Ancient Sharks With Teeth Shaped Spacecraft Named After Vintage Video Games


Artist's depiction of Galagadon swim along the riverbed.
Image: Velizar Simeonovski, Field Museum

The freshly described freshwater shark from the Cretaceous has teeth that resemble icons Galaga video game spacefighter. Remarkably, the remains of this shark were found in the same pile of debris containing Sue T. rex– the largest and most complete fossil of the species ever found.

Introduce Galagadon nordquistaethe newly discovered freshwater shark that swims on the Cretaceous river in South Dakota about 67 million years ago. It's not too big, measuring about 12 to 18 inches in length, and it's possible to explore the riverbed to look for small fish, snails and crayfish, according to new research published today in the Journal of Paleontology. Scientists who discovered Galagadon The word shark is related to modern shark carpets, odd-shaped wobbegong sharks are a good example.

What's left of Galagadon are two dozen small teeth, which are found in the same sediment that produces Sue, the famous one T. rex framework. The scary remains of tyrannosaurus were discovered 20 years ago in the Hell Creek Formation in South Dakota. Smartly, the remaining deposits of this work, called matrices, are not discarded, and are instead stored in the Field Museum in Chicago for safekeeping. Recently, a team of scientists and volunteers decided to look at this two-tonne pile of dirt in hopes of finding some fossils – which turned out to be a good idea.

Left: One of Galagaon's fossil small teeth. Right: The Galaga Starfighter.
Image: Terry Gates / Gizmodo

As noted, only teeth Galagadon permanent. Other body parts have long been lost, mostly because the cartilage does not maintain well. Paleontologist Terry Gates, lead author of the new study and lecturer at North Carolina State University, and his colleagues concluded the size, shape, and behavior of Galagadon by comparing its teeth with those of the same shark species, both extinct and still present.

"Fortunately, the sharks in our study show a close relationship with living carpet sharks so we have plausible conclusions about their ancient lifestyle," Eric Gorscak, a paleontologist at the Field Museum and co-author of the new study, told Gizmodo. "Teeth are usually an indicator of a good diet for obvious reasons. This kind of reconstruction is usually more difficult with other extinct animals, such as non-avian dinosaurs, because they differ significantly from most living animal analogues. "

GalagadonTeeth are less than one millimeter, so they can be easily ignored.

"It's very small, you can miss it if you don't look very carefully," Karen Nordquist, a retired chemist and volunteer who helped find teeth in sediments, said in a statement. "For the naked eye, it only looks like a small lump, you have to have a microscope to get a good view of it."

Nordquist was shocked by the shape of this tooth, which reminded him of a spacecraft Galaga. His colleagues appreciated the comparison, and they decided to name the shark after the classic video game and Nordquist himself.

Various Galgadon teeth.
Image: Terry Gates, NC State University

Galagadon and T. Rex, as these findings say, are contemporaries. The discovery of freshwater sharks in this part of the world, however, challenged conventional thinking about the environment in South Dakota at that time. Sue, presumably, lived and died near the lake formed from a river that evaporated, but its existence Galagadon shows that the area is connected to the sea, possibly by rivers, allowing sea-based sharks to move to land and develop the capacity to live in fresh water.

"This may seem strange today, but about 67 million years ago, what is now South Dakota is covered in forests, swamps and winding rivers," Gates said in a statement. "Galagadon not swoop to prey T. rex, Triceratops, or other dinosaurs that occur in the stream. This shark has teeth that are good for catching small fish or destroying snails [crayfish]"

This discovery is also important because it will help scientists "understand the diversity and potential dynamics of ancient ecosystems, especially in the context of non-avian dinosaurs such as the world-famous Sue. T. rex, "Gorscak said. "The sharks described in our paper help inform the evolutionary history of modern carpet sharks, a group of sharks that currently live around Southeast Asia and Australia, but we now know they have a greater range in their millions of years of history."

Future discoveries can give more light Galagadon and its habitat, but for now, the discovery of ancient sharks in sediments is the same as that of Sue T. rex seems right and makes no sense.

[Journal of Paleontology]


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