Sea Monsters

dinosaurs. They were more closely related to lizards and snakes.
    Dinosaurs ruled the land, but giant marine reptiles ruled the seas. Many had enormous bodies, heads, and teeth. They were deadly hunters, often moving at fast speeds.
    When you see thefossils of ancient sea creatures, you can hardly believe your eyes. Never in your wildest dreams could animals be so huge and scary!

Dunkleosteus (dun-kul-OS-tee-us)
    Dunkleosteus
was part of a family whose name means “terrible fish.” And they were really
TERRIBLE
! These twenty-foot-long predators lived about 400 million years ago—long before theMesozoic Era.

    Dunkleosteus
had the strongest jaws of any fish ever. If this monster bit you, 8,000 pounds of pressure per square inch would crush you like a bug. In fact,
Dunkleosteus
could cut a big shark cleanly in half!
    You might think an animal this fierce had huge teeth. But
Dunkleosteus
didn’t have real teeth. Instead, it had two long, sharp, bony blades. The front of the jawbones came to a fang-like point.
    Their mouths opened in a flash and sucked their prey right in. And guess what?Fossils show that
Dunkleosteus
threw up alot as well. Fossil lumps of half-eaten prey appear to come from these terrible fish. It seems they ate many things that they couldn’t digest.
Liopleurodon (ly-uh-PLUH-ruh-don)
    Yikes! Talk about colossal! This was the biggest carnivore ever.
Liopleurodon
could be over eighty feet long! Imagine an animal longer than the biggest trucks on the high-way. Imagine an animal twenty times heavier than a
T. rex.

    These Mesozoic creatures had long bodies with two flippers on each side. Their huge heads were over ten feet long, bigger than many cars. They had super-strong jaws with powerful eight-inch teeth shaped like tigers’ fangs.
Liopleurodon
used their noses to smell prey underwater. Imagine if one of these monsters got a whiff of you!
Elasmosaurus (ih-laaz-muh-SAW-rus)
    Elasmosaurus
looks like a mistake. Nothing with such a small head could have a neck this long! Picture an animal that is forty-six feet long, and half of its body is its neck! The neck was made up of seventy vertebrae (VUR-tuh-bray), or back bones.

    Elasmosaurus
ate squid and fish. It may have used its long neck to sweep the ocean floor for crabs and fish. Plus, it swallowed rocks. Piles of rocks are found in the stomachs of
Elasmosaurus
fossils. Maybe the stones helped grind up shells. Croco-diles swallow rocks to do this today.
    When fossils of
Elasmosaurus
were first discovered over one hundred years ago, a famous scientist namedEdward Drinker Cope put them together. But he made a big mistake. He put the head on the tail end instead of on the neck!
    When his mistake was discovered, Cope spent the rest of his life feeling bad about it—even though he was one of the best prehistoric marine-reptile experts of his day.
Xiphactinus (zuh-FACK-tuh-nus)
    Xiphactinus
is nicknamed the “bulldog fish.” Its lower jaws jut out, showing rows of terrible sharp teeth. But another name for these big fish could be “speedy.”

    Xiphactinus
swam really fast. Their powerful tails helped them reach speeds up to thirty-five miles per hour!
    Xiphactinus
sometimes grew up to twenty feet long. Scientists have found theirfossils with much bigger animals inside their stomachs. Thanks to those fierce jaws and teeth, these bulldog fish weren’t afraid of anything!
Megalodon (MEG-uh-loh-don)
    Sometimes people find giantsharks’ teeth along the Maryland, North Carolina, and California coasts. They’re as big as dinner plates! The teeth belonged to a huge shark called
Megalodon,
which means “giant tooth.” These massive sharks lived after theMesozoic Era had ended.
    There are almost nofossils of
Mega-lodon
skulls and skeletons. That’s because shark skeletons are made of
cartilage
(KAR-tuh-lidge), not bone. Cartilage rots after the animal dies. But teeth turn into long-lasting fossils.

    We know by their teeth that
Megalodon
were three times bigger than great white sharks. It’s possible they reached over fifty feet long! Their jaws could open over seven feet high and six feet wide.
    An animal this size could wolf down a whole cow in one gulp! It could eat a class of third graders in three gulps! But we know that
Megalodon
atewhales instead.Fossils of whale skeletons have been found with cut marks on their ribs and fins. The cuts match
Megalodon
teeth. And right next to the whale fossils were
Megalodon
teeth!

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