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!

In my blog-post announcing Haestasaurus as the new generic name for the misassigned species “Pelorosaurusbecklesii, I briefly surveyed the three phylogenetic analyses in the paper. Of the third — the one based on the Mannion et al. (2013) Lusotitan matrix using both discrete and continuous characters — I wrote that it …

… recovers Haestasaurus as a titanosaur — as sister to Diamantinasaurus and then Malawisaurus, making it a lithostrotian well down inside Titanosauria.

My mistake! I was working from the result of an earlier version of that analysis. In the final version included in the paper, things are rather different:

Fig 17. Strict consensus tree (LCDM). A strict consensus tree based on the 17 most parsimonious trees generated by analysis of the Mannion et al. [18] LCDM with the revised scores for Haestasaurus and the addition of six new characters. GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. Abbreviations: Brc, Brachiosauridae; Dd, Diplodocoidea. N.B. the tree topology shown here means that the clades defined by Brachiosaurus+Saltasaurus (Titanosauriformes) and Andesaurus+Saltasaurus (Titanosauria) are identical. See main text for details.

Upchurch et al. (2015: Fig 17). Strict consensus tree (LCDM).
A strict consensus tree based on the 17 most parsimonious trees generated by analysis of the Mannion et al. [18] LCDM with the revised scores for Haestasaurus and the addition of six new characters. GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. Abbreviations: Brc, Brachiosauridae; Dd, Diplodocoidea. N.B. the tree topology shown here means that the clades defined by Brachiosaurus+Saltasaurus (Titanosauriformes) and Andesaurus+Saltasaurus (Titanosauria) are identical. See main text for details.

As you can see, Haestasaurus is indeed a titanosaur in this analysis — but not a derived one at all. In fact, it’s part of the most basal clade of titanosaurs, along with Janenschia and Dongbeititan. In this tree, we have a really nice, big Brachiosauridae, containing 19 OTUs split fairly evenly between two subclades.

[Side-note: Upchurch et al. (2015) uses phylogenetic definitions that I’m not crazy about. I prefer the arrangement that I followed in my brachiosaur paper (Taylor 2009), in which Titanosauriformes = Brachiosauridae + Titanosauria is a node-stem triplet. Hopefully, some time soon, the wretched PhyloCode will finally be implemented, and we’ll be in a position to nail down a single set of definitions for the whole community to use.]

Anyway, the upshot of all this is that all three phylogenetic analyses in the paper return Haestasaurus as a pretty basal macronarian, and on the balance of evidence it’s likely not a titanosaur after all. (That’s the the name “Haestatitan“, which was in some earlier drafts of the paper, was changed to Haestasaurus. Kind of a shame, given how mundane -saurus names are, but probably the wisest course of action.)

What is the takeaway lesson from this? It’s not just “Haestasaurus is not a derived titanosaur”. It’s that all our phylogenetic hypotheses are just that — hypotheses. Papers that publish only a single cladogram are always at risk of being misinterpreted as conveying much more certainty than they really do, and Paul and Phil are to be commended for included the whole messy story in this paper. The position of Haestasaurus shifts around far too easily for us to have a strong sense of what it is, and it’s good that the paper makes that clear.

(It also makes glad that way back in Taylor and Naish (2007), I and Darren didn’t give a more precise position of Xenoposeidon than that it’s probably some kind of neosauropod. And even that is not something I would put money on.)

References

I found myself needing a checklist so that I could make sure I’d updated all the various web-pages that needed tweaking after the Haestasaurus paper came out. Then I thought others might find it useful for when they have new papers. So here it is.

  • Write a blog-post on SV-POW!
  • Create a new page about paper in the SV-POW! sidebar.
  • Add the full-resolution figures to the sidebar page.
  • Update my online publications list.
  • Update my University of Bristol IR page.
  • Update my ORCID page.
  • Update my LinkedIn page.
  • Mendeley, if you do it (I don’t).
  • ResearchGate, if you do it (I don’t).
  • Academia.edu, if you do it (I don’t).
  • Keep an eye on the new taxon’s Wikipedia page (once it exists).
  • Add the paper to the Paleobiology Database (or ask someone to do it for you if you’re not authorised). [Credit: Jon Tennant]
  • Tweet about it! [Credit: Matt Hodgkinson]
  • Update Google Scholar, if it doesn’t pick up on the publication on its own [Credit: Christopher Taylor]
  • Post on Facebook [Credit: Andy Farke]
  • Send PDF to the institution that hosts the material [Credit: Andy Farke]
  • Email colleagues who might be interested [Credit: Andy Farke]
  • Write short popular language account for your institution if applicable [Credit: Andy Farke]
  • Submit any silhouettes to PhyloPic [Credit: Mike Keesey]

Have I forgotten any?

I think I have now completed all these tasks for the Haestasaurus paper. And a right pain it was, entering the same new paper in SV-POW!, my own list, the Bristol IR, the ORCID page and LinkedIn.

The IR was definitely by far the clumsiest — it took ages, and many different screens, before I was done. I kind of expected that (it turns out that PURE, which is what Bristol’s IR uses, is supplied by Elsevier, so supply your own punchline). But what really disappointed me was the clumsiness of having to enter all the details by hand yet again when I got to ORCID. Why couldn’t I just enter the DOI and let it fill in the rest?

You would think that ORCID, of all people, would appreciate the value of referring to things by unique IDs!

Well, who knew? There I was posting images of “Pelorosaurusbecklesi‘s humerus, radius and ulna, and skin impression. There I was saying that this beast is due a proper description, and warrants its own generic name. And what should come out today but a new paper by Paul Upchurch, Phil Mannion and, oh yes, me, which does exactly that.

Screen Shot 2015-06-03 at 19.05.12

The headline news is the long-overdue establishment of a new genus name for this species — something that we’ve known was needed at least since Upchurch’s (1993) dissertation. Paul and Phil came up with the name Haestasaurus, from “Haesta”, the name of the putative pre-Roman chieftain whose people apparently settled the area of Hastings and gave the town its name. It’s nice that I can finally stop typing the scare-quotes around the no-longer-relevant old genus name “Pelorosaurus“!

Upchurch et al. 2015: figure 2. Left humerus of Haestasaurus becklesii (NHMUK R1870). A, anterior view; B, posterior view; Abbreviations: af, anconeal fossa; dp, deltopectoral crest; hh, humeral head; ltf, lateral triceps fossa; mtf, medial triceps fossa.

Upchurch et al. (2015: figure 2). Left humerus of Haestasaurus becklesii (NHMUK R1870). A, anterior view; B, posterior view; Abbreviations: af, anconeal fossa; dp, deltopectoral crest; hh, humeral head; ltf, lateral triceps fossa; mtf, medial triceps fossa.

(As you can see, the photography is rather better than in my own illustrations, which I made independently some years ago.)

Of course Paul has had an eye on this work, on and off, since the early 1990s. Then in the late 2000s, when I was working on Xenoposeidon and other Wealden sauropods, I started work independently on a redescription — which of course is why I prepared the figures that have appeared in the last few posts. But that work petered out as I started working more on other specimens and on the problems of the sauropod neck. More recently, Paul and Phil hunkered down and got the nitty-gritty descriptive work done.

Once they had a complete draft manuscript, they very graciously invited me onto the authorship — not something they had to do, but they chose to based on my previous interest in the specimen. My contribution was minor: I provided two of the illustrations, tidied up the early versions of several others, and did an editing pass on the text.

Upchurch et al. (2015: figure 1). Map showing England and Wales, with boundaries for English counties. The magnified inset shows the Isle of Wight and East and West Sussex in more detail, marking the positions of selected major towns/cities and the fossil localities mentioned in the main text. Based on

Upchurch et al. (2015: figure 1). Map showing England and Wales, with boundaries for English counties. The magnified inset shows the Isle of Wight and East and West Sussex in more detail, marking the positions of selected major towns/cities and the fossil localities mentioned in the main text. Based on “English ceremonial counties 1998″ by Dr. Greg, http://en.wikipedia.org/wiki/File:English_ceremonial_counties_1998.svg. CC By-SA 3.0.

(This map is one of the two illustrations that I provided; the other is the multi-view photograph of the Pelorosaurus conbeari humerus.)

I’m grateful to Paul and Phil, both for inviting me onto this project, and for taking into account my strong preference for an open-access venue. It’s largely because of the latter that the paper now appears in PLOS ONE, where the glorious colour illustrations appear at full resolution and may be re-used for any purpose subject to attribution.

So: what actually is Haestasaurus? Is it the early titanosaur that we’ve all been assuming? The unexciting answer is: we don’t really know. Our paper contains three phylogenetic hypotheses (all of them Paul and Phil’s work, I can’t take any credit). These results are from adding Haestasaurus to the Carballido and Sander (2014) matrix, to the Mannion et al. (2013) standard discrete matrix and to the Mannion et al. (2013) continuous-and-discrete matrix. Only the last of these recovers Haestasaurus as a titanosaur — as sister to Diamantinasaurus and then Malawisaurus, making it a lithostrotian well down inside Titanosauria.

Both both of the other analyses find Haestasaurus as a very basal macronarian — outside of Titanosauriformes. Here is the result of the analysis based on Carballido and Sander’s Europasaurus matrix:

Upchurch et al. (2105: figure 15). Strict consensus tree (CSM). A strict consensus tree based on the 28 most parsimonious trees generated by analysis of the Carballido and Sander [19] data matrix with the addition of Haestasaurus and six new characters (Tendaguria excluded a priori). GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. The monophyletic Diplodocoidea has been collapsed to a single branch in order to reduce figure size. Abbreviation: Brc, Brachiosauridae.

Upchurch et al. (2105: figure 15). Strict consensus tree (CSM). A strict consensus tree based on the 28 most parsimonious trees generated by analysis of the Carballido and Sander [19] data matrix with the addition of Haestasaurus and six new characters (Tendaguria excluded a priori). GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. The monophyletic Diplodocoidea has been collapsed to a single branch in order to reduce figure size. Abbreviation: Brc, Brachiosauridae.

As you can see, Haestasaurus is here a camarasaurid, making it (along with Camarasaurus itself) the most basal of all macronarians. In the second analysis — the one using discrete characters only from Mannion et al.’s Lusotitan paper — Haestasaurus is again in the most basal macronarian clade, but this time as sister to Janenschia and then Tehuelchesaurus. (In this topology, Camarasaurus is the next most basal macronarian after that three-taxon clade.)

So it looks like Haestasaurus is either a very basal macronarian or a pretty derived titanosaur. We don’t know which.

But, hey, at least it has a proper name now!

Acknowledgements

It’s Matt’s birthday today. I’d like to dedicate a sauropod to him, but I don’t have the authority to do that. So instead, I dedicate this blog-post to him, and declare it the Mathew J. Wedel Memorial Blog Post.

References

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).
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