Liparoceratidae is a family of eoderoceratoidean ammonites from the Lower Jurassic that combines genera with a variety of forms including dimorphs that change from one form to another during ontogeny. Three genera and six subgenera are included in the Liparoceridae according to D.T. Donovan in Donovan et al. 1981; Liparoceras including L. (Liparoceras), L. (Becheiceras), and L. (Vicininodiceras); Aegoceras including A. (Aegoceras), A. (Beaniceras), and A. (Oistoceras); and Androgynoceras. Arkell, et al. (1957) in the Treatise on Invertebrate Paleontology, Part L list Liparoceras with Becheiceras and Vincininodiceras along with Parinodiceras separately as subgenera; Beaniceras, Metacymbites, Oistoceras, and Platynoticeras but leave out Aegoceras. Parinodiceras and its equivalent, Platynoticeras are removed (Donovan 1981) to the Polymorphitidae. Metacymbites is a smooth dwarf and may form a dimorphic pair with Liparoceras. The Liparoceratidae are thought to have evolved from the Eoderoceratidae along with the Coeloceratidae and Polymorphidae close to the same time during the Sinemurian stage of the Early Jurassic, and in the following Pliensbachian gave rise to the Amaltheidae. References Arkell, et al., 1957. Mesozoic Ammonoidea, in Treatise on Invertebrate Paleontology, (Part L); Geological Soc. of America and University of Kansas press. Donovan, Callomon and Howarth 1981 Classification of the Jurassic Ammonitina; Systematics Association. Ammonitida families Eoderoceratoidea Pliensbachian first appearances Early Jurassic extinctions