Mexican (?) Dagger for Identification?

[Conogre]

Now that you bring up the Portugese aspect, you may be more correct than you realize with an original N. African beginning.
Many people don't realize that Brazil is a source of some excellent antique African weaponry as a large number of escaped African slaves fled into the jungle and managed to create a mini-Africa that grew large and strong enough to fight off the Portugese slavers/priests and colonists for over 100 years.
I used the slavers/priests because the "Church" felt that the hethen savages were an affront to everything holy and actually pulled most of the strings that led to final major onslought and massacre.
Through their contact with the escaped Africans, some of the native Indian population from the region (also enslaved) also ended up with some surprisingly Africanized spears and knives, so don't automatically write off African weapons and weapons of African derivation from S. America, Brazil in particular.
Mike