Brontosaurus, the animal formerly known as Apatosaurus, the animal formerly known as Brontosaurus.

YPM 1980: Brontosaurus excelsus, the animal formerly known as Apatosaurus excelsus, the animal formerly known as Brontosaurus excelsus.

Today is a good day for sauropod science. Since we’re not getting this up until the afternoon, you’ve probably already seen that Emanuel Tschopp and colleagues have published a monstrous specimen-level phylogenetic analysis of Diplodocidae and, among other things, resurrected Brontosaurus as a valid genus. The paper is in PeerJ so you can read it for free (here).

I’ve already been pinged by lots of folks asking for my thoughts on this. I know that the return of Brontosaurus is what’s going to catapult this paper into the spotlight, but I hope what everyone takes away from it is just what a thorough piece of work it is. I’ve never seen so many phylogenetic characters illustrated so well. It sets a new standard, and anyone who wants to overturn this had better roll up their sleeves and bring a boatload of data. I’m also very, very happy that it’s open-access so everyone in the world can see it, use it, question it, tear it apart or build on it. Getting Brontosaurus back is just gravy. Although, being pro-brontosaur enough to have named a dinosaur in honor of Brontosaurus, I’m also pretty happy about that. If you need a quick guide to who’s who now, A. ajax and A. louisae are still Apatosaurus, and B. excelsus, B. yahnahpin (formerly Eobrontosaurus), and B. parvus (originally Elosaurus) are all Brontosaurus. For more details, go read the paper.

A louisae from Wikipedia - full

Apatosaurus lousiae CM 3018: still Apatosaurus. Photo from Wikipedia.

My personal feelings aside, a lot of people are asking how solid is this generic re-separation. I haven’t read the entire paper yet – it’s 299 pages long, for crying out loud – but the separation of Brontosaurus and Apatosaurus seems solid enough. Tschopp et al. didn’t do it lightly, they justify their decision in detail. I don’t hold with the idea that just because two taxa are sisters, means that they cannot be separated generically. As usual in phylogenetic taxonomy, it comes down to what we decide as a community constitutes “diagnosably distinct”. Tschopp et al. have actually put some thought into what that might mean here, and whether you agree with them or not, they’ve at least made all of their evidence and reasoning explicit. That’s both an opportunity and a challenge for critics: an opportunity to pin down exactly where and why you may disagree, and a challenge to do exactly that. You can’t just sit back and say, “I think the analysis is flawed” or “I wouldn’t have coded that character that way” (well, you can, but if that’s all you say, no-one is obliged to take that kind of lazy, drive-by criticism seriously). There are 477 characters here, most of them illustrated, for 81 OTUs, and a lot of post-hoc discussion of the results. So whether you agree with the authors or not, in whole or in part, both fans and critics should dig in and build on this work. Is it the last word on diplodocid taxonomy? Of course not. But it does move the field forward significantly, and the Tschopp et al. should be applauded for that.

There’s a lot more in there than just bringing back Brontosaurus. “Diplodocus” hayi is elevated to its own genus, Galeamopus. Neither of those things are super surprising. There have been rumors since the 90s at least that Brontosaurus might be coming back, and everyone has known for a while that D. hayi was a bit wonky. I was also not surprised to see Australodocus returned to Diplodocidae – when I saw the type material in 2011, it looked diplodocid to me (based on some characters I’ll have to unpack in some other post). More surprising to me are the sinking of Dinheirosaurus into Supersaurus, the finding that Tornieria is not particularly close to Diplodocus, and the uncertain positions of AMNH 460, the American Museum mount, which is an indeterminate apatosaurine pending further study, of FMNH 25112, the Field Museum “Apatosaurus”, which might not even be an apatosaurine at all(!). In several cases, Tschopp et al. come right out and say that X is going to need further study, so if you want to work on sauropods and you’re stuck for project ideas, go see what needs doing.

AMNH mounted Apatosaurus with Taylor for scale

AMNH 460: we don’t know who this is anymore.

As I was scanning the paper again while composing the last paragraph, I almost fell down the rabbit hole. So much interesting stuff in this paper. Even if all you care about is morphology, the hundred or so figures illustrating the phylogenetic characters ought to keep you happy for a very long time. I look forward to reading through the vertebral characters in detail and seeing what I’ve been missing all these years.

I’m contractually obliged to point out that the authors chose to publish the complete peer-review history of the paper, so you can see what the editor (Andy Farke) and reviewers had to say. As always, I think this transparency (and credit for the reviewers) is great for science, and I can’t wait until it’s the norm at more journals.

FMNH 25112 formerly Apatosaurus

FMNH 25112: what even IS that thing?

In addition to the paper, there’s also an interview with lead author Emanuel Tschopp on the PeerJ blog, and a nice shout-out for SV-POW!

Parting shot: why did Tschopp et al. get different results than anyone had previously? Because they used more specimens and more taxa – more data full stop. That’s also why their paper warrants serious consideration. It’s serious work. Let’s go stand on their shoulders.

Reference

Tschopp E, Mateus O, Benson RBJ. (2015) A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda) PeerJ 3:e857 https://dx.doi.org/10.7717/peerj.857

According to Rare Historical Photos from the 1860s to the 1960s, this is the iceberg that sank the Titanic:

 photo of the iceberg that sunk the Titanic, taken the morning of April 15, 1912 from board of the ship “Prinz Adalbert”, before knowing the Titanic had sunk. The smear of red paint along the base of the berg (bottom right) prompted the chief steward to take the picture.

photo of the iceberg that sunk the Titanic, taken the morning of April 15, 1912 from board of the ship “Prinz Adalbert”, before knowing the Titanic had sunk. The smear of red paint along the base of the berg (bottom right) prompted the chief steward to take the picture.

Clearly this was no iceberg, but a gigantic Apatosaurus vertebra, most of it hidden under water. Here is an artist’s impression:

iceberg

They get everywhere, don’t they?

apatosaurus-maquette-whole-lateral cropped - angle 2

I made these for my own use in talks, and then thought, why be selfish? Like everything else on this blog, these images are now released to the world under the CC-BY license. Have fun with them.

apatosaurus-maquette-whole-lateral cropped

You can read my review of the Sideshow Apatosaurus here; the TL;DR is that it’s awesome. And if you’re bummed that you missed out on getting one last time around, they’re rereleasing it later this spring with a slightly different paint job – details here.

A while back, Ben Miller reminded me that when I posted about the old Yale “Brontosaurus” skull, I promised:

So how did the YPM come to make such a monstrosity? What was it based on? Tune in next time for the surprising details!

I told him at the time that I’d soon get around to writing a post. But before I did, he wrote a post on this himself: Bully for Camarasaurus. And it’s excellent. Go and read it!

I don’t have a lot to add to what Ben has written, except regarding this:

What Marsh had instead [when restoring the skull for his 1891 “Brontosaurus” reconstruction] were a few fragmentary bits of Camarasaurus cranial material, plus a snout and jaw (USNM 5730) now considered to be Brachiosaurus.

Here’s what Marsh came up with:

Marsh1891-plateXVI-Apatosaurus-skull-UNREVERSED

But what of the supposed Brachiosaurus skull that he used as a reference? It was finally described 107 years later by Carpenter and Tidwell (1998), in a paper that helpfully also lays out the history behind it. Here’s how it looks:

CarpenterTidwell1998-fig1

The skull was found by a crew under the supervision of M. P. Felch in the western part of his Quarry 1, Garden Park, Colorado. Felch reported it to O. C. Marsh in a letter of 8 September 1883. It was found by a meter-long cervical vertebra that probably belonged to Brachiosaurus “which was destroyed during attempts to collect it” (McIntosh and Berman 1975:196). [Of course, Felch and Marsh could hardly have been expected to identify this vertebra correctly, as Brachiosaurus would not be discovered and named for another twenty years (Riggs 1903), and the nature of its neck would not become apparent until Janensch (1914) described the related brachiosaurid Giraffatitan (= “Brachiosaurus“) brancai.]

The Felch skull, along with other material from the quarry, was shipped to Marsh at Yale in October of that year, and was initially assigned the specimen number YPM 1986. At that time it was only partially prepared, hence the rather poor resemblance between the restored version above and Marsh’s hypothetical “Brontosaurus” [= Apatosaurus] skull that was based on it.

It’s notable that Holland (1915) was quite certain that this was not a skull of Brontosaurus, and that a Diplodocus-like skull found with the A. louisae holotype belonged to it. It’s worth reading the skull section of his paper to see just how solid his reasoning was. And it’s extraordinary to think that Osborn’s power, all the way over in New York, was so great that he was able to successfully bully Holland, 370 miles away in Pittsburgh, into not putting the evidently correct skull on the Carnegie Museum’s Apatosaurus mount. That mount remained sadly headless until after Holland’s death.

Aaanyway, YPM 1986 was pretty much ignored after Marsh’s abuse of it as a reference for the Brontosaurus reconstruction’s skull. After Marsh’s death in 1899, much of the material collected by Felch was transferred to the Smithsonian (US National Museum of Natural History). The skull was among these specimens, and so was re-catalogued as USNM 5730.

As so often, it was Jack McIntosh who rediscovered this skull and recognised its true affinities. Some time after his tentative identification of the skull as pertaining to Brachiosaurus (presumably on the basis of its resemblance to that of Giraffatitan), Carpenter borrowed the skull, had it more fully prepared, wrote the description, and had a restored model constructed from casts of the preserved elements and models of the missing ones.

Carpenter and Tidwell (1998:fig. 2) also handily showed the restored Felch quarry skull alongside those of other sauropods:

CarpenterTidwell1998-fig2

By re-ordering the top row, we can see what a neat intermediate it is between the skulls of Camarasaurus (left) and Giraffatitan (= “Brachiosaurus” of their usage):

CarpenterTidwell1998-fig2-top-row-reordered

I provisionally accepted USNM 5730 as belonging to Brachiosaurus in my re-evaluation of 2009, and included it in my reconstruction (Taylor 2009:fig. 7):

Taylor (2007: figure 7). Skeletal reconstruction of Brachiosaurus altithorax. White bones represent the elements of the holotype FMNH P 25107. Light grey bones represent material referred to B. altithorax: the Felch Quarry skull USNM 5730, the cervical vertebrae BYU 12866 (C?5) and BYU 12867 (C?10), the "Ultrasauros" scapulocoracoid BYU 9462, the Potter Creek left humerus USNM 21903, left radius and right metacarpal III BYU 4744, and the left metacarpal II OMNH 01138. Dark grey bones modified from Paul's (1988) reconstruction of Giraffatitan brancai. Scale bar equals 2 m.

Taylor (2007: figure 7). Skeletal reconstruction of Brachiosaurus altithorax. White bones represent the elements of the holotype FMNH P 25107. Light grey bones represent material referred to B. altithorax: the Felch Quarry skull USNM 5730, the cervical vertebrae BYU 12866 (C?5) and BYU 12867 (C?10), the “Ultrasauros” scapulocoracoid BYU 9462, the Potter Creek left humerus USNM 21903, left radius and right metacarpal III BYU 4744, and the left metacarpal II OMNH 01138. Dark grey bones modified from Paul’s (1988) reconstruction of Giraffatitan brancai. Scale bar equals 2 m.

But as noted by Carpenter and Tidwell (1998:82), the lack of comparable parts between the Felch skull and the Brachiosaurus holotype (which remains the only definitive Brachiosaurus material) means that the assignment has to remain tentative.

What we really need is a more complete Brachiosaurus specimen: one with both a skull and good postcervical elements that let us refer it definitively to Brachiosaurus altithorax by comparison with the holotype. And heck, while we’re at it, let’s have a specimen with a good neck, too!

The real question remains: how did Marsh, using a brachiosaur skull as his basis, come up with this?

Marsh1891-plateXVI-Apatosaurus-skull-UNREVERSED

 

And stranger still, how someone at the Yale Peabody Museum — we don’t know who — used it, or more likely Marsh’s reconstruction, as a basis for this sculpture:

IMG_0517

 

The Yale mount didn’t go up until 1931 — the last of the Big Four Apatosaurus mounts after the AMNH, Carnegie and Field Museum, which is surprising as it was the first of those specimens to be found. So by the time the skull was sculpted, sauropod skulls were actually reasonably well known. It’s not clear quite how anyone working from a decent reconstruction of, say, a Camarasaurus skull — the one in Osborn and Mook (1921:figure 30), say — could come up with this monster.

The last thing to say is this: it does credit to the YPM that they display this historically important sculpture rather than hiding it away and pretending it never happened. For me, part of the fascination of palaeontology is seeing not just how organisms evolved through prehistory but how ideas evolved through history. It’s great that we can still see important mistakes, alongside their corrections (i.e. the new and lovely skull on the YPM Apatosaurus mount.)

 

References

  • Carpenter, Kenneth, and Virginia Tidwell. 1998. Preliminary description of a Brachiosaurus skull from Felch Quarry 1, Garden Park, Colorado. Modern Geology 23:69-84.
  • Holland, William J. 1915. Heads and tails: a few notes relating to the structure of the sauropod dinosaurs. Annals of the Carnegie Museum 9:273-278.
  • Janensch, Werner. 1914. Ubersicht uber der Wirbeltierfauna der Tendaguru-Schichten nebst einer kurzen Charakterisierung der neu aufgefuhrten Arten von Sauropoden. Archiv fur Biontologie, Berlin III, 1(1):81-110.
  • Marsh, O. C. 1891. Restoration of Triceratops (with plates XV and XVI). American Journal of Science, 3rd series 41(244):339-342.
  • McIntosh, John S., and David, S. Berman. 1975. Description of the palate and lower jaw of the sauropod dinosaur Diplodocus (Reptilia: Saurischia) with remarks on the nature of the skull of Apatosaurus. Journal of Paleontology 49(1):187-199.
  • Osborn, Henry Fairfield, and Charles C. Mook. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3:247-387, and plates LX-LXXXV.
  • Riggs, Elmer S. 1903. Brachiosaurus altithorax, the largest known dinosaur. American Journal of Science 15(4):299-306.
  • Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806.

 

Last night, I submitted a paper for publication — for the first time since April 2013. I’d almost forgotten what it felt like. But, because we’re living in the Shiny Digital Future, you don’t have to wait till it’s been through review and formal publication to read it. I submitted to PeerJ, and at the same time, made it available as a preprint (Taylor 2014).

It’s called “Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs”, and frankly the results are weird. Here’s a taste:

Taylor (2014:figure 3). Effect of adding cartilage to the neutral pose of the neck of Apatosaurus louisae CM 3018. Images of vertebra from Gilmore (1936:plate XXIV). At the bottom, the vertebrae are composed in a horizontal posture. Superimposed, the same vertebrae are shown inclined by the additional extension angles indicated in Table 1. If the slightly sub-horizontal osteological neutral pose of Stevens and Parrish (1999) is correct, then the cartilaginous neutral pose would be correspondingly slightly lower than depicted here, but still much closer to the elevated posture than to horizontal. (Note that the posture shown here would not have been the habitual posture in life: see discussion.)

Taylor (2014:figure 3). Effect of adding cartilage to the neutral pose of the neck of Apatosaurus louisae CM 3018. Images of vertebra from Gilmore (1936:plate XXIV). At the bottom, the vertebrae are composed in a horizontal posture. Superimposed, the same vertebrae are shown inclined by the additional extension angles indicated in Table 1. If the slightly sub-horizontal osteological neutral pose of Stevens and Parrish (1999) is correct, then the cartilaginous neutral pose would be correspondingly slightly lower than depicted here, but still much closer to the elevated posture than to horizontal. (Note that the posture shown here would not have been the habitual posture in life: see discussion.)

A year back, as I was composing a blog-post about our neck-cartilage paper in PLOS ONE (Taylor and Wedel 2013c), I found myself writing down the rather trivial formula for the additional angle of extension at an intervertebral joint once the cartilage is taken into account. In that post, I finished with the promise “I guess that will have to go in a followup now”. Amazingly it’s taken me a year to get that one-pager written and submitted. (Although in the usual way of things, the manuscript ended up being 13 pages long.)

To summarise the main point of the paper: when you insert cartilage of thickness t between two vertebrae whose zygapophyses articulate at height h above the centra, the more anterior vertebra is forced upwards by t/h radians. Our best guess for how much cartilage is between the adjacent vertebrae in an Apatosaurus neck is about 10% of centrum length: the image above shows the effect of inserting that much cartilage at each joint.

And yes, it’s weird. But it’s where the data leads me, so I think it would be dishonest not to publish it.

I’ll be interested to see what the reviewers make of this. You are all of course welcome to leave comments on the preprint itself; but because this is going through conventional peer-review straight away (unlike our Barosaurus preprint), there’s no need to offer the kind of detailed and comprehensive comment that several people did with the previous one. Of course feel free if you wish, but I’m not depending on it.

References

Gilmore Charles W. 1936. Osteology of Apatosaurus, with special reference to specimens in the Carnegie Museum. Memoirs of the Carnegie Museum 11:175–300 and plates XXI–XXXIV.

Stevens, Kent A., and J. Michael Parrish. 1999. Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284(5415):798–800. doi:10.1126/science.284.5415.798

Taylor, Michael P. 2014. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs. PeerJ PrePrints 2:e588v1 doi:10.7287/peerj.preprints.588v1

Taylor, Michael P., and Mathew J. Wedel. 2013c. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs. PLOS ONE 8(10):e78214. 17 pages. doi:10.1371/journal.pone.0078214

Actually we had the Jurassic talks today, but I can’t show you any of the slides*, so instead you’re getting some brief, sauropod-centric highlighs from the museum.

* I had originally written that the technical content of the talks is embargoed, but that’s not true–as ReBecca Hunt-Foster pointed out in a comment, the conference guidebook with all of the abstracts is freely available online here.

IMG_5136

Like this Camarasaurus that greets visitors at the entrance.

IMG_5143

And this Apatosaurus ilium ischium with bite marks on the distal end, indicating that a big Morrison theropod literally ate the butt of this dead apatosaur. Gnaw, dude, just gnaw.

IMG_5147

And the shrine to Elmer S. Riggs.

IMG_5191

One of Elmer’s field assistants apparently napping next to the humerus of the Brachiosaurus alithorax holotype. This may be the earliest photographic evidence of someone “pulling a Jensen“.

Cary and Matt with Brachiosaurus forelimb

Here’s the reconstructed forelimb of B. altithorax, with Cary Woodruff and me for scale. The humerus and coracoid (and maybe the sternal?) are cast from the B.a. holotype, the rest of the bits are either sculpted or filled in from Giraffatitan. The scap is very obviously Giraffatitan.

Matt with MWC Apatosaurus femur

Cary took this photo of me playing with a fiberglass 100% original bone Apatosaurus femur upstairs in the museum office, and he totally passed up the opportunity to push me down the stairs afterward. I kid, I kid–actually Cary and I get along just fine. It’s no secret that we disagree about some things, but we do so respectfully. Each of us expects to be vindicated by better data in the future, but there’s no reason we can’t hang out and jaw about sauropods in the meantime.

Finally, in the museum gift shop (which is quite lovely), I found this:

Dammit Nova

You had one job, Nova. ONE JOB!

So, this is a grossly inadequate post that barely scratches the surface of the flarkjillion or so cool exhibits at the museum. I only got about halfway through the sauropods, fer cryin’ out loud. If you ever get a chance to come, do it–you won’t be disappointed.

How can it be?

IMG_0517

All credit to the Yale Peabody Museum for having the courage to display this historically important object in their public gallery instead of hiding it in a basement. It’s the skull from the original mount of the Brontosaurus (= Apatosaurus) excelsus holotype YPM 1980.

Needless to say, it bears no resemblance at all to the actual skull of Apatosaurus, and the one they now have on the mount is much, much better:

IMG_0500-skull

But how did the YPM people ever arrive at this double-plus-ugly skull above? We see a similar skull in Marsh’s (1891) second attempt at restoring the skeleton of Brontosaurus:

Marsh1891-plateXVI-Apatosaurus-skull

But even this is not as ugly and Just Plain Wrong as the physical model they made. (Marsh’s first restoration of the Brontosaurus skeleton, in 1893, had a much less clear skull.)

So how did the YPM come to make such a monstrosity? What was it based on? Tune in next time for the surprising details!

Bizarrely, we’ve never really featured the  YPM 1980 mount here on SV-POW! — we’ve often shown individual bones, but the mounted skeleton appears only in the background of the much less impressive Morosaurus (= Camarasaurus) lentus mount. We’ll fix that real soon.

 

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