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 auxiliary elements, with saddles and lobes that are much frilled.
Speciesedit
P. whitfieldi showing punctures caused by the bite of a mosasaur
Arkell et al., 1957, Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geological Soc. of America, Univ of Kansas Press. R.C. Moore, (Ed)
W. A. Cobban and Hook, S. C. 1983 Mid-Cretaceous (Turonian) ammonite fauna from Fence Lake area of west-central New Mexico. Memoir 41, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
W. A. Cobban and Hook, S. C. 1979, Collignoniceras woollgari wooollgari (Mantell) ammonite fauna from Upper Cretaceous of Western Interior, United States. Memoir 37, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.
Discovering Fossils: How to Find and Identify Remains of the Prehistoric Past (Fossils & Dinosaurs) by Frank A. Garcia, Donald S. Miller, and Jasper Burns
placenticeras, genus, ammonites, from, late, cretaceous, fossils, have, been, found, asia, europe, north, south, america, temporal, range, late, cretaceous, meekiscientific, classificationdomain, eukaryotakingdom, animaliaphylum, molluscaclass, cephalopodasubc. Placenticeras is a genus of ammonites from the Late Cretaceous Its fossils have been found in Asia Europe North and South America PlacenticerasTemporal range Late CretaceousPlacenticeras meekiScientific classificationDomain EukaryotaKingdom AnimaliaPhylum MolluscaClass CephalopodaSubclass AmmonoideaOrder AmmonitidaFamily PlacenticeratidaeGenus PlacenticerasMeek 1870SynonymsDiplacmoceras Contents 1 Taxonomy 2 Description 3 Species 4 ReferencesTaxonomy editPlacenticeras named by Fielding Bradford Meek 1870 is the type genus for the Placenticeratidae a family that is part of the Hoplitoidea a superfamily of the Ammonitida Description editPlacenticeras 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 auxiliary elements with saddles and lobes that are much frilled Species edit nbsp P whitfieldi showing punctures caused by the bite of a mosasaurSpecies list according to 1 Placenticeras bidorsatum Placenticeras costatum Placenticeras cumminsi Placenticeras fritschi Placenticeras grossouvrei Placenticeras intercalare Placenticeras kolbajense Placenticeras maherndli Placenticeras mediasiaticum Placenticeras memoriaschloenbachi Placenticeras meeki Placenticeras orbignyanum Placenticeras paraplanum Placenticeras placenta Placenticeras polyopsis Placenticeras pseudoplacenta Placenticeras semiornatum Placenticeras syrtale syn Stantonoceras pseudocostatum Placenticeras tamulicum Placenticeras vredenburgi Placenticeras whitfieldiReferences editArkell et al 1957 Mesozoic Ammonoidea Treatise on Invertebrate Paleontology Part L Geological Soc of America Univ of Kansas Press R C Moore Ed W A Cobban and Hook S C 1983 Mid Cretaceous Turonian ammonite fauna from Fence Lake area of west central New Mexico Memoir 41 New Mexico Bureau of Mines amp Mineral Resources Socorro NM W A Cobban and Hook S C 1979 Collignoniceras woollgari wooollgari Mantell ammonite fauna from Upper Cretaceous of Western Interior United States Memoir 37 New Mexico Bureau of Mines amp Mineral Resources Socorro NM Discovering Fossils How to Find and Identify Remains of the Prehistoric Past Fossils amp Dinosaurs by Frank A Garcia Donald S Miller and Jasper Burns Placenticeras in the Paleobiology Database nbsp This Ammonitina related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Placenticeras amp oldid 1165996789, wikipedia, wiki, book, books, library,
