It lived during the late Atdabanian stage,[3] which lasted from 521 to 514 million years ago during the early part of the Cambrian Period.

As with most early trilobites, Archaeaspis has an almost flat exoskeleton that is only thinly calcified, and has crescent-shaped eye ridges.

The superfamily Fallotaspidoidea, to which Archaeaspis belongs can be distinguished from all other Olenellina by features of the cephalon and in particular the glabella.

The eye ridges (or ocular lobes) contact, but do not merge with, the entire frontal margin of the glabella.

[7] In Archaeaspis the frontal lobe of the glabella (L4) does not contact the anterior border furrow, but is connected with it by a ridge at midline (called plectrum).