Wikipedia
The Fabrosauridae is an obsolete group of basal ornithischian dinosaurs from the Early to Middle Jurassic, originally proposed by Galton ( 1972). Recent studies indicate the Fabrosaurs are not a natural grouping of dinosaurs, and instead consist of unrelated genera.
The proposed "Fabrosaurs" descended from a Lesothosaurus-like animal. Proposed fabrosaurids were 1–2 meters long, and were lightly built and bipedal. Their skulls were triangular and had very large eye sockets. They were herbivorous and would have used agility to escape predators.
Fabrosaurids are known from southern Africa in the Upper Triassic and Lower Jurassic, as well as in China from the Middle and Upper Jurassic periods. Fabrosaurids bear a semblance to many other members of Ornithischia, and have attracted much interest in phylogenetic studies. However, most genera that were previously referred to as Fabrosauridae are only known from fragmented and partial remains, with most based on no more than isolated teeth, and their place in Fabrosauridae is questionable.
Galton in 1972 originally proposed the creation of Fabrosauridae based on the finding of cheek teeth. The successive discovery (1990) of a Middle Jurassic primitive ornithischian, Agilisaurus louderbacki, found in the Xiashaximiao Formation of Zigong, Sichuan Basin, China, has led to paleontologists learning more about the phylogeny of fabrosaurids.
Fabrosaurids have many characters that are unique to their physiology, particularly unique tooth morphology and structure, and short forelimb lengths compared to hindlimbs. Unlike many other primitive Ornithischians, such as heterodontosaurids and hypsilophodontids, the teeth of fabrosaurids are very thinly and uniformly enameled. Compared to Agilisaurus, Fabrosaurus is much more primitive in that it has six premaxillary teeth, and a stout prepubis. Agilisaurus differs from Fabrosaurus in that it appears to be larger and more well developed in structure.
The Upper Jurassic ornithischian dinosaur, Gongubusaurus, from China, is thought to be more closely related to fabrosaurids than hypsilophodontids. The type species, G. shiyii, is from the Shangshaximiao Formation in the Rongxian County in Sichuan Basin, has been classified from only a few scattered teeth.