| Ancyloceratoidea Temporal range: Cretaceous | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | † Ammonoidea |
| Order: | † Ammonitida |
| Suborder: | † Ancyloceratina |
| Superfamily: | † Ancyloceratoidea Hyatt, 1900 |
| Families | |
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.
The taxonomy content, or families, 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 Part L included just the Ancyloceratidae Meek 1876, Bochianitidae Spath 1922, Hemihoplitidae Spath 1924, and Heteroceratidae Hyatt 1900 within the Ancylocerataceae. The Crioceratitidae Wright 1952 was considered a subfamily, the Crioceratitinae, within the Ancycloceratidae, the other being the Ancyloceratinae. [1]
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 Vermeulen 2004, Himantoceratidae Dimitrova 1970, Leptoceratoididae Thieuloy 1966.
The Treatise on Invertebrate Paleontology, Part L, placed the Ancylocerataceae in the suborder Lytoceratina along with the Lytocerataceae, Turrilitaceae, and Scaphitaceae, with superfamily endings as then used. [1]
The Ancyloceratoidea is now generally accepted as being within the separate suborder from the Ammonitida, the Ancyloceratina established by Wiedmann in 1966.
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 during the Early Cretaceous.
Ancyloceratoidea was renamed from Ancylocerataceae to accordance with the ICZN which gives invertebrate superfamilies the name suffix which was formerly used for subclasses.
Ammonitida is an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures.
Parahoplitidae is an extinct family of Cretaceous ammonites with stoutly ribbed, compressed, generally involute shells lacking or with only minor tubercles included in the Deshayestoidea, a superfamily now separated from the Hoplitacaceae.
Acanthoceratidae is an extinct family of acanthoceratoid cephalopods in the order Ammonitida, known from the Upper Cretaceous. The type genus is Acanthoceras.
Anisoceratidae is an extinct family of heteromorph ammonites which belong to the Ancyloceratina superfamily Turrilitoidea. Members of the family range is from the lower Albian to the upper Turonian. The family is possibly derived from a member of the Hamitidae.
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.
Lytoceratina is a suborder of Jurassic and Cretaceous ammonites that produced loosely coiled, evolute and gyroconic shells in which the sutural element are said to have complex moss-like endings.
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 rather take on a variety of unique forms. Separation of Turrilitoidea along with Ptychoceratoidea and Scaphatoidea into a different suborder, Turrilitina, was proposed by Beznosov and Mikhailova in 1983 however this view is not accepted by most authors.
Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, listed below.
Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed to be mostly granular (Granulaptycus) or concentrically ribbed on the surface (Praestriaptychus)
Collignoniceratidae is a family of Upper Cretaceous ammonites characterized by typically more or less evolute shells with compressed, oval, or square whorl sections; serrate or entire keels; and dense ribs with one to 5 tubercles.
Oxynoticeratidae is a family of true ammonites included in the superfamily Psiloceratoidea.
Turrilites is a genus of helically coiled ammonoid cephalopods from the lower part of the Upper Cretaceous ; generally included in the Ancyloceratina. Previously it was included in the ammonoid suborder, Lytoceratina.
Engonoceratidae is a family of typically compressed, more or less flat sided and involute ammonites from the mid Cretaceous belonging to the Hoplitoidea. shells have flat sided outer rims ( venters), at least in some stage. Single or branching irregular ribs and variably placed tubercles may occur. Sutures have numerous auxiliary and adventive elements of similar form, in general radially arranged. Forwardly divergent saddles tend to be simple, without subdivision. Lobes, pointing apically, may be simple and undivided or may be frilled with short irregular serrations.
Lytoceratidae is a taxonomic family of ammonoid cephalopods belonging to the suborder Lytoceratina, characterized by very evolute shells that generally enlarge rapidly, having whorls in contact but mostly overlapping very sightly, or not at all.
Turrilitina is a proposed suborder of Cretaceous heteromorph ammonoid cephalopods derived from the Lytoceratidae in the Hauterivian stage of the Lower Cretaceous that would include the superfamilies Turrilitoidea, Ptychoceratoidea, and Scaphatoidea.
Ancyloceratidae is a family of heteromorphic 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 at end. Coarse ribbing and spines are common.
The Crioceratidae constitute a family of loosely to closely coiled Ammonitida included in the Ancyloceratoidea that lived during the Early Cretaceous; characterized by Crioceratites and other genera such as Hoplocrioceras and Paracrioceras.
Neocomitidae is a family of Lower Cretaceous ammonitids comprising genera with strongly ribbed evolute to smooth, fairly involute shells.
Kossmaticeratidae is an extinct ammonoid family belonging to the order Ammonitida.
The Acanthoceratinae comprise a subfamily of ammonoid cephalopods that lived during the Late Cretaceous from the latter early Cenomanian to the late Turonian