![]() Until they were wiped out at the same extinction event as the dinosaurs 65 million years ago. ![]() to link the rock layer in which they are found to specific geological time periods. Ammonites were common during the Mesozoic Era, but are not found after the Cretaceous period (when they went extinct). Ammonites could be as small as an inch, to as large as nine feet wide!Īmmonites survived three mass extinctions, most notably the Permian extinction about 252 million years ago that killed off 96% of the planet’s marine species. Ammonites, also known as ammonoids, are a group of marine mollusks. You can tell the difference between species by their shape and pattern of the sutures. They swam by jet propulsion from their shells. Ammonoids are related to the other Cephalopods such as squid, octopus, cuttlefish and Nautilus. They were once the most abundant animals of the ancient seas, with over 10,000 identified species. (419.2 to 358.9 million years ago) The Devonian Period (The Age of Fishes) is named after Devon, England, where rocks from this period were first studied. Ammonites appeared in the Early Jurassic Period. Ammonites appeared in the Jurassic Period, which began around 201.3 mya. ![]() ![]() True ammonites are a suborder of ammonoids that didn’t appear until the Jurassic period about 200 million years ago. Ammonoids (the group of animals that includes ammonites and other, related animals) first appeared around 409 mya (million years ago), during the Devonian Period of the Paleozoic Era. Ammonites are an extinct group of marine animals ( subclass Ammonoidea) in the phylum Mollusca and class Cephalopoda. One supplied.Īmmonites (ammonoids) were a type of pre-historic marine predator that evolved around 416 million years ago during the Devonian period. At least 57 species of ammonites, which were widespread and belonged to six superfamilies, were extant during the last 500,000 years of the Cretaceous. Small whole Ammonite fossil with a natural Iridescent shell. ![]()
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