Scorpions of the Ancient Seas
During the Silurian Period, approximately 405 to 430 million years ago Eurypterids were the top predators of the shallow seas, lagoons and estuaries. These “Sea Scorpions” grew to over 8 feet in length but typically measured to 1 to 2 feet in length.
Scientists believe and infer that some species may have had a poisonous stinger in its tail like present day scorpions. These eurypterids were present and abundant in different water environments such as shallow seas, lakes, and estuaries. They preyed on the creatures of the period such as trilobites and early versions of the fish. Eurypterids had flexible bodies due to the plated arrangement of their “body armor”. This flexibility helped in locomotion and enabled swifter movement to capture their prey, slow moving trilobites and primitive fish of the time. Many trilobite fossils found have their backsides cut off. During my trilobite fossil hunting days 99% of the specimens I found had their butts missing. It is reasonable to believe that their mortal enemies the Eurypterids may have had taken a bite?
The earliest fossil record of Eurypterids appears during the end of the Cambrian and they disappeared after the great Permian Extinction. The Permian extinction eradicated about 95% of all life on earth. Eurypterids are an important index fossil for specific geologic periods showing their abundance, scarcity, decline and absence due to extinction. Climatic change, atmospheric changes and landmass changes along with an increase in oxygen may have led to this mass extinction. Also with the development of Fish especially during the Devonian, the eurypterids may have become the hunted instead of the hunter. The Devonian is regarded as the period of “The Fish”. Fish grew much more diverse, larger, faster and more predatory. The eurypterids quickly became extinct in a relatively short period in geologic terms. According to the fossil record the eurypterid numbers and species began to decline. Fish developed and evolved during the Devonian Period much as they are today with streamlined bodies, fins and powerful tails for swift movement, more than a match for the slow moving Eurypterids.
Many fossils found of creatures that shed their exoskeletons are exactly that and not the creature itself. That is also true for trilobites and other creatures that had shed their outer shell like bodies during growth periods.
As we move through the Geologic Scale life became more diverse with many new species competing for food and territory on land and in the sea. After the Permian extinction approximately 250 million years ago, 95% of all life on earth vanished and new creatures began to flourish on land, air and in the sea. This is the beginning and the start of the Age of Dinosaurs and “Sea Monsters”.