Ancyloceratoidea, formerly Ancylocerataceae, is a superfamily of typically uncoiled and loosely coiled heteromorph

ammonoids Ammonoids are a group of extinct 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 (i.e., octopuses, squid and cuttle ...

established by

Alpheus Hyatt Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Biography Alpheus Hyatt II was born in Washington, D.C. to Alpheus Hyatt and Harriet Randolph (King) Hyatt. He briefly attended the Maryla ...

in 1900, that may contain as many as 11 families, depending on the classification accepted.

Taxonomy

The taxonomy content,

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

, of the Ancycloceratoidea has grown over the year, partly with the addition of newly defined families and partly with the moving of families from other superfamilies. Arkell, ''et al.'' (1957) in the

Treatise A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject and its conclusions."Treat ...

Part L included just the

Ancyloceratidae Ancyloceratidae is a family of heteromorphic Ammonitida, ammonites that lived during the Early Cretaceous. Their shells begin as a loose spiral with whorls not touching which then turns into a straight shaft that ends in a J-shape hook or bend ...

Meek 1876, Bochianitidae Spath 1922,

Hemihoplitidae Hemihoplitidae is an extinct family of ammonoid cephalopods belonging to the superfamily Ancyloceratoidea. Fossils of species within this genus have been found in the Cretaceous The Cretaceous ( ) is a geological period that lasted from about 1 ...

Spath 1924, and Heteroceratidae Hyatt 1900 within the Ancylocerataceae. The

Crioceratitidae Crioceratitidae is an extinct cephalopod family belonging to the subclass Ammonoidea and included in the order Ammonitida. Genera * ''Acantholytoceras'' Spath, 1932 * '' Balearites'' Sarkar, 1954 * ''Crioceratites'' Leveillé, 1837 * '' Diamant ...

Wright 1952 was considered a subfamily, the Crioceratitinae, within the Ancycloceratidae, the other being the Ancyloceratinae. Families recognized in the Treatise and subsequently removed to the Ancycloceratoidea from other taxa include the Ptychoceratidae Meek 1876, Macroschaphitidae Hyatt 1900, and Labeceratidae Spath 1925. Those established since include the

Acrioceratidae Acrioceratidae is a family of heteromorph ammonites included in the Ancyloceratoidea comprising ancyloceratid-like forms that start off with a coiled juvenile section, followed by a straight or curved shaft ending in a hook. Two described gener ...

Vermeulen 2004, Himantoceratidae Dimitrova 1970, Leptoceratoididae Thieuloy 1966. The Treatise on Invertebrate Paleontology, Part L, placed the Ancylocerataceae in the suborder

Lytoceratina Lytoceratina is a Suborder (biology), suborder of Jurassic and Cretaceous Ammonitida, ammonites that produced loosely coiled, evolute and gyroconic shells in which the sutural element are said to have complex moss-like endings. Morphologic chara ...

along with the Lytocerataceae,

Turrilitaceae Turrilitoidea is a diverse superfamily of Cretaceous ammonites generally considered as heteromorphic and commonly included in the suborder Ancyloceratina. Shells of this diverse group do not coil planospirally, as typical for most ammonites, but ...

, and Scaphitaceae, with superfamily endings as then used. The Ancyloceratoidea is now generally accepted as being within the separate suborder from the Ammonitida, the

Ancyloceratina The Ancyloceratina were a diverse suborder of ammonite most closely related to the ammonites of order Lytoceratina. They evolved during the Late Jurassic but were not very common until the Cretaceous period, when they rapidly diversified and beca ...

established by Wiedmann 1966.

Phylogeny

There are two main competing theories regarding the origin of the Ancyloceratoidea, and Ancyloceratina (unless polyphyletic). The first derives the Ancycloceratoidea, and by inference the Ancyloceratina, from the Lytoceratina late in the Jurassic through the ancestral Bochianitidae. The other derives the Ancyloceratina, including the Ancyloceratoidea, from the

Ammonitida Ammonitida is an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, a ...

during the Early Cretaceous.

Renaming

Ancyloceratoidea was renamed from Ancylocerataceae to accordance with the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

which gives invertebrate superfamilies the name suffix which was formerly used for subclasses.

References

Ancyloceratoidea
Paleobiology Database 16 Mar 2013

jsdammonite

{{Taxonbar, from=Q4753140 Ammonitida superfamilies Cretaceous first appearances Cretaceous extinctions