Mounted skeleton, North American Museum of Ancient Life
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Chordata
Clade:
Dinosauria
Clade:
†Ornithischia
Clade:
†Thyreophora
Clade:
†Stegosauria
Family:
†Stegosauridae
Subfamily:
†Stegosaurinae
Genus:
†Hesperosaurus Carpenter, Miles & Cloward, 2001
Species:
†H. mjosi
Binomial name
†Hesperosaurus mjosi
Carpenter, Miles & Cloward, 2001
Hesperosaurus (meaning "western lizard", from Classical Greek ἕσπερος (hesperos) "western" and σαυρος (sauros) "lizard") is a herbivorous stegosaurian dinosaur from the Kimmeridgian age of the Jurassic period, approximately 156 million years ago.
Fossils of Hesperosaurus have been found in the state of Wyoming and Montana in the United States of America since 1985. The type species Hesperosaurus mjosi was named in 2001. It is from an older part of the Morrison Formation, and so a little older than other Morrison stegosaurs. Several relatively complete skeletons of Hesperosaurus are known. One specimen preserves the first known impression of the horn sheath of a stegosaurian back plate.
Hesperosaurus was a member of the Stegosauridae, quadrupedal plant-eaters protected by vertical bony plates and spikes. It was closely related to Stegosaurus and was similar to it in having two rows of, possibly alternating, plates on its back and four spikes on its tail end. The plates on its back were perhaps not as tall, but were longer. It possibly had a deeper skull than Stegosaurus.
Fossils of Hesperosaurus have been found in the state of Wyoming and Montana in the United States of America since 1985. The type species Hesperosaurus mjosi...
cervicals and 17 dorsals, the total number being one greater than in Hesperosaurus, two greater than Huayangosaurus, although Miragaia preserves 17 cervicals...
stegosaurians, being closely related to either Dacentrurus and Hesperosaurus, or Hesperosaurus and Stegosaurus, depending on phylogenetic analysis. Carpenter...
pair pointing to the rear. The most derived species, like Stegosaurus, Hesperosaurus and Wuerhosaurus, have very large and flat back plates. To discern them...
Stegosaurid specimens originally described under the genera Wuerhosaurus and Hesperosaurus were referred to the genus Stegosaurus, under the names Stegosaurus...
basal stegosaurian Huayangosaurus. Later forms like Stegosaurus or Hesperosaurus had twelve or thirteen. Remarkably Miragaia had more neck vertebrae...
premaxilla is preserved. Like in Huayangosaurus but not Stegosaurus or Hesperosaurus, the nasal fenestra faces anterolaterally, being visible from the front...
found to be a heterodontosaurid. Plate-backed stegosaurids included Hesperosaurus mjosi, Stegosaurus armatus, S. ungulatus, S. stenops, and Alcovasaurus...
base length of twenty centimetres, are similar in profile to those of Hesperosaurus, though of a more reduced relative size. They were not "splates",[clarification...
comprising at least two species of Stegosaurus and the slightly older Hesperosaurus, and the early ankylosaurs, Mymoorapelta and Gargoyleosaurus, most notably...
found in the very lowest layer of the Morrison Formation, along with Hesperosaurus mjosi, Brontosaurus yahnahpin, and Allosaurus jimmadseni. There are...
American stegosaurians Stegosaurus stenops, Stegosaurus sulcatus and Hesperosaurus in that its sacrum is connected to the ilia by six pairs of sacral ribs...
Clifford Miles, and Karen Cloward described the new genus and species Hesperosaurus mjosi. Neil Donald Lewis Clark reported the discovery of near ends of...
Amphicoelias. Three genera of stegosaurs, Alcovasaurus, Stegosaurus and Hesperosaurus, have been found there. Finally, ornithopods found in the Morrison include...
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