Huayangosauridae

Huayangosaurids Temporal range: Callovian to Barremian/Aptian boundary line,
Holotype skull of Huayangosaurus taibaii
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Thyreophora
Clade:	†Stegosauria
Family:	†Huayangosauridae Dong et al., 1982
Genera
Chungkingosaurus Huayangosaurus
Synonyms
Huayangosaurinae Dong et al., 1982

Huayangosauridae (derived from Huayangosaurus, "Huayang reptile") is a family of stegosaurian dinosaurs from the Jurassic of China. The group is defined as all taxa closer to the namesake genus Huayangosaurus than Stegosaurus, and was originally named as the family Huayangosaurinae by Dong Zhiming and colleagues in the description of Huayangosaurus. Huayangosaurinae was originally differentiated by the remaining taxa within Stegosauridae by the presence of teeth in the premaxilla, an antorbital fenestra, and a mandibular fenestra. Huayangosaurinae, known from the Middle Jurassic of the Shaximiao Formation, was proposed to be intermediate between Scelidosaurinae and Stegosaurinae, suggesting that the origins of stegosaurs lay in Asia. Following phylogenetic analyses, Huayangosauridae was expanded to also include the taxon Chungkingosaurus, known from specimens from younger Late Jurassic deposits of the Shaximiao Formation. Huayangosauridae is either the sister taxon to all other stegosaurs, or close to the origin of the clade, with taxa like Gigantspinosaurus or Isaberrysaura outside the Stegosauridae-Huayangosauridae split. Huayangosauridae was formally defined in 2021 by Daniel Madzia and colleagues, who used the previous definitions of all taxa closer to Huayangosaurus taibaii than Stegosaurus stenops, and chose the 2020 phylogeny of Susannah Maidment et al. to illustrate the relationships of the clade:

Stegosauria	Gigantspinosaurus Isaberrysaura Stegosauridae Huayangosauridae Chungkingosaurus Huayangosaurus