Baculites is an extinct genus of cephalopods with a nearly straight shell, included in the heteromorph ammonites. The genus, which lived worldwide throughout most of the Late Cretaceous, and which briefly survived the K-Pg mass extinction event, was named by Lamarck in 1799.
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 became one of the most distinctive components of Cretaceous marine faunas. They have been recorded from every continent and many are used as zonal or index fossils. The most distinctive feature of the majority of the Ancyloceratina is the tendency for most of them to have shells that are not regular spirals like most other ammonites. These irregularly-coiled ammonites are called heteromorph ammonites, in contrast to regularly coiled ammonites, which are called homomorph ammonites.
Scaphites is a genus of heteromorph ammonites belonging to the Scaphitidae family. They were a widespread genus that thrived during the Late Cretaceous period.
Didymoceras is an extinct genus of ammonite cephalopod from the Late Cretaceous epoch. It is one of the most bizarrely shaped genera, with a shell that spirals upwards into a loose, hooked tip. It is thought to have drifted in the water vertically, moving up and down. The generic name is Greek for "paired horns".
Inoceramus is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus Pteria. They lived from the Early Jurassic to latest Cretaceous.
Kamerunoceras is an extinct cephalopod genus belonging to the ammonite family Acanthoceratidae, found in Upper Cretaceous formations of Africa, Europe and North and South America.
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico.
Placenticeras is a genus of ammonites from the Late Cretaceous. Its fossils have been found in Asia, Europe, North and South America.
The Tres Hermanos Formation is a geologic formation in central and west-central New Mexico. It contains fossils characteristic of the Turonian Age of the late Cretaceous.
The genus Cibolaites is a strongly ribbed and nodose ammonoid cephalopod from the middle Cretaceous of western New Mexico, included in the taxonomic family Collignoniceratidae. A single species Cibolaites molenaari is known.
Neoptychites is an extinct ammonoid cephalopod genus from the Turonian stage of the Upper Cretaceous, with a worldwide distribution.
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.
Mammites is a Late Cretaceous ammonite genus included in the acanthoceratoidean family, Acanthoceratidae, and the type genus for the subfamily Mammitinae. Mammites was named by Laube and Bruder in 1887.
The Acanthoceratinae comprise a subfamily of ammonoid cephalopods that lived during the Late Cretaceous from the latter early Cenomanian to the late Turonian
The Lewis Shale is a geologic formation in the Western United States. It preserves fossils dating back to the Campanian to Maastrichtian stages of the late Cretaceous period.
Watinoceras is a genus of acanthoceratid ammonite that lived during the early Turonian stage of the Late Cretaceous.
Neocardioceras is a genus of evolute acanthoceratid ammonites from the uppermost Cenomanian, Upper Cretaceous, of Europe, western U.S. and Brazil.
Quitmaniceras is a genus of small, compressed, fairly evolute ammonites from the lower Turonian of Grant County, New Mexico and Trans-Pecos Texas, included in the subfamily Acanthoceratinae. The shell has a carinate venter in juveniles and one that is arched in adults, usually with a raised siphonal line,(siphonal referring to the marginal siphuncle). Ribs are very weak to moderately strong, flexious, typically sloping forward toward the rim, bending further forward at the outer shoulder.
Diplomoceratidae is a family of ammonites included in the order Ammonitida. Fossils of species within this genus have been found in the Cretaceous sediments. Studies of Diplomoceras suggest that members of this family could reach lifespans of over 200 years.
Clioscaphites is an extinct genus of ammonite belonging to the family Scaphitidae. Species in this genus are important index fossils of the Western Interior Seaway of the Coniacian to Santonian Ages of the Cretaceous.
