Sauropelta edwardsorum

Sauropelta edwardsorum was a large nodosaurid ankylosaur from the Early Cretaceous of Montana and Wyoming. A mosaic of bony plates protected its neck, back and tail, while two pairs of especially long spines guarded the shoulder region. Unlike later ankylosaurids, Sauropelta lacked a tail club. Several partial skeletons preserve much of its armor in place, making it one of the clearest examples of early nodosaurid defence.

Its fossils occur between approximately 115 and 108 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The small, low skull ended in a broad plant-cropping beak. The neck carried half-rings of armor, and rows of rounded and keeled osteoderms covered the broad back. Large triangular spines projected sideways from the shoulders. Stout limbs supported a low, wide body, while the long tail remained flexible and lacked a terminal club.

• Two pairs of very large shoulder spines
• Armored neck half-rings
• Rows of keeled and rounded osteoderms
• Broad beak and small leaf-shaped teeth
• Long tail without a terminal club
• Stout, weight-bearing limbs

Barnum Brown collected the holotype, AMNH 3032, from the Cloverly Formation of Montana during the early 1930s but did not formally describe it. John Ostrom combined Brown's material with discoveries from Yale expeditions and named Sauropelta edwardsi in 1970. The grammatically corrected spelling edwardsorum is now widely used and honours Nell and Tom Edwards.

Discovery credit: Barnum Brown, American Museum field crews.

Naming authors: John H. Ostrom.

Sauropelta inhabited the same Cloverly floodplains and seasonal woodlands as Tenontosaurus. It browsed among conifers, cycads, ferns and early flowering plants while large theropods such as Acrocanthosaurus occupied the ecosystem.

Low jaws and small teeth suit selective browsing on ground-level vegetation. Armor and shoulder spines provided passive protection and may also have served for display. There is no direct evidence for herd size, combat behaviour or parental care.

• Its longest shoulder spines approached half a metre in length.
• Unlike Ankylosaurus, it had no tail club.
• Barnum Brown informally called the fossils Peltosaurus before Ostrom published the name Sauropelta.
• Much of its armor was found close to its original position on the skeleton.

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1. 01
   The Paleobiology Database

   Open source
2. 02
   Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana

   John H. Ostrom · Bulletin of the Peabody Museum of Natural History 35 · 1970

   Open source
3. 03
   Sauropelta

   Natural History Museum, London

   Open source