Stephanoceras is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian. It is the type genus of the family Stephanoceratidae.
Acanthoceras is an extinct cephalopod genus belonging to the subclass Ammonoidea and family Acanthoceratidae that lived from the Albian to early Coniacian stages of the Cretaceous.
Anagaudryceras is an extinct genus of ammonite from the later Cretaceous belonging to the Ammonoidea family Gaudryceratidae. Anagaudryceras has a moderately involute shell with a deep umbilicus and strongly ribbed outer whorl. Ribs are thick and rounded and cross over the venter uninterrupted.
Astieridiscus is an extinct lower Cretaceous ammonite. Its shell evolute, covered by dense, simple or branching, slightly flexuous ribs. The sides are slightly flattened, the venter rounded. No umbilical or other tubercles except on innermost whorl. Superficially resembles Olcostephanus.
Armatites is an Upper Devonian goniatitid included in the tornoceratid family. The shell, or conch, is discoidal, with flattened flanks, a flattened venter with a double keel, and a deep ventral sinus, but without ventrolateral grooves. The lateral saddle of the suture is broad. Armatites is known from the Upper Devonian (Fammenian) of Canning Basin in Australia. The subfamily in which it is included, the Aulatornoceratinae is also known from France with the genus Aulatornoceras.
Anisoceras is a heteromorph ammonite belonging to the turrilitoid family Anisoceratidae. The shell forms a loose open helical spiral in the early stages, ending in one or two straight shafts in the mature adult. Surface ornament consists of prominent rounded nodes on the lower and upper flanks, connected by strong looped ribs. The nodes may have been the bases of long sharp spines.
Barremites is an ammonoid cephalopod belonging to the family Desmoceratidae, that lived during the Hauterivian and Barremian stages of the Early Cretaceous. Its shell is moderately to very involute, with the outer whorl strongly embracing the inner whorls, and variably compressed. Sides are generally smooth and marked with sinuous or falcate collars marking intervals of growth and bearing feeble striae to moderately distinguished ribs.
Coilopoceratidae is a family of generally large, proper ammonites with strongly involute shells from the Cretaceous, Albian to Turonian. Coilopoceratids have variably compressed shells with flattish to broadly rounded sides and narrowly rounded to sharp keel-like venters. Whorl sections are generally lanceolate. The suture is ammonitic with an overall clumpy appearance.
Ammonitina comprises a diverse suborder of ammonite cephalopods that lived during the Jurassic and Cretaceous periods of the Mesozoic Era. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods.
Bostrychoceras is a genus of heteromorph ammonite from the family Nostoceratidae. Fossils have been found in Late Cretaceous sediments in Europe and North America.
Heteroceras is a Lower Cretaceous heteromorph ammonite belonging to the ancyloceratacian family, Heteroceratidae, characterized by a helically coiled juvenile shell at the apex followed by slightly curved adult shaft, with a J-shaped section at the end of it. The shell is ribbed; ribs are concave and oblique on the helix, straight and transverse on the later stages.
Hoploscaphites is an extinct ammonite genus from the Upper Cretaceous and the Lower Paleocene, included in the family Scaphitidae.
Zetoceras is an extinct ammonoid cephalopod genus from the suborder Phylloceratina that lived during the Early and Middle Jurassic in what is now Europe, and is included in the (family) Phylloceratidae.
Hildoceratidae is a family of ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian to lower Bajocian substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae, Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea.
Perisphinctidae is a family of Middle and Upper Jurassic discoidal ammonites in the order Ammonitida. They have a shell morphology that is mostly evolute, typically with biplicate, simple, or triplicate ribbing. Large forms have simple apertures and smooth body chambers while small forms have lappets and ribbed body chambers.
Grammoceras is an extinct genus of ammonite found in Yorks Ravenscar, England, from Jurassic period sediments. Its overall distribution is fairly worldwide.
Polonoceras is a genus included in the goniatitid subfamily Aulatornoceratinae named by Dybczynski, 1913. The type species is Polonoceras planum Dybczynski. According to Miller, et al. in the American Treatise on Invertebrate Paleontology, 1957, Polonoceras is a subgenus of Tornoceras.
Bisatoceras is a late Paleozoic Ammonoidea, a member of the goniatitid family Bisatoceratidae.
The Acanthoceratinae comprise a subfamily of ammonoid cephalopods that lived during the Late Cretaceous from the latter early Cenomanian to the late Turonian
Euomphaloceras is an early Upper Cretaceous ammonite genus,, included in the Acanthoceratinae until established as the type genus for the Euomphaloceratinae by Cooper, 1978.
