their DinoMorph work.

There has been plenty written about habitual sauropod posture — including by us (Taylor et al. 2009).  But actually the high-browsing and low-browsing explanations of sauropod neck elongation have much in common.  Most crucially, they both relate to enlarging the feeding envelope; more broadly they are both explanations that rely on the neck having a survival benefit.  But Senter (2006) proposed a completely different explanation — that sauropod necks were sexual signals, selected not for survival advantage but for reproductive success.  The idea is that female sauropods, being very shallow, would go for the males with the biggest protuberances.

Are there other candidate explanations that I’ve missed?

Or is it between high browsing, low browsing and sexual selection?

Comments are open!

References