Sauropods stomping theropods, redux
April 6, 2011
A month ago, I posted an article containing all the examples known to me of that sadly neglected palaeo-art theme, Sauropods Stomping Theropods: Mark Hallet’s Jobaria squishing Afrovenator, Luis Rey’s Astrodon biting/carrying a raptor, Mark Witton’s Camarasaurus grinding juvenile theropods to dust, and of course Francisco Gascó’s and Emily Willoughby’s Brontomerus pieces, both of them showing Bronto giving Utahraptor a good kicking.
I closed that article with a question and a challenge: had I missed any existing pieces on this theme? And would anyone go out and make a new one?
Well, there were a few interesting responses in the comments and by email, so I thought I’d report back.
First, I am delighted that David Maas was provoked by the earlier article to produce a speedpaint entitled Sauropod Stomp, whose progress he described on his own site (version 1, version 2, version 3), and which I reproduce here:
I love the boldness of this, and the “Hey! Quit it!” expression on the theropod’s face.
Also partly provoked by the earlier post — it’s an old project, but only brought to completion in response to our challenge — is Brian Engh’s new Shunosaurus whacking the head of a theropod with its tail club. (We’ve previously discussed Shunosaurus tail clubs here and here.) Brian also chronicled the evolution of his image on his own blog (version 1 [scroll down], version 2, version 3), and here is the result:
There are a few more Shunosaurus pieces out there, of which my favourite is Mark Hallett’s Direct Hit:
This image was used in Czerkas & Czerkas’s book Dinosaurs: A Global View. The original painting is for sale on Mark’s site (as other pieces, including the classic Long March).
Todd Marshall also has a Shunosaurus, but I don’t know anything about its history as the only non-tiny version of this image I’ve found is in Wikidino:
(I think Todd Marshall’s pencil drawings are absolutely sensational, as for example in this Spinosaurus, but for me the colour versions of his work seem to lose something in comparison.)
There’s also a Shunosaurus-whacking-Gasosaurus piece that’s cropped up in various places, but I won’t reproduce it here because I am keen to avoid violating his copyright.
And now for something completely different: Brad McFeeters’s unintentionally carnivorous Omeisaurus, about to find a Scansoriopteryx in its salad. This was done for ArtEvolved’s sauropod challenge.
Har har.
As we now start to head towards the sillier end of the spectrum, there is this, which Jonathan Kane says is by Emily Willoughby (though I’ve not not been able to find it on her DeviantArt site):
And of course this never-to-be-forgotten classic by our own Darren Naish (previously featured here):
Finally, I urge you to watch this video, which has given me many hours of uncomplicated joy.
In a comment on the initial Shunosaurus tail-club post, Jaime Headden pointed out the passage in the Spinophorosaurus paper (Remes et al. 2009) that discusses the club of Shunosaurus (as justification for positioning the Spinophorosaurus osteoderms on the end of its tail):
With the holotypic skeleton, two closely associated dermal ossifications were found originating from contralateral sides (Fig. 4A–C). These elements have a subcircular base that is rugose and concave on its medial side, and bear a caudodorsally projecting bony spike with a rounded tip laterally. Although these elements were found in the pelvic region under the dislocated scapula, we regard it as most probable that they were placed on the distal tail in the living animal for the following reasons: First, the close association of the contralateral elements indicates they were originally placed near the (dorsal) midline of the body. Second, the stiffening of the distal tail by specialized chevrons is also found in other groups of dinosaurs that exhibit tail armor [42,43]. Third, osteoderms of similar shape are known from the closely related basal eusauropod Shunosaurus [26]. In the latter form, these elements cover the middle part of a tail club formed by coalesced distal vertebrae; however, the decreasing size of the distal-most caudal vertebrae of Spinophorosaurus indicate that such a club was not present in this genus. The right osteoderm is slightly larger and differs in proportions from the left element, indicating that, as in Shunosaurus [26], originally two pairs of tail spines were present (Fig. 5).
— Remes et al. (2009:6-8)
And this gives the reference that I needed for the Shunosaurus tail-spikes (as opposed to the club) — reference 26 is Zhang (1988), which, embarrassingly, we’ve featured here on SV-POW! in our first Shunosaurus post. Evidently I was so focussed on preparapophyses when I looked at that monograph that I completely failed to register the tail-club spikes — but then, which of us can truly say he has not made that mistake?
Anyway, here’s what Zhang has to show us:
And here’s that tail again, this time from the poorly reproduced photographic plate 12, part 1, and in right lateral view:
It’s apparent that this really is the other side of the distal tail (rather than a reversed image of the same side) because the osteoderms are in front of the club vertebrae in the left-lateral figure, but behind them in the right-lateral plate.
It would be great to say more about these, but the English language summary of Zhang’s monograph is understandably brief, constituting six pages of the 90. What’s not quite so understandable is that neither the diagnosis of the genus Shunosaurus nor that of the species S. lii mentions the tail-club or spikes, which are arguably the most distinctive features. The “revised diagnosis” on pp. 78-79 does, however — just:
Posterior caudals platycoelous, with small cylindrical centra; neural spines low, rod-like. In several last caudals swollen ralidly [sic] and forming “tail-mace”; in addition there are two pairs of little caudal spines, being analogous to that of stegosaurs.
Not much to go on, but something. That’s all, though — there is no further description, and crucially, no indication of whether the tail elements were found articulated or whether the spikes were found isolated and subsequently moved to the end of the tail. It may be that Remes at al. know something I don’t, of course — they might have a translation of Zhang (1988) — but if not, then it’s amusing to consider that the spikes on the tail of Shunosaurus may or may not be supported by evidence, and that the inference of tail-spikes on Spinophorosaurus might be based on dodgy premises.
The other thing that struck me forcibly, as I looked at the figure and plate above, is that the caudal vertebrae remain fairly complex all the way to the end: they retain distinct and prominent neural spines, unlike the distal caudal vertebrae of diplodocids and brachiosaurs. I notice that the distal caudals of Spinophorosaurus also seem to be complex, based on fig. 3H-I and also on the skeletal reconstruction that is fig. 5 — both of which we’ve reproduced before, in our old Spinophorosaurus article.
So what’s going on here? Are Shunosaurus and Spinophorosaurus unusual in having distal caudals that retain complex neural spines? If so, is this property correlated with the possession of a tail-club and/or spines? Is it causally related? Or could it be that this is normal for basal eusauropods, and my ideas of sauropod tails have been too coloured by extreme neosauropodocentricity? Clearly I ought to go and look at a lot more basal sauropods’ distal tails before publishing this post. And prosauropods’, theropods’, ornithischians’, pterosaurs’, crocadilians’ and lizards’ distal tails.
As it happens, the one non-neosauropod group of reptiles whose distal tails I do know something about is monitor lizards, thanks to my adventures with the corpse of “Charlie”. And those caudals do maintain astonishingly detailed structure right to the end of the tail, with even absolutely tiny caudals having distinct processes. Here are some photographs that show this.
First, one showing all 56 caudal vertebrae (the 1st is half in frame at top right, next to the sacrum; the rest read from left to right on successive rows, like words on a page).
Now here are five representative caudals from different regions on the tail — the last ones from each row in the picture above, as it happens: caudals 1, 10, 21, 30, 42 and 56. They are in more or less dorsal view, though caudal 1 has fallen forward onto its anterior face. In this and subsequent pictures, caudal 10 (the second shown) is for some reason back to front.
Now here are the same vertebrae, in the same order and orientation, but now in left dorsolateral aspect (except caudal 10 which is of course in right dorsolateral):
Finally, here are the three smallest of these vertebrae (numbers 30, 42 and 56) in close-up, again in left dorsolateral view, so you can more easily see how much structure even the distalmost caudal has:
That last caudal is about 2.5 mm long.
(It’s interesting that caudals 30 and 42 have those cute fused chevrons.)
So anyway: we know that caudal vertebrae retain distinct structure all the way down to the tip of the tail in monitor lizards at least some basal eusauropods: could it be that this is the primitive state, and that degenerate caudals are found only in neosauropods and mammals? Gotta prep out some more animals’ skeletons and find out!
References
- Remes, Kristian, Francisco Ortega, Ignacio Fierro, Ulrich Joger, Ralf Kosma, Jose Manuel Marin Ferrer, for the Project PALDES, for the Niger Project SNHM, Oumarou Amadou Ide, and Abdoulaye Maga. 2009. A new basal sauropod dinosaur from the Middle Jurassic of Niger and the early evolution of Sauropoda. PLoS ONE 4(9):e6924. doi:10.1371/journal.pone.0006924
- Zhang Yihong. 1988. The Middle Jurassic dinosaur fauna from Dashanpu, Zigong, Sichuam, vol. 1: sauropod dinosaur (I): Shunosaurus. Sichuan Publishing House of Science and Technology, Chengdu, China.
What’s the deal with your wacky tail-club, Shunosaurus?
June 11, 2010
In a comment on an earlier article, What’s the deal with your wacky postparapophyses, Shunosaurus?, brian engh asked:
What’s the deal with most Shunosaur “life restorations” showing spikes on the tail club? I can’t find a picture anywhere of a skeleton with any indication of spikes, and yet almost every fleshed-out illustration of Shunosaurs has spikes on it’s tail. Anybody know what that’s about?
It seems we’ve never actually featured the famous Shunosaurus tail-club here before — an amazing oversight, and one that I’m going to remedy right now, thanks to Dong et al. (1989). This short paper is written in Chinese, so I can’t tell you anything beyond what’s in the figures, captions and English-language abstract.
First up, though, here is his illustration of the famed tail-club:
I can’t help noticing, though, that although the fused clump of enlarged distal caudal vertebrae constitutes a nice club, it’s noticably devoid of spikes. So it remains a mystery why so many restorations show a spiked club. Anyone out know why?
Dong et al. (1989) also obligingly includes a figure of the tail-club of Omeisaurus:
And also a photographic plate showing both clubs (though, as is so often the case, the scan has lost a lot of details):
Now, the big question is: why do Shunosaurus and Omeisaurus — and Mamenchisaurus, for that matter — have tail-clubs when they are not closely related, according to modern phylogenies such as those of Wilson (2002) and Upchurch et al. (2004)? [To be precise, Wilson (2002:fig. 13) had Omeisaurus and Mamenchisaurus clading together, but that clade well separated from Shunosaurus; and Upchurch et al. (2004:fig. 13.18) had all three separate, though with the former two as consecutive branches on the paraphyletic sequence leading to Neosauropoda.]
One possibility is just sheer coincidence: but it’s asking a lot to believe that of the 150 or so known sauropods, the only three for which tail-clubs are known just happened to live more or less at the same time and in the same place.
Another option is some oddity in the environment that strongly encouraged the evolution of tail clubs. Yes, this is wildly hand-wavy, but you can sort of imagine that maybe all the local theropods thought it was cool to hunt sauropods by biting their tails, and the clubs evolved in response to that. Or something. There’s a similar, but even more mystifying, situtation in the late Early Cretaceous Sahara, where the theropod Spinosaurus, the ornithopod Ouranosaurus and arguably even the sauropod Rebbachisaurus all evolved sails. Why then? When there? No-one knows and no-one’s even advanced a hypothesis so far as I know.
Getting back to Jurassic Chinese sauropod tail-clubs, though, there is a third option: could it possibly be that Shunosaurus, Omeisaurus and Mamenchisaurus all form a clade together after all, as proposed back in the day by Upchurch (1998:fig. 19)? Upchurch’s pioneering (1995, 1998) analyses both recovered a monophyletic “Euhelopodidae” — a clade of Chinese sauropods that included the three genera above plus the early Cretaceous Euhelopus, also from China. The existence of this clade was one of the two major points of disagreement between Upchurch’s and Wilson’s phylogenies (the other being the position of the nemegtosaurids, Nemegtosaurus and Quaesitosaurus, which Upchurch placed basally within Diplodocoidea but Wilson recovered as titanosaurs).
Upchurch himself has abandoned the idea of the monophyletic Euhelopodidae, as seen in that 2004 analysis and also in Wilson’s and his joint (2009) reassessment of Euhelopus: everyone now agrees that Euhelopus is a basal somphospondyl, i.e. close to Titanosauria, which is a looong way from the basal position that the other Chinese sauropods hold within Sauropoda.) And so the name Euhelopodidae is no longer used. But could it be that Upchurch was half-right, and that when Euhelopus is removed that the group that was named after it, a clade remains?
[If so, then that clade is called Mamenchisauridae: as noted by Taylor and Naish (2007), this name was coined by Young and Zhao (1972) and so has priority over the Omeisauridae of Wilson (2002), as Wilson himself now recognises. Mamenchisauridae was phylogenetically defined (or, as they have it, “diagnosed”) by Naish and Martill (2007:498) as “all those sauropods closer to Mamenchisaurus constructus Young, 1954 than to Saltasaurus loricatus Bonaparte”.]
As already noted, Omeisaurus and Mamenchisaurus are close together in the recent analyses of both Upchurch and Wilson, so the question becomes: how many additional steps are required to recover Shunosaurus as a member of their clade rather than in its usual more basal position (in the the case of Upchurch’s analysis, to move Omeisaurus up a node)? And to this, I do not know the answer — to the best of my knowledge, it’s never been tested (or if it has, the result has never been published). I’d test it myself, but I need to stop working on this post and watch Inca Mummy Girl soonest. If , say, 20 additional steps are needed, then forget it. But if we only need, say, three steps, then maybe someone should look at this more closely. Back in 2004, when he was Young And Stupid, Matt Wedel wrote to me, in a private email which I now quote without permission because I am pretty sure he’s not going to sue me:
Now that I’ve defended the status quo [of using unweighted characters in cladistic analysis], there are some things I’d be happy to bend the rules for. If an Omeisaurus pops up with a tail club, then Wilson and Sereno be damned, Omeisaurus and Shunosaurus belong in the same clade. […] So my final word is unweighted characters, please, except for sauropod tail clubs.
Food for thought.
Finally, I leave you with the skeletal reconstruction of Omeisaurus from Dong et al. (1989:fig 3). Long-time readers will notice a more than passing resemblance to the reconstruction from He et al. (1988:fig. 63), which you can see in Omeisaurus is Just Plain Wrong.
It looks very much as though Dong et al. produced their reconstruction by flipping that of He et al. horizontally and pasting on a tail-club. Well, we can’t hold that against them — I’d have done the same.
References
- Dong Zhiming, Peng Guangzhao and Huang Daxi. 1988. The Discovery of the bony tail club of sauropods. Vertebrata PalAsiatica 27(3):219-224.
- He Xinlu, Li Kui and Cai Kaiji. 1988. The Middle Jurassic dinosaur fauna from Dashanpu, Zigong, Sichuan, vol. IV: sauropod dinosaurs (2): Omeisaurus tianfuensis. Sichuan Publishing House of Science and Technology, Chengdu, China. 143 pp. + 20 plates.
- Naish, Darren, and David M. Martill. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London, 164: 493-510. (Bicentennial Review issue.)
- Taylor, Michael P. and Darren Naish. 2007. An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England. Palaeontology 50 (6): 1547-1564. doi: 10.1111/j.1475-4983.2007.00728.x
- Upchurch, Paul. 1995. The evolutionary history of sauropod dinosaurs. Philosophical Transactions of the Royal Society of London Series B, 349: 365-390.
- Upchurch, Paul. 1998. The phylogenetic relationships of sauropod dinosaurs. Zoological Journal of the Linnean Society 124: 43-103.
- 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.
- Wilson, Jeffrey A. 2002. Sauropod dinosaur phylogeny: critique and cladistic analysis. Zoological Journal of the Linnean Society 136: 217-276.
- Wilson, Jeffrey A. and Paul Upchurch. 2009. Redescription and reassessment of the phylogenetic affinities of Euhelopus zdanskyi (Dinosauria – Sauropoda) from the Early Cretaceous of China. Journal of Systematic Palaeontology 7: 199-239. doi:10.1017/S1477201908002691
- Young, Chung-Chien, 1954. On a new sauropod from Yiping, Szechuan, China. Acta Palaeontologica Sinica II(4):355-369.
- Young, Chung-Chien, and X. Zhao. 1972. [Chinese title. Paper is a description of the type material of Mamenchisaurus hochuanensis]. Institute of Vertebrate Paleontology and Paleoanthropology Monograph Series I, 8:1-30. English translation by W. Downs.
Shunosaurus lii is a basal eusauropod from the Middle Jurassic of China. Outside of palaeontological circles, it’s not at all well known — which is kind of surprising, as it’s one of the best represented of all sauropods. It’s known from numerous complete skeletons, including skulls, and has been described in detail in Zhang’s (1988) monograph: 89 pages and 15 plates. Here’s a skeleton of one individual, as found in the ground:
Shunosaurus lii, referred adult individual ZDM T5402, skeleton as found. From Zhang (1988:fig. 2)
Apart from being so well represented, Shunosaurus is known mostly for its tail club, which at the time of its discovery was unique among sauropods. Despite recent discoveries of Mamenchisaurus hochuanensis individuals with preserved tail-clubs, and of Spinophorosaurus, the Shunosaurus tail-club is the best developed and best preserved.
But I don’t want to show you that. I want to show you something I’ve been wanting to see for many years, and today finally saw for the first time: a feature of the dorsal vertebrae totally unique to Shunosaurus, known as postparapophyses.
Shunosaurus lii, referred juvenile individual ZDM T5401, dorsal vertebrae 3, 7 and 11 in left lateral view. Note postparapophyses on dorsals 7 and 11. From Zhang (1988:figs. 31-32)
Sadly, these are the only figures in the paper that show the postparapophyses (and as far as I know the only published figures anywhere). So we have them in lateral view only, and lack what would be an informative posterior view. Plate 10, part 1, supposedly shows one of the posterior dorsals in posterior view, but in my PDF at least the reproduction is so poor as to be wholly uninformative.
What makes things even worse is that the extended English-language abstract on pages 86-91 of Zhang (1988) does not mention this feature at all — in fact it occurs only in the list of anatomical abbreviations on page 6. So, to the best of my knowledge, here is the entirety of what has been published in the English language about this feature based on observation of the material:
ppp, postparapophysis
Wilson and Sereno (1998:14-15) expanded a little on this, but it’s not clear that what they wrote was based on anything more than the figure above. Here it is anyway, for completeness:
Comments–Zhang’s (1988:78-79) diagnosis listed numerous features, only a few of which appear to be autapomorphies of Shunosaurus lii. One of the more striking autapomorphies is an unusual articulation between the ribs and the posterior dorsal vertebrae. The parapophyseal articulation is split between adjacent vertebrae, with a portion of the articulation in its usual position by the prezygapophyses and an anterior extension located near the postzygapophysis on the preceding vertebra (Zhang, 1988:figs. 31, 32; “postparapophysis”).
That’s your lot.
So if we’re to make anything at all of the PPPs, it will have to be on the basis of the figure reproduced above. And I don’t really know how much we can say. The PPPs look sort of like postzygapophyses, havng a distinct ventrally oriented facet. This makes me wonder whether they are in fact lateral extensions of the postzygapohyseal facets, perhaps connected by a lamina that would be visible in posterior view.
The bottom line is, I don’t know, and I would greatly appreciate comments (or better still, photos!) from anyone who has seen the material first-hand.
I leave you with Zheng’s (1988:fig. 57) skeletal reconstruction of this distinctively dumpy-looking sauropod. Note by the way that the plantigrade manus reconstruction is almost certainly wrong: the metacarpals should be held in a more or less vertical arcade as in other sauropods.
Shunosaurus lii, referred adult individual ZDM T5402, skeletal reconstruction in left lateral view. From Zheng (1988:fig. 7). Man, that thing is ugly.
References
- Wilson, Jeffrey A. and Paul C. Sereno. 1998. Early evolution and Higher-level phylogeny of sauropod dinosaurs. Society of Vertebrate Paleontology, Memoir 5: 1-68.
- Zhang Yihong. 1988. The Middle Jurassic dinosaur fauna from Dashanpu, Zigong, Sichuam, vol. 1: sauropod dinosaur (I): Shunosaurus. Sichuan Publishing House of Science and Technology, Chengdu, China.
Update (9 March 2010)
Rob Taylor found this nice photograph of what is apparently a skeletal mount of Shunosaurus: the original is here. Any information about this mount will be gratefully received: please comment below if you know anything.
Sauropod Vertebra Picture of the Week 
