I got an email a couple of days ago from Maija Karala, asking me a question I’d not come across before (among several other questions): how much poop did Argentinosaurus produce in a day?

I don’t recall this question having been addressed in the literature, though if anyone knows different please shout. Having thought about it a little, I sent the following really really vague and hand-wavy response.

Suppose Argentinosaurus massed 73 tonnes (Mazzetta et al. 2004). In cattle, food intake varies roughly with body mass to the power 0.7 (Taylor et al. 1986), so let’s assume that the same is true of sauropods.

Let’s also assume that sauropods are like scaled-up elephants, in that both would have subsisted on low-quality forage. Wikipedia says elephants “can consume as much as 150 kg (330 lb) of food and 40 L (11 US gal) of water in a day.” Let’s assume that the “as much as” suggests we’re talking about a big elephant here, maybe 6 tonnes. So Argentinosaurus is 73/6 = 12 times as heavy, which means its food intake would be 12 ^ 0.7 = 5.7 times as much. That’s 850 kg per day.

Hummel et al. (2008, table 1) show that for a range of foods, the indigestible “neutral detergent fibre” makes up something around half of the mass, so let’s assume that’s the bulk of what gets pooped out, and halve the input to get about 400 kg of poop per day.

References

  • Hummel, Jürgen, Carole T. Gee, Karl-Heinz Südekum, P. Martin Sander, Gunther Nogge and Marcus Clauss. 2008. In vitro digestibility of fern and gymnosperm foliage: implications for sauropod feeding ecology and diet selection. Proceedings of the Royal Society B, 275:1015-1021. doi:10.1098/rspb.2007.1728
  • Mazzetta, Gerardo V., Per Christiansen and Richard A. Farina. 2004. Giants and Bizarres: Body Size of Some Southern South American Cretaceous Dinosaurs. Historical Biology 2004:1-13.
  • Taylor, C. S., A. J. Moore and R. B. Thiessen. 1986. Voluntary food intake in relation to body weight among British breeds of cattle. Animal Science 42(1):11-18.

You could drive several trucks through the holes in that reasoning, but it’s a start. Can anyone help to refine the reasoning, improve the references, and get a better estimate?

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I have before me the reviews for a submission of mine, and the handling editor has provided an additional stipulation:

Authority and date should be provided for each species-level taxon at first mention. Please ensure that the nominal authority is also included in the reference list.

In other words, the first time I mention Diplodocus, I should say “Diplodocus Marsh 1878″; and I should add the corresponding reference to my bibliography.

Marsh (1878: plate VIII in part). The only illustration of Diplodocus material in the paper that named the genus.

Marsh (1878: plate VIII in part). The only illustration of Diplodocus material in the paper that named the genus.

What do we think about this?

I used to do this religiously in my early papers, just because it was the done thing. But then I started to think about it. To my mind, it used to make a certain amount of sense 30 years ago. But surely in 2016, if anyone wants to know about the taxonomic history of Diplodocus, they’re going to go straight to Wikipedia?

I’m also not sure what the value is in providing the minimal taxonomic-authority information rather then, say, morphological information. Anyone who wants to know what Diplodocus is would be much better to go to Hatcher 1901, so wouldn’t we serve readers better if we referred to “Diplodocus (Hatcher 1901)”

Now that I come to think of it, I included “Giving the taxonomic authority after first use of each formal name” in my list of
Idiot things that we we do in our papers out of sheer habit three and a half years ago.

Should I just shrug and do this pointless busywork to satisfy the handling editor? Or should I simply refuse to waste my time adding information that will be of no use to anyone?

References

  • Hatcher, Jonathan B. 1901. Diplodocus (Marsh): its osteology, taxonomy and probable habits, with a restoration of the skeleton. Memoirs of the Carnegie Museum 1:1-63 and plates I-XIII.
  • Marsh, O. C. 1878. Principal characters of American Jurassic dinosaurs, Part I. American Journal of Science, series 3 16:411-416.

 

I’ve been lucky enough to acquire another beautiful specimen. It arrived in a box (though not from Amazon, despite what the box itself might suggest):

2016-03-17 15.45.01

What’s inside?

2016-03-17 15.45.48

Can it be? It is!

2016-03-17 15.46.14

Now I’ve wanted a tortoise for a long time, because they are (Darren will back me up here) the freakiest of all tetrapods. Their scapulae and coracoids have somehow migrated inside their rib-cages (which bear the shell), and their dorsal vertebrae are fused to the shell all along its upper midline. Just ridiculous. Look, this is what I’m talking about. Compare with the much saner approach that armadillos use to having a shell.

Here’s my baby in left anterodorsolateral view:

2016-03-17 15.46.27

And in right posteodorsolateral:

2016-03-17 15.46.39

Can anyone tell me what species I have here?

Here he is (or she?) upside down, in left posteroventolateral view.

2016-03-17 15.46.54

Come to think of it, can anyone tell me the sex of my specimen?

Here he or she is in anterior view, looking very stern.

2016-03-17 15.47.25

The problem is — and I can’t quite believe this never occurred to me until I had a tortoise of my own — how on earth do you deflesh such a creature? I have no idea (and obviously no experience). Any hints?

Folks,

For a forthcoming minor paper, I need a good-quality scan of Hatcher’s 1901 monograph on Diplodocus carnegii — specifically, plate VI, the photographs of the cervicals in posterior view.

Here is the best scan I have of it:

CERIVICAL SERIES POSTERIOR

(Click through for full resolution.)

If anyone has something better, please leave a comment or email me on dino@miketaylor.org.uk

Thanks!

A couple of times now, I’ve pitched in an abstract for a Masters project looking at neck cartilage, hoping someone at Bristol will work on it with me co-supervising, but so far no-one’s bitten. Here’s how I’ve been describing it:

Understanding posture and motion in the necks of sauropods: the crucial role of cartilage in intervertebral joints

The sauropod dinosaurs were an order of magnitude bigger than any other terrestrial animal. Much sauropod research has concentrated on their long necks, which were crucial to their success (e.g. Sander et al. 2010). One approach to understanding neck function tries to determine neutral posture and range of motion by modelling the cervical vertebrae as a mechanical system (e.g. Stevens and Parrish 1999).

The raw material of such studies is fossilised vertebrae, but these are problematic for several reasons. The invariable incompleteness and distortion of sauropod neck fossils causes fundamental difficulties; but even given perfect fossils, the lack of preserved cartilage means that the bones are not shaped or sized as they were in life.

Ignoring cartilage has dramatic consequences for neutral posture, range of motion and even length of necks: pilot studies (Cobley 2011, Taylor 2011) found that intact bird necks are 8–12% longer than articulated sequences of their dry bones, and that figure is as high as 24% for a juvenile giraffe neck. A turkey neck postzygapophysis was 26% longer when cartilage was included than after being stripped down to naked bone.

We do not yet know how much articular cartilage sauropods had in their necks, nor even what kind of intervertebral joints they had: crocodilians have fibrocartilaginous discs like those of mammals, while birds have synovial joints, so the extant phylogenetic bracket is uninformative.

The project will involve dissection and measurement of bird and crocodilian necks, documenting the extent and shape of articular cartilage, identifying osteological correlates of fibrocartilaginous and synovial joints, and applying this data to sauropods to determine the nature of their neck joints and length of their necks, to reconstruct the lost cartilage, and to determine its effect on neutral pose and range of motion.

Following completion, we anticipate publication of the project.

References

Cobley, Matthew J. 2011. The flexibility and musculature of the ostrich neck: implications for the feeding ecology and reconstruction of the Sauropoda (Dinosauria: Saurischia). MSc Thesis, Department of Earth Sciences, University of Bristol. vi+64 pages.

Sander, P. Martin, Andreas Christian, Marcus Clauss, Regina Fechner, Carole T. Gee, Eva-Maria Griebeler, Hanns-Christian Gunga, Jürgen Hummel, Heinrich Mallison, Steven F. Perry, Holger Preuschoft, Oliver W. M. Rauhut, Kristian Remes, Thomas Tütken, Oliver Wings and Ulrich Witzel. 2010. Biology of the sauropod dinosaurs: the evolution of gigantism. Biological Reviews 86:117–155. doi:10.1111/j.1469-185X.2010.00137.x

Stevens, Kent A., and J. Michael Parrish. 1999. Neck Posture and Feeding Habits of Two Jurassic Sauropod Dinosaurs. Science 284:798–800. doi:10.1126/science.284.5415.798

Taylor, Michael P., and Mathew J. Wedel. 2011. Sauropod necks: how much do we really know?. p. 20 in Richard Forrest (ed.), Abstracts of Presentations, 59th Annual Symposium of Vertebrae Palaeontology and Comparative Anatomy, Lyme Regis, Dorset, UK, September 12th–17th 2011. 37 pp. http://www.miketaylor.org.uk/dino/pubs/svpca2011/TaylorWedel2011-what-do-we-really-know.ppt

(Obviously some part of this have since been covered by my and Matt’s first cartilage paper, but plenty has not.)

I now think there are two reasons no-one’s taken up this project: first, because I wrote it as very focussed only on the question of what type of joint was present, whereas there are plenty of related issues to be investigated along the way; and second, because I wrote it as a quest to discover a specific treasure (an osteological correlate), with the implication that if there’s no treasure to be found then the project will have been a failure.

But I do think there is still plenty of important work to be done in this area, and that there’s lots of important information to be got out of comparative dissection of extant critters.

If anyone out there fancies working in this area, I’d be delighted. I’d also be happy to offer whatever advice and help I could.

Update (18 October 2014)

Somehow I’d forgotten, when I wrote this post, that I’d previously written a more detailed post about the discs-in-sauropod-necks problem. If you’re interested in the problem, you should read that.

Recently, I published an old manuscript of mine as a PeerJ Preprint.

I wrote this paper in 2003-4, and it was rejected without review when I submitted it back then. (For, I think, specious reasons, but that’s a whole nother discussion. Forget I mentioned it.)

I haven’t touched the manuscript since then (except to single-space it for submission as a preprint). It’s ten years old. That’s a problem because it’s an analysis of a database of dinosaur diversity, and as everyone knows, the rate of recognising new dinosaurs has gone through the roof. That’s the reason I never made any attempt to update and resubmit it: dinosaur diversity is a fast-moving target, and each time through the submit-reject cycle takes long enough for the data to be outdated.

So much for the history. Now the question: how should I cite this paper? Specifically, what date should I give it? If I cite it as from 2004, it will give the misleading impression that the paper has been available for ten years; but if I cite it as from 2014, it will imply that it’s been worked on at some point in the last ten years. Both approaches seem misleading to me.

At the moment, I am citing it as “Taylor (2014 for 2004)”, which seems to more or less capture what’s meant, but I don’t know whether it’s an established convention. Is there an established convention?

Releated: where in mv publications list should it appear? At present I am sorting it under 2014, since that’s when it came out; but should it be under  2004, when it was written? I guess publication date is the one to go far — after all, it’s not unusual even now for papers to spend a year or more in press, and it’s the later (publication) date that’s cited.

Help me out. How should this be done?

References

I just read this on Zen Faulkes’ NeuroDojo blog:

How should scientists, and reporters, discuss work that has failed to replicate? The original Barr and colleagues article remains in the scientific literature; failed replication alone is not grounds for retraction.

He’s right, of course: we certainly don’t want to retract every paper whose conclusions can’t be replicated, for all sorts of reasons: they may subsequently be replicated after all; the paper may contain other useful information even if the experiment in question was flawed; the replication studies themselves probably rely on the original’s Methods section; authors should not be punished for unfortunate outcomes unless they were fraudulently obtained.

What we want is for that Barr et al paper, whenever anyone looks at it, to be displayed with a prominent header that says “The following studies attempted to replicate this finding but failed:”, and a list of references/links. And, for that matter, another header saying that the following other studies did replicate it.

For web-sites to automatically produce that kind of annotation, they need articles that cite the original to include an additional piece of metadata, along with the author/year/title/journal/etc. metadata that identifies the cited paper. That additional ingredient is the citation’s type, which should be one of a small set of defined values.

What values are relevant? I won’t try to come up with an exhaustive list at this point, but obvious ones include:

  • Replicates — the current paper replicates work done in the cited paper (and so provides evidence, though not proof, that the cited paper’s conclusion is correct).
  • FailsToReplicate — the current paper attempts to replicate work done in the cited paper, but fails (and so provides evidence that the cited paper is mistaken).
  • Falsifies — the current paper shows definitely that the cited paper is wrong. This is a stronger statement than FailsToReplicate, and would be used for example when the new work shows conclusively that the experimental protocol of the original was critically flawed.
  • DependsOn — the current paper depends on information from the cited paper, such as the phylogeny that it proposes or the vertebral formula that it gives. For these purposes, the cited paper is treated as an authoritative source.
  • Acknowledges — the current paper uses ideas proposed in the cited paper, and gives credit to the original.

(We discussed the distinction between those last two previously.)

There are all sorts of practical issues that will impede the adoption of this idea (not least the idiot fact that the citation graph is a trade secret rather than a freely available database), but let’s ignore those for now, and figure out what taxonomy of citation-types we want.