Bone Wars scraps hid Stegosaurus until a full skeleton arrived
Stegosaurus, the roof lizard, was a Late Jurassic plated herbivore from the western United States and Portugal, found in Kimmeridgian to Tithonian rocks about 155 to 145 million years old. Kite-shaped back plates and a spiked tail made it iconic long before complete skeletons showed how the armor actually sat.
The first bones were scraps. Arthur Lakes and H. C. Beckwith dug a few tail vertebrae, a plate and other pieces from a quarry north of Morrison, Colorado, and in 1877 Othniel Charles Marsh named them Stegosaurus armatus. Marsh first pictured a turtle-like water animal with plates lying flat across its back like roof tiles, hence the name. His rival Edward Drinker Cope answered in 1878 with Hypsirhophus from Garden Park, which most later researchers fold into Stegosaurus, though Peter Galton argued in 2010 that it is distinct.
Better material followed. In 1879 Lakes and William Harlow Reed pulled many fossils from Quarry 13 at Como Bluff, Wyoming, including the type of S. ungulatus with a partial skull and tail spikes. The breakthrough came in 1885 and 1886, when Marshall Felch cut a nearly complete, articulated subadult out of his Garden Park quarry in labelled blocks, preserving the whole skull, throat bones and plates in place. Marsh named it S. stenops, narrow-faced roof lizard, in 1887, and it has been on show at the Smithsonian since 1915.
How the plates stood took decades to settle. Marsh's flat armour gave way to Frederick Lucas's two paired rows in 1901, which Charles R. Knight painted, before Lucas himself switched to staggered rows a year later. The first mounted stegosaur went up at Yale's Peabody Museum in 1910, and it remained the world's only one until 1918.
Today scientists mostly read the spiked tail as a weapon and the plates as display, possibly with a secondary role in regulating heat. Over 80 individuals are known, but many museums still mount composites from several animals.
Source: Stegosaurus
