#placenticeras

[kiabugboy]

Ouf of the way! The fast bois, Placenticeras are moving. These underwater frisbees and similarly shelled ammonites experience less drag during higher speeds underwater as their shell shape is more streamlined

[squirming-verm]

placenticeras, the flat fuck

[abitmoredetail]

Placenticeras intercalare #newyorkcity #newyork #manhattan #amnh #alberta #canada #ammonite #mollusk #shell #fossil #placenticerasintercalare #placenticeras #americanmuseumofnaturalhistory #latergram (at American Museum of Natural History)

[bijoux-et-mineraux]

Ammolite (Placenticeras, Cretaceous) - Bearpaw Formation, Southern Alberta, Canada

[bijoux-et-mineraux]

Ammolite (Placenticeras, Cretaceous) - Bearpaw Formation, Southern Alberta, Canada

[okinawae33]

Sphere ammonite placenticeras

[palaeopedia]

The Placenticeras (1870)

Phylum : Mollusca Class : Cephalopoda Subclass : Ammonoidea Order : Ammonitida Superfamily : Hoplitaceae Family : Placenticeratidae Genus : Placenticeras Species : P. cumminsi, P. placenta, P. syrtale, P. vredenburgi, P. whitfieldi

Late Cretaceous

8 cm (size)

Eurasia and America (map)

Placenticeras, named by Meek, 1870, is the type genus for the Placenticeratidae, a family that is part of the Hoplitaceae, a superfamily of the Ammonitida. yup.

Placenticeras has a very involute shell with slightly convex sides and a very narrow venter. Side are smooth or with faint sinuous ribs. Early whorls have umbilical tubercles that in later whorls appear higher on the sides. Earlier whorls normally have lower and fine upper ventrolateral clavi. Ornament weakens in the adult and the last whorl may be smooth. The suture is with numerous adventitious and autxiliary elements, with saddles and lobes that are much frilled.