Long-time SV-POW! readers will remember that three years ago, full of enthusiasm after speaking about Barosaurus at the Edinburgh SVPCA, Matt and I got that talk written up in double-quick time and had it published as a PeerJ Preprint in less than three weeks. Very quickly, the preprint attracted substantive, helpful reviews: three within the first 24 hours, and several more in the next few days.

This was great: it gave us the opportunity to handle those review comments and get the manuscript turned around into an already-reviewed formal journal submission in less then a month from the original talk.

So of course what we did instead was: nothing. For three years.

I can’t excuse that. I can’t even explain it. It’s not as though we’ve spent those three years churning out a torrent of other awesome papers. We’ve both just been … a bit lame.

Anyway, here’s a story that will be hauntingly familiar. A month ago, full of enthusiasm after speaking about Barosaurus at the Liverpool SVPCA, Matt and I found ourselves keen to write up that talk in double-quick time. It’s an exciting tale of new specimens, reinterpretation of an important old specimen, and a neck eight times as long as that 0f a world-record giraffe.

But it would be crazy to write the new Barosaurus paper without first having dealt with the old Barosaurus paper. So now, finally, three years on, we’ve done that. Version 2 of the preprint is now available (Taylor and Wedel 2016), incorporating all the fine suggestions of the people who reviewed the first version — and with a slightly spiffed-up title. What’s more, the new version has also been submitted for formal peer-review. (In retrospect, I can’t think why we didn’t do that when we put the first preprint up.)

Taylor and Wedel 2016: Figure 3. Barosaurus lentus holotype YPM 429, vertebra R, C?15. Top row: dorsal view; middle row, left to right: posterior, right lateral and anterior views; bottom row: ventral view, from Lull (1919: plate II). Note the apparently very low, undivided neural spine at the intersection of the PRSLs and POSLs, forward-shifted neural arch, broad prezygapophyses, broad, wing-like prezygadiapophyseal laminae, and great width across the diapophyses and across the parapophyses. Abbreviations: dia, diapophysis; para, parapophysis; prz, prezygapophysis; prdl, prezygadiapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar = 500 mm.

Taylor and Wedel 2016: Figure 3. Barosaurus lentus holotype YPM 429, vertebra R, C?15. Top row: dorsal view; middle row: posterior, right lateral and anterior views; bottom row: ventral view, from Lull (1919: plate II). Note the apparently very low, undivided neural spine at the intersection of the SPRLs and SPOLs, forward-shifted neural arch, broad prezygapophyses, broad, wing-like prezygadiapophyseal laminae, and great width across the diapophyses and across the parapophyses. Abbreviations: dia, diapophysis; para, parapophysis; prz, prezygapophysis; prdl, prezygadiapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar = 500 mm.

A big part of the purpose of this post is to thank Emanuel Tschopp, Mark Robinson, Andy Farke, John Foster and Mickey Mortimer for their reviews back in 2013. I know it’s overdue, but they are at least all acknowledged in the new version of the manuscript.

Now we cross our fingers, and hope that the formally solicited reviews for the new version of the manuscript are as helpful and constructive as the reviews in that first round. Once those reviews are in, we should be able to move quickly and painlessly to a formally published version of this paper. (I know, I know — I shouldn’t offer such a hostage to fortune.)

Meanwhile, I will finally be working on handling the reviews of this other PeerJ submission, which I received back in October last year. Yes, I have been lax; but I am back in the saddle now.

References

  • Taylor, Michael P., and Mathew J. Wedel. 2016. The neck of Barosaurus: longer, wider and weirder than those of Diplodocus and other diplodocines. PeerJ PrePrints 1:e67v2 doi:10.7287/peerj.preprints.67v2

UPDATE 19 May 2016

I belatedly realized that I caused some confusion in the original version of this post. This will hopefully sort things out:

NAMAL Barosaurus cervical with features labeled

The ventrolateral processes (1) are nothing new. As Ken Carpenter pointed out in a comment, Hatcher noted them back in 1901 in his monograph on Diplodocus carnegii. These are the features I describe below as being, “huge in Barosaurus, big in Diplodocus, small in Apatosaurus, and nonexistent in Haplocanthosaurus, Camarasaurus, and the brachiosaurids, at least from what I’ve seen.” To clarify: occasionally in camarasaurs and frequently in brachiosaurs you can trace a ridge along the ventrolateral margin of the centrum from the parapophysis to the cotyle. But these ridges are basically just the ‘corners’ of the centrum, leftover by the lateral and ventral waisting of the centrum – they do not project beyond the margin of the cotyle. In contrast, what I’ve been calling the ventrolateral flanges in diplodocids do project beyond the margins of the cotyle – they are additive structures, not just architectural leftovers. They also don’t vary much, other than to be more pronounced in more posterior cervicals.

The irregular ventral ridges (2) are a totally different thing. They’re on or near the sagittal midline of the centrum, usually restricted to the anteroposterior middle of the ventral centrum (so, about halfway between the condyle and the cotyle), and as my preferred term implies, highly variable among individuals and even among vertebrae in a series.

Hope that helps! (Original post starts below.)

– – – – – – – – – – – – – – – – – – – – –

2005-07-29 BYU 16918 Diplodocus left lateral

Back in 2005 I visited BYU while I was working on my dissertation. Back then I noted ventral ridges in a few diplodocine cervical vertebrae. (I hesitate to call such flimsy things ‘keels’.)

Up above is BYU 16918, a mid-to-posterior cervical vertebra of Diplodocus from the famous Dry Mesa Quarry. Here it is again in posterior view:

2005-07-29 BYU 16918 Diplodocus posterior view labeled

The things I have labeled VLF here are ventrolateral flanges, which are huge in Barosaurus, big in Diplodocus, small in Apatosaurus, and nonexistent in Haplocanthosaurus, Camarasaurus, and the brachiosaurids, at least from what I’ve seen. See this post for details. I know that the left VLF here looks like a second ridge, but the cotyle is broken off in such a way that we’re seeing the fossa just dorsal to the VLF margin. The ridge itself is skewed to the right, which could be natural or a result of taphonomy – as you can see from the photo at the top of the post, this vert has seen better days.

Here’s another Dry Mesa vert, BYU 11617, this time an anterior cervical of Barosaurus and in left lateral view:

2005-07-29 BYU 11617 Barosaurus left lateral

Again in right lateral view – on this side you can see the fossa in the VLF more clearly:

2005-07-29 BYU 11617 Barosaurus right lateral

And here’s the ventral view showing the ridge:

2005-07-29 BYU 11617 Barosaurus ventral view labeled

I noted these things in my notebook back when, filed them under, “Huh. How about that?” and went on with life.

Then last week Mike and I were at the North American Museum of Ancient Life in Lehi, Utah, and we saw this super-nice Barosaurus cervical on display in the prep lab (left ventro-lateral view). Check out the monster ventrolateral flanges, and the ridges between them at about mid-centrum.

IMG_4605

Here’s another view, a more square-on ventral this time:

IMG_4604

We owe a big thank you to Rick Hunter, who let us into the prep lab at the North American Museum of Ancient Life to see the Barosaurus material up close.

So what’s the deal with these ridges? I assume that they’re caused by pneumatic diverticula remodeling the ventral surface of the centrum. We know that such diverticula were down there because there are actual foramina on the ventral centrum in Supersaurus, many apatosaurines (Lovelace et al., 2008), many brachiosaurids, and probably loads of other things that haven’t been checked. Oddly enough, I’ve never seen the ridges in any of those other taxa. It seems that you get foramina or ridges, but not both. I have no idea what’s up with that – to paraphrase Neal Stephenson, Barosaurus cervicals are confections of air and marketing, and you’d think that if any sauropod would have straight-up foramina down there, it would be Barosaurus. But Barosaurus gets ridges and clunky old Apatosaurus gets foramina (sometimes, not all the time).

It’s a sick world, I tell you.

Reference

  • Lovelace, D. M., Hartman, S. A., & Wahl, W. R. (2007). Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional, Rio de Janeiro 65(4):527-544.

Wedel 2005 Morrison sauropod cervicals 1 - Diplodocus

When I was back in Oklahoma in March, I met with Anne Weil to see some of the new Apatosaurus material she’s getting out of her Homestead Quarry. It’s nice material, but that’s a post for another day. Anne said something that really resonated with me, which was, “I love it when you guys post about vertebral morphology, because it helps me learn this stuff.” Okay, Anne, message received. This will begin to make things right.

Wedel 2005 Morrison sauropod cervicals 2 - Barosaurus and centra shapes

I spent a week at BYU back in 2005, collecting data for my dissertation. One of the first things I had to do was teach myself how to identify the vertebrae of different sauropods, because BYU has just about all of the common Morrison taxa. These are the notes I made back then.

Wedel 2005 Morrison sauropod cervicals 3 - Brachiosaurus and Apatosaurus

I always planned to do something with them – clean them up, get them into a more usable form. There are a lot of scribbly asides that are probably hard for others to read, and it would be more useful if I put the easily confused taxa next to each other – Barosaurus next to Brachiosaurus, for example. And I didn’t go into serial changes at all.

Wedel 2005 Morrison sauropod cervicals 4 - Camarasaurus and Haplocanthosaurus

Still, hopefully someone will find these useful. If there are things I missed or got wrong, the comment thread is open. And if you want all four spreads in one convenient package, here’s a PDF: Wedel 2005 notes on Morrison sauropod cervicals

Mike and I leave for the Sauropocalypse tomorrow. I’m hoping to post at least a few pretty pictures from the road, as I did for the Mid-Mesozoic Field Conference two years ago. Stand by…

Utah Field House Diplodocus 1

Mounted Diplodocus at the Utah Field House of Natural History State Park Museum in Vernal.

I love Utah. I love how much of the state is given over to exposed Mesozoic rocks. I love driving through Utah, which has a strong baseline of beautiful scenery that is frequently punctuated by the absolutely mind-blowing (Arches, Bryce Canyon, Zion, Monument Valley…). I love doing fieldwork there, and I love the museums, of which there are many. It is not going too far to say that much of what I learned firsthand about sauropod morphology, I learned in Utah (the Carnegie Museum runs a close second on the dragging-Matt-out-of-ignorance scale).

DNM baby Camarasaurus

Cast of the juvenile Camarasaurus CM 11338 at Dinosaur National Monument.

There is no easy way to say this so I’m just going to get it over with: Mike has never been to Utah.

I know, right?

But we’re going to fix that. Mike’s flying into Salt Lake City this Wednesday, May 4, and I’m driving up from SoCal to meet him. After that we’re going to spend the next 10 days driving around Utah and western Colorado hitting museums and dinosaur sites. We’re calling it the Sauropocalypse.

UMNH Barosaurus mount

Mounted Barosaurus at the Natural History Museum of Utah in Salt Lake City.

Why am I telling you this, other than to inspire crippling jealousy?

First, Mike and I are giving a pair of public talks next Friday evening, May 6, at the USU-Eastern Prehistoric Museum in Price. The talks start at 7:00 and will probably run until 8:00 or shortly after, and there will be a reception with snacks afterward. Mike’s talk will be, “Why giraffes have such short necks”, and my own will be, “Why elephants are so small”.

Second, occasionally people leave comments to the effect of, “Hey, if you’re ever passing through X, give me a shout.” I haven’t kept track of all of those, so this is me doing the same thing in reverse. Here’s our itinerary as of right now:

May 4, Weds: MPT flies in. MJW drives up from Cali. Stay in SLC/Provo area.
May 5, Thurs: recon BYU collections in Provo. Stay in SLC/Provo area.
May 6, Fri: drive to Price, visit USU-Eastern Prehistoric Museum, give evening talks. Stay in Price.
May 7, Sat: drive to Vernal, visit DNM. Stay in Vernal.
May 8, Sun: visit Utah Field House, revisit DNM if needed, drive to Fruita.
May 9, Mon: visit Rabbit Valley camarasaur in AM, visit Dinosaur Journey museum in PM. Go on to Moab.
May 10, Tues: drive back to Provo, visit BYU collections.
May 11, Weds: BYU collections.
May 12, Thurs: drive to SLC to visit UMNH collections, stay for Utah Friends of Paleontology meeting that evening.
May 13, Fri: BYU collections.
May 14, Sat: visit North American Museum of Ancient Life. MPT flies home. MJW starts drive home.

We’re planning lots of time at BYU because we’ll need it, the quantity and quality of sauropod material they have there is ridiculous. As for the rest, some of those details may change on the fly but that’s the basic plan. Maybe we’ll see you out there.

IMG_5272

Brian Engh (bottom left, enthusing about the Ceratosaurus just off-screen) and I are recently returned to civilization after a stint of fieldwork in Utah. On the way home, we made a detour to Salt Lake to visit the new Natural History Museum of Utah.

IMG_5257

The NHMU is one of the nicest museums I’ve ever had the pleasure of roaming through. They have a ton of stuff on display, including lots of real fossils and quite a few touchable specimens, with an understandably heavy emphasis on Utah’s extensive paleontological record.

IMG_5261

The museum is also beautifully laid out – you can walk around almost all of the mounts and see most of them from multiple levels of elevation. The signage hits a new high for being both discreet and informative. Almost everything on display is clearly identified either as a cast or by specimen number (or maybe both), and the real specimens typically list both the discoverer and the preparator. I’ve never seen that before, and I like it a lot.

IMG_5290

I suppose I should say a few words about the Barosaurus mount. It’s pretty cool – you can get very close to it, walk all the way around the body, and – crucially for a true sauropod lover – count vertebrae. They gave it 16 cervicals and 9 dorsals, just as hypothesized by McIntosh (2005), and unlike the AMNH Barosaurus, which has the neck cheated out by one extra cervical.

On the left in the photo above is the famous wall of ceratopsian skulls. More about that next time.

Reference

McIntosh, J.S. 2005. The genus Barosaurus Marsh (Sauropoda, Diplodocidae); pp. 38-77 in Virginia Tidwell and Ken Carpenter (eds.), Thunder Lizards: the Sauropodomorph Dinosaurs. Indiana University Press, Bloomington, Indiana, 495 pp.

Peggy Sue's Diner-saurs - London with sauropod

A couple of weekends ago, London and I went camping and stargazing at Afton Canyon, a nice dark spot about 40 miles east of Barstow. On the way home, we took the exit off I-15 at Ghost Town Road, initially because we wanted to visit the old Calico Ghost Town. But then we saw big metal dinosaurs south of the highway, and that’s how we came to Peggy Sue’s Diner and in particular the Diner-saur Park.

Peggy Sue's Diner-saurs - spinosaur

The Diner-saur Park is out behind the diner and admission is free. There are pools with red-eared sliders, paved walkways, grass, trees, a small gift shop, and dinosaurs. Here’s a Spinosauruscuriously popular in the Mojave Desert, those spinosaurs.

Peggy Sue's Diner-saurs - stegosaur

Ornithischians are represented by two stegosaurs, this big metal one and a smaller concrete one under a tree.

Peggy Sue's Diner-saurs - turtles

The turtles are entertaining. They paddle around placidly and crawl out to bask on the banks of the pools, and on little islands in the centers.

Peggy Sue's Diner-saurs - sign

The gift shop is tiny and the selection of paleo paraphernalia is not going to blow away any hard-core dinophiles. But it is not without its charm. And, hey, when you find a dinosaur gift shop in the middle of nowhere, you don’t quibble about size. London got some little plastic turtles and I got some cheap and horribly inaccurate plastic dinosaur skeletons to make a NecroDinoMechaLaser Squad for our Dinosaur Island D&D campaign.

Now, about that sauropod. The identification sign on the side of the gift shop notwithstanding, this is not a Brachiosaurus. With the short forelimbs and big back end, this is clearly a diplodocid. The neck is too skinny for Apatosaurus or the newly-resurrected Brontosaurus, and too long for Diplodocus. I lean toward Barosaurus, although I noticed in going back through these photos that with the mostly-straight, roughly-45-degree-angle neck, it is doing a good impression of the Supersaurus from my 2012 dinosaur nerve paper. Compare this:

Peggy Sue's Diner-saurs - sauropod 1

to this:

Wedel RLN fig1 - revised

If I had noticed it sooner, I would have maneuvered for a better, more comparable shot.

Guess I’ll just have to go back.

Reference

Wedel, M.J. 2012. A monument of inefficiency: the presumed course of the recurrent laryngeal nerve in sauropod dinosaurs. Acta Palaeontologica Polonica 57(2):251-256.

Introduction and Background

2005-09-27 CM 555 c6 480

An epipophysis in a neural arch of a juvenile Apatosaurus, CM 555. From this post.

I have three goals with this post:

  1. To document the range of variation in epipophyses in the cervical vertebrae of sauropods.
  2. To show that the “finger-like processes” overhanging the cervical postzygapophyses in the newly described Qijianglong are not novel or mysterious structures, just very well developed epipophyses.
  3. Finally, to show that similar long, overhanging epipophyses are present in other mamenchisaurids, although as far as I can tell no-one has noted them previously.

Epipophyses are muscle attachment points dorsal to the postzygapophyses, for the insertion of long, multi-segment epaxial (dorsal) neck muscles in birds and other dinosaurs. I know that they turn up occasionally in non-dinosaurian archosaurs, and possibly in other amniotes, but for the purposes of this post I’m only considering their distribution in sauropods. For some quick background info on epipophyses and the muscles that attach to them, see the second half of this post, and see Wedel and Sanders (2002) and Taylor and Wedel (2013a) for further discussion and more pictures.

OMNH emu vert 480

Before we start with the pictures, a fiddly nomenclatural point: this muscle attachment point dorsal to the postzyg has traded under at least six names to date.

  1. The ‘Owenian’ term, used by virtually all non-avian theropod workers, by Sereno et al. (1999) for Jobaria, and probably by loads of other sauropod workers (including myself, lately) is epipophysis.
  2. Beddard (1898) referred to this feature in birds as the hyperapophysis; this term seems to have fallen completely out of use.
  3. Boas (1929), again referring to birds, called it the processus dorsalis. Zweers et al. (1987: page 138 and table 1) followed this terminology, which is how I learned of it when I was an undergrad at OU.
  4. Baumel and Witmer (1993) called this feature in birds the torus dorsalis (note 125 on page 87), which some authors have informalized to dorsal torus (e.g., Harris 2004: page 1243 and fig. 1). Baumel and Witmer (1993: page 87) note that, “the use of ‘Torus’ is preferable since it avoids confusion with the spinous [dorsal] process of the neural arch”.
  5. In my own early papers (e.g., Wedel et al. 2000b) and blog posts I called this feature the dorsal tubercle, which was my own attempt at an informal term matching ‘processus dorsalis’ or ‘torus dorsalis’. That was unfortunate, since there are already several other anatomical features in vertebrates that go by the same name, including the dorsal-facing bump on the dorsal arch of the atlas in many vertebrates, and a bump on the humerus in birds and some other taxa. In more recent papers (e.g., Taylor and Wedel 2013a) I’ve switched over to ‘epipophysis’.
  6. In the last post, Mike coined the term parapostzygapophysis for this feature in Qijianglong. [Note: he now regrets this.]

As usual, if you know of more terms for this feature, or additional history on the ones listed above, please let us know in the comments.

Now, on to the survey.

Prosauropods

Leonerasaurus_cervical_vertebrae - Pol et al 2011 fig 5

I haven’t seen very many prominent epipophyses in basal sauropodomorphs. Probably the best are these in the near-sauropod Leonerasaurus, which is very sauropod-like in other ways as well. Modifed from Pol et al. (2011: fig. 5).

This combination of photograph and interpretive drawing neatly shows why it’s often difficult to spot epipophyses in photos: unless you can make out the postzygapophyseal facet, which is often located more anteriorly than you might guess, you can’t tell when the epipophysis projects further posteriorly, as in the last of these vertebrae. In this case you can make it out, but only because the interpretive drawing shows the facet much more clearly than the photo.

Basal sauropods

Tazoudasaurus cervical - Allain and Aquesbi 2008 fig 9i-j

The most basal sauropod in which I have seen clear evidence of epipophyses is Tazoudasaurus. They’re not very apparent in lateral view, but in posterior view the epipophyses are clearly visible as bumps in the spinopostzygapophyeal laminae (SPOLs). Modified from Allain and Aquesbi (2008: fig. 9).

Jobaria epipophyes

In addition to Qijianglong, some other basal eusauropods have prominent epipophyses. Probably the best known is Jobaria; Sereno et al. (1999: fig. 3) figured and labeled the epipophysis in one of the cervical vertebrae. The vertebra image in that figure is tiny (nice work, glam-magz!), so here are some sketches of Jobaria mid-cervicals (from two different individuals) that I made back in the day when I was doing the research for Gary Staab’s Jobaria neck sculpture (see Sanders et al. 2000 for our SVP abstract about that project).

Turiasaurus also has prominent, overhanging epipophyses in at least some of its cervical vertebrae. You can just make one out as a tiny spike a few pixels long in Royo-Torres et al. (2006: fig. 1K). I have seen that cervical firsthand and I can confirm that the epipophyses in Turiasaurus are virtually identical to those in Jobaria.

Other mamenchisaurids

It’s not air-tight, but there is suggestive evidence of projecting epipophyses in some other mamenchisaurids besides Qijianglong.

Mamenchisaurus epipophyses - lateral view

If you’re really hardcore, you may remember that back in 2005, Mike got to go up on a lift at the Field Museum of Natural History to get acquainted with a cast skeleton of Mamenchisaurus hochuanensis that was mounted there temporarily. During that adventure he took some photos that seem to show projecting epipophyses in at least two of the mid-cervicals. At least, if they’re not epipophyses, I don’t know what they might be.

Mamenchisaurus epipophyses - medial view

Here they are again in medial view. My only reservation is that these vertebrae were distorted to begin with, and some features of the cast are very difficult to interpret. So, probably epipophyses, but it would be nice to check the original material at some point.

Mamenchisaurus youngi epipophyses

Something similar may be present in some posterior cervical vertebrae of Mamenchisaurus youngi. Here’s Figure 17 from Ouyang and Ye (2002). The “poz” label does not not seem to be pointing to the articular facet of the postzygapophysis, which looks to be a little more anterior and ventral, below the margin of the PODL. If that’s the case, then C15 has long, overhanging epipophyses like those of Jobaria. C16 has a more conservative bump, which is to be expected – the epipophyses typically disappear through the cervico-dorsal transition.

Omeisaurus epipophysis

Finally, here’s a cervical vertebra of Omeisaurus junghsiensis from Young (1939: fig. 2). I don’t want to hang very much on just a few pixels, but my best guess at the extent of the postzygapophyseal articular facet is shown in the interpretation above. If that’s correct, then this specimen of Omeisaurus had really long epipophyses, rivaling those of Qijianglong. Unfortunately that’s impossible to check, because this specimen has been lost (pers. comm. from Dave Hone, cited in Taylor and Wedel 2013).

Diplodocoidea

Haplocanthosaurus epipophyses - Hatcher 1903

Haplocanthosaurus nicely shows that the epipophyses can be large in terms of potential muscle attachment area without projecting beyond the posterior margins of the postzygapophyses. Here is C14 of H. priscus, CM 572, in posterior and lateral views, modified from Hatcher (1903: plate 1).

diplodocid epipophyses

Epipophyses that actually overhang the postzygapophyses are not common in Diplodocidae but they do occasionally occur. Here are prominent, spike-like epipophyses in Diplodocus (upper left, from Hatcher 1901: plate 3), Barosaurus (upper right), Kaatedocus (lower left, Tschopp and Mateus 2012: fig. 10), and Leinkupal (lower right, Gallina et al. 2014: fig. 1).

NIgersaurus cervical - Sereno et al 2007 fig 3

Of course, the champion epiphysis-bearer among diplodocoids is the weird little rebbachisaurid Nigersaurus. Here’s a Nigersaurus mid-cervical, from Sereno et al. (2007: fig. 3). Note that the projecting portions of the epipophysis is roughly as long as the articular surface of the postzygapophysis.

Macronaria

Australodocus epipophysis

The epipophysis in this cervical of Australodocus just barely projects beyond the posterior margin of the postzygapophysis.

Giraffatitan c8 epipophyses

In Giraffatitan, epipophyses are absent or small in anterior cervicals but they are prominent in C6-C8. Here’s a posterolateral view of C8, showing very large epipophyses that are elevated several centimeters above the postzygapophyses. You can also see clearly in this view that the spinopostzygapophyseal lamina (SPOL) and postzygodiapophyseal lamina (PODL) converge at the epipophysis, not the postzygapophysis itself.

Sauroposeidon epipophyses

The holotype of Sauroposeidon, OMNH 53062, is similar to Giraffatitan in that the two anterior cervical vertebrae (possibly C5 and C6) have no visible epipophyses, but epipophyses are prominent in the two more posterior vertebrae (possibly C7 and C8). Click to enlarge – I traced the articular facet of the postzygapophysis in ?C8 to more clearly separate it from the epipophysis. For a high resolution photograph of that same vertebra that clearly shows the postzyg facet and the epipophysis dorsal to it, see this post.

Oddly enough, I’ve never seen prominent epipophyses in a titanosaur. In Malawisaurus, Trigonosaurus, Futalognkosaurus, Rapetosaurus, Alamosaurus, and Saltasaurus, the SPOLs (such as they are – inflated-looking titanosaur cervicals do not have the same crisply-defined laminae seen in most other sauropods) merge into the postzygapophyseal rami and there are no bumps sticking up above or out beyond the articular facets of the postzygs. I don’t know what to make of that, except to note that several of the animals just mentioned have mediolaterally wide, almost balloon-shaped cervical neural spines. In our 2013 PeerJ paper, Mike and I argued that the combination of tall neural spines and tall epipophyses in the cervical vertebrae of sauropods made them functionally intermediate between crocs (huge neural spines, no epipophyses) and birds (small or nearly nonexistent neural spines, big epipophyses). Perhaps most titanosaurs reverted to a more croc-like arrangement with most of the long epaxial neck muscles inserting on the neural spine instead of the postzygapophyseal ramus. I’ve never seen that possibility discussed anywhere, nor the apparent absence of epipophyses in most titanosaurs. As usual, if you know otherwise, please let me know in the comments!

malawisaurus-cervicals

Cervical vertebrae of Malawisaurus from Gomani (2005: fig. 9): not an epipophysis in sight. But check out the spike-like neural spines – these are so wide from side to side that from the front they look like party balloons.

And as long as we’re discussing the phylogenetic distribution of epipophyses, it is interesting that long, overhanging epipophyses are so broadly but sporadically distributed. They turn up in some non-neosauropods (Jobaria, Turiasaurus, Omeisaurus) and some diplodocoids (Nigersaurus, the occasional vertebra in Diplodocus and Leinkupal), but not in all members of either assemblage, and they seem to be absent in Macronaria (although many non-titanosaurs have shorter epipophyses that don’t overhang the postzygs). I strongly suspect that a lot of this is actually individual variation that we’re not perceiving as such because our sample sizes of almost all sauropods are tiny, usually just one individual. Epipophyses are definitely muscle attachment sites in birds and no better hypothesis has been advanced to explain their presence in other archosaurs. Muscle attachment scars are notoriously variable in terms of their relative development and expression among individuals, and it would be odd if epipophyses were somehow exempt from that inherent variability.

It also seems more than likely that ontogeny plays a role: progressive ossification of tendons attached at the epipophyses would have the effect of elongating the preserved projection. And since for some aspects of sauropod vertebral morphology, serial position recapitulates ontogeny (Wedel and Taylor 2013b), it shouldn’t be surprising that we see differences in the prominence of the epipophyses along the neck.

Back to Qijianglong

By now it should be clear that the “finger-like processes” in Qijianglong are indeed epipophyses, and although they are quite long, they aren’t fundamentally different from what we see in many other sauropods. I haven’t gone to the trouble, but one could line up all of the vertebrae figured above in terms of epipophysis size or length, and Qijianglong would sit comfortably at one end with Omeisaurus and Mamenchisaurus, just beyond Nigersaurus and Jobaria.

FIGURE 11. Anterior cervical series of Qijianglong guokr (QJGPM 1001) in left lateral views unless otherwise noted. A, axis; B, cervical vertebra 3; C, cervical vertebra 4; D, cervical vertebrae 5 and 6; E, cervical vertebra 7 and anterior half of cervical vertebra 8 (horizontally inverted; showing right side); F, posterior half of cervical vertebra 8 and cervical vertebra 9; G, cervical vertebra 10; H, cervical vertebra 11; I, close-up of the prezygapophy- sis-postzygapophysis contact between cervical vertebrae 3 and 4 in dorsolateral view, showing finger-like process lateral to postzygapophysis; J, close- up of the postzygapophysis of cervical vertebra 5 in dorsal view, showing finger-like process lateral to postzygapophysis. Arrow with number indicates a character diagnostic to this taxon (number refers to the list of characters in the Diagnosis). All scale bars equal 5 cm. Abbreviations: acdl, anterior centrodiapophyseal lamina; cdf, centrodiapophyseal fossa; plc, pleurocoel; pocdl, postcentrodiapophyseal lamina; poz, postzygapophysis; pozcdf, post- zygapophyseal centrodiapophyseal fossa; pozdl, postzygodiapophyseal lamina; ppoz, finger-like process lateral to postzygapophysis; ppozc, groove for contact with finger-like process; przdl, prezygodiapophyseal lamina; sdf, spinodiapophyseal fossa.

Cervical vertebrae of Qijianglong (Xing et al. 2015: fig. 11)

The strangest thing about the epipophyses in Qijianglong is that they seem to be bent or broken downward in two of the vertebrae (B and H in the figure above). I assume that’s just taphonomic distortion – the cervical shown in H wouldn’t even be able to articulate with the vertebra behind it if the epipophysis really drooped down like that. The epipophyses in Qijianglong seem to mostly manifest as thin spikes of bone (or maybe plates, as shown in B and I), so it’s not surprising that they would get distorted – most of the vertebrae shown above have cervical ribs that are incomplete or missing as well.

One more noodle-y thought about big epipophyses. I wrote in the last section that I’ve never seen them in titanosaurs, possibly because titanosaurs have big neural spines for their epaxial muscles to attach to. Maybe long, overhanging epipophyses are so common in mamenchisaurids because their neural spines are so small and low. Although we tend to think of them as a basal group somewhat removed from the “big show” in sauropod evolution – the neosauropods – mamenchisaurids did a lot of weird stuff. At least in terms of their neck muscles, they may have been the most birdlike of all sauropods. Food for thought.

References

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Previous posts in this series are here.

Today (12th February) is the one-year anniversary of the first PeerJ papers! As Matt put it in an email this morning:

Hard to believe it’s been a year already. On the other hand, it’s also hard to believe that it’s only been a year. PeerJ is just such an established part of my worldview now.

That’s exactly right. PeerJ has so completely rewritten the rule-book (on price, speed and quality of service) that now when I’m thinking about new papers I’m going to write, the question I ask myself is no longer “Where shall I send this?” but “Is there any reason not to send it to PeerJ?”

dorsals-ab-composite

Dorsals A and B (probably D8 and D9) of NHM R5937, “The Archbishop”, a still-undescribed brachiosaurid sauropod from the Upper Jurassic Tendaguru Formation of Tanzania, which I will get done this year, and which is destined for PeerJ. Top row: dorsal view with anterior to the right. Bottom row, from left to right: left lateral, posterior, right lateral, anterior.

Yesterday in the comments of a post on The Scholarly Kitchen, Harvey Kane asked me “I am curious as to where you get the notion that publishing OA is less expensive and in some way “better” than the traditional model?” My reply was (in part):

My notion that OA publishing yields better results than traditional is rooted in the online-only nature of articles, which allows them to ignore arbitrary limits on word-count, number of figures, use of colour, etc., and to exploit online-only formats such as video, 3d models, CT-slice stacks, etc. In my own field of vertebrate palaeontology, it’s now routine to see in PLOS ONE descriptive articles that are many times more comprehensive than their equivalents in traditional journals — see for example the recent description of the frog Beelzebufo.

Of course there is nothing specific to open-access about this: there is no technical reason why an online-only subscription journal shouldn’t publish similarly detailed articles. But my experience so far has been that they don’t — perhaps because they are tied to the mindset that pages and illustrations are limited resources.

For Beelzebufo in PLOS ONE, read baby Parasaurolophus in PeerJ, which we described as “the world’s most open-access dinosaur“. This paper is 83 pages of technicolour goodness, plus all the 3d models you can eat. And the crazy thing is, this sort of detail in descriptive papers is not even exceptional any more — see for example the recent description of Canardia in PLOS ONE, or this analysis of croc respiration in PeerJ

Years ago, I said that in the Archbishop descriptions I wanted to raise the bar for quality of illustration. Well, I’ve taken so long over getting the Archbishop done that the bar has been raised, and now I’m scrambling to catch up. Certainly the illustrations even in our 2011 description of Brontomerus are starting to look a bit old-fashioned.

And of course, the truly astonishing thing about PeerJ is that it does this so very cheaply. Because I’m already a member (which cost me $99), the Archbishop description is going to be free to me to publish this year. (This year for sure!) If we also get our Barosaurus neck preprint published properly this year,then I’ll have to find $100 to upgrade my Basic membership to Enhanced. That’s cheap enough that it’s not even worth going through the hassle of trying to get Bristol to pay for me. And if I ever hit a year when I publish three or more papers, I’ll upgrade once more (for another $100) to the Investigator plan and then that’s it: I’m done paying PeerJ forever, however many papers I publish there. (Matt jumped straight to the all-you-can-eat plan, so he wouldn’t even have to think about it ever again.)

Barosaurus lentus holotype YPM 429, Vertebra Q (C?13). Top row: left ventrolateral view. Middle row, from left to right: anterior view, with ventral to the right; ventral view; posterior view, with ventral to the left. Bottom row: right lateral view, inverted. Inset shows diapophyseal facet on right side of vertebra, indicating that the cervical ribs were unfused in this individual despite its great size. Note the broad, flat prezygapophyseal facet visible in anterior view. (Taylor and Wedel 2013b: figure 6)


Barosaurus lentus holotype YPM 429, Vertebra Q (C?13). Top row: left ventrolateral view. Middle row, from left to right: anterior view, with ventral to the right; ventral view; posterior view, with ventral to the left. Bottom row: right lateral view, inverted. Inset shows diapophyseal facet on right side of vertebra, indicating that the cervical ribs were unfused in this individual despite its great size. Note the broad, flat prezygapophyseal facet visible in anterior view. (Taylor and Wedel 2013b: figure 6)

PeerJ’s pricing is making PLOS ONE’s $1350 APC look distinctly old-fashioned; and the $3000 charged by the legacy publishers (for a distinctly inferior product) is now frankly embarrassing. You might expect that as such low prices, PeerJ’s quality of service would suffer, but that’s not been our experience: editing, reviewing, typesetting and proofing for our neck-anatomy paper were all up there with the best we’ve received anywhere.

And it’s great to see that it’s not just minor researchers like Matt and me who are persuaded by PeerJ: they’ve now accumulated a frankly stellar list of 20 universities (so far) with institutional plans for researchers to publish there. When I say “stellar” I mean that the list includes Harvard, MIT, Cambridge, Berkeley, Stanford, Johns Hopkins, UCL, Carnegie Mellon, Duke … the list goes on.

We can only hope that the next year, and the next ten and twenty, are as successful for PeerJ as the first has been; and that other New Generation publishers will join it in pushing the field forward.

I leave the last word to Matt:

I’m getting Vicki a lifetime membership for Valentine’s Day. Because I’m a romantic.

She’s a lucky, lucky woman.

Yesterday I announced that our new paper on Barosaurus was up as a PeerJ preprint and invited feedback.

I woke up this morning to find its third substantial review waiting for me.

That means that this paper has now accumulated as much useful feedback in the twenty-seven hours since I submitted it as any previous submission I’ve ever made.

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Taylor and Wedel (2013b: figure 7). Barosaurus lentus holotype YPM 429, Vertebra S (C?12). Left column from top to bottom: dorsal, right lateral and ventral views; right column: anterior view. Inset shows displaced fragment of broken prezygapophysis. Note the narrow span across the parapophyses in ventral view, and the lack of damage to the ventral surface of the centrum which would indicate transverse crushing.

It’s worth reviewing the timeline here:

  • Monday 23rd September, 1:19 am: I completed the submission process.
  • 7:03 am: the preprint was published. It took less than six hours.
  • 10:52 am: received a careful, detailed review from Emanuel Tschopp. It took less than four hours from publication, and so of course less than ten from submission.
  • About 5:00 pm: received a second review, this one from Mark Robinson. (I don’t know the exact time because PeerJ’s page doesn’t show an actual timestamp, just “21 hours ago”.)
  • Tuesday 24th September, about 4:00 am: received a third review, this from ceratopsian-jockey and open-science guru Andy Farke.

Total time from submission to receiving three substantial reviews: about 27 hours.

It’s worth contrasting that with the times taken to get from submission to the receipt of reviews — usually only two of them — when going through the traditional journal route. Here are a few of mine:

  • Diplodocoid phylogenetic nomenclature at the Journal of Paleontology, 2004-5 (the first reviews I ever received): three months and 14 days.
  • Revised version of the same paper at PaleoBios, 2005 (my first published paper): one month and 10 days.
  • Xenoposeidon description at Palaeontology, 2006: three months and 19 days, although that included a delay as the handling editor sent it to a third, tie-breaking, reviewer.
  • Brachiosaurus revision at the Journal of Vertebrate Paleontology, 2008: one month and 11 days.
  • Sauropod neck anatomy (eventually to be published in a very different form in PeerJ) at Paleobiologyfive months and two days.
  • Trivial correction to the Brachiosaurus revision at the Journal of Vertebrate Paleontology, 2010: five months and 11 days, bizarrely for a half-page paper.

Despite the wide variations in submission-to-review time at these journals, it’s clear that you can expect to wait at least a month before getting any feedback at all on your submission at traditional journals. Even PeerJ took 19 days to get the reviews of our neck-anatomy paper back to us.

So I am now pretty such sold on the pre-printing route. As well as getting this early version of the paper out there early so that other palaeontologists can benefit from it (and so that we can’t be pre-emptively plagiarised), issuing a preprint has meant that we’ve got really useful feedback very quickly.

I highly recommend this route.

By the way, in case anyone’s wondering, PeerJ Preprints is not only for manuscripts that are destined for PeerJ proper. They’re perfectly happy for you to use their service as a place to gather feedback for your work before submitting it elsewhere. So even if your work is destined for, say, JVP, there’s a lot to be gained by preprinting it first.