prehistoric vs prehistorical

prehistoric and prehistorical both are adjectives.

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

As adjectives, prehistoric and prehistorical are synonyms defined as:

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

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outdated