Ammonoidea - Wikipedia
Ammonoids are extinct coiled, typically spiral-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to shelled nautiloids (such as the living Nautilus). [1]
What is an ammonite? - Natural History Museum
Ammonites were shelled cephalopods that died out about 66 million years ago. Fossils of them are found all around the world, sometimes in very large concentrations. The often tightly wound shells of ammonites may be a familiar sight, but how much do you know about the animals that once lived inside? What were ammonites?
fossil identification by shape - Earth Sci
Most commonly found fossils can usually be classified to their group by observing some simple shapes and features. If your fossil has one of the shapes below, look down the guide for that shape and you will be presented with some possibilities of it's origins.
DISCOVERING FOSSILS | What is an ammonite?
Ammonites are perhaps the most widely known fossil, possessing the typically ribbed spiral-form shell as pictured above. These creatures lived in the seas between 240 - 65 million years ago, when they became extinct along with the dinosaurs.
Ammonite Fossils Unravel the Geological History of Ancient …
2023年7月8日 · Today, ammonite fossils are highly prized by collectors and paleontologists alike. They serve as important indicators of past geological ages and provide valuable clues about ancient ecosystems and evolutionary history.
The Intriguing World of Ammonite Fossils! - Rock Seeker
2023年4月17日 · Ammonite fossils are the preserved remains of ammonoids, which were marine creatures with a spiral shell that resembled a ram’s horn. These fossils are often found in sedimentary rocks, such as limestone and shale, and can provide valuable insights into the evolution and ecology of ancient marine life.
Ammonites - British Geological Survey
Some genera of ammonites had shells that were coiled in more bizarre ways than the usual spiral. These are known as heteromorphs, from the Greek heteros meaning ‘different’ and morphe meaning ‘form or shape’. The coiled shell is generally the only part of the ammonite to be preserved as a fossil.
About Ammonites - FossilEra.com
These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. Ammonites first appearing in the fossil record 240 million years ago, descending from straight shelled cephalopods.
Ammonite Fossils - University of Oregon
Ammonite and nautiloid fossils have been prized from antiquity for their mesmerizing logarithmic spiral. In Hindu religion they are held sacred as saligram (a Nepali example is included here), a reminder of the unfolding of the universe by Lord Vishnu the creator.
Ammonite - Shape of Life
2021年5月7日 · Ammonites may be the most familiar fossil to us — aside from dinosaurs. What are those spiral rocks that seem to come in every size? Ammonites were molluscs, specifically cephalopods, most closely related to octopus and squid living today.