mud puppy vs hellbender

mud puppy and hellbender both are nouns.

Word	Noun	Adjective	Verb	Adverb
mud puppy	Yes	No	No	No
hellbender	Yes	No	No	No

As nouns, mud puppy and hellbender are synonyms defined as:

mud puppy and hellbender: large salamander of North American rivers and streams

Other synonyms of mud puppy include Cryptobranchus alleganiensis.

mud puppy (noun)	hellbender (noun)
aquatic North American salamander with red feathery external gills	large salamander of North American rivers and streams
larval salamander of mountain lakes of Mexico that usually lives without metamorphosing
large salamander of North American rivers and streams