Sauropod Vertebra Picture of the Week

Posterior dorsal vertebra of the Upper Cretaceous nanoid saltasaurid LPP-PV-0200. Three-dimensional reconstruction from CT scan in left lateral view (A). Circle and rectangle show sampling planes and the respective thin sections are in (B,C). ce centrum, ns neural spine, pn pneumatopore, poz postzygaphophysis, prz prezygapophysis. Scale bar in (A) 10 cm; in (B,C) 1 cm. Computed tomography data processed with 3D Slicer version 4.10.

Well, this is a very pleasant surprise on the last day of the semester:

Tito Aureliano, Aline M. Ghilardi, Bruno A. Navarro, Marcelo A. Fernandes, Fresia Ricardi-Branco, & Mathew J. Wedel. 2021. Exquisite air sac histological traces in a hyperpneumatized nanoid sauropod dinosaur from South America. Scientific Reports 11: 24207.

You may justly be wondering what I’m doing on a paper on a South American titanosaur. It came about like this:

• I wrote to Tito Aureliano back in March to congratulate him on his 2019 paper, “Influence of taphonomy on histological evidence for vertebral pneumaticity in an Upper Cretaceous titanosaur from South America”, which I’d just reread, and was impressed by;
• he told me he was working on a manuscript on saltasaur pneumaticity and would be grateful for my thoughts;
• I sent him said thoughts, with no strings attached;
• he asked me if I’d be willing to come on the project as a junior author;
• I said yes;

and a few months later, here we are.

Dorsal vertebra internal structures of LPP-PV-0200. Reconstructed tomography model in distal (A) and right lateral (B) views illustrating subvertical tangential CT scan slices in false color (1–9). Images show that only a few structures had survived diagenesis which restricted the assessment of the internal architecture to limited spaces. Lighter blue and green indicate lower densities (e.g., pneumatic cavities). Purple and darker blue demonstrate denser structures (e.g., camellate bone). Dashed lines indicate internal plates of bone that sustain radial camellae. ce centrum, cc circumferential chambers, cml camellae, hc-cml ‘honeycomb’ camellae, ns neural spine, pf pneumatic foramen, pn pneumatopore, pacdf parapophyseal-centrodiapophyseal fossa, pocdf postzygapophyseal-centrodiapophyseal fossa, rad radial camellae. Computed tomography data processed with 3D Slicer version 4.10.

My correspondence to Tito basically boiled down to, “All the things you’ve identified in your CT scans are there, but there are also a few more exciting things that you might want to draw attention to” — specifically circumferential and radial camellae near the ends and edges of the centrum, and pneumatic chambers communicating with the neural canal, which were previously only published in Giraffatitan (Schwarz and Fritsch 2006; see Atterholt and Wedel 2018 and this post for more). The internal plates of bone inside the cotyle, which help frame the radial camellae, were first noted by Woodward and Lehman (2009), and discussed in this post.

I can’t think of any reason not to just post the notes I sent to Tito back in March, so here you go:

Wedel suggestions for Aureliano et al Saltasauridae dorsal

I may have more to say about this in the coming days, but at the moment I have two extant dinosaurs — ducks, to be precise — smoking on the grill, and I need to get back to them. The new paper is open access, free to the world (link), so go have fun with it.

UPDATE the next day: here’s another post on the new paper:

• Here’s a video on the new saltasaur pneumaticity paper by Aureliano et al. (2021)

References

• Atterholt, J., and Wedel, M. 2018. A CT-based survey of supramedullary diverticula in extant birds. 66th Symposium on Vertebrate Palaeontology and Comparative Anatomy, Programme and Abstracts, p. 30 / PeerJ Preprints 6:e27201v1
• Aureliano, T., Ghilardi, A.M., Silva-Junior, J.C., Martinelli, A.G., Ribeiro, L.C.B., Marinho, T., Fernandes, M.A., Ricardi-Branco, F. and Sander, P.M. 2020. Influence of taphonomy on histological evidence for vertebral pneumaticity in an Upper Cretaceous titanosaur from South America. Cretaceous Research 108: 104337.
• Schwarz D, and Fritsch G. 2006. Pneumatic structures in the cervical vertebrae of the Late Jurassic Tendaguru sauropods Brachiosaurus brancai and Dicraeosaurus. Eclogae Geologicae Helvetiae 99:65–78.
• Woodward, H.N., and Lehman, T.M. 2009. Bone histology and microanatomy of Alamosaurus sanjuanensis (Sauropoda: Titanosauria) from the Maastrichtian of Big Bend National Park, Texas. Journal of Vertebrate Paleontology 29(3):807-821.