Pronunciation: hes-PEHR-o-SOR-us
Meaning: Western lizard
Author/s: Carpenter et al. (2001)
Synonyms: None known
First Discovery: Wyoming, USA
Discovery Chart Position: #482
Hesperosaurus mjosi
Hesperosaurus is a spike-tailed stegosaurine dinosaur hailing from the Late Jurassic Morrison Formation of Wyoming, and is the oldest and most primitive stegosaur known from North America.
Well, that was the original diognosis. It had only been named for seven years before Susannah Maidement swung her axe in the general direction of Stegosauria and trimmed its numbers somewhat, assigning Hesperosaurus to Stegosaurus as Stegosaurus mjosi, but not every palaeontologist agreed.
Aside from wider than high alternating plates on its back and a deeper, broader skull, its remains were found very low in the Morrison Formation which makes it older than any known species of Stegosaurus. It appears to be closer to Dacentrurus.
Well, that was the original diognosis. It had only been named for seven years before Susannah Maidement swung her axe in the general direction of Stegosauria and trimmed its numbers somewhat, assigning Hesperosaurus to Stegosaurus as Stegosaurus mjosi, but not every palaeontologist agreed.
Aside from wider than high alternating plates on its back and a deeper, broader skull, its remains were found very low in the Morrison Formation which makes it older than any known species of Stegosaurus. It appears to be closer to Dacentrurus.
(Mjos's Western Lizard)
Etymology
Discovery
The fossils of Hesperosaurus were discovered in Buffalo Quarry at S.B. Smith Ranch, stratigraphic zone 1 of the Morrison Formation, Johnson County, Wyoming, USA, by Patrick McSherry in June 1985.
The holotype (HMNH 001) is a skull and partial skeleton, minus the legs.
Preparators
Ronald G. Mjos.
