Armored rats are just that, rats with bony armor plates.
The head plate is like a bony skullcap. The plates on the back of the armored rat are slightly over lapping to allow the animals back to bend. While rodent like the armored rat has many sharp teeth rather than just two front incisors. Native to Coruscant the armored rats are well known on the lowest levels. Even thugs in the Crimson Corridor know better to avoid this ravage little creature.