The fossil material includes an exceptionally well preserved skin impression.

"Why should I let perfectly good fossil material go?"

Some, but not all, of this fossil material has been reclassified as E. primus.

Some of the known fossil material may also be from the Upper Cretaceous.

After 1924 no fossil materials were removed from the dinosaur quarry.

It was initially described based on fossil material, but was later found to be extant.

Most of these have now been placed in other genera or are understood to be dubious names, based on poor fossil material.

There has been considerable confusion about the attribution of the fossil material.

More complete fossil material is needed in order to resolve the placement of Pachystropheus.

The fossil material now recognized as belonging to this species were historically described under a multitude of different names.