Which, of course, has my favorite bass line. (Unrelated: I've listened to just about every recording of this on YouTube, which gives a new appreciation for how incredible this ensemble is. In particular, that weird black wind instrument next to the lead violinist is a cornett, or cornetto, not to be confused with a cornet, coronet, or a corneto. I think I may have at last internalized the correct spelling. Regardless, Wikipedia is plagiarizing someone's book somewhere that says it's a devilish hard instrument to play, which explains why maybe 5% of the YouTube performances have one.)
I recognize the style, from years ago when I performed Monteverdi's Beatus Vir with a local chorus.
See? The round/call-and-response between voice sections, and the voice parts mirroring the instruments.
For some reason, I remember covering Renaissance music (Josquin, Palestrina, Praetorius) in Music Theory, and also Bach, but not Monteverdi, who apparently bridged Renaissance and Baroque music; so it makes a lot of sense that his music has elements of both.
That's all normal, right?