A remarkably well preserved bi-valve clam fossil dated to the Jurassic period roughly 150 million years ago. This fossil was sourced from Madagascar.
The Cambrian explosion took place around 540 to 520 million years ago. In this geologically brief period, all the major animal phyla diverged and these included the first creatures with mineralized skeletons. Brachiopods and bivalves made their appearance at this time.