Scientists Discover “Snakey Crocodile-Face” Monster in Wyoming

Written by Colby Maxwell
Updated: April 11, 2023
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Key Points

  • Serpentisuchops lived about 70 million years ago.
  • It was a strange combination of both categories of plesiosaurs.
  • Although the serpentisuchops was 23 feet long, it was dwarfed by the kronosaurus, the largest plesiosaur which grew to 36 feet.

Serpentisuchops Is a Newly Discovered Dinosaur-Era Reptile That Has One of the Strangest Names Around

Toddlers are notoriously good at naming things incorrectly. Whether it’s calling a rhino a “pokie horse” or anything else from their endlessly creative brains, everybody loves to hear them misname and mispronounce things. Even still, there is often a shred of truth to their naming convention. (See pokie horse above.) Well, as one recent discovery shows, scientists also have a bit of fun naming things. Enter: Snakey Crocodile-Face.

Illustration of Serpentisuchops chasing a fish under water

It’s easy to understand why scientists named this extinct animal Snakey



©SpinoDragon145, CC BY-SA 4.0 <>, via Wikimedia Commons – License

It’s not often that researchers discover new creatures in the fossil record, but one team recently discovered one of the coolest reptiles seen in a long time. Serpentisuchops was a massive marine reptile that lived during the time of the dinosaurs, roughly 70 million years ago, but its name is what’s drawing so much attention!

Serpentisuchops sounds like a good name, but like most scientific names, it translates to something that literally describes it. In the case of Serpentisuchops, the literal name is “snakey crocodile-face.” It seems that scientists and toddlers alike have a propensity to name things as they see them!

Why did they name Serpentisuchops the way they did? It all has to do with head shape. Serpentisuchops belongs to a group of marine reptiles known as plesiosaurs, of which scientists have discovered many individuals from different species groups. Generally, the plesiosaurs are split into two categories: those with long necks and small heads (snake-like), and those with short necks and big jaws (crocodile-like). Serpentisuchops is a strange combination of both.

“When I was a student,” said Persons, “I was taught that all late-evolving plesiosaurs fall into one of two anatomical categories: those with really long necks and tiny heads, and those with short necks and really long jaws. Well, our new animal totally confounds those categories.”


Plesiosaurs, Oceanic Predators


had two pairs of wing-like flippers.


Serpentisuchops, despite looking extremely dinosaur-like, wasn’t technically considered a dinosaur. Plesiosaurs are more technically considered to be marine reptiles that happened to live during the time of the dinosaurs. The first plesiosaurs appeared around 203 million years ago, but went extinct around the time of the mass extinction caused by the asteroid that killed off the dinosaurs.

Plesiosaurs lived in marine habitats, with some species potentially living in freshwater locations as well. They were distributed all over the world and were actually some of the first fossils to have ever been discovered. Serpentisuchops, like all plesiosaurs, had a streamlined body with flippers that helped it to move through water more efficiently. In the long-necked smalled-headed individuals, they quite looked like a brontosaurus that was evolved for the water.

How Big Was Serpentisuchops?

Serpentisuchops wasn’t among the largest of the plesiosaurs, but it was still a large marine reptile. From the fossil remains, researchers estimate that Serpentisuchops was around 23 feet long and likely weighed a few tons. The largest of all plesiosaurs was a creature known as Kronosaurus, a reptile that measured up to 36 feet long. Another potential contender is a fossil only known as “The Monster” which measured 50 feet long. Serpentisuchops would have been about average in regard to other plesiosaurs.

What Did Serpentisuchops Eat?

As a general rule, plesiosaurs had two distinct diets, depending on their build. The long-necked small-headed species is up for a bit of debate as to their diets, as it was recently discovered their necks weren’t flexible, but actually rigid. With this new insight, long-necked plesiosaurs likely ate cephalopods and other small fish they could potentially catch without moving their neck.

On the other end of the spectrum is the short-necked, large-jawed plesiosaurs. These creatures would have been apex predators with massive teeth and anatomy designed for killing. These reptiles likely ate large fish and other large animals.

Since Serpentisuchops is a combination of the two, it’s not all that clear as to the kinds of food it ate. With its large jaws, it’s possible it had the ability to eat larger soft-bodied fish, but it’s lack of neck mobility would have kept it from chasing smaller darting prey.

Where Was Serpentisuchops Found?

The initial Serpentisuchops remains were discovered in Wyoming, in a place known as Old Woman Anticline located in the upper Pierre Shale. The fossils are recognized as some of the most well-preserved fossils around. This was caused by the individual sinking to the ocean floor and getting buried by fine sediment almost immediately. Nearly 70 million years later and humans ended up finding the fossils buried in the rock!

What Other Examples of Plesiosaurs Were There?

Archaeonectrus: This dinosaur lived during the Sinemurian or the Early Jurassic, a period which extended between about 193 – 200 million years ago. It was relatively small for a plesiosaur with a length of 12 feet and lived in what is now the south of England.

In keeping with its status as a pliosaur, it had a short neck, large jaws, and conical teeth ending in sharp points. Like other members of the genus which lived between the Early Jurassic to the Cretaceous Period, it was a carnivore which most likely had a penchant for hunting other plesiosaurs, ichthyosaurs, sharks, or fish.

What Was the Kronosaurus Like?

kronosaurus vs mosasaurus

The Kronosaurus was an expert swimmer capable of moving at great speeds

©Daniel Eskridge/

Arguably one of the best-known pliosaurs that ever lived, the Kronosaurus also came with the characteristic short neck and powerful, toothy jaws of the genus. The largest plesiosaur lived during the Early Cretaceous Period (between 100 – 145 million years ago), in Australia.

The marine creature is believed to have lived in a cold inland sea and had four flippers and a short tail. According to experts, it was a predator which measured between 30 – 36 feet and weighed between 10.6 – 12.1 tons.

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The photo featured at the top of this post is ©

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About the Author

Colby is a writer at A-Z Animals primarily covering outdoors, unique animal stories, and science news. Colby has been writing about science news and animals for five years and holds a bachelor's degree from SEU. A resident of NYC, you can find him camping, exploring, and telling everyone about what birds he saw at his local birdfeeder.

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