Possible giant ammonite fossil found in the Ibiza mountains

The social media account 'Ibiza sin filtro' has published a video recorded during a hiking route in Ibiza showing what appears to be the fossil of an ammonite, an extinct cephalopod that lived hundreds of millions of years ago.

In the footage, the person filming compares the size of the formation with his own hand.

“Look at my hand next to it. It is huge”, the hiker says as he points to the raised shape in the rock, which is located in a wooded area far from the sea.

The post does not reveal the exact location on the island where the apparent discovery was made.

“I am in the middle of nowhere and just look at this formation. It is beautiful. The rock is enormous”, he says in the video.

An ancient seabed transformed into mountains

In the caption accompanying the footage, the account says it found “what appears to be an enormous fossilised shell” in the middle of the mountains and questions how it could have ended up there, so far from the coast.

The post explains that millions of years ago, much of Ibiza lay beneath the sea and that many of the rocks that now form the island’s mountains originated on ancient seabeds.

Over time, movements in the Earth’s crust would have lifted these materials, eventually turning them into part of Ibiza’s present-day landscape.

There is currently no evidence that the suspected fossil has been examined or identified by a specialist.

A trace of Ibiza’s distant past

The formation shown in the video could be an ammonite, although the rock would need to be examined by an expert before its origin could be confirmed.

Despite their shell-like appearance, ammonites were not gastropods. They were spiral-shelled marine cephalopods related to modern-day octopuses and squid.

They were extremely common in the seas of the Mesozoic Era and became extinct around 66 million years ago, during the same mass extinction event that wiped out the non-avian dinosaurs.

Their fossils can be found in mountainous areas because the rocks in which they were preserved originally formed on ancient seabeds. Subsequent geological movements lifted these materials, meaning they can now be found at high elevations and far from the coast.

This would not be the first ammonite discovered in Ibiza. A small geological curiosity measuring just 14 by 16 centimetres can be seen in plain sight at Ibiza harbour.

The fossil is embedded in the limestone pavement and dates from the Kimmeridgian stage of the Jurassic Period, around 150 million years ago.

In September last year, Ibiza Town Council installed a plaque marking its location, together with a QR code providing access to scientific information about the extinct marine animal.