Search results
Results From The WOW.Com Content Network
The biology of the heteromorph ammonites is not clear, but one certainty is that their uncoiled shells would have made these forms very poor swimmers. Open shells, particularly ones with spines and ribs, create a lot of drag; but more importantly, the orientation of the shell, with the body hanging below the buoyant part of the shell, would ...
Hamites ("hook-like") is a genus of heteromorph ammonite that evolved late in the Aptian stage of the Early Cretaceous and lasted into the Cenomanian stage of the Late Cretaceous. The genus is almost certainly paraphyletic but remains in wide use as a "catch all" for heteromorph ammonites of the superfamily Turrilitoidea that do not neatly fit ...
Bostrychoceras is a genus of heteromorph ammonite from the family Nostoceratidae. Fossils have been found in Late Cretaceous sediments in Europe and North America.. The shell of Bostrychoceras begins as a tightly wound helical spire, like that of Nostoceras, from which hangs a U- or J-shaped body chamber, at least in the adult.
Polyptychoceras is a heteromorph ammonite, meaning that its shell does not curl up into the tight spiral shape which shells of ammonites from the subclass Ammonoidea typically do. Polyptychoceras shells have an abrupt weight increase after formation of the initial shaft, which represents the shell's automatic balance condition. [ 4 ]
Heteroceras is a genus of Lower Cretaceous heteromorph ammonites belonging to the ancyloceratoidean family, Heteroceratidae. [1] Description
Nostoceratidae is a diverse family of heteromorph ammonites found throughout the oceans of the world during the Late Cretaceous. The nostoceratids are famous for the bizarre coiling of their shells. The nostoceratids are famous for the bizarre coiling of their shells.
A rare heteromorph ammonite fossil from the south of France. The species is Crioceratites nolani and the spines have been partially restored to show how it might have appeared in life. Crioceratites is an ammonite genus from the Early Cretaceous belonging to the Ancyloceratoidea.
A variety of ammonite forms, from Ernst Haeckel's 1904 Kunstformen der Natur.. This list of ammonites is a comprehensive listing of genera that are included in the subclass †Ammonoidea, excluding purely vernacular terms.