Trilobites: Trilobites were ancient marine arthropods that lived during the Paleozoic era. They had segmented bodies and were typically small in size.
Giant Squids: Giant squids are believed to have lived in the Cretaceous period and could grow up to 40 meters in length.
Megalodon: Megalodon was an enormous prehistoric shark that lived during the Miocene and Pliocene epochs. It is considered one of the largest sharks to have ever existed.
Ammonites: Ammonites were cephalopods related to today's squid and octopuses. They had elaborate spiral or curved shells and thrived in ancient oceans.
Crinoids: Crinoids were marine organisms resembling flowers or plants on stems. They anchored to the ocean floor and lived during the Paleozoic era.
Dunkleosteus: Dunkleosteus was a massive armored fish that lived during the Devonian period. It could grow up to 10 meters in length and had powerful jaws resembling armor.
Saber-toothed Salmon: Saber-toothed salmon, as the name suggests, possessed long, canine-like teeth and inhabited ancient oceans during the Miocene epoch.
Sea Scorpions: Sea scorpions, or eurypterids, were large aquatic predatory arthropods that flourished during the Silurian and Devonian periods. They could reach formidable sizes.
Giant Sea Turtles: Archelon is an example of a giant sea turtle that existed during the late Cretaceous period. It had an estimated shell length of over 4 meters.
Plesiosaurs: Plesiosaurs were marine reptiles with long necks and bodies resembling giant flippers. They thrived during the Mesozoic era.
Mosasaurus: Mosasaurs were massive marine lizards that belonged to the mosasaur family. They flourished during the late Cretaceous period.
These are just a few examples of extinct ocean animals that once inhabited our planet's marine environments.