7-745: See text 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
14-729: 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 . This Ammonitina -related article is a stub . You can help Misplaced Pages by expanding it . Eoderoceratoidea Eoderoceratoidea
21-426: Is a superfamily of true ammonites (suborder Ammonitina ) from the Lower Jurassic , comprising seven phylogenetically related families, characterized in general by having ribbed evolute shells that commonly bear spines or tubercles. Adult shell size ranges from 2 or 3 cm to giants reaching 50 cm in such genera as Apoderoceras , Epideroceras , and Liparoceras . The earliest known eodoceroceratoidean
28-515: Is the eoderoceratid genus Microderoceras . Although its origin is uncertain, it is likely that it is derived from the Psiloceratoidea . It has also been proposed, with some imagination, that Microderoceas has its origin some earlier Jurassic lytoceratid such as Analytoceras . Seven families are included, beginning with the Eoceroceratidae, which gave rise at about the same time to
35-524: 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
42-799: The Phricodoceratidae, Coeloceratidae, Liparoceratidae, and Polyhmorphitidae. The Phricodoceratidae left no descendants but the Coeloceratidae later gave rise to the Dactylioceratidae and the Liparoceratidae to the Amaltheidae. The Polymorphitidae became the source for the superfamilies Hildocerataceae beginning with the Hildoceratidae. The more recent taxonomy of Donovan et al. (1981) with seven families, differs from that of Arkell, et al. in
49-633: The Treatise (1957) which included just five families. The phricodoceratids and coeoloceratids were then considered as subfamilies (Phricodoceratinae and Coeloceratinae, respectively) of the Eoderoceratidae. As later (1981) the Liparoceratidae and Polyhmorphitidae were derived from the Eoderoceratidae but the Dactylioceratidae were derived separately (1957) from the Lytoceratidae - a source since then largely rejected. This Ammonitina -related article
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