What’s the buzz? It’s all about helicoprion, dubbed the strangest shark in Earth’s history. But don’t fret next time you visit the beach — the freakish fish has been extinct for millions of years.
Helicoprion was a member of an entire genus of saw-toothed cartilaginous (aka, shark-like) fish called Edestoids. This name comes from the Greek word, Edeste, which means “to devour.” Edestoids were prevalent in the world’s oceans during the Permian period, before the greatest extinction in Earth’s history.
Habitat
The first remains were discovered in Russia, and were then analyzed and documented by Geologist Alexander Karpinsky. However, the most famous and well-preserved fossils were unearthed in the US — from Idaho, Utah, and Wyoming.
Aside from this, the additional helicoprion remains were scattered across several locations worldwide. This includes Europe, Asia/Pacific, the Middle East, Australia, North America, and Mexico.
Helicoprion existed in the days of Pangea, which explains the wide distribution of fossil remains across the globe. The only regions where they have not yet been found are South America and Africa.
Fossils and Features
At first glance, the Russian fossil resembled those more commonly seen, such as ammonites and nautilus. However, Karpinsky knew better. This was no shell formation but rather a series of spiraling teeth, all connected to the same base within a jaw.
This led him to recognize that the remains belonged to a fish of the Edestus genus. Like helicoprion, its relatives were armed with extended jawlines full of dagger-like teeth, called whorls. The spiral shape of the helicoprion’s whorls led to its nickname, “buzz saw shark.”
Gnawing Questions
Helicoprion whorls held about 180 teeth. Towards the base of the whorl were the largest of which, but they scaled down in size from there. The closer the tooth was to the whorl tip, the smaller its size. But a question remained: where exactly was the helicoprion’s whorl located on its body?
Some believed it was inside the fish’s mouth and towards its throat, centered between its bottom jaw. Others postulated it was attached to its upper jaw, spiraling upwards and outside its mouth. A more outlandish theory was that it was attached to the fish’s dorsal fin as a form of defense.
It was initially hard to say because, before the 1950s, whorls were the only remains found. This is a cartilaginous fish we’re talking about, after all. Cartilage decays — it doesn’t fossilize unless deposited in specific, low-bacteria environments. So most of helicoprion remains no longer exist, outside of the whorls.
Thankfully, in the 1950s, a piece to the puzzle was discovered in the Waterloo Mine of Idaho. Once again, it was a whorl. But this time, (due to very lucky circumstances), it contained a bit of cranial cartilage, proving that the whorl was indeed attached to the helicoprion’s mouth.
Fast forward to 2013, scientists used CT scans to examine helicoprion whorl specimens. This revealed the true placement — in the lower jaw.
Not Quite a Shark
Other skeletal remains suggest that helicoprion had streamlined bodies (a shape that minimizes friction between water and the body’s surface). Similar forms can be seen in other fast-moving predatorial fish, including sharks and tuna.
It was initially assumed that helicoprion were closely related to sharks. Although, more recent evidence suggests it’s more closely related to ratfish and other Chimaeras. That said, Chimaeras did diverge from the same family as Carcharadon (sharks’ genus) millions of years ago — so that explains the resemblance.
The average size of helicoprion is estimated to have been between 20-25 feet long — a little larger than a great white. Helicoprion would have most likely had triangular-shaped fins and gill slits on both sides of their heads.
Diet
Their piercing teeth suited a carnivorous diet well. But there was still some initial confusion about what the fish actually ate. It only had this one saw-like set of teeth, while its upper jaw didn’t have teeth at all.
At one point, it was proposed that helicoprion used their rigid jaws to consume ammolite — an extinct marine mollusk with a hard outer shell. The only problem is that there was no significant wear on helicoprion teeth to support this theory. Plus, with the narrow shape of its jaw, ammonite would likely have no problem slipping out of its grasp.
Today’s generally-agreed upon hypothesis is that helicoprion hunted soft-bodied prey, like squids and other cephalopods. Helicoprion would have used their whorl to trap squid, then rotated their teeth backward, guiding the prey towards their mouth.
Extinction
The buzz saw shark has not been around since the Triassic period, or about 225 million years ago. Along with helicoprion, about 96% of the seas’ creatures perished during Earth’s largest extinction event — the Permian-Triassic extinction.
Scientists generally concede that the “Great Dying” was triggered after a violent streak of eruptions in the Siberian Traps. As the volcanoes erupted, they released excessive amounts of carbon dioxide. In turn, ocean oxygen levels dramatically reduced as acidity levels skyrocketed.
About 80% of the oceans’ oxygen was gone, with some parts of the sea containing zero oxygen — especially the deepest parts of the seafloor. As a result, the majority of marine species from this period went extinct due to suffocation, including helicoprion
