Ammonoids are an extinct group of 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 than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species died out in the Cretaceous–Paleogene extinction event.
Goniatids, informally Goniatites, are ammonoid cephalopods that form the order Goniatitida, derived from the more primitive Agoniatitida during the Middle Devonian some 390 million years ago. Goniatites (goniatitida) survived the Late Devonian extinction to flourish during the Carboniferous and Permian only to become extinct at the end of the Permian some 139 million years later.
Nautiloids are a large and diverse group of marine cephalopods (Mollusca) belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus and Allonautilus. Nautiloids flourished during the early Paleozoic era, where they constituted the main predatory animals, and developed an extraordinary diversity of shell shapes and forms. Some 2,500 species of fossil nautiloids are known, but only a handful of species survive to the present day.
Ammonitida is an order of more highly evolved ammonoid cephalopods that lived from the Jurassic through Cretaceous time periods, commonly with intricate ammonitic sutures.
The Emsian is one of three faunal stages in the Early Devonian epoch. It lasted from 407 ± 2.8 million years ago to 397.5 ± 2.7 million years ago. It was preceded by the Pragian stage and followed by the Eifelian stage.
The Pragian is one of three faunal stages in the Early Devonian epoch. It lasted from 411.2 ± 2.8 million years ago to 407 ± 2.8 million years ago. It was preceded by the Lochkovian stage and followed by the Emsian stage. The most important lagerstätte of the Pragian is Rhynie chert in Scotland.
Xenodiscus is an extinct ammonoid cephalopod genus and one of the earliest ceratites, found in the Upper Permian of northern India and Timor. Xenodiscus is included in the family Xenodiscidae which is part of the ceratite superfamily Xenodiscaceae
Agathiceras is a subglobose goniatitid from the family Agathiceratidae, widespread and locally abundant in Lower Pennsylvanian to Middle Permian sediments, e.g. the Urals, Sicily, and Texas.
The Xenodiscaceae is a superfamily within the ammonoid order Ceratitida. The Xenodiscaceae, 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.
Goniatitina is one of two suborders included in the order Goniatitida; extinct Paleozoic ammonoid cephalopods only distantly related to the Nautiloidea.
Cheiloceratidae is a family of ammonoid cephalopods included in the goniatitid suborder Tornoceratina in which the suture has 4 to 12 lobes, the ventral one undivided and those in the lateral areas originating as subdivisions of internal and external lateral saddles.
Prionoceratidae is one of seven families of the Prionocerataceae families, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.
Tornoceratoidea, also known as Tornocerataceae, is a superfamily of goniatitid ammonoids included in the suborder Tornoceratina. Tornoceratoidea, or Tornocerataceae, is essentially the Cheilocerataceae of Miller, Furnish, and Schindewolf (1957) in the Treatise Part L, revised to accommodate new taxa and new perspectives on the phylogeny.
Tornoceratidae is a family of goniatitid ammonoids from the middle and upper Devonian. The family is included in the suborder Tornoceratina and the superfamily Tornoceratoidea.
The Cravenoceratidae is one of six families included in the ammonoid superfamily Neoglyphiocerataceae, which lived during the latter part of the Paleozoic era.
Eryonidae is a family of fossil decapod crustaceans which lived from the Upper Triassic to the Lower Cretaceous. It contains four genera: An aggregation of three unidentified eryonids was reported in 2012 inside a Late Jurassic ammonoid of the species Harpoceras falciferum; they represent the earliest evidence of gregarious behaviour in decapods.
Clymeniida is an order of ammonoid cephalopods from the Upper Devonian characterized by having an unusual dorsal siphuncle. They measured about 4 cm (1.6 in) in diameter and are restricted to Europe, North Africa, and possibly Australia.
Clymeniidae is a family in the ammonoid order Clymeniida. It is characterized by a dorsal siphuncle that runs along the inside of the whorls, unusual for ammonoids.
Phyllopachyceras is an extinct genus of ammonoid cephalopods belonging to the family Phylloceratidae. These nektonic carnivores lived in the Cretaceous, from Hauterivian to Maastrichtian to age.
Protrachyceras is a genus of ceratitid ammonoid cephalopods belonging to the family Trachyceratidae.
