Sauropod Vertebra Picture of the Week

FMNH P13018 with me for scale. Photo by Holly Woodward.

Some of the Burpee Museum folks and PaleoFest speakers visited the Field Museum of Natural History in Chicago after the 2020 ‘Fest. I hadn’t been there since 2012, and a lot had changed. More on that in future posts, maybe. Here I am with FMNH 13018, a right femur referred by von Huene (1929) to Argyrosaurus superbus (note, though, that Mannion and Otero 2012 considered this specimen to be Titanosauria indet., hence the hedge in the title of the post). It’s 211cm long, which is pretty darn big but still well short of the record.

Speaking of the record, here’s a list of the largest sauropod femora (as always, updates in the comments are welcome!):

1. 250cm – Argentinosaurus huinculensis, MLP-DP 46-VIII-21-3 (estimated when complete)
2. 238cm – Patagotitan mayorum, MPEF-3399/44
3. 236cm – Patagotitan mayorum, MPEF-PV 3400/27
4. 235cm – Patagotitan mayorum, MPEF-PV 3400/27
5. 235cm – “Antarctosaurus” giganteus, MLP 26-316
6. 214cm – Giraffatitan brancai, XV1
7. 211cm – cf. Argyrosaurus superbus, FMNH P13018
8. 203cm – Brachiosaurus altithorax, FMNH P25107
9. 200cm – Ruyangosaurus giganteus, 41HIII -0002 (estimated when complete)
10. 191cm – Dreadnoughtus schrani, MPM-PV 1156

The list is necessarily incomplete, because we have no preserved femora for Puertasaurus, Notocolossus, Futalognkosaurus, or the largest individuals of Sauroposeidon and Alamosaurus, all of which probably had femora in the 210-250cm range. For that matter, most elements of the giant Oklahoma apatosaurine are 25%-33% larger than the equivalent bones in CM 3018, which implies a femur length of 223-237cm (scaled up from the 178.5cm femur of CM 3018). I’m deliberately not dealing with Maraapunisaurus or horrifying hypothetical barosaurs here.

In any case, it’s still a prodigious bone, and well worth spending a moment with the next time you’re at the Field Musuem.

References

• Mannion, P.D. and Otero, A., 2012. A reappraisal of the Late Cretaceous Argentinean sauropod dinosaur Argyrosaurus superbus, with a description of a new titanosaur genus. Journal of Vertebrate Paleontology, 32(3):614-638.
• Von Huene, F. 1929. Los saurisquios y ornitisquios del Creta´ceo Argentino. Anales del Museo de La Plata 3:1–196.