prehistorical vs prehistoric

prehistorical and prehistoric both are adjectives.

Word	Noun	Adjective	Verb	Adverb
prehistorical	No	Yes	No	No
prehistoric	No	Yes	No	No

As adjectives, prehistorical and prehistoric are synonyms defined as:

prehistorical and prehistoric: belonging to or existing in times before recorded history

prehistorical (adjective)	prehistoric (adjective)
belonging to or existing in times before recorded history	of or relating to times before written history
	belonging to or existing in times before recorded history
	outdated