If you’ve ever been to Arizona, you know that the state’s landscape is a treasure trove of geological and ecological wonders. Sparsely populated, and with massive stretches of open land that invites scientists to search for clues about the earth’s history, Arizona has yielded many fantastic finds over the years. Now, researchers have discovered that 270 million years ago, the state was home to an incredibly diverse shark population. Here, we’ll see what Arizona has to reveal about the sharks that populated the planet during the Middle Permian era.
Excellent Conditions for Shark Life
During the Middle Permian era, a warm, shallow sea covered the Kaibab Formation, which is a high plateau region that now supports a forest comprised mainly of Ponderosa Pine trees. In this sea, sharks preyed on sharks; something that still occurs today, but with much less frequency. According to David Elliot of the Museum of Northern Arizona’s Geology and Paleontology Department, sharks were the most prevalent predatory vertebrates living in worldwide marine environments. Not only were these animals diverse, they were numerous. Niches currently occupied by marine mammals and bony fishes were filled by sharks, meaning that sharks preying on other sharks was once a much more common occurrence then it is today.
Of the many shark species being discovered in the area, three sharks in particular have piqued researchers’ interest:
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Kaibabvenator swiftae – A large shark just under 20 feet long, this huge apex predator acted much like today’s Great White sharks do. Also known as Swift’s Kaibab Hunter, it had enormous serrated cutting teeth designed for ripping and tearing flesh, and it was large enough to prey on other big animals.
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Neosaivodus flagstaffensis – The “New Saivodus from Flagstaff” was a medium-sized shark that grew to be just under seven feet long. It was equipped with gripping teeth that enabled it to feed on a wide range of prey once it reached adulthood. Juveniles most likely fed on nautiloids.
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Nanoskalme natans – Also known as the “swimming dwarf blade,” this shark had strong cutting teeth that resembled small blades. This shark was a small one, growing to a little more than three feet long. It was likely a small fish predator; in addition, it probably acted as a scavenger, as many of today’s sharks do.
All these species belonged to an order of primitive sharks that is now extinct. Their bodies were characterized by a pair of ornamental spines on the dorsal fins, plus teeth with large, well-developed central cusps. The sharks possessed symmetrical tails and short-snouted heads. In comparison, many of today’s sharks have developed asymmetrical tails, and some have longer snouts.
These incredible sharks ruled the seas about 45 million years before dinosaurs came into existence. On land, pre-mammalian synapsids including animals like Dimetradon, the lizard-like creature with a big sail on its back, were the largest beasts.
The sharks discovered in Arizona disappeared around the end of the Permian era, which marks a time of major changes in the world of sharks. It was then that ancient species disappeared and more modern species took their places; sharks and rays as we know them today developed beginning in the early Jurassic era. Researchers working to learn more about these ancient species are using their findings to make new discoveries about life on earth today, and to gain insight that may help conservationists as they work to promote enhanced public knowledge that could help give today’s endangered shark species a greater chance at future survival.