First recognized proturan

The first species of proturan recognized by science was Acerentomon doderoi, discovered in Syracuse, New York State, USA, which was formally described and named by Genoa-based entomologist Dr Filippo Silvestri in 1907. Also known as coneheads, proturans are soil-dwelling arthropods that are currently known to number around 800 species, but they are all so tiny and inconspicuous that their very existence had remained entirely unknown to science prior to this species' early-20th-century discovery.

Pale in colour, proturans are superficially insect-like and possess three pairs of legs like them, but lack eyes, wings and antennae. Moreover, they possess internal mouthparts, whereas insects' mouthparts are external. Nevertheless, until quite recently proturans were taxonomically categorized as very primitive insects, but nowadays, together with springtails and diplurans, and based upon the above-noted anatomical differences, they are generally removed from the taxonomic class of insects and housed in a separate one, allied to – but distinct from – true insects.