"Ammonite" redirects here. For other uses, see Ammonite (disambiguation).
Not to be confused with Amniote.
Extinct subclass of cephalopod molluscs
Ammonoids
Temporal range: 409–65 Ma
PreꞒ
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
Devonian - Danian (controversial early Paleocene records)
Specimen of Pleuroceras solare, from the Lower Jurassic of Bavaria, Germany
Scientific classification
Domain:
Eukaryota
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Cephalopoda
Clade:
Neocephalopoda
Subclass:
†Ammonoidea Zittel, 1884
Orders
†Agoniatitida
†Ammonitida
†Ceratitida
†Clymeniida
†Goniatitida
†Prolecanitida
Ammonoids are extinct spiral shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) than they are to shelled nautiloids (such as the living Nautilus).[1] The earliest ammonoids appeared during the Devonian, with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event. They are often called ammonites, which is most frequently used for members of the order Ammonitida, the only living group of ammonoids from the Jurassic up until their extinction.[2]
Ammonites are excellent index fossils, and linking the rock layer in which a particular species or genus is found to specific geologic time periods is often possible. Their fossil shells usually take the form of planispirals, although some helically spiraled and nonspiraled forms (known as heteromorphs) have been found.
The name "ammonite", from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder (d. 79 AD near Pompeii) called fossils of these animals ammonis cornua ("horns of Ammon") because the Egyptian god Ammon (Amun) was typically depicted wearing rams' horns.[3] Often, the name of an ammonite genus ends in -ceras, which is from κέρας (kéras) meaning "horn".
^Klug, Christian; Kröger, Björn; Vinther, Jakob; Fuchs, Dirk (August 2015). "Ancestry, Origin and Early Evolution of Ammonoids". In Christian Klug; Dieter Korn; Kenneth De Baets; Isabelle Kruta; Royal H. Mapes (eds.). Ammonoid Paleobiology: From macroevolution to paleogeography. Topics in Geobiology 44. Vol. 44. Springer. pp. 3–24. doi:10.1007/978-94-017-9633-0_1. ISBN 978-94-017-9632-3.
^"What is an ammonite?". www.nhm.ac.uk. Retrieved 2023-12-21.
Ammonoids are extinct spiral shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living coleoids (i.e., octopuses, squid...
cephalopods have been identified. Two important extinct taxa are the Ammonoidea (ammonites) and Belemnoidea (belemnites). Extant cephalopods range in...
The Nusplingen Limestone (German: Nusplingen Plattenkalk) is a geological formation in Baden-Württemberg, Germany. It preserves fossils dating to the Kimmeridgian...
Barremitinae is a subfamily belonging to the Ammonoidea subclass. Whorl section in this group ranges from more or less circular through rectangular to...
the Anarcestida, is the ancestral order within the cephalopod subclass Ammonoidea originating from bactritoid nautiloids, that lived in what would become...
is not elaborate. Arkel et al., Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geological Society of America & University...
Permian Ammonoidea. Miller, Furnish, and Schindewolf (1960) ; Paleozoic Ammonoidea, in the Treatise on Invertebrat Paleontology, Part L, Ammonoidea Furnish...
primarily orthoconic orders (including the ancestors for Bacritida and Ammonoidea); and Nautilitoidea, which includes the first coiled cephalopods, Tarphycerida...
Eleniceras is an extinct genus of cephalopods belonging to the Ammonoidea subclass. The genus was named after the Bulgarian town of Elena. The holotype...
Cyclolobidae: Goniatitid Ammonoidea belonging to the Cycloloboidea with thickly discoidal to subglobular shells with a small but open umbilicus and ammonitic...
List of mollusc orders illustrates the 97 orders in the phylum Mollusca, the largest marine animal phylum. 85,000 extant species are described, making...
crinoids are all abundant in the oceans. First fully coiled cephalopods (Ammonoidea and Nautilida, independently) with the former group very abundant (especially...
Eleniceras nikolovi is an extinct species of cephalopods belonging to the Ammonoidea subclass. This animal lived 140–129 million years ago during the Hauterivian...
a comprehensive listing of genera that are included in the subclass †Ammonoidea, excluding purely vernacular terms. The list includes genera that are...
Eleniceras stevrecensis is an extinct species of cephalopods belonging to the Ammonoidea subclass. This animal lived 140–129 million years ago during the Hauterivian...
2017-10-19. Bibliography W.J. Arkell, et al. 1957. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Ammonoidea. University of Kansas Press....
simple goniatitic sutures. Treatise on Invertebrate Paleontology, Part L, Ammonoidea; Geological Society of America and University of Kansas, 1957, Database...
early Emsian (Devonian) in the Tafilalt (Morocco), the origin of the Ammonoidea, and the first African pyrgocystid edrioasteroids, machaerids and phyllocarids"...
as a subfamily. Arkell et al. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geol Soc of America and Univ Kansas press...
The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community. The...
Furnish, and Schindewolf; Paleozoic Ammonoidea in the Treatise on Invertebrate Paleontology, Part-L, Ammonoidea, 1957, Geological Society of America...
Bibliography Arkell, et al., 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L (Ammonoidea). Geol. Soc. of America and Univ. Kansas...
and even possibly from the Silurian. The Bactritidae gave rise to the Ammonoidea in the Early Devonian starting with an early Bactrites and going with...
Eleniceras tchechitevi is an extinct species of cephalopods belonging to the Ammonoidea subclass. This animal lived 140–129 million years ago during the Hauterivian...
a number of organic materials used as gems, including: Amber Ammolite Ammonoidea Bone Copal Coral Ivory Jet Nacre (Mother of pearl) Operculum Pearl Seashell...
Bibliography Arkell et al. 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L (Ammonoidea). Geol Soc. of America and Univ. Kansas...
The largest prehistoric animals include both vertebrate and invertebrate species. Many of them are described below, along with their typical range of size...
2024.921.2413. Mitta, V. V. (2024). "The Genus Alatyroceras gen. nov. (Ammonoidea: Cardioceratidae, Arctocephalitinae) from the Upper Bathonian (Middle...
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