Served as reconstructed proto-romance!? edit

Currently, the article says:

Being a written language, Late Latin is not identifiable with Vulgar Latin. The latter during those centuries served as proto-Romance, a reconstructed ancestor of the Romance languages.

I'm nobody's linguist and I'm not quite sure how to fix this, but it seems to me that saying an actual spoken language "served as" a reconstructed proto-lanaguage is a bass-ackwards way of thinking about it. I wonder if there's a usual way of talking about a proposed correspondence between an actual spoken language and a reconstruction that would be more accurate here?