The Ginsu shark, or Cretoxyrhina, was a mackerel shark that lived during the Late Albian to Campanian of the Late Cretaceous period, more than 100 to 84 million years ago. The sharks looked similar to the modern great white shark, even though the two species are not related.
This apex predator were one of the top of the Cretaceous seas. They fed on mosasaurs and plesiosaurs. One specimen was even found to have undigested remains of a giant Cretaceous fish. The Cretoxyrhina sharks were more than 23 feet long, and they swam in the Cenomanian-Campanian seas all across the world.
The Ptychodus sharks were part of the genus of hybondontiform and durophagous sharks that populated during the Late Cretaceous era. Experts estimate that they died more than 85 million years ago.
Also known as crusher sharks, these sharks were known for their plate teeth and their dietary preferences of mollusks, shellfish, invertebrates, carrion, and other sea creatures. These sharks crushed the shells of their prey while they were eating. The sharks were 33 feet long, and their fossils had been primarily located in the Western Interior Sea. They are considered to be the most enormous shellfish-eating creatures ever.
This kind of freshwater shark lived from the later Devonian period until the end of the Triassic. Scientists estimate that the sharks disappeared from the fossil record more than 202 million years ago. The Xenacanthus is often referred to as the “eel shark” because it has an elongated dorsal fin that extends along the spine.
These sharks were small, only three feet in length. The dorsal fin was ribbon-like, and it ran the entire length of the body to the tail, where an anal fin joined it. The closest living relatives are the stingray and other sea-dwelling species.
Another extinct freshwater shark, the Orthacanthus, lived in swamps and bayous approximately 225 million years ago. Scientists have also found fossils dated back to the Denovian era more than 400 million years ago. These sharks had long spines that extended from the back of the skull to the end of the body.
The Orthacanthus sharks were about 10 feet in length, and they looked more like a giant eel. The sharks were found in Europe and North America. Experts believe the sharks could have been cannibalistic because developing teeth were often found in the coprolites of adults.
The Anisopleurodontis was a genus of shark that was known to only one species. The sharks were closer concerning modern chimaeras than sharks, and they lived during the Permian era approximately 300 million years ago.
While not much has been uncovered about these sharks, the creatures were almost 10 feet in length, and they had an enlarged heart. The fossils have been found in the Parnaiba Basin of South America.
The Helicoprion is mostly known for its unique mouth. A cartilaginous structure helped the shark develop a strange tooth structure. Scientists believe that it lived during the Permian age approximately 290 million years ago.
The spirally-arranged cluster of teeth was known as “tooth whorls,” and the structures measure up to 18 inches in length. Experts believe these sharks were quite large and could grow up to 39 feet long. The fossils have been found in China, Australia, the Ural Mountains, and North America.
The Edestus shark swam the oceans during the Late Devonian to Late Carboniferous more than 300 million years ago. These sharks grew teeth in curved brackets, and they would not shed their teeth as they became worn like today’s sharks. There was only a single row of teeth on each jaw, and the sharp and serrated teeth were like scissoring shears.
These sharks are believed to have swum in all of the world’s oceans during their time on earth. While there are no extant relatives, the helicoprion is believed to be a relative to the Edestus.
The Stethacanthus was a part of the shark-like genus Holocephalian, a primitive form of fish and early modern shark ancestor. These creatures lived between the Late Denovian period to the Early Carboniferous epoch, between 420 and 324 million years ago.
Also known as the anvil shark, the Stethacanthus had a dorsal fin that was shaped like the tool. It also had small spikes that protruded through the top. The peaks continued along the top of its head, which were formed from its scales. These relatively small creatures were approximately 2.3 feet long, and the fossils have been found in Asia, Europe, and North America. The Stethacanthus are more closely related to chimaeras, like the ratfish, spookfish, and ghost shark.
The Cladoselache were living in the ocean during the Denovian period more than 400 million years ago. This species was known as one of the oldest known sharks with a nearly fully preserved fossil. It swam in oceans of what is now considered North America.
This shark is considered by scientists to be the first “true” shark. The sharks were covered in scales, and it had a small patch along the edges of its fins. They were about 5.9 feet in length, and they had little mouths and smooth-edged teeth, which were suited for grasping, tearing, and chewing.
The McMurdodus is considered the earliest known modern shark, which lived in the middle of the Devonian period about 390 million years ago. The classification is based on the tooth enamelooid, meaning it is more closely related to modern sharks than other extinct species.
These sharks were thought to be between 4.6 and 18 feet long. Most of their fossils have been found in Western Queensland, Australia. The closest living relative is believed to be the cowshark; however, scientists say there is nearly a 200 million year gap in the fossil record between these two species.
The Cretolamna shark existed during the Cretaceous and Paleogene periods, which was approximately 50 to 90 million years ago. Fossil records have been found in the waters of North America, Africa, and the Middle East.
Although not one of the biggest prehistoric sharks, the Cretolamna still had an impressing length of about nine feet long. They preyed mostly upon sizeable bony fish, turtles, squids, mosasaurs, and other sharks.
The Cobelodus shark looked very different in comparison to today’s modern sharks. They had round heads and an arched back. The single dorsal fin was located at the end of the back. The sharks came from the Symmorlida family.
Scientists have nicknamed the shark the Godzilla shark because its teeth resembled its namesake. This prehistoric species lived in North America during the Carboniferous period. They were about seven to nine feet in length.
The Carboniferous Period was about 360 to 286 million years ago, and scientists have dubbed the era like the Golden Age of Sharks because shark diversity flourished. By the end of the period, there were approximately 45 families of sharks!
The Falcatus falcatus were tiny but mighty; scientists estimated that the sharks were six inches in length. One preserved fossil even depicts a couple of the sharks mating, with the larger female grabbing the male by its head spine!
The Elegestolepis is shrouded in much mystery. Scientists only know what they could gleam from fossilized placoid scales. It is believed that the sharks were covered in placoid scales that were hydro dynamically shaped to keep down water resistance.
These sharks were believed to have lived in the late Silurian period, more than 420 million years ago. They are thought to be one of the earliest sharks, even predating much of the life on land.
The borneo shark was once thought to have been extinct. The scarce species was discovered in 2004. The small gray shark is only 26 inches in length. The slender body includes a long pointed snout and a second dorsal fin behind its anal fin. The sharks mostly feed on bony fishes.
It is the only member of its genus to have a row of enlarged pores above the corners of its mouth. Before its sighting, the last recorded time a Borneo shark was spotted was in 1937. The shark continues to gain conservation concern from scientists.
Previously known as the false smalltail shark, the Carcharhinus obsolerus has not been seen in more than 80 years, and scientists believe they may have become extinct. The species was known to swim in the Western Central Pacific Ocean area, and the last three specimens found were in Borneo, Vietnam, and Thailand.
Although they have not been seen since 1937, scientists are hopeful that the lost sharks are not entirely lost. The rediscovery of the borneo sharks gives them hope that these sharks could be found again.