The Ammonites (Speetoniceras versicolor) - (Reference|Index} Fossils
Ammonites have actually been understood to humanity for countless years. They are the source of numerous stories and misconceptions. The name of this spiral-shelled cephalopod comes from the Egyptian god Ammon. Ammon was imagined as a man with the horns of a ram protruding from his head. The curled ammonite shells looked like the horns and were called Ammon's Stones or ammonites. Ammonites have been known to mankind for thousands of years. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.
Many cultures throughout history have attributed special powers to this fossil.
In ancient Greece, it was said that if you put an ammonite under your pillow it would treat sleeping disorders and bring good dreams.
If you put a golden ammonite (pryritized) under your pillow you would have prophetic dreams, the Romans believed that.
A Brief History of Ammonites
Ammonites first appeared in the Devonian Period. Early curled types had basic septa with a single arc like the members of the class orthocerida. Ammonites of later durations established septa that had complex folds called saddles and lobes. They likewise established delicate lacey patterns on the external shell. These patterns together with the shape of the shell and the structure of the septa are how this cephalopod is categorized. Ammonites such as Speetoniceras subinversum are very beautiful often on auction.
Given that all living cephalopods (nautilus, squid, and octopus) are predators, we can assume that ammonites were. The only living cephalopod with an external shell is the chambered nautilus. It can swim and manage its depth. It does this by utilizing the siphuncle. The siphuncle is a tube that links all the chambers in the look at this site shell with the living animal. The nautilus can include or subtract gas in these chambers to control buoyancy.
Ammonites have a broad variety of size. Early ammonites, till the middle Jurassic, were smaller sized, generally less than 9 inches or 23 centimeters.
The difficult shell of the ammonite was quickly fossilized. This, integrated with important source the sheer abundance of this group of cephalopods and its evolutionary period through numerous geologic periods, make it a good index fossil. If you find an ammonite from a genus understood to be from the Triassic Period, then the rock layer it came from need to be Triassic.
It needs to have large circulation.
There need to be a great deal of them.
It needs to come from a group that progresses quickly.
They should be easy to recognize.
Ammonites please all the above criteria quickly.
Termination of The Ammonites
Completion of the Cretaceous Period was also the end of the ammonites. This was about 65 million years ago. Dinosaurs and lots of other types of plants and animals died out at about this same time. It is thought that a huge meteor colliding with earth caused these mass extinctions.
The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.
Ammonites of later periods established septa that had elaborate folds called saddles and lobes. The hard shell of the ammonite was quickly fossilized. If you discover an ammonite from a genus understood to be click over here now from the Triassic Period, then the rock layer it came from must be Triassic. The end of the Cretaceous Period was likewise the end of the ammonites.