Stephanoceratidae

	Stephanoceratidae Stephanoceratidae is a family of planulate and coronate ammonites within the Stephanoceratoidea.Arkell, Kummel, and Wright, 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Shells are evolute so that all whorls are exposed and have strong ribbing that bifurcates, that is splits in two, on the flanks. Many have tubercles at the point of bifurcation. Whorl sections are generally subequant; the outer rim, or venter, commonly rounded. Stephanoceratidae is derived from the Otoitidae Otoidtidae: stephanoceratoid ammonitina from the early Middle Jurassic that begin as cadicones but become more planualte with age; derived from the Hammitoceratidae (Hildoceratoidea), probably through '' Erycites'' by way of ''Abbasites''. Sh .... Their fossils are found in upper Middle- and lower Upper Jurassic sediments. Subfamilies and genera * Cadomitinae * Frebolditinae * Garantianinae * Mollistephaninae * Stephanoceratinae '' Ermoceras'' '' Kosmermoceras' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Stephanoceratoidea Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed to be mostly granular (Granulaptycus) or concentrically ribbed on the surface (Praestriaptychus) (Arkell ''et al.'' 1957) Morphologic variation The shells of the Stephanoceratoidea, which determine the different included families, are highly variable in form. They are discoidal and evolute with all whorls exposed, spheroidal and involute with only the outer whorl showing, cadiconic with a deep umbilicus and broad ventral margin, and oxiconic with the ventral margin sharp. They are united by being generally sharply ribbed and by their complex suture lines with a dominant 1st lateral lobe and a well-developed umbilical lobe. (Arkell ''et al.'' 1957) Taxonomy Stephanoceratoidea contains five families according to Donovan ''et al.'' (1981), a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Skirroceras ''Skirroceras'' is a Stephanoceratacean (ammonite) genus belonging to the family Stephanoceratidae. These fast-swimming carnivores lived during the Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), 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 J ... period, in the Bajocian age.Sepkoski, JacSepkoski's Online Genus Database – Cephalopoda/ref> Selected species '' Skirroceras bayleanum'' (Oppel, 1857) '' Skirroceras macrum'' (von Quenstedt) '' Skirroceras leptogyrale'' Buckman References External links Jurassic ammonites Jurassic animals of Africa Jurassic animals of Europe Ammonitida genera Stephanoceratoidea {{ammonitina-stub ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
	Otoitidae Otoidtidae: stephanoceratoid ammonitina from the early Middle Jurassic that begin as cadicones but become more planualte with age; derived from the Hammitoceratidae (Hildoceratoidea), probably through '' Erycites'' by way of ''Abbasites''. Shells begin barrel shaped with depressed whorls, broad outer rims, and deep, crater-like umbilici—cadiconic—but become compressed, with the out rims becoming bluntly rounded—planulate. Ribbing is common; may be heavy and tuberculate on the umbilical shoulders and may divide along the flanks before crossing the outer rim -the venter- uninterrupted. The Otoitidae is the ancestral family of the Stephanoceratoidea and is known only from a relatively short interval of time within the Bajocian In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.3 Ma to around 168.3 Ma (million years ago). The Bajocian Age succeeds the Aalenian Age and precedes the Bathonian Age. Stra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Ermoceras ''Ermoceras'' is a genus of ammonite belonging to the Thomboceratidae family of the Middle Jurassic ( u Baj) found in deposites of central Arabia, Sinai, and Algeria with strong primary and secondary ribs and a single row of lateral tubercles; described as having a deep ventral groove Arkell et al 1957, Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Ammonoidea ''Telermoceras'', with low, depressed whorls, and ''Kosmermoceras'' with high, compressed whorls are considered subgenera of ''Ermoceras'' Both are from the same time and region. ''Telermoceras'' has coarse secondary ribs and a deep umbilicus surrounded by large tubercles or spines. ''Kosmermoceras''has fine sharp to coarse ribbing and a flattish venter ''Ermoceras'' ''s.l.'' is derived from '' Arkelloceras''. Westermann (1965)Westernamm ,G. E. G. 1965.Septal and Sutural Patterns in Evolution and Taxonomy of Thamboceratidae and Clydoniceratidae (M Jurassic Ammonitina).Jour of Paleontology 39(5)864 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), 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, 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, 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 Anoxic event, oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar, Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Ammonitida Families Ammonitida is an order of Ammonoidea, ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, and Ammonitina. The Phylloceratina is the ancestral stock, derived from the Ceratitida near the end of the Triassic. The Phylloceratina gave rise to the Lytoceratina near the beginning of the Jurassic which in turn gave rise to the highly specialized Ancyloceratina near the end of the Jurassic. Both the Phylloceratina and Lytoceratina gave rise to various stocks combined in the Ammonitina. These four suborders are further divided into different stocks, comprising various families combined into superfamilies. Some like the Hildoceratoidea and Stephanoceratoidea are restricted to the Jurassic. Others like the Hoplitoidea and Acanthoceratoidea are known only from the Cretaceous. Still others like the Perisphinctoidea are found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Kumatostephanus ''Kumatostephanus'' is an extinct genus from a well-known class of fossil cephalopods, the ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...s. It lived during the Jurassic Period, which lasted from approximately 200 to 145 million years ago. It was slow moving and likely to fall victim to large predators such as Liopleurodon, or small mosasaurs. References Jurassic ammonites Ammonites of Europe Ammonitida genera Stephanoceratoidea {{ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Kosmermoceras ''Kosmermoceras'' is an extinct genus from a well-known class of fossil cephalopods, the ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...s. It lived during the Jurassic Period, which lasted from approximately 200 to 145 million years ago. References Jurassic ammonites Ammonitida genera Stephanoceratoidea {{ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]