10 Amazing Extinct Sea Creatures


Ammonites, ancient marine mollusks with spiral shells, serve as valuable indicators for paleontologists studying rock layers and prehistoric marine ecosystems, and they are evolutionary ancestors of modern cephalopods.


Mosasaurs, large marine reptiles of the Late Cretaceous, were formidable predators with streamlined bodies, powerful jaws, and paddle-like limbs, ultimately going extinct with the dinosaurs.


Ichthyosaurs, Mesozoic marine reptiles, were highly adapted for an aquatic lifestyle, ranging in size from small and agile to giant predators before going extinct around 90 million years ago.

Steller’s Sea Cow

Steller's sea cow, a large marine mammal related to manatees, went extinct in the 18th century due to extensive hunting and exploitation, serving as a reminder of the consequences of human impact on the environment.


Dunkleosteus, an extinct prehistoric fish, was a large, armored predator with a formidable set of jaws and teeth, believed to have gone extinct due to various factors, and remains an intriguing subject for paleontologists and popular culture.


Helicoprion, an extinct shark-like fish with a distinctive whorl-shaped tooth structure, lived during the Late Carboniferous to Early Triassic periods, and its exact body shape and habits are still being researched and debated.


Pliosaurs, large aquatic reptiles of the Jurassic and Cretaceous periods, were apex predators with powerful jaws, short necks, and robust bodies, but eventually went extinct due to various environmental factors and competition.


Trilobites, diverse marine arthropods, thrived from the Cambrian to the Permian periods, displaying unique segmented bodies and complex eyes, providing valuable insights into ancient ecosystems and evolution before their extinction.