[1] This genus is based on what is now AMNH 5767, parts of three vertebrae, a coracoid, and a metatarsal.

[3] Other authors have gone further and considered E. amplexus as simply a large individual of Allosaurus fragilis.

They also considered its holotype specimen not diagnostic and classified it as a nomen dubium.

The word amplexus refers to the copulatory position of amphibians in which males clasp their mates.

Therefore, the specific epithet means "clasping buttressed vertebrae" in Latin.