You! Shall not! Pass!
August 22, 2020
OK, technically this is MB.R.3822, a dorsal vertebra of Giraffatitan brancai formerly known as HMN Ar1, in posterior view, rendered from a 3D scan provided by Heinrich Mallison.
But you can’t tell me that when you look at that you don’t see Gandalf shouting at a balrog.
Saltapotamus, meet Obesethocoelicaudia
August 21, 2020
This just in from John Conway:
John doesn’t say much about it in the tweet where he unveiled this piece: just “A new #painting, of a Saltapotamus”. His website is just a little more forthcoming:
Saltapotamus
Saltasaurus was a small (for a sauropod) sauropod from the Late Cretaceous of Argentina. It had a some armour, and a lot of girth.
This reminds me very strongly of Obesethocoelicaudia, a fat restoration of Opisthocoelicaudia that John kindly did for Matt and me to use in our 2014 SVPCA talk, “Slender Giants”:
(Saltasaurus and Opisthocoelicaudia are both derived titanosaurs, and in most phylogenies they come out as pretty closely related.)
Is this kind of restoration credible? After all, it’s a long way from how we’ve been used to seeing Saltasaurus. Here, for example, is how E. Guanuco restored a group of four Saltasaurus individuals in Powell (2003: plate 78):
In this illustration they are tubby in a Normanpedia kind of way, but nothing very different from how (say) Apatosaurus was being restored not too long before then.
But the truth is that lots of animals have flesh envelopes very different from what you might predict based on the skeleton alone. Exhibit A, the inspiration for John’s new piece: the humble hippopotamus. Skeleton:
And life appearance:
It seems more than reasonable that across a clade as diverse, disparate and long-lived as the sauropods, there would have been some that were similarly heavy with flesh. In fact, I think it would be special pleading to argue that there were not.
Which specific sauropods were obese? That is much harder to tell. Hippos can be very heavy with little penalty as they spend much of their time in the water. Perhaps the same was true of some sauropods. If that’s so, then our quest must be for sauropods whose skeletons show adaptations for a semi-aquatic lifestyle, and on that basis Opisthocoelicaudia may have at least two feature supporting this interpretation: very robust limb bones and (if the interpretation of Borsuk-Bialynicka 1977: figure 5 is to be trusted) a transversely broad torso.
References
- Powell, Jaime E. 2003. Revision of South American Titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum 111:1-94.
Long before Matt and others were CT-scanning sauropod vertebrae to understand their internal structure, Werner Janensch was doing it the old-fashioned way. I’ve been going through old photos that I took at the Museum für Naturkunde Berlin back in 2005, and I stumbled across this dorsal centrum:
Dorsal vertebra centum of ?Giraffatitan in ventral view, with anterior to top.
You can see a transverse crack running across it, and sure enough the front and back are actually broken apart. Here there are:
The same dorsal vertebral centrum of ?Giraffatitan, bisected transversely in two halves. Left: anterior half in posterior view; right: posterior half in anterior view. I had to balance the anterior half on my shoe to keep it oriented corrrectly for the photo.
This does a beautiful job of showing the large lateral foramina penetrating into the body of the centrum and ramifying further into the bone, leaving only a thin midline septum.
But students of the classics will recognise this bone immediately as the one that Janensch (1947:abb. 2) illustrated the posterior half of in his big pneumaticity paper:
It’s a very strange feeling, when browsing in a collection, to come across a vertebra that you know from the literature. As I’ve remarked to Matt, it’s a bit like running into, say, Cameron Diaz in the corner shop.
Reference
- Janensch, W. 1947. Pneumatizitat bei Wirbeln von Sauropoden
und anderen Saurischien. Palaeontographica, supplement
7:1-25.
Help! Running phylogenetic analyses in TNT
August 7, 2020
I’ve got a problem. For a paper I’m working on, I need to run a phylogenetic analysis based on that of Mannion et al. (2013) — the Lusotitan paper. The most recent version of that matrix, greatly expanded from the original version, is that of Mannion et al. (2019) — the Jiangshanosaurus paper — so I am working from that matrix.
But what exactly do I do with that Matrix? The analysis protocol is described on pages 12-13 of the PDF:
Several unstable and fragmentary taxa were excluded from the analyses (Astrophocaudia, Australodocus, Brontomerus, Fukuititan, Fusuisaurus, Liubangosaurus, Malarguesaurus, Mongolosaurus). Using equal weighting of characters, this pruned data matrix was analysed using the ‘Stabilize Consensus’ option in the ‘New Technology Search’ in TNT v. 1.5. Searches employed sectorial searches, drift and tree fusing, with the consensus stabilized five times, prior to using the resultant trees as the starting topologies for a ‘Traditional Search’, using Tree Bisection-Reconstruction. We then re-ran the analysis, using the same pruned matrix and protocol, but also applying extended implied weighting in TNT.
There is no problem downloading TNT: it’s freely available thanks to subsidy by the Willi Hennig Society. But the program is tricky to use, and documentation is rather cryptic. You drive TNT with scripts that look like this (short excerpt):
ttags =;
<tag generating commands>
ttags );
tsave *tags.tre;
save * <tree number>;
tsave /;
It seems, for example that = and ) are values that the ttags command accepts. But I’ve not been able to find documentation that spells out such things. (There is a help command, but its output too is cryptic.)
So here is my problem: how do I translate the Mannion et al. (2019) protocol into a TNT script? If anyone can help me with this, I will acknowledge the heck out of them the paper that eventually emerges from this rubble.
(Why not just ask Phil Mannion, you ask? I’ve been talking with Phil and he has been super-helpful: but he’s been using a Windows-only version of TNT in which you don’t write scripts, but invoke various menu options, so he’s not able to help with this directly.)
Thank you!
References
- Mannion, Philip D., Paul Upchurch, Rosie N. Barnes and Octávio Mateus. 2013. Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society 168(1):98–206. doi:10.1111/zoj.12029
- Mannion, Philip D., Paul Upchurch, Xingsheng Jin and Wenjie Zheng. 2019. New information on the Cretaceous sauropod dinosaurs of Zhejiang Province, China: impact on Laurasian titanosauriform phylogeny and biogeography. Royal Society Open Science 6:191057. doi:10.1098/rsos.191057
John Conway’s BRONTOSMASH!
August 4, 2020
As John himsef admits in the tweet that announced this picture, it’s five years late … but I am prepared to forgive that because IT’S NEVER TOO LATE TO BRONTOSMASH!
As always, John’s art is not just scientifically accurate, but evocative. Here’s a close-up of the main action area:
As you see, he has incorporated the keratinous neck spikes that we hypothesized, based on the distinct knobs that are found at the ventrolateral ends of apatosaurine cervical rib loops.
John has also incorporated a lot of blood — which is exactly what you get when elephant seals collide:
By the way, if John’s BRONTOSMASH! art can be said to be five years late — so can the actual paper. It was of course at SVPCA 2015 that we first presented our apatosaur-neck-combat hypothesis (Taylor et al. 2015), and it’s not at all to our credit that nearly five years later, we have not even got a manuscript written. We really need to get our act together on this project, so consider this post my apology on behalf of myself, Matt, Darren and Brian.
Reference
- Taylor, Michael P., Mathew J. Wedel, Darren Naish and Brian Engh. 2015. Were the necks of Apatosaurus and Brontosaurus adapted for combat?. p. 71 in Mark Young (ed.), Abstracts, 63rd Symposium for Vertebrate Palaeontology and Comparative Anatomy, Southampton. 115 pp. doi:10.7287/peerj.preprints.1347v1
Sauropod Vertebra Picture of the Week 