The Ammonites (Speetoniceras versicolor) - (Reference|Index} Fossils



Ammonites have been understood to mankind for thousands of years. They are the source of lots of stories and myths. The name of this spiral-shelled cephalopod comes from the Egyptian god Ammon. Ammon was pictured as a man with the horns of a ram protruding from his head. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites. Ammonites have been known to humanity for thousands of years. The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.

Ammonite Myths
Lots of cultures throughout history have actually associated special powers to this fossil.

In ancient Greece, it was said that if you put an ammonite under your pillow it would cure insomnia 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 periods established septa that had actually detailed folds called lobes and saddles. They likewise established delicate lacey patterns on the outer shell. These patterns along with the shape of the shell and the structure of the septa are how this cephalopod is classified. Ammonites such as Speetoniceras are great addition to a fossil collection often on auction.

Since all living cephalopods (octopus, nautilus, and squid) are predators, we can presume that ammonites were. The only living cephalopod with an external shell is the chambered nautilus. The siphuncle is a tube that connects all the chambers in the shell with the living animal.

Ammonite Size
Ammonites have a broad variety of size. Early ammonites, till the middle Jurassic, were smaller, normally less than 9 inches or 23 centimeters.

Biostratigraphy
The hard shell of the ammonite was easily fossilized. This, combined with the large abundance of this group of cephalopods and its evolutionary duration through a number of geologic durations, make it an excellent index fossil. Index fossils help paleontologists and geologists to figure out the age of rock layers. This is called biostratigraphy. It works like this. The rock layer it came from should be Triassic pop over to this web-site if you discover an ammonite from a genus understood to be from the Triassic Period. Rare Russian Ammonite To be an excellent index fossil:

It should have broad distribution.

There should be a lot of them.

It must belong to a group that evolves rapidly.

They must be simple to acknowledge.

Ammonites please all the above requirements easily.

Extinction of The Ammonites
The end of the Cretaceous Period was likewise the end of the ammonites. Dinosaurs review and numerous other species of animals and plants passed away out at about this exact same time.

The curled ammonite shells resembled the horns and were called Ammon's Stones or ammonites.

Ammonites of later durations established septa that had intricate folds called saddles and lobes. The tough shell of the ammonite was easily fossilized. If you find an ammonite from a genus understood to be from the Triassic Period, then the rock layer it came from should be Triassic. The end of the Cretaceous Period was also the end of the ammonites.

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