Description
- Perisphinctes sp.
- Late Jurassic Age (160 Million Years Old)
- Near Sakaraha, Madagascar
- Specimen measures approx. 3 3/8″ wide
Ammonites are an extinct group of marine invertebrate animals similar to the modern nautilus. (Cephalopoda) Like the nautilus, ammonites had a soft body with tentacles that emerged from a hollow chambered shell utilized in the manner of a submarine’s ballast tanks. Ammonites are often identified by their shell ornamentation and the structures of the wall that divide the shell’s chambers.