AIUI, USA didn't adopt copyright as an unregistered right, ratifying the Berne Convention, until 1988, 100 years after most of the rest of the World.
I don't quite know how registration works (see copyright.gov) but it seems there might be a presumption of ownership that's established? They still have registration in USA and it affords greater rights (higher damages in cases of infringement I think). Notably, novelty is not an absolute requirement for copyright registration.
The requirement that the author must hold copyright seems to be implicit in earlier versions of copyright law all the way back to the 1790 Copyright Act; I don't see any provision that would let one copyright a work one was not the author of.
Registration creates prima facie evidence that the registrant is the legitimate owner of the copyright. Anyone who disputes the claim in the face of a registered copyright has the burden of proof to demonstrate that the registration was erroneous.
The actual law for the US (17 USC ยง201 (a)):
> Copyright in a work protected under this title vests initially in the author or authors of the work. The authors of a joint work are coowners of copyright in the work.
You cannot own copyright on a work that you have not authored, unless it has been (lawfully) transferred to you.
Incidentally, this is basically the core of the "Happy Birthday" copyright dispute: it was never established that the Hill sisters authored the lyrics, so they never had a copyright interest in it.