Ammonitida or "True ammonites" are an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures.
Arctogymnites is a genus of ammonoid cephalopods from the middle Triassic included in the ceratitid subfamily Beyrichitinae. Related genera include Beyrichites, Frechites, Gymnotoceras, and Salterites
Badiotites is a genus of extinct ammonoid cephalopods belonging to the ceratitid family Badiotitidae. It was previously included with Lecanites in the Lecanitidae, a family formerly of the Clydonitaceae but reassigned by Tozer (1981) to the Danubitaceae. The Badiotitidae is included in the Ceratitaceae.
Dobrogeites is a genus of ammonoids from the order Ceratitida, included in the family Megaphyllitidae that produced evolute compressed planispiral shells with rounded venters, inner whorls ornamented as in Tirolites, outer whorls smooth, suture with multiple smooth lobes; Initially found in Anisian sediments in Romania.
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic ammonites.
Xenodiscoidea, formerly Xenodiscaceae, is a superfamily within the ammonoid order Ceratitida. The superfamily was named by Frech in 1902, presently contains ten families, only one of which was included in the original Otocerataceae of Hyatt, 1900, the remaining having been added.
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.
Ancyloceratoidea, formerly Ancylocerataceae, is a superfamily of typically uncoiled and loosely coiled heteromorph ammonoids established by Alpheus Hyatt in 1900, that may contain as many as 11 families, depending on the classification accepted.
Ceratitoidea, formerly Ceratitaceae, is an ammonite superfamily in order Ceratitida characterized in general by highly ornamented or tuberculate shells with ceratitic sutures that may become goniatitic or ammonitic in some offshoots.
The Trachyceratidae is an extinct family of ceratitid ammonoid cephalopods.
The Tropitidae is a family of Upper Triassic Ammonoidea belonging to the Tropitoidea, a superfamily of the Ceratitida
Lecanites is a ceratitid genus assigned to the Danubitaceae, with an essentially smooth, evolute, discoidal shell and a goniatitic suture with many elements. It is the type and now only genus of the Lecanitidae.
The Danubitoidea is a large and diverse superfamily in the order Ceratitida of the Ammonoidea that combines five families removed from the Ceratitaceae, Clydonitaceae, and Ptychitaceae.
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.
Gymnites is a genus of ammonoid cephalopod from the Middle Triassic belonging to the ceratitid family Gymnitidae. These nektonic carnivores lived during the Triassic period, the Anisian age.
Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute, discoidal shells.
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.
Aplococeratidae is a family of ceratitids from the Middle Triassic with very simplified sutures and a tendency to lose their ornamentation. Shells are generally evolute, more or less compressed, with rounded venters. Ornamentation if present consists of umbilical ribs that disappear outwardly, toward the venter. The suture is ceratitic or goniatitic.
Dieneria is a genus of ceratitid ammonoid cephalopods from the Late Triassic of western North America with a smooth discoidal shall of which the venter is truncate and the suture simple. Only the first lateral lobe is slightly serrated, the other lobes entire (smooth)
Protrachyceras is a genus of ceratitid ammonoid cephalopods belonging to the family Trachyceratidae.
