Ammonite - extinct marine mollusc

Ammonites are extinct marine molluscs of the class Cephalopodia that appeared midway through the Paleozoic Era (400 Mya). They typically had a ribbed spiral-form shell that encased soft body parts and a hardened beak. Ammonites had a wide dispersion and their remains have been found in large numbers around the world. To date no trace fossil has been found of the soft body parts of an ammonite but they are believed to have been similar in anatomy to modern cephalopods such as squid.

Ammonites were able to move widely through the water column using a combination of buoyancy adjustment and siphoned jet propulsion to control their movement. The buoyancy was created by filling and emptying the chambers (camera) of the shell with water via a feature called the siphuncle. Propulsion was created by squirting water through an organ similar to the extant cephalopod hypernome.

Ammonites came in all sizes from the very small to the very large and many grew striking protuberances and spines - thought to have been evolving defence mechanisms against ever larger predators. They are presumed to have had good eyesight so markings and colouration are also thought to have been on display, playing an important role in their appearance.

Ammonites are thought to have been predators - adept at gliding across seabeds using their arms and tentacles to grab prey as it passed by. If attacked themselves they could pull back into the hardened shell and close down a leathery mantle. This dual ability to hunt and protect themselves proved very effective as ammonites survived for over 300 million years.

Because of their wide distribution over such an extensive period of time, ammonites have become important index fossils for evolutionary science.

Paleozoo Evolutionary Models are highly detailed portraits of some of the first animals to evolve on Earth. This detailed, museum grade model has been created by paleoartist Bruce Currie.

Other Paleozoo animations include:

[joseramonvelazquezgranados]

Cool video, in fact ammonoids (ammonoidea) came in a wide variety of shell shapes depending on the genus of ammonites or family. One of the strangest ones in my opinion is the nipponites

[yippeeyay]

Ancestors be like:
Ancestor: "Look a shell!"
Ancestor 2: "No"

[sandrostaub]

i've found hundreds of those in the Chalk-Stone of the Jura-Mountains in switzerland

[geologyjohnson]

Nice models and animation, are these based on the ammonite Perisphinctes from the middle Jurassic? Just a wee point; ammonites existed from the Jurassic to the end of the Cretaceous, but the family ammonoidea first appeared in the Devonian. Sorry for being such a palaeo -pedant! 😅

[GeckoTech_Engineer]

The mollusc world sure is an interesting one

[Nihilisterplayz]

The closest thing we have to ammonites are Nautilus

[MrOystein]

I own a fossil of these animals... Its intresting to see how they once lived. Wich also goes for the ammonite fossil i got in my book shelf....

[snowysmile]

I can't believe they went extinct despite their abundance and diversity while sharks, nautiloids, and horseshoe crabs didn't

[AlphonseWeebay]

So what’s the deal were they delicious or just their time was up?

[Superguru]

Ammonites didn't fly in water; they were marine animals that swam using gas chambers for buoyancy. They didn't stick to algae but lived in various ocean environments.

[Dragon-Slayr]

It's not extinct it's a genies lamp who is behind the remarkable house

[jayapriyan]

the eggs of ammonite has been found in tamil nadu

[captainnosmic]

Almost the day where dinosaurs went extinct.

[cgpcgp]

Why did they go extinct? Seems like they could last as long as there are seas.

[dogancanozgokceler]

I have a question sir. How can we know it really look like???

[Dragon-Slayr]

Ammonite aka pharoahs beard bro from the mehbooba corner

[ADRIAN-zhti]

They need wheels if they want to know us

[petosdana]

Its inacurret becuse ammonites dont have hoods