Eurypterids

• Kingdom: Animalia

• Phylum: Arthropoda

• Subphylum: Chelicerata

• Class: Merostomata

• Order: Eurypterida

• Often called Sea Scorpions Eurypterids are an extinct group of mostly carnivorous marine arthropods in the order Eurypterida with some moving to fresh water around the Pennsylavanian.

• They first appeared during the Ordovician and survived until the end of the Permian, around 212 MA later!

• The group went extinct during the P-Tr extinction event in which 96% of all marine species went extinct

• Eurypterids had a carapace consisting of twelve segments and 6 appendages; the mouth claws, the 2^nd to the 4^th appendage were placed at the front of the body and covered in spines, the fifth was also used in food capture but was not covered in spines, the sixth acted as a claw in the benthic species and a paddle in the swimming.

• The dorsal section of the eurypterid had two laterally placed compound eyes and two ocelli in the center.

• Eurypterids are commonly around 8 inches long but some species like jaekelopterus got up to over 8 feet.

• Jaekelopterus thought to have gotten to be around 8.2 feet in length, lived in fresh water in rivers and lakes. The second largest was the sea scorpion Pterygotus who reached sizes around 7.7 feet the size of a crocodile