Loricarioidea is currently diagnosed by the derived presence of a reduced gas bladder, encapsulated in expansions of the parapophysis of the first vertebrae, and of odontodes, small dermal denticles.
Loricarioidea is now recognized through the detection of a reduced air sac, contained within enlargements of the first spinal vertebra's parapophysis, as well as the presence of tiny tooth-like scales on its skin.