Amaltheus is an oxyconic ammonite with a fairly open umbilicus, serrated keel, and slightly sigmoidal ribs from the Lower Jurassic, many of which are strigate. Amaltheus, named by de Montfort, 1808, is indicative of the upper Pliensbachian stage in Europe, north Africa, Caucasus, Siberia, N. Alaska, Canada, Oregon, and possibly Honduras; and is the type for the Amaltheidae and a member of the Eoderoceratoidea.
Aspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae.
Asthenoceras is a genus of ammonoid from the Middle Jurassic with dwarfish, evolute, smooth, compressed, discoidal, strongly keeled shell. Asthenoceras belongs to the Sonniniidae and may be a subgenus of the Lower Jurassic Grammoceras.
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.
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.
Cadomites is an extinct ammonite genus from the superfamily Stephanoceratoidea that lived during the Middle Jurassic.
Newmarracarroceras is an ammonite from the early middle Jurassic with a ribbed subinvolute shell with a keel running along the venter, or outer rim. The umbilicus is moderately wide, exposing the inner whorls exposed in part.
Metrolytoceras is an extinct cephalopod genus that lived during the Middle Jurassic, characterized by a planispiral evolute shell with smooth middle and outer whorls, flat sides and simplified sutures.
Hebetoxyites is a genus of ammonoid cephalopod from the middle part of the Bajocian stage, middle Jurassic, included in the Strigoceratidae, Haploceratoidea. The shell is oxyconic, with a sharp rim but no keel, and involute, with the inner whorls hidden. The umbilicus is very small. Sides have a spiral ridge but are not striate.
Haplopleuroceras is a Middle Jurassic ammonite and likely member of the Hildoceratacean family Sonniniidae with which it shares the same sort of ribbing.
Graphoceras is an extinct ammonite genus included in the hildoceratacean family Graphoceratidae that lived during the Aalenian and Bajocian stages, Middle Jurassic in what is now Europe, north Africa, and Iran.
Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, listed below.
Peltoceras is an extinct ammonite genus from the aspidoceratid subfamily Peltoceratinae that lived during the later part of the Middle Jurassic.
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.
Kepplerites is a moderately evolute ammonite from the lower Callovian included in the Stephanoceratoidea.
The Aspidoceratinae is a subfamily in the perisphictacean ammonite family, Aspidoceratidae found world wide in middle and upper Jurassic sediments.
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.
Euaspidoceras is an extinct ammonoid cephalopod genus that lived during the Middle Jurassic.
Parkinsoniidae is a family of ammonites belonging to the order Ammonitida. The cephalopod family lived from the Bajocian stage to the Bathonian age of the Middle Jurassic.
