Sophie, Apex and the type specimen
Most Stegosaurus fossils are less than half a skeleton. These three are the exceptions.
Sophie, London
Sophie went on show at the Natural History Museum in London on 4 December 2014. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014 Sophie is about 150 million years old and the only Stegosaurus in a public collection outside the USA. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014 · checked 27 Oct 2026
The skeleton has over 300 bones, with only the left arm and base of the tail missing. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014 The Museum’s 3D model has 360 bones. Natural History Museum news: Weight of the world’s most complete Stegosaurus revealed, 2015
Bob Simon found it in spring 2003 at Red Canyon Ranch in Wyoming. It took three weeks to dig out. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014 He spotted it after accidentally grazing a hillside with a bulldozer during a severe windstorm. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE
It was so well preserved because it was buried quickly in a pond or other standing water just after death. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE Sophie comes from the Morrison Formation near Shell, Wyoming. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE
Museum scientists spotted a cast of it at the Tucson Gem and Mineral Fair in 2012. Natural History Museum: Stegosaurus Q&A with Prof Paul Barrett It is named after Sophie Herrmann, daughter of Jeremy Herrmann, who helped 70 donors buy it. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014
Sophie’s sex is unknown: the name doesn’t mean it was female. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE Sophie was a young adult, still growing, when it died. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014
Some gaps between bones were still open, and at just over 5.5 m it still had a way to grow. Natural History Museum: Stegosaurus Q&A with Prof Paul Barrett One toenail looks trodden on and infected, but probably wasn’t fatal. Nobody knows why Sophie died. Natural History Museum: Stegosaurus Q&A with Prof Paul Barrett
Its skull bones are three-dimensional and separate, one of the most scientifically valuable dinosaur skulls ever found. Natural History Museum press release: World’s most complete Stegosaurus goes on show, 2014 Before Sophie, the last detailed study of Stegosaurus was in 1914. Natural History Museum: Stegosaurus Q&A with Prof Paul Barrett
Only about a fifth of known dinosaur species are known from essentially complete skeletons. Natural History Museum: Stegosaurus Q&A with Prof Paul Barrett Sophie belongs to the species Stegosaurus stenops. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE
The Smithsonian’s Stegosaurus
The Smithsonian’s Stegosaurus stenops is the type specimen of its species: the first of its kind to be found and named. Smithsonian Magazine: Meet the dinos of “Deep Time”, 2019 Before it was dug up in 1886, scientists had only bits and pieces of Stegosaurus skeletons. Smithsonian Magazine: Meet the dinos of “Deep Time”, 2019
It is displayed in the death pose it was found in, in Colorado. Smithsonian Magazine: Meet the dinos of “Deep Time”, 2019 Older complete specimens like this one are ‘road kill’ fossils: many bones are crushed flat. Maidment, Brassey & Barrett (2015), The postcranial skeleton of an exceptionally complete individual of Stegosaurus stenops, PLOS ONE
The Smithsonian’s Deep Time hall shows a composite cast of Stegosaurus stenops facing a Ceratosaurus. Smithsonian NMNH virtual tour: Stegosaurus spikes vs. Ceratosaurus claws The Smithsonian’s label dates that Stegosaurus to 157 to 153 million years ago. Smithsonian NMNH virtual tour: Stegosaurus spikes vs. Ceratosaurus claws · checked 27 Oct 2026
Apex, New York
In 2024 a Stegosaurus called Apex sold at auction for a record $44.6 million, the most expensive fossil ever auctioned. Smithsonian Magazine: “Apex” sells for $44.6 million, 2024 Apex was discovered in May 2022 in the Morrison Formation in northwest Colorado. Smithsonian Magazine: “Apex” sells for $44.6 million, 2024
Apex has 254 of about 320 bones, roughly 80 percent of the skeleton. Smithsonian Magazine: Apex on display in New York, 2024 · checked 27 Oct 2026 Apex, a big old Stegosaurus, is 11.5 feet (3.5 m) tall and 27 feet (8.2 m) long, about 30 percent larger than others. Smithsonian Magazine: Apex on display in New York, 2024 · checked 27 Oct 2026
Apex went on display at the American Museum of Natural History in New York on 8 December 2024, on loan for four years. Smithsonian Magazine: Apex on display in New York, 2024 · checked 27 Oct 2026 Apex lived into old age, and the museum is studying a thigh-bone sample to learn how stegosaurs grew. American Museum of Natural History: Apex Stegosaurus fossil and “11 Questions About Stegosaurus” · checked 27 Oct 2026
Apex’s shoulder blade has a puncture wound with a bit of its own tail bone inside. It may have stabbed itself. Smithsonian Magazine: Apex on display in New York, 2024
Many scientists worry when important fossils go to private buyers, because they may not stay available for research. Smithsonian Magazine: “Apex” sells for $44.6 million, 2024
When it was sold, Apex was reported as 11 feet (3.4 m) tall and 20 feet (6.1 m) long, and more than 30 percent larger than Sophie. Smithsonian Magazine: “Apex” sells for $44.6 million, 2024 · checked 27 Oct 2026 Apex, a big old Stegosaurus, is 11.5 feet (3.5 m) tall and 27 feet (8.2 m) long, about 30 percent larger than others. Smithsonian Magazine: Apex on display in New York, 2024 · checked 27 Oct 2026 The two articles were written months apart. We haven’t found an explanation for the different lengths, so treat both as reported figures.