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Simoceratinae
The Simoceratinae is a subfamily in the Aspidoceratidae, a family of ammonites in the Perisphinctaceae Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic (Bajocian) to Lower Cretaceous (Barremian) ammonites, commonly with evolute shells with strong ribbing that typically divides about mid flank before crossing the ven ..., that lived during most of the Late Jurassic, especially in the Pacific and Tethyan realms. Early genera more closely resemble Perisphictidae and have constricted apertures. Later, more aberrant forms are unconstricted and develop grooved or concave venters. ''References'' * Arkell, et al., 1957. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L. (Ammonoidea). Geol Soc of America and Univ Kansas Press. Jurassic ammonites Aspidoceratidae {{Ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspidoceratidae
The Aspidoceratidae comprise a family of middle and upper Jurassic ammonites that make up part of the superfamily Perisphinctoidea, characterized by evolute shells, commonly stocky, that tend to develop tubercles. The Aspidoceratidae are thought to be derived from the Perisphinctidae and have been subdivided into three subfamilies, the Aspidoceratinae, Peltoceratinae, and Simoceratinae. Subfamilies and genera * Aspidoceratinae Zittel 1895 ** '' Aspidoceras'' ** '' Chinamecaceras'' Cantu-Chapa 2006 ** ''Epaspidoceras'' ** '' Euaspidoceras'' ** ''Orthaspidoceras'' * Peltoceratinae Spath 1924 ** ''Peltoceras'' ** '' Peltoceratoides'' ** ''Rursiceras'' * Simoceratinae The Simoceratinae is a subfamily in the Aspidoceratidae The Aspidoceratidae comprise a family of middle and upper Jurassic ammonites that make up part of the superfamily Perisphinctoidea, characterized by evolute shells, commonly stocky, tha ... ** '' Simoceras'' ** '' Virgatosimoceras'' References * Arkel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perisphinctaceae
Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic (Bajocian) to Lower Cretaceous (Barremian) ammonites, commonly with evolute shells with strong ribbing that typically divides about mid flank before crossing the venter. Classification Some 16 families have been recognized in the Perisphinctoidea. The following is based on Donovan ''et al.'' 1981Donovan, Callomon and Howarth 1981 Classification of the Jurassic Ammonitina; Systematics Association. with modification from the Treatise on Invertebrate Paleontology, Part L (1957) *Perisphinctidae: Middle and Upper Jurassic root stock, derived from the Stephanoceratidae (Middle Jurassic direct derivatives of the Perisphinctidae) * Morphiceratidae * Tulitidae *Reineckeiidae *Pachyceratidae *Aspidoceratidae (early Upper Jurassic (Oxfordian) derivatives of Perisphinctidae) *Aulacostephanidae *Ataxioceratidae (mid Upper Jurassic (Kimmeridgian) derivatives of the Ataxioceratidae) * Dorsoplanitidae * V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic Ammonites
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined. By the beginning of the Jurassic, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
