Sauropelta Solved!


The ever-problematic Sauropelta, as restored by John Conway.

A nagging problem in our dataset has been the issue of the Sauropelta edwardsi specimen AMNH 3032. Its tibia seems way, way too short (even for ankylosaurs), and it’s thus a bizarro outlier.

So, I finally got my behind into gear to check out the problem. Was the measurement a typo? Was the tibia incompletely preserved? Was it from a smaller individual? On p. 115, I found the answer. The tibia for AMNH 3032 is here listed as 57.5 cm (575 mm) in length. This makes much, much more sense, so we’ll go with that number. Apparently, the value given in the table was simply an error. On further looking, I was able to confirm that the table heading for Sauropelta measurements on p. 120 was actually transposed with a Tenontosaurus table (as Rob Taylor had ably picked up on some time ago)! It looks like the measurements here are all from AMNH 3032, not YPM 5456 and 5459. Mystery (finally) totally solved, and the database is fixed!

It also turns out that the tabular error has been perpetuated across a few more publications. The Tenontosaurus-turned-Sauropelta YPM 5456 makes an appearance in Ford and Kirkland 2001 as well as Maidment et al. 2008. It in no way harms the conclusions of these papers (after all, the error is in the specimen number, not the measurements). But, I have removed all references for a YPM 5456 Sauropelta from our data tables.

Ford TL, Kirkland JI (2001) Carlsbad ankylosaur (Ornithischia, Ankylosauria): an ankylosaurid and not a nodosaurid. In: Carpenter K, editor. The Armored Dinosaurs. Bloomington: Indiana University Press. pp. 239–260.
Maidment SCR, Norman DB, Barrett PM, Upchurch P (2008) Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia). Journal of Systematic Palaeontology 6: 367-407.
Ostrom JH (1970) Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana. Bulletin of the Peabody Museum of Natural History 35: 1–234.

Image Credit: Restoration by John Conway, from Wikimedia Commons. This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License. In short: you are free to share and make derivative works of the file under the conditions that you appropriately attribute it, and that you distribute it only under a license identical to this one. Official license

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2 Responses to Sauropelta Solved!

  1. Rob Taylor says:

    Yikes! I’d forgotten all about the headache that was Ostrom 1970. Glad to know the mystery has been unraveled and the database put to rights!

  2. John Dziak says:

    Cool! This helps show the power of the various graphing and data visualization approaches that you have been using.

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