Hallipterus

Reconstruction

Hallipterus was a gigantic Hardieopterid eurypterid. Though some previous estimates have placed its size at over 1.5 meters in length, these were likely excessive.[1] Still, assigned specimens suggest a size of over 1 meter long.[1]

The carapace was subelliptical, greater in length than in width, with a prominent and unornamented marginal rim. The eyes were very small, close to each other and separated by a prominent median ridge with large ocelli at the posterior extremity.[2]

The chelicerae were simple and elongated. The first walking legs possessed flat and movable spines. The rest of the legs and the opisthosoma remain unknown.[2]

Hallipterus contains one valid species, H. excelsior, from the Devonian of New York.[3] Another species was once recognized from similarly aged deposits in Pennsylvania, "H. lacoanus",[2] but it is today seen as synonymous with H. excelsior.[1]

• List of eurypterids