Thursday, March 8, 2012

Sea Scorpion - Fos 126

FOS 126
Eurypterus lacustris
Location: Buffalo Area, NY
Age: Silurian

And the Sholesonian finally has a Eurypterid for the fossil collection! These creatures are otherwise known as 'sea scorpions' and populate New York rock formations from the Silurian (~440 million years ago)! So much so that the species Eurypterus remipes has become the state fossil. These were the largest arthropods to ever exist with Jaekelopterus rhenaniae reaching sizes of 2.5 meters (that's about 8 feet tall!), however most species reach average lengths comparable to this specimen.

These fierce bottom-dwelling predators first appeared in the Ordovician (460 million years ago) and lasted for another 210 million years before they went extinct along with over 90% of marine life at the end of the Permian.  Contrary to their name, many species lived in freshwater areas or brackish water (a mix of salt water and non-salt water, i.e. less salt than marine environments) and are more closely related to horseshoe crabs than they are scorpions. This specimen of Eurypterus lacustris can be distinguished from the most common and closely related species Eurypterus remipes, as these have eyes that are further back and has a narrower metastoma (the tail-like appendage).

This particular specimen comes from the Williamsville (A) Formation of Western New York and is a negative impression. I had been searching for a good quality specimen that showed both swimming paddles, and was able to acquire this piece after receiving a generous graduation gift years ago that was earmarked for a fossil. There is a plethora of information available on these guys so check out the eurypterus page to give you a head start. Also, for those in New York, the Paleontological Research Institute has the largest complete eurypterid specimen on display if you get a chance to check it out.

Photo: Ohio State Geology Department

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