Not a similarity but maybe connection, NamJap ji.
The Atlantic ocean did not extend as far down long ago as it does now. Africa and South America were connected. The separation occurred slowly over time. The ocean may have been much narrower when African and South American civilizations were developing. Maritime travel may have caused a sharing of cultural influences. So there may have been more cross currents of knowledge than we recognize.
Also a pyramid is a stable structure and engineers in two civilizations could have realized that independently. Just like the water wheel -- you remember that -- was probably invented independently in Greece and Asia Minor and in China independently. These are step pyramids I believe.
Anyway, the space invader hypothesis continually comes up because it is spookier than the idea that plain ingenuity may be the answer.