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EURYPTERID (SEA SCORPION) FOSSILS FOR SALE
What Is A Eurypterid?
Eurypterids are an extinct order of arthropods, commonly called sea scorpions. The order contains about 250 species, including the largest known arthropod. Eurypterids are related to modern arthropods like spiders, scorpions, and horseshoe crabs.
When Did Eurypterids Appear In The Fossil Record?
Eurypterids first appear in the Darriwilian stage of the Ordivician about 467.3 million years ago. Their diversity expanded greatly during the Silurian Period.
When Did Eurypterids Go Extinct?
Eurypterids went through several stages of declining diversity before their ultimate extinction in the Late Devonian. All but four families of eurypterids disappeared from the fossil record. The last remaining members of the order Eurypterida disappeared during or shortly after the Permian-Triassic extinction, about 252 million years ago.
What Did Eurypterids Look Like?
Eurypterid bodies consisted of a horseshoe crab-like shell head, segmented body, and a tail-like appendage called a telson. They had six pairs of appendages under the shell of the head, and eyes above. The first set of appendages were modified into pincers for getting food to the mouth. The remaining sets were used for locomotion. The last set of appendages were either wide and flat like paddles for swimming, or long and thin like legs for walking.
Reconstruction of Eurypterus in life. Image by "Obsidian Soul" Creative Commons License
Eurypterus anatomy. Image by "Obsidian Soul" Creative Commons License
How Big Were Eurypterids?
Most eurypterids were smaller than about 8 inches (20cm); the smallest were about 1.2 inches (3 cm). The species Jaekelopterus rhenaniae was the largest arthropod known, reaching 8.2 feet (2.5 meters)! Other large species ranged between 20 inches (50 cm) and 6 feet (180 cm).
How Did Eurypterids Move?
Eurypterids had two basic forms of locomotion: swimming and walking. Two subfamilies were differentiated by the way they move. The family Eurypterina had its last set of appendages modified into a set of blade-shaped paddles for swimming. The family Stylonurina had this same pair of appendages modified into a strong, thin set of legs for walking. It is likely that both subfamilies swam and walked or crawled. It is also likely that Stylonurina could leave the water at least for a short time since its species had legs, while Eurypterina would have been confined to the water.
What Did Eurypterids Eat?
Eurypterids were carnivores. It is likely they ate whatever they could safely subdue, such as fish, invertebrates, etc. Fossilized eurypterid coprolites (feces) have been found containing trilobite and eurypterid shells, indicating that they were also cannibalistic. Given their diversity and morphology, it is likely that sea scorpions were among the apex predators of the environments they inhabited.
Where Did Eurypterids Live?
Despite their moniker as sea scorpions, most eurypterids lived in brackish or freshwater environments. Only the early species that lived in the Ordovician Period lived in marine environments. Most probably lived in brackish water where fresh and saltwater mixed, such as estuaries and river mouths. The last living eurypterids were freshwater dwellers.
How Did Eurypterids Breathe On Land?
It is not known if they actually could breathe on land or if they could simply survive out of the water for a few hours: no fossilized breathing apparatus has been found. If they did breathe oxygen from the air, it was likely by a modification of their vascular systems to allow oxygen exchange.
What Is The Difference Between Sea Scorpions And Modern Scorpions?
Sea scorpion is the common name for members of the arthropod order Euryptida. Scorpions are members of the order Scorpiones, class Arachnida. Taxonomically, they are only distantly related. Sea scorpions were aquatic, while scorpions are terrestrial. Perhaps the biggest differences are in the tail and pincers: sea scorpion tails resemble the stingers of terrestrial scorpions, but were not used to deliver venom. Sea scorpion pincerse are the first set of appendages under the shell, while a scorpion’s pincers are the second set of appendages. Overall, the relationship between eurypterids and the first terrestrial arachnids is not well understood.
What Is The Closest Living Relative Of Eurypterids?
The four living species of horseshoe crabs are the closest living relatives of the Eurypterids.
Did You Know?
The eurypterid species Eurypterus remipes is designated as the state fossil of New York.
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