Hemiarthrum setulosum is a species of chiton in the family Hemiarthridae,[1] the only member of the genus Hemiarthrum.

It was previously assigned to the family Hanleyidae.

[2] Hemiarthrum setulosum represent one of the five major clades of chitons that are living.

Hemiarthrim setulosum has an incomplete lateral tract in the nerve ring.

[3] This species occurs off the Kerguelen Islands and Cape Horn.