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Genus: | Oecoptychius |
Oecoptychius is an extinct genus of fossil ammonite cephalopods. The species lived during the Middle Jurassic. [1]
Oecophtychius was named by Neumayr[ who? ] in 1878. It is placed into Oecoptychitidae, a family of dwarf ammonites established by Arkell[ who? ], 1957, that is a part of the superfamily Stephanoceratoidea.[ citation needed ]
Oecoptychius is an eccentrically coiled, dwarf ammonite. Inner whorls smooth, spheroidal; outer whorls with fine biplicate ribbing, ventral groove, and an acute elbow at half a whorl before the aperture; peristome contracted, with outwardly directed lappets.[ citation needed ]
Fossils of the Oecophtychius species have been found in Jurassic sediments of France, Germany and Madagascar. [2]
Stephanoceras is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian. It is the type genus of the family Stephanoceratidae.
Australiceras is an extinct ammonite genus from the upper part of the Early Cretaceous, Aptian stage, included in the family Ancyloceratidae.
Alsatites is an extinct genus of cephalopod belonging to the Ammonite subclass. They lived during the Early Jurassic, Hettangian till the Sinemurian and are generally extremely evolute, many whorled. Keel broad and blunt organisms, they also exhibit a primary ribbing which is close and persistent.
Aspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae.
Audaxlytoceras is an extinct genus of lytoceratid ammonites.
Balticeras is an involute, discoidal Upper Jurassic (Oxfordian) ammonite found in England, Germany, and Switzerland, belonging to the Perisphinctidae. The shell is strongly embracing, tending to be oxyconic. Sides are gently curved, converging on a narrow to sharp ventral rim.
Docidoceras is an extinct ammonite genus from the order Ammonitida that lived during the Middle Jurassic. Docidoceras is included in the family Otoitidae which makes up part of the ammonite superfamily Stephanoceratoidea.
Zurcheria is a genus of dwarf ammonites from the Middle Jurassic included in the Hammatoceratidae and lacking a keel. The shell is evolute, inner whorls exposed; whorls compressed and slightly overlapping. Bears ribs, which are sinuous folds that project strongly onto the arched venter.
Dorsetensia is a narrowly coiled discoidal ammonite from the early Middle Jurassic, lower Bajocian, belonging to the family Sonniniidae of the superfamily Hildoceratoidea. The inner whorls are ribbed or smooth, outer whorl is smooth. The outer rim (venter) is narrow, with a keel running along the middle. The umbilicus, the opening in the middle of the shell exposing inner whorls, is of moderate size with a sharp, sometimes undercut edge.
Oecotraustes is an extinct cephalopod genus included in the ammonid family Oppeliidae and named by Waagen in 1869. The genus lived during the Middle Jurassic.
Normannites is a strongly ribbed evolute Middle Jurassic genus of ammonite included in the stephanoceratoid family Stephanoceratidae.
Liparoceras is an extinct fossil ammonite species from the Early Jurassic period of England, and is found in lower Lias deposits. Its name means 'fat head' and this is due to its broad shell. The venter is wide and finely ribbed with no keel and it has two rows of tubercules on each whorl.
Peltoceras is an extinct ammonite genus from the aspidoceratid subfamily Peltoceratinae that lived during the later part of the Middle Jurassic.
Oxynoticeratidae is a family of true ammonites included in the superfamily Psiloceratoidea.
Eoderoceras is an evolute, round whorled ammonite from the Lower Jurassic with an outer row of distinct spines, and in some, an inner row of tubercles, on either side; ribs only on the inner whorls.
Kepplerites is a moderately evolute ammonite from the lower Callovian included in the Stephanoceratoidea.
Megalytoceras is an extinct genus of ammonite from the middle Jurassic, belonging to the suborder Lytoceratina.
Hemilytoceras is a lytoceratin ammonite genus with round inner whorls, outer whorls becoming depressed and in some developing high lamellae (ribs) that bend forward over the venter. The type species H. immanae came from the Tithonian of Europe. The genus is known from the overall Upper Jurassic of central and southern Europe, North Africa, and western India.
Lobolytoceras is an extinct genus of ammonite in which only the inner whorls have large swollen ribs, later whorls have wrinkled growth lines which coarsen somewhat, near the aperture. The genus is known from the Lower Jurassic Toarcian of Europe. The type species L. siemensi (Denck) came from the Upper Toarcian of Germany.
Holcodiscus is an ammonite genus placed in the family Holcodiscidae. Species in this genus were fast-moving nektonic carnivores. The type species of the genus is Ammonites caillaudianus.
This article includes a list of general references, but it remains largely unverified because it lacks sufficient corresponding inline citations .(March 2015) |