What is the first thing that comes to mind when you think of the word ‘scorpion?’ For me, I instantly picture a creature with two claws and a menacing, arched tail hanging over its’ back as if it were a famous contortionist. Then, I think of the movie Scorpion King with Dwayne “The Rock” Johnson, and finally, those strange lollipops with the Thumbelina sized scorpions encased in the middle. Never once did it cross my mind that scorpions lived anywhere else than dry, solid land, but they did, and they were called a Eurypterid.

These creatures lived in water. Some of these prehistoric scorpions were really big. The sea scorpion or Eurypterid could grow to be larger than a human, reaching an enormous eight feet in length. During their time, they were one of the largest predators in the water.

Eurypterid: Animal, with upside down triangular body with grooves, in water. Legs from upper portion of body and claws.

Photo courtesy of Obsidi♠nSoul, via Wikimedia Commons and background by Dimitris Siskopoulos from Alexandroupolis, Greece. Rendering of Sea Scorpions, genus Eurypterus.

The Dino Eurypterid

In terms of scientific classification, Eurypterids are categorized under the Animalia Kingdom and the Phylum Arthropoda just as the creature from the previous article in this installment, Aegirocassis benmoulae. The subphylum is Chelicerata while the class is Merostomata, but most importantly, the order is Eurypterida. Like with anything, there are several different species. There are approximately 300 species known in the Eurypterida order followed by categories of 20 different families and 60 different genera, or subfamilies. So, although these creatures may fall under the order Eurypterida and are colloquially referred to as sea scorpions, each one is a little different.

Animal, with upside down triangular body with grooves. Legs from upper portion of body and claws on rock.

Photo courtesy of Daderot, via Wikimedia Commons. Fossil of Sea Scorpions, species Eurypterus remipes, from an exhibit in Houston, Texas at the Houston Museum of Natural Science.

Did you know? Eurypterus remipes has been New York’s State fossil since 1984. 


Take size, for instance. Not all Eurypterids were as massive as the eight-footer Jaekelopterus rhenaniae. This particular species is classified under the Family Pterygotidae and Genus Jaekelopterus. Some were as small as 10 centimeters. Yet, Eurypterids are still considered to be one of the largest arthropods to live.

On another note, habitat is another difference among some Sea Scorpions. From shallow brackish, freshwater lakes to the sea or even a combination of both at a river delta, these creatures lived in different bodies of water while some were even land walkers. It just depended on the particular species of Eurypterid. For instance, the giant Jaekelopterus rhenaniae didn’t mate on land as other, smaller, sea scorpions had, thus, making them one of the species that wasn’t a land walker much to the luck of small land dwellers. It was actually physically impossible. The size and weight of Jaekelopterus rhenaniae’s body was no match for its’ thin, little legs. Unless the Jaekelopterus rhenaniae was going to army crawl with its’ claws, it’s highly unlikely that this creature left its’ aquatic lair.

Eurypterid: Animal, with upside down triangular body with grooves. Legs from upper portion of body and claws on rock.

Photo courtesy of Ghedoghedo, via Wikimedia Commons. Fossil of the Sea Scorpion, species Eurypterus Podolicus, taken at De Groene Poort, Boxtel.

Unlike the rather peaceful Aegirocassis benmoulae, sea scorpions were fierce predators, usually consuming any animal smaller than itself. Its claws, with many ridges that allowed the creature to grasp fish and other food, were a major asset to capturing prey. However, it is said that Eurypterid, among other prehistoric marine arthropods, began tol shrink when more competition arose. Chiefly, when fish developed jawbones. Although these creatures are extinct, the fossils of Eurypterids have been uncovered all over the world, including Australia, Germany, and the United States.

Eurypterids To Go

Although the creatures Aegirocassis enmoulae and Eurypterid had their differences, they did exist at the same time, both having fossils that trace back to the Paleozoic era. Fossils can be dated back to the Ordovician period, which was the second period of the Paleozoic era, and it appears that these creatures became extinct by the end of the Permian period or the last period of the Paleozoic era. Interestingly, the Permian period is known for the extinction of several species. During this time, more than 70 percent of terrestrial species and 95 percent of marine life perished due to possible factors including rising temperatures and low oxygen levels. But this didn’t happen overnight, this period of extinction occurred over many, many years.

Eurypterid: Animal, with upside down triangular body with grooves. Legs from upper portion of body and claws.

Photo courtesy of Ryan Somma, via Wikimedia Commons. Model rendering of the Sea Scorpion, genus Eurypterus, on display at the Smithsonian National Museum of Natural History: Hall of Fossils.

Interesting Facts

Now, it is only fair that I indulge you in a shocking fact about Eurypterids. They are related to our modern day scorpions, but they aren’t real scorpions. Sure, they share similar characters, such as a tail and pincers, which is the reasoning behind their colloquial name, but the Eurypterid isn’t considered to be direct ancestors to our modern day scorpions.

Just like a particular sea cucumber’s nickname is ‘sea pig’ for its resemblance to a plump, pink pig, the sea scorpions received its nickname for its appearance.

Shockingly, this is not the only creature of the sea with a nickname involving ‘scorpion.’ The species Taurulus bubalis, a type of fish, is known as the long-spined sea scorpion, and yes, there is also a short-spined sea scorpion found in British waters.



Final Words

Overall, it is fascinating to see how modern creatures connect to their prehistoric relatives and to think of these creatures, such as the Eurypterid, that once dominated their time. Now we are left to wonder if large scorpion-like creatures may one day return to the sea… hopefully not!

This article is a part of the article series called Prehistoric Tank, written in homage to the classic Jurassic Park movies and the more recent Jurassic World. This series of articles will discuss different sea creatures –extinct or still among us. If you have any thoughts or have any suggestions for the new Prehistoric Tank series, please comment below! Thanks for reading 🙂 


Feature Photo: Photo courtesy of Martin Cathrae on flickr.com (2009). <https://www.flickr.com/photos/suckamc/4252136101/>

Photo One: Photo of Sea Scorpion courtesy of Obsidi♠nSoul; Background Water_floor.jpg courtesy of Dimitris Siskopoulos from Alexandroupolis, Greece (Own work Water_floor.jpg) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons. <https://commons.wikimedia.org/wiki/File:Eurypterus_Paleoart.jpg>.

Photo Two: Photo courtesy of Daderot (Daderot) [CC0 or CC0], via Wikimedia Commons. <https://commons.wikimedia.org/wiki/File:Eurypterus_remipes,_sea_scorpion,_Silurian,_Fiddlers_Green_Formation,_Phelps_Member,_Herkimer_County,_New_York,_USA_-_Houston_Museum_of_Natural_Science_-_DSC01976.JPG>.

Photo Three: Photo courtesy of Ghedoghedo (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons. <https://commons.wikimedia.org/wiki/File:Eurypterus_podolicus_1.jpg>.

Photo Four: Photo courtesy of Ryan Somma [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons <https://commons.wikimedia.org/wiki/File:Eurypterus_Smithsonian.jpg>.