"Amargastegos''' (meaning "covered being from La Amarga") is the informal name for a genus of extinct stegosaurid ornithischian dinosaur. The type species and only current species is "A. brevicollus", the species name derived from the unique trait of short cervical vertebrae. "Amargastegos" is one of few genera of stegosaurid from the Southern Hemisphere, along with traces from Bolivia and the South African genus Paranthodon. The new name is registered in the Official Registration of Zoological Nomenclature, or Zoobank, a requirement for validity. The "Amargastegos" holotype and only specimen, MACN N-43, comes from the La Amarga Formation of Argentina, and dates specifically to the boundary of the Barremian and Aptian, about 125mya. It includes some dorsal osteoderms, the cervical and caudal vertebrae, and one skull bone. In 2016, Peter Malcolm Galton and Kenneth Carpenter declared it a nomen nudum, establishing it as an indeterminate stegosaur.
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