Search results
Results From The WOW.Com Content Network
Ammonites of prehistoric North America — a marine molluscs group of the prehistoric Cephalopods in North America. Subcategories This category has the following 5 subcategories, out of 5 total.
All ammonites were wiped out during or shortly after the K-Pg extinction event, caused by the Chicxulub impact. It has been suggested that ocean acidification generated by the impact played a key role in their extinction, as the larvae of ammonites were likely small and planktonic , and would have been heavily affected. [ 43 ]
Ammonitida or "True ammonites" are an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina , Lytoceratina , Ancyloceratina , and Ammonitina .
Ammonitina comprises a diverse suborder of ammonite cephalopods that lived during the Jurassic and Cretaceous periods of the Mesozoic Era. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods.
Pages in category "Early Jurassic ammonites of North America" The following 6 pages are in this category, out of 6 total. This list may not reflect recent changes .
Sphenodiscus is an extinct genus of acanthoceratacean ammonite.The genus has been found from many continents and is thought to have had a large global distribution during the Maastrichtian stage of the Late Cretaceous.
Perisphinctes is an extinct genus of ammonite cephalopod. They lived during the Middle to Late Jurassic epochs and serve as an index fossil for that time period. [ 5 ] The species P. boweni was named after the English chemist and geologist E. J. Bowen (1898–1980).
Oxynoticeras is an extinct genus of ammonite from the Early Jurassic [1] of Europe and North America. [2] This genus is characterized by its smooth shell, with almost invisible undulations on the flank, and a sharp keel. [3] Synonym Oxynotoceras was created by Buckman as misspelling. [4]