English: Megalograptus ohioensis Caster & Kjellesvig-Waering, 1955 - fossil eurypterid from the Ordovician of Ohio, USA. (replica; Orton Geology Museum, Ohio State University, Columbus, Ohio, USA)

The eurypterids, or sea scorpions, are an extinct group of chelicerate arthropods. They have an elongated, scorpion-like body that could reach enormous sizes (2.5 to 3 meters!), with a nonmineralizing exoskeleton composed of chitinous material. They are generally found in shallow to very shallow water marine and marginal marine facies.

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From exhibit signage:

Megalograptus ohioensis

This is a hand-painted [replica] of the holotype (the specimen by which the species is defined) produced by the Cincinnati Museum Center for the Ohio Geological Survey. It shows the underside of the body and the top of the head. Other specimens found at the same and subsequent sites have allowed paleontologists to reconstruct the animal more completely.

The large front appendages with long spines may have been used to rake the sea floor for prey - likely smaller invertebrates including trilobites.

With the remains were found coprolites filled with chewed pieces of eurypterids. Megalograptus may have preyed on other members of its own species or, like some arthropods today, maybe females ate the males after mating.

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Classification: Animalia, Arthropoda, Chelicerata, Merostomata, Xiphosura, Eurypterida, Megalograptidae

Stratigraphy: Elkhorn Formation, upper Richmondian Stage, uppermost Cincinnatian Series, upper Upper Ordovician

Locality: near the town of Manchester, Adams County, far-southern Ohio, USA

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See info. at:

en.wikipedia.org/wiki/Megalograptus