Rulers of the Waves:
While dinosaurs roamed the Earth, the seas were ruled by some of the most ferocious creatures that ever lived. Let's step back in time and discover some of the most unique and bizarre creatures to ever live in the seas and oceans. Indeed, they were the 'Rulers of the Waves".
Cameraceras:
Measuring up to 36 feet long, Cameraceras was a squid-like animal that lived inside a long, straight shell. This unusually large sea creature lived during the Late Ordovician Period. It was an orthocone. Orthocones are mollusks and distant relatives of the ammonites and the nautilus that exists today. Like them, orthocones had a shell that was divided into many empty compartments that it could fill with air or water, depending on whether it wanted to rise or fall in the water. Cameraceras had poor eyesight, so they may have smelt out their prey using chemical sensors. With their eight grooved tentacles, they would grab on to the prey and old it, while a sharp beak slowly ripped the animal to pieces.
Cryptoclidus:
Cryptoclidus was a short-necked plesiosaur that lived in the shallow, coastal seas around western Europe during the Jurassic time. Although being a predator, its small teeth and head would have limited its prey to small fish, ammonites, and squids. Most likely, it would have hunted by swimming into large shoals and using its 6.5 foot neck to grasp them. Its bulky body meant that it was not a fast swimmer, so instead of pursuing its prey, it would have waited to ambush it and strike suddenly. Because Cryptoclidus had small, thin teeth, most paleontologists postulate it could sift through the soft-bed of the seabed sediments and search for crabs, small fish, and worms. Once caught, its prey was swallowed whole. Being a smaller plesiosaur, it may have hauled itself onto land at times.
Dunkleosteus:
Growing up to 33 feet long, Dunkleosteus was the largest predator in the Devonian seas. This terrifying sea creature had a head encased in solid and inflexible armor-plates with a muscular body that was streamlined, much like that of a shark. The secret of Dunkleosteus was its mouth. Instead of teeth, it had razor-sharp, shearing plates made from bone, and the jaws were powerful - anything caught between them would have been sliced clean in two. Having powerful jaws and sharp teeth allowed Dunkleosteus to hunt and kill other large animals, and it may explain why many large scorpions, such as Pterygotus declined during the Devonian Period.
Elasmosaurus:
Although Elasmosaurus could reach a total of 49 feet, most of its length was in neck and tail. Its body was comparatively small and barrel-like with four diamond-shaped flippers. This sea creature lived in the cool, coastal waters of the northern United States and only stray to the warmer tropical waters of the south for short periods of time. It was a graceful swimmer, but could only move with its neck straight out in front. Any bending or kinking in its neck would affect its ability to steer. Elasmosaurus had 75 vertebrae to support its long neck.
Helicoprion:
The geologic age range of this bizarre-looking shark, Helicoprion, is Carboniferous to Early Triassic. Little is known about it; however, at one time, the fossil remains of its lower jaw was thought to be of a loosely coiled ammonite. Paleontologists now believe that its strange lower jaw slowly revolved over a lifetime, bringing new, sharp teeth into position. The teeth are serrated, thus indicating that it was an active predator. The whorl may have been enrolled like a party favor, snaring and grasping fish as it reeled them in.
Leedsichthys:
Measuring about 88.5 feet long, Leedsichthys was the largest known fish of all time. Although it was large, it was a gentle giant with a simple lifestyle. Leedsichthys swam near the sea's surface taking in mouthfuls of water-rich plankton, tiny shrimps, jelly fish, and small fish. Such delicacies were sieved through the mesh plates at the back of its mouth. These plates, at the back of the mouth, were made from tens of thousands of fine teeth. This gentle giant had no means of defending itself against large and persistent attackers. Fossilized tooth-marks show that many were attacked by apex predators such as the Tylosaurus and Liopleurodon, and marine crocodilians.
Liopleurodon
Measuring around 82 feet long, Liopleurodon was one of the mightiest predators of the Late Jurassic Period. It could easily cruise silently through the warm, shallow seas propelling itself by alternating flapping of its four gigantic flippers. If you saw this sea monster lurking around in the water, you'd best take cover. Its heavy head attached to a short, thick neck gives it the characteristics of a Pliosaur. The long jaws and rolls of needle-sharp teeth were capable of killing any other animal in the seas at the time. Lipleurodon's skull and jaw bones were specially strengthened to allow them to withstand the powerful biting force produced by the jaws. An important evolutionary trait for Liopleurodon was its ability to smell with its nose while breathing underwater.
Megalodon:
Megalodon, also known as Carcharodon, is the largest known of all the predatory sharks. It had a streamlined muscular body and resembled a giant version of the much-feared Great White Shark. Weighing around 48 tons, it spent much of its time feeding. Megalodon was a powerful predator, capable of making high-speed attack runs. Its mouth could open up to 6.5 feet, revealing a set of giant teeth, some of which were 8.5 inches long. Such teeth were capable of cutting through the toughest flesh and bone. Its main diet was dolphins and large whales that lived in deep offshore waters. Fossilized teeth of Megalodon have been found worldwide. From such distribution, it is possible that it preferred tropical and temperate seas and avoided cold waters. This powerful sea creature measured around 60 feet long and patrolled the seas and oceans during the Cenozoic Era (Mid Miocene to Late Pliocene).
Nothosaurus:
Nothosaurus was a late Triassic reptile measuring up to 13 feet long. It could live both in the water and out of the water. This predatory creature had a streamlined body and a long flattened tail. It hunted in shallow, coastal seas, but it would periodically come on shore to rest and sunbathe. Nothosaurus had webbed feet and dozens of needle-sharp, interlocking teeth. Once caught, few animals would be able to shake themselves free from the mouth of this sea creature. Fossil remains of Nothosaurus have been found in Europe, Middle East Asia, and North Africa.
Ophthalmosaurus:
Ophthalmosaurus was a medium-sized ichthyosaur marine reptile that inhabited the warm, tropical waters of the Late Jurassic Period. It had a long, pointed snout and its body was streamlined and dolphin-like in shape, which allowed it to swim at high-speed in pursuit of fish, squid, and other small marine animals. Its large eyes gave it excellent eyesight, even in almost pitch-black conditions. This allowed it to make deep dives in darker waters where competition for food was less than in the crowded surface waters. As an air-breather, this "dolphin from hell" would not have been able to live in the deeper ocean waters. It would have needed to return to the surface regularly in order to breathe. It could, however, hold its breath for extended periods, possibly up to 20 minutes.
Pterygotus:
Scorpions have changed very little since they first evolved around 430 million years ago. The oldest known species lived in the sea or in rivers, and some grew to be very large. Pterygotus was the largest of the sea scorpions ever to evolve, and was one of the top predators in the sea. Measuring around 9.2 feet long, it lived in shallow coastal areas, hunting fish, trilobites and other animals by stealth. It would have ambushed its prey by partially burying itself in the sand. Then, when a fish or other unwitting animal came within range, Pterygotus would rise up and grab it with its claws.
Stethacanthus:
Stethacanthus was one of the first sharks to swim the waters of the Devonian Period and become a successful predator. Although Stethacanthus was a predator, its smaller size (2.4 to 6.5 feet long) would have limited its diet to small fish, cephalopods and perhaps some types of arthropods, such as trilobites. Based on its skeletal structure and lean body, it most likely swam relatively fast. This terrorizing shark had a gigantic, tooth-laden mouth, which may have scared other predators away. The most obvious feature on it was its strange-shaped dorsal fin, which is a wide, flattened top covered in hundreds of rough, tooth-shaped scales.
Tanystropheus:
Tanystropheus was about as the Nile crocodile, but almost three-quarters of this length was taken up by its neck and tail, which makes it look almost impossibly unbalanced. When first discovered, it was thought that Tanystropheus would stand on the seashore with its long neck raised in the air, ready to strike down at any fish swimming in the sea below. However, it is now known that the neck was very rigid and contained only 9-12 vertebrae. Therefore, it couldn't bend up and down, although it may have had some ability to move its head and neck side-to-side. Tanystropheus lived and thrived during the Triassic Period of the Mesozoic Era.
Tylosaurus:
Tylosaurus was the most feared marine reptile of the Cretaceous Period. It belongs to a group of marine reptiles known as Mosasaurs. Measuring up to 60 feet in length, this apex predator dominated the seas which inundated the land (i.e., Kansas). With its huge size and powerful biting force and sharp, back-curving teeth, this sea monster could have easily taken on a Ginsu Shark (see image) without even a struggle. All mosasaurs had terminator teeth that were set on the underneath side of the upper mouth.
Xiphactinus:
Xiphactinus was one of the swiftest predators of the Cretaceous seas. It was also possibly one of the ugliest and has been nicknamed the "bulldog fish" because of its compressed face. Its streamlined body (~19.5 feet long) and broad, muscular tail could propel it at speeds of up to 37.5 mph, easily fast enough to outrun any fish. Its lower jaw was specially hinged so that its mouth could be made particularly wide. When in pursuit of prey, it would accelerate rapidly for the kill and swallow its victim whole. It hunted fish, seabirds, and possibly pterosaurs.
