Acanthoceras
Neumayr
An adult's shell reached about a metre across. It was covered in ornate ribs whose function is unknown.
Photo: Hectonichus (CC BY-SA 3.0)
Ammonites coiled their shells into a spiral and divided them into chambers with walls called septa. The animal lived in the last one. They appeared in the Devonian about 400 million years ago and vanished with the dinosaurs. Their straight-shelled cousins already roamed Ordovician seas.
A few cards of the album
The start of their anecdote. The album's other cards are for you to discover in the game.
Amaltheus
de Montfort
Its flattened shell had a serrated keel as sharp as a blade. Slightly sigmoid ribs covered it.
Photo: Viehmann (CC BY-SA 3.0)
Baculites
Jean-Baptiste de Lamarck
This ammonite had a shell that was almost straight, like a long cone. Adults ranged from about 7 cm to 2 m in length.
Photo: El fosilmaníaco (CC BY-SA 4.0)
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