North African, European and Rest of the World Ammonites
Ammonites first appeared around 240 Million years ago during the Triassic period. They descended from straight shelled Cephalopods, Orthoceras being a well known species characterised by its long straight chambered body. Ammonoids and their relatives in general, go all the way back to the Devonian, so by the time the Triassic came around, there was many well evolved species of Ammonite in existence. It is thought that the Permian extinction, 252 Million years ago, may have given the newly formed ammonite species a helping hand in becoming so prolific. At the end of the Permian, some 96% of all marine life, and 70% of terrestrial life became extinct. It is one of the worst extinction events the world has ever experienced. At the end of the Triassic era, only one species of ammonite survived. Amazingly, from this one species, they began to thrive again and became widespread during the Jurassic and Cretaceous. It was at the end of the Cretaceous that ammonites, along with dinosaurs and many other species finally became extinct. The Nautilus, a cousin of the ammonite however, survived and is frequently found in the warmer oceans of the world today.
Heteromorph Ammonites from North Africa HeteromorphAncyloceras (Audiloceras) ammonite Cretaceous (Barremian stage) 127 million years old. Agadir, Morocco, Prepared on matrix rock, As it's from Morocco, the nature of extracting them from their rock means they are often repaired and some restoration here and there. The Ancyloceratina were a diverse suborder of ammonite most closely related to the ammonites of order Lytoceratina. They evolved during the Late Jurassic but were not very common until the Cretaceous period, when they rapidly diversified and became one of the most distinctive components of Cretaceous marine faunas.