The “finger-like” parapostzygapophyseal processes of Qijianglong
January 29, 2015
There’s a new mamenchisaurid in town! It’s called Qijianglong (“dragon of Qijiang”), and it’s the work of Xing et al. (2015).
Life restoration of Qijianglong, by Cheung Chungtat.
As far as I can make out, the life restoration is also due to Xing Lida: at least, every instance of the picture I’ve seen says “Credit: Xing Lida”. If that’s right, it’s an amazing display of dual expertise to produce both the science and the art! We could quibble with details, but it’s a hundred times better than I could ever do. [Update: no, it’s by Cheung Chungtat, but being uniformly mis-attributed in the media. Thanks to Kevin for the correction in the comment below.]
There’s a mounted skeleton of this new beast in the museum local to where it was found, though I don’t know how much of the material is real, or cast from the real material. Here it is:
A reconstructed skeleton of Qijianglong now on display in Qijiang Museum
A new sauropod is always great news, of course, and it’s a source of shame to us that we cover so few of them here on SV-POW!. (Just think of some of the ones we’ve missed recently … Leikupal, for example.)
But as is so often the case, the most interesting thing about this new member of the club is its vertebrae — specifically the cervicals. Here they are:
Xing et al. (2015), 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.
(At first, I couldn’t figure out what this pocdl abbreviation meant. Then I realised it was a vanilla posterior centrodiapophyseal lamina. Come on, folks. That element has had a standard abbreviation since 1999. Let’s use our standards!)
The hot news in these cervicals is the presence of what the authors call “a distinct finger-like process extending from the postzygapophyseal process beside a zygapophyseal contact”. They don’t give a name to these things, but I’m going to call them parapostzygapophyses since they’re next to the postzygapophyses. [Update: see the comment from Matt below.]
You can get some sense of this morphology from the figure above — although it doesn’t help that we’re looking at tiny greyscale images which really don’t convey 3d structure at all. The best illustration is part J of the figure:
What are these things? The paper itself says disappointingly little about them. I quote from page 9:
From the axis to at least the 14th cervical vertebra, a finger- like process extends posteriorly above the postzygapophysis and overlaps onto the dorsolateral surface of the prezygapophysis of the next vertebra (Fig. 11I, J). These processes are unique to Qijianglong, unlike all previously known mamenchisaurids that are preserved with cervical vertebrae (e.g., Chuanjiesaurus, Mamenchisaurus spp., Omeisaurus spp., Tonganosaurus). Therefore, the neck of Qijianglong presumably had a range of motion restricted in sideways.
That’s it.
So what are these things? The authors — who after all have seen the actual fossils, not just the rather inadequate pictures — seem to assume that they are a stiffening adaptation, but don’t discuss their reasoning. My guess — and it’s only a guess — it that they assumed that this is what was going on with these processes because it’s what people have assumed about extra processes on xenarthrous vertebrae. But as best as I can determine, that’s not been demonstrated either, only assumed. Funny how these things seem to get a pass.
Armadillo lumbar vertebrae in posterior, anterior and right lateral views.
So what are these processes? It’s hard to say for sure without having seen the fossils, or at least some better multi-view photos, but the obvious guess is that they are our old friends epipophyses, in extreme form. That is, they are probably enlarged attachment points for posteriorly directed dorsal muscles, just as the cervical ribs are attachment points for posteriorly directly ventral muscles.
It’s a shame that Xing et al. didn’t discuss this (and not only because it would probably have meant citing our paper!) Their new beast seems to have some genuinely new and interesting morphology which is worthy of a bit more attention than they gave it, and whose mechanical implications could have been discussed in more detail. Until more is written about these fossils (or better photographs published) I think I am going to have to suspend judgement on the as-yet unjustified assumption that the parapostzygs were there to make the neck rigid against transverse bending.
A final thought: doesn’t JVP seem terribly old-fashioned now? It’s not just the paywall — apologies to those many of you who won’t be able to read the paper. The greyscaling of the figures is part of it — something that makes no sense at all in 2015. The small size and number of the illustrations is also a consequence of the limited page-count of a printed journal — it compares poorly with, for example, the glorious high-resolution colour multiview illustrations in Farke et al.’s (2013) hadrosaur description in PeerJ. Seems to me that, these days, all the action is over at the OA journals with infinite space — at least when it comes to descriptive papers.
References
- Farke, Andrew A., Derek J. Chok, Annisa Herrero, Brandon Scolieri and Sarah Werning. (2013) Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids. PeerJ 1:e182. doi:10.7717/peerj.182
- Xing Lida, Tetsuto Miyashita, Jianping Zhang, Daqing Li, Yong Ye, Toru Sekiya, Fengping Wang & Philip J. Currie. 2015. A new sauropod dinosaur from the Late Jurassic of China and the diversity, distribution, and relationships of mamenchisaurids. Journal of Vertebrate Paleontology. doi:10.1080/02724634.2014.889701
Sideshow Apatosaurus sans background
January 23, 2015
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.
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.
What have you done with Aquilops!?
January 16, 2015
Awesome things, that’s what. In a previous post I asked people to make cool things with Aquilops. And you have. In spades. Here’s a compilation of the best things so far.
First, a blast from the past. As far as I know, the first life restoration of Aquilops was actually this sketch by Mike Keesey, which he executed while sitting in the audience for Andy Farke’s talk on our not-yet-named ceratopsian at SVP 2013. Mike kindly sat on it for over a year, and then posted it to his Flickr stream after the paper came out last month. A small adventure ensued – a site called News Maine (which I refuse to link to) used Mike’s image without his knowledge or permission in their Aquilops article. When he wrote to them and pointed out their breach, they swapped his image for one of Brian Engh’s, but still did not provide an image credit! Now their Aquilops article appears to have been taken down entirely. Good riddance.
Mike says of his Aquilops, “I’d like to make it clear that it was done from looking at a slide during a talk and not meant to be rigorous or accurate.” But I dig it (and I did get his permission to repost it!). It has character – it looks weary, maybe a little grumpy, like a pint-size curmudgeon. And it definitely wants you kids to get off its damn lawn. If you want to see more of Mike’s sketches in this style from SVP 2013 – and you should, they’re very good – go here.
Dinosaur skull or starfighter? You decide!
Second, people have taken the paper skull I posted before and used it as the raw material for significantly more awesome versions. Gareth Monger made the more-fully-3D version shown here, and posted about it at his Pteroformer blog. I think it’s totally wicked, and I’d make my own if I had the patience and skill.
But I don’t. Fortunately, there is help for me: Kathy Sanders, the Director of Outreach at the Raymond M. Alf Museum here in Claremont (where Aquilops lead author Andy Farke is based), took my skull drawings and turned them into a papercraft finger puppet suitable for all ages. I know it’s suitable for all ages because at the Alf Museum’s Family Science Discovery Day last Saturday, almost every one of many children going through the museum had an Aquilops puppet on one hand. London and I each made one, and we spent a lot of time Saturday evening goofing off with them.
Alas, poor Aquilops! I knew him, readers; a fellow of minuscule crest, of most excellent beak; he hath borne my career on his head a whole month; and now, how adored in my imagination he is!
You can see a little video of the puppet in action on Ashley Hall’s Tumblr, Lady Naturalist. And you can get the files to make your own from the Alf Museum website, here. You’ll also need a couple of brads to make the jaw hinge joints, and a smaller-than-normal hole punch is handy for making the holes, but ultimately any method that produces a small, round hole will work.
Heads not enough for you? Want a complete Aquilops to call your own? You are in luck – not one but two such critters have emerged from the virtual undergrowth. James Appleby, a 16-year-old who blogs at Edaphosaurus.com, did something that would not have occurred to me in a million years: he took the baby Aquilops (Aquilopses?) from Brian Engh’s awesomely detailed Cloverly environment scene and made a paper model. It’s a great example of how releasing something under an open license – in this case CC-BY – encourages people to do cool new things with your work. You can get the parts here.
Want something cuter? Try this papercraft Aquilops toy, another creation of the apparently indefatigable Gareth Monger. Post and parts here. I love Gareth’s concluding exhortation: “Edit it, share it, distribute it. Keep it fun and keep it free.” That’s practically the Aquilops motto.
I’m probably just scratching the surface here. I know there has been a flowering of awesome Aquilops restorations on DeviantART. David Orr has an adorkable ‘Pixel Aquilops‘ t-shirt on Redbubble. Tell me what else is out there, and keep making new stuff. Let’s keep this thing rolling.
And a big thank you to Mike, Gareth, Kathy, Ashley, and James for making cool Aquilops stuff and posting it for people to see and build. You all rock.
*yawn*
Sauropod Vertebra Picture of the Week 