Re-reading an email that Matt sent me back in January, I see this:

One quick point about [an interesting sauropod specimen]. I can envision writing that up as a short descriptive paper, basically to say, “Hey, look at this weird thing we found! Morrison sauropod diversity is still underestimated!” But I honestly doubt that we’ll ever get to it — we have literally years of other, more pressing work in front of us. So maybe we should just do an SV-POW! post about the weirdness of [that specimen], so that the World Will Know.

Although as soon as I write that, I think, “Screw that, I’m going to wait until I’m not busy* and then just take a single week* and rock out a wiper* on it.”

I realize that this way of thinking represents a profound and possibly psychotic break with reality. *Thrice! But it still creeps up on me.

(For anyone not familiar with the the “wiper”, it refers to a short paper of only one or two pages. The etymology is left as an exercise to the reader.)

It’s just amazing how we keep on and on falling for this delusion that we can get a paper out quickly, even when we know perfectly well, going into the project, that it’s not going to work out that way. To pick a recent example, my paper on quantifying the effect of intervertebral cartilage on neutral posture was intended to be literally one page, an addendum to the earlier paper on cartilage: title, one paragraph of intro, diagram, equation, single reference, DONE! Instead, it landed up being 11 pages long with five illustrations and two tables.

I think it’s a reasonable approximation to say that any given project will require about an order of magnitude more work than we expect at the outset.

Even as I write this, the top of my palaeo-work priority list is a paper that I’m working on with Matt and two other colleagues, which he kicked off on 6 May, writing:

I really, really want to kill this off absolutely ASAP. Like, seriously, within a week or two. Is that cool? Is that doable?

To which I idiotically replied:

IT SHALL BE SO!

A month and a bit later, the answers to Matt’s questions are clear. Yes, it’s cool; and no, it’s not doable.

The thing is, I think that’s … kind of OK. The upshot is that we end up writing reasonably substantial papers, which is after all what we’re meant to be trying to do. If the reasonably substantial papers that end up getting written aren’t necessarily the ones we thought they were going to be, well, that’s not a problem. After all, as I’ve noted before, my entire Ph.D dissertation was composed of side-projects, and I never got around to doing the main project. That’s fine.

In 2011, Matt’s tutorial on how to find problems to work on discussed in detail how projects grow and mutate and anastamose. I’m giving up on thinking that this is a bad thing, abandoning the idea that I ought to be in control of my own research program. I’m just going to keep chasing whatever rabbits look good to me at the time, and see what happens.

Onwards!

We’ve seen the humerus of the Wealden-supergroup putative titanosaur “Pelorosaurusbecklesi. We’ve seen the bones of the forearm, the radius and ulna. That’s it for bony remains: no other bones have been found.

But there is one other fossil that’s part of the same specimen: this skin impression:

Skin impression of

Skin impression of “Pelorosaurusbecklesii holotype NHMUK R1868. (Note that the other elements of this specimen are all catalogued as R1870.)

As you can see, the body — or at least this part of the body — was covered with roughly hexagonal tessellating (non-overlapping) scales, of about 1-2 cm diameter. But what part of the body is it from? The initial — extremely brief — description of this specimen, by Mantell (1852:143) hardly mentions the skin impression at all. All it says is:

A portion of the scaly cuirass which covered the limbs and is composed of hexagonal plates, was exhibited.

Still, this does at least suggest that the skin impression was from a limb — hardly surprising given then the left forelimb was the only part of the skeleton recovered. Upchurch et al. (2004:295) were more specific:

This skin impression was found in close association with the elbow region of the forelimb of Pelorosaurus becklesii.

But I don’t know whether this assertion is based on something written earlier, or is just a surmise.

Assuming that the skin impression is indeed from the elbow, and putting it all together, here’s what we know of “Pelorosaurus” becklesii:

Schematic of

Schematic of “Pelorosaurusbecklesi holotype NHMUK R1870, showing the preserved humerus, radius, ulna, and skin impression of the elbow. Based on Scott Hartman’s skeletal reconstruction of Alamosaurus. This is not a skeletal reconstruction of “Pelorosaurusbecklesi.

It’s not much, but it’s enough to be diagnostic.

But what actually is this beast? A titanosaur, as often assumed? A more basal macronarian? Something else entirely? Who can tell? Someone really ought to get onto that.

References

  • Mantell, Gideon A. 1852. On the structure of the Iguanodon, and on the fauna and flora of the Wealden Formation. Notices of the proceedings at the meetings of the members of the Royal Institution, with abstracts of the discourses delivered at the evening meetings 1:141-146.
  • Upchurch, Paul, Paul M. Barrett and Peter Dodson. 2004. Sauropoda. pp. 259-322 in D. B. Weishampel, P. Dodson and H. Osmólska (eds.), The Dinosauria, 2nd edition. University of California Press, Berkeley and Los Angeles. 861 pp.

Yesterday, we looked at (mostly) the humerus of the Wealden sauropod “Pelorosaurusbecklesii, which you will recall is known from humerus, radius, ulna and a skin impression, and — whatever it might be — is certainly not a species of Pelorosaurus.

Now let’s look at the radius and ulna.

Left forearm of

Left forearm of “Pelorosaurusbecklesii holotype NHMUK R1870, articulated, in anterior view, with proximal to the left: radius in front, ulna behind.

They fit together pretty neatly: the proximal part of the radius is a rounded triangular shape, and it slots into the triangular gap between the anteromedial and anterolateral processes of the proximal part of the ulna.

Left forearm of “Pelrosaurus” becklesii holotype NHMUK R1870 in proximal view, with anterior to the right. The arms of the ulna enclose the radius.

Left forearm of “Pelorosaurusbecklesii holotype NHMUK R1870 in proximal view, with anterior to the right. The “arms” of the ulna enclose the radius.

Let’s take a closer look at the ulna:

Left ulna of

Left ulna of “Pelorosaurusbecklesii holotype NHMUK R1870. Top row: proximal view, with anterior to the bottom. Middle row, from left to right: medial, anterior, lateral and posterior views. Bottom row: distal view, with anterior to top.

And the radius:

Left radius of

Left radius of “Pelorosaurus” becklesii holotype NHMUK R1870. Top row: proximal view, with anterior to the bottom. Middle row, from left to right: medial, anterior, lateral and posterior views. Bottom row: distal view, with anterior to top.

As you can see, it’s pretty well preserved: there’s no evidence of significant crushing in any of the bones, and the 3d shape is apparent.

In short, it’s a really sweet specimen. Someone really ought to get around to describing it properly, and giving it the new generic name that it clearly warrants.

It’s an oddity that in eight years of SV-POW!, we’ve never written about one of the best of all the Wealden-formation sauropod specimens: the forelimb and associated skin impression NHMUK R1870 that is known as “Pelorosaurusbecklesii.

Let’s fix that. Here is all the bony material (i.e. everything except the skin patch) in a photo taken in the basement of the Natural History Museum back in 2007:

Left forelimb material of

Left forelimb material of “Pelorosaurusbecklesii holotype NHMUK R1870. Left: humerus, in posterior view. Right, from top to bottom: ulna in anterior view; radius in anterior view. Yes, I should have turned the humerus over before taking this photo. What can I tell you? I was young and stupid then.

As you can see, the two lower-limb bones were broken back then (though I believe they have since been repaired), but the breaks are very clean, and it’s actually quite interesting to see inside the bones:

Breakage in bones of the lower left forelimb of

Breakage in bones of the lower left forelimb of “Pelorosaurusbecklesii holotype NHMUK R1870. Left: proximal part of radius in distal view. Right: proximal part of ulna in distal view.

I wish I knew enough about mineralisation to comment intelligently on what we can see there. If anyone has thoughts, do leave them in the comments.

We can look in more detail at those lower-limb bones in a subsequent post, but for now, here’s the humerus:

Pelorosaurusbecklesii holotype NHMUK R1870, left humerus. Top row: proximal view, with anterior to the bottom. Middle row, from left to right: medial, anterior, lateral and posterior views. Bottom row: distal view, with anterior to the top.

As you can see it’s in really nice shape, and pretty distinctive. Way back in my 2007 Progressive Palaeo talk (Taylor 2007), I coded up the humerus (alone, without the other elements) in the Harris-based phylogenetic matrix that I’ve used repeatedly in other projects. It came out as the sister taxon to the titanosaur Malawisaurus (which in that matrix comes out fairly basal within Titanosauria): in fact, it could hardly do anything else, since the coding was exactly the same as that of Malawisaurus.

And indeed it’s been pretty widely accepted that “P.” becklesii is a titanosaur — one of the earliest known, and the only name-bearing one from the Wealden Supergroup, unless you count the extremely indeterminate Iuticosaurus, which predictably enough is based on a single eroded partial mid-caudal centrum. Still, the titanosaurian identity of “P.” becklesii has never been convincingly demonstrated — only inferred by non-cladistic means.

Pelorosaurusbecklesii holotype NHMUK R1870, left humerus in anterodistal view (anterior to the left).

So why the quotes around the genus name “Pelorosaurus“? Because it’s long been recognised that, whatever this specimen might be, it ain’t Pelorosaurus, which is based on the Cetiosaurusbrevis caudals and a much more slender humerus.

Here’s that humerus, so you can see how different it is from that of “Pelorosaurusbecklesii:

Right humerus of Pelorosaurus conybeari holotype NHMUK 28626. Top row: distal view, anterior to bottom. Middle row, left to right: lateral, anterior and medial views. Bottom row: distal, anterior to top. Missed parts reconstructed from the humerus of Giraffatitan brancai (Janensch 1961: Beilage A)

Right humerus of Pelorosaurus conybeari holotype NHMUK 28626. Top row: distal view, with anterior to bottom. Middle row, left to right: lateral, anterior and medial views. Bottom row: distal view, with anterior to top. Missing parts reconstructed from the humerus of Giraffatitan brancai (Janensch 1961: Beilage A)

Paul Upchurch recognised the generic distinctness of “Pelorosaurusbecklesii way back in his (1993) dissertation. But because of Cambridge University’s policy of only making copies of dissertations available for £65, that work is effectively unknown. (Perhaps we should all chip in a fiver, buy a copy and “liberate” it. Or maybe 22 years on, Paul would rather leave it in obscurity and let his reputation continue to rest on his impressive body of later work.)

What has happened to this specimen in the last 22 years? Very little has been published about it. It got a mention in the systematic review of sauropods in Dinosauria II (Upchurch et al. 2004), but the only mention that is more than in passing, as far as I’m aware, is that of see Upchurch’s first published (1995) phylogenetic analysis. From page 380:

The only reliable Lower Cretaceous titanosaurid material, apart from Malawisaurus, comes from Europe, especially England. The earliest of these forms may be represented by the forelimb of ‘Pelorosaurus becklesii‘ (Mantell 1852) from the Valanginian of Sussex. This specimen was considered to be Sauropoda incertae sedis by McIntosh (1990b). However, a skin impression shows polygonal plates of a similar shape and size to those found in Saltasaurus (Bonaparte & Powell 1980). The ulna and radius are robust and the ulna bears the typical concavity on its anteromedial proximal process. Upchurch (1993) therefore argued that this form should be provisionally included within the Titanosauridae.

[Update: as Darren points out in the comment below, Upchurch et al. (2011) figure the specimen in colour and devote three pages to it. They leave it as Titanosauria, and “refrain from naming a new taxon until more comparative data are available” (p. 501).]

Given my interest in the Wealden, it’s surprising that we’ve never blogged about “Pelorosaurusbecklesii before, but it’s true: I’ve mentioned it three times in comments, but never in a post. It’s good to finally fix that!

Next time: the radius and ulna.

References

  • Janensch, Werner. 1961. Die Gliedmaszen und Gliedmaszengurtel der Sauropoden der Tendaguru-Schichten. Palaeontographica (Suppl. 7) 3:177-235.
  • Taylor, Michael P. 2007. Diversity of sauropod dinosaurs from the Lower Cretaceous Wealden Supergroup of southern England. p. 23 in Graeme T. Lloyd (ed.), Progressive Palaeontology 2007, Thursday 12th-Saturday 14th April, Department of Earth Sciences, University of Bristol. 38 pp.
  • Upchurch, Paul. 1993. The Anatomy, Phylogeny and Systematics of Sauropod Dinosaurs. Ph.D dissertation, University of Cambridge, UK. 489 pages.
  • Upchurch, Paul. 1995. The evolutionary history of sauropod dinosaurs. Philosophical Transactions of the Royal Society of London Series B, 349:365-390.
  • Upchurch, Paul, Paul M. Barrett and Peter Dodson. 2004. Sauropoda. pp. 259-322 in D. B. Weishampel, P. Dodson and H. Osmólska (eds.), The Dinosauria, 2nd edition. University of California Press, Berkeley and Los Angeles. 861 pages.
  • Upchurch, Paul, Philip D. Mannion and Paul M. Barrett. 2011. Sauropod dinosaurs. pp. 476-525 in: Batten, David J. (ed.), English Wealden Fossils. The Palaeontological Association (London).

I recently reread Dubach (1981), “Quantitative analysis of the respiratory system of the house sparrow, budgerigar and violet-eared hummingbird”, and realized that she reported both body masses and volumes in her Table 1. For each of the three species, here are the sample sizes, mean total body masses, and mean total body volumes, along with mean densities I calculated from those values.

  • House sparrow, Passer domesticus, n = 16, mass = 23.56 g, volume = 34.05 mL, density = 0.692 g/mL
  • Budgerigar, Melopsittacus undulatus, n = 19, mass = 38.16 g, volume = 46.08 mL, density = 0.828 g/mL
  • Sparkling violetear,* Colibri coruscans, n = 12, mass = 7.28 g, volume = 9.29 mL, density = 0.784 g/mL

* This is the species examined by Dubach (1981), although not specified in her title; there are four currently-recognized species of violetears. And apparently ‘violetear’ has overtaken ‘violet-eared hummingbird’ as the preferred common name. And as long as we’re technically on a digression,  I’m almost certain those volumes do not include feathers. Every volumetric thing I’ve seen on bird masses assumes plucked birds (read on).

This is pretty darned interesting to me, partly because I’m always interested in how dense animals are, and partly because of how the results compare to other published data on whole-body densities for birds. The other results I am most familiar with are those of Hazlehurst and Rayner (1992) who had this to say:

There are relatively few values for bird density. Welty (1962) cited 0.9 g/mL for a duck, and Alexander (1983) 0.937 g/mL for a domestic goose, but those values may not take account of the air sacs. Paul (1988) noted 0.8 g/mL for unspecified bird(s). To provide more reliable estimates, the density of 25 birds of 12 species was measured by using the volume displacement method. In a dead, plucked bird the air-sac system was reinflated (Saunder and Manton 1979). The average density was 0.73 g/mL, suggesting that the lungs and air sacs occupy some quarter of the body.

That result has cast a long shadow over discussions of sauropod masses, as in this paper and these posts, so it’s nice to see similar results from an independent analysis.  If you’re curious, the weighted mean of the densities calculated from Duchard’s Dubach’s (1981) data is 0.77. I’d love to see the raw data from Hazlehurst and Rayner (1992) to see how much spread they got in their density measurements.  Unfortunately, they did not say which birds they used or give the raw data in the paper (MYDD!), and I have not asked them for it because doing so only just occurred to me as I was writing this post.

There will be more news about hummingbirds here in the hopefully not-too-distant future. Here’s a teaser:

SkeletonFULL

Yes, those are its hyoids wrapped around the back of its head–they go all the way around to just in front of the eyes, as in woodpeckers and other birds that need hyper-long tongue muscles. There are LOADS of other interesting things to talk about here, but it will be faster and more productive if I just go write the paper like I’m supposed to be doing.

Oh, all right, I’ll say a little more. This is a  young adult female Anna’s hummingbird, Calypte anna, who was found by then-fellow-grad-student Chris Clark at a residential address in Berkeley in 2005. She was unable to fly and died of unknown causes just a few minutes after being found. She is now specimen 182041 in the ornithology collection at the Museum of Vertebrate Zoology at Berkeley. Chris Clark and I had her microCTed back in 2005, and that data will finally see the light of day thanks to my current grad student, Chris Michaels, who generated the above model.

This bird’s skull is a hair over an inch long, and she had a body mass of 3.85 grams at the time of her death. For comparison, those little ketchup packets you get at fast-food burger joints each contain 8-9 grams of ketchup, more than twice the mass of this entire bird when it was alive!

References

  • Dubach, M. 1981. Quantitative analysis of the respiratory system of the house sparrow, budgerigar and violet-eared hummingbird. Respiration Physiology 46(1): 43-60.
  • Hazlehurst, G.A., and Rayner, J.M. 1992. Flight characteristics of Triassic and Jurassic Pterosauria: an appraisal based on wing shape. Paleobiology 18(4): 447-463.

If you’ll forgive me a rather self-indulgent post, the neck-anatomy paper that I and Matt recently had published in PeerJ is important to me for three reasons beyond the usual satisfaction of getting a piece of work out in a good journal.

fig4

Taylor and Wedel (1023:figure 4). Extent of soft tissue on ostrich and sauropod necks. 1, ostrich neck in cross section from Wedel (2003, figure 2). Bone is white, air-spaces are black, and soft tissue is grey. 2, hypothetical sauropod neck with similarly proportioned soft-tissue. (Diplodocus vertebra silhouette modified from Paul 1997, figure 4A). The extent of soft tissue depicted greatly exceeds that shown in any published life restoration of a sauropod, and is unrealistic. 3, More realistic sauropod neck. It is not that the soft-tissue is reduced but that the vertebra within is enlarged, and mass is reduced by extensive pneumaticity in both the bone and the soft-tissue.

Three milestones

First, it brings a drought to an end. For one reason and another, I didn’t get a single paper published in 2012 — my last hit was the neck sexual-selection paper in September 2011, and I’d started to feel that I was drifting off into the distance a bit. Good to be back on the horse.

Second, amazing though it may seem, it’s the first Taylor/Wedel paper (in either order). Matt and I have been collaborating in one form or another for more than thirteen years now (even if the first couple of years of that were just me asking dumb questions and him telling me interesting things). Along the way, we’ve shared the authorship of a few papers with other authors (Taylor, Wedel and Naish 2009 on habitual neck posture; Taylor, Wedel and Cifelli 2011 on Brontomerus; and Taylor, Hone, Wedel and Naish 2011 on sexual selection) but of all the many Mike-‘n’-Matt projects we’ve started, this is the first to make it out into the world.

(As it happens — and at the risk of leaving the stadium before the fat lady sings — we should be adding to that tally of one Real Soon Now. Further bulletins as events warrant.)

Third, and most important, it means that my entire Ph.D is now published. Chapter 1 (the sauropod-history review) was in the Geological Society dinosaur-history volume;  chapter 2 (the Brachiosaurus revision) was in JVP; chapter 3 (the Xenoposeidon description) was in Palaeontology; chapter 4 (the Brontomerus description) was in Acta Palaeontologica Polonica, and now chapter 5 (neck anatomy) is in PeerJ. I’m pretty happy with the selection of venues there: I’m pleased to have had papers in JVP and Palaeontology even though I won’t be going back to either until they’re open access.

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.

Taylor and Wedel (2013: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.

Dissertation thoughts

Actually I have strangely conflicted feelings about my Ph.D all being published now. I like the feeling of closure, but I also feel a bit sad that the dissertation itself — by far the most substantial single piece of work I’ve produced in any field — is now wholly obsolete. Really, the only reason anyone would possibly want to read it now would be for the acknowledgements or the laughably incorrect predictions of what I’d be working on next. Happily, I don’t have to lament time wasted on the dissertation: all five chapters were originally written to be papers, and the versions in the dissertation are all formatted as for the journals they were initially submitted to. (Three of them ended up in different venues, having initially been rejected, but that’s another story.)

An oddity of my Ph.D is that all five chapters were side-projects. They’re all things that I worked on when I was supposed to be working on a core project to do with the Archbishop and the mechanics of neck support. Every one of them I thought would be a quick job that I could push out before returning to my main work. And every one of them “grew in the telling” until it was substantial enough to function as a chapter. I am sure there’s a moral to this story, but heck if I can figure out what it is.

For reasons that seemed to make sense to me at the time, I did not post my dissertation on the Internet when it was accepted. I feared scooping myself on the as-yet unpublished material (Brontomerus and neck anatomy). Honestly, I don’t know what I was thinking. If I was doing it today I would certainly make it available from the moment it was okayed. As of just a couple of days ago it is now available — just in time to be of no interest to anyone.

xx

Taylor and Wedel (2013:figure 2). Full skeletal reconstructions of selected long-necked non-sauropods, to scale. 1, Paraceratherium. 2, Therizinosaurus. 3, Gigantoraptor. 4, Elasmosaurus. 5, Tanystropheus. Elasmosaurus modified from Cope (1870, plate II, figure 1). Other image sources as for Fig. 1. Scale bar = 2 m.

Co-authoring dissertation chapters

A final thing worth mentioning: as noted above, three of the chapters of my dissertation (Xenoposeidon, Brontomerus, neck anatomy) were co-authored. I think this is not particularly common, so it’s probably worth commenting on.

How does it work? For one of the papers, the Brontomerus description, I just excised Matt’s and Rich’s contributions, which were quite separate from the core of the paper, and used a sole-authored version as the chapter. For the other two, I put an explicit statement in the front-matter saying who did what:

Chapter 3 (description of Xenoposeidon): I was responsible for the anatomical part of the introduction, the systematic palaeontology section, description, comparisons and interpretation, phylogenetic analysis, length and mass calculations, diversity discussion, references, figures with their captions except figure 2, and both tables. Darren Naish of the University of Portsmouth was responsible for the geological and historical part of the introduction, the historical taxonomy section, and figure 2.

Chapter 5 (evolution of long necks): this chapter was written by me as a consequence of a series of discussions with Mathew J. Wedel. Dr. Wedel also contributed figure 5.

My sense was that the examiners were perfectly happy with this. Arguably it’s a good preparation for functioning as a researcher, since so many papers are co-authored. It’s not really realistic practice to sole-author all your work. That said, I doubt papers where I wasn’t lead author would have been welcomed.

I mention this because co-authoring may be a more widely available option than is recognised. My advice would be simple: check with your own supervisor first!

The gloves are off!

October 12, 2011

A package!  A package has arrived!

What can it be?

All right!  Let’s get down to business?

Now, where did I leave that monitor-lizard neck skeleton?  Ah yes …

That’s what I’m talkin’ about.

Stay tuned for exciting news about turkey zygapophyses.

 

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