Kingdom Animalia
Phylum Arthropoda
Subphylum Chelicerata
Class Merostomata
Order Eurypterida
Suborder Eurypterina
Family Eurypteridae
Genus Eurypterus
1st Species Eurypterus remipes
2nd Species Eurypterus dekayi
3rd Species Eurypterus hankeni
4th Species Eurypterus laculatus
Other attributes
Time Range 432-418.1 mya
Location United States of America, Canada, Norway, Sweden, Ukraine, Estonia (possibly United Kingdom)
Name Meaning Broad wing
Physical Dimensions 1.3 meters long
Dietary Classification Carnivore

Eurypterus is a eurypterid eurypterid merostomate arthropod from the Wenlock-Early Devonian of the United States of America, Canada, Norway, Sweden, Ukraine, Estonia, and possibly the United Kingdom. It was named in 1825 by James Ellsworth De Kay. It was the most common eurypterid during the Silurian, and was confused for either being a catfish or a branchiopod, right before people discovered that it was a eurypterid.


Eurypterus had a build very similar to generic eurypterids, with a rounded cephalothorax, large eyes, 4 pairs of walking legs, a pair of paddles for swimming, and a long tail ending in a spear-like telson. However, it had a few major differences; for example, the 1st 3 pairs of walking legs were short, while the 4th pair was long, and it had very small claws, something very different from the long arms of Megalograptus and Pterygotus. Its body would have been covered in a hard, chitinous exoskeleton.


Eurypterus was a predator, preying on small invertebrates. Its small claws were used to get a hold of prey, as well as tear them into pieces.


Eurypterus had a very interesting swimming style, mainly known as ¨subaqueous flight¨. Its paddles would row back and forth, with their broad side facing forwards as they went forward and downwards as they went backwards, leaving it capable at swimming slightly faster than a turtle or otter. Smaller individuals would have flailed their paddles at a faster rate (similarly to swimming crabs and water beetles), propelling themselves through the water at higher speeds. As well as this, Eurypterus would be able to step out of the sea to mate and lay eggs, similar to horseshoe crabs.

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