Alcovasaurus

Type Species: Alcovasaurus longispinus

Classification: Dinosauria – Ornithischia – Thyreophora – Stegosauria – Stegosauridae – Dacentrurinae

Time Period: Late Jurassic

Location: North America

Diet: Herbivore

The North American stegosaur Alcovasaurus grew up to eighteen feet in length; this medium-sized stegosaur would’ve been a low browser in prehistoric North America. Its main enemies would’ve included the theropods Allosaurus, Torvosaurus, and perhaps Ceratosaurus. Much of Alcovasaurus’ anatomy is unknown, but because what we do know is similar to the African Kentrosaurus, most reconstructions make it similar to its African contemporary. Alcovasaurus was originally identified as a species of Stegosaurus. This classification was questioned, however, due to five significant anatomical differences, not least its long dermal spikes. Alcovasaurus had two tail spike pairs as its thagomizer that were slender and elongated and ninety percent of the thighbone length. Some scientists argued that these larger spike pairs weren’t indicative of a different species but of sexual dimorphism used for display; perhaps, the argument went, male stegosaurs had flashier thagomizers. Other scientists argued that this stegosaur was less closely related to Stegosaurus and had more affinity with the African Kentrosaurus. Serious studies of this dispute were hampered when the type specimen was damaged by water after a pipe burst at the University of Wyoming; studies couldn’t continue until more specimens were recovered. Recently those scientists who argued for Alcovasaurus being a different genera won out, and Alcovasaurus is now differentiated from its contemporary Stegosaurus.