All of Niadra's Zerg Mutalisks evolved into Zerg Devourer with no precedessor units any longer. On other side though, Niadra's Devourers got their acid strengthened to point it can literally both melt and burn a target.

Nocturnal Zerg Guardians got specific mutation when speaking of armament. Instead of toxic spores, these Zerg Guardians are armed with nebula-colored plasma projectiles.

(Zerg Devourer and Zerg Guardian belongs to Blizzard)