Differences between Personas and Archetypes?

I am new to UX and just started using personas for validating the UX of an existing project, then I was pointed out the fact that since my 'personas' were created from observing existing users instead of interviewing users, they are 'archetypes'. Read: Archetypes not Personas

When your UX team creates personas — they are creating fictional characters that represent your user base. Personas include details such as age, sex, occupation, education, interests and more. These personas are often created in a vacuum — with little insight into their behavior....A person's characteristics and behavior do not always align.

Archetypes are modeled around a behavioral perspective.... Using archetypes gives us a better view of behavior in interaction design.

Now, term and creation method aside, how are they different? Do they serve different purposes?