Toxidium ultimum is a species of beetle in the family Staphylinidae. This species is found in south-eastern Brazil (Minas Gerais).
Adults reach a length of about 1.56âÂÂ1.70 mm and have a dark brown body. The apex of the elytra is yellow-ochreous.
Adults have been collected from an Inonotus species located on a tree in front of an avenue.
The species epithet is a Latin word meaning âÂÂthe last oneâÂÂ, referring both to it being the last species described in the author's manuscript and the final specimen collected and dissected for the author's project.