@GordonIsenburg @[email protected] That article seems to be quite misleading. According to this article about the paper, it only compared the T. rex DNA to 21 different species. It concluded that they are closer related to birds than to alligators, but it did not pinpoint a specific species that is the closest relative.

Unfortunately neither article directly links to the research papers, and it's a bit inconvenient to search for them on mobile.

It would be quite funny though if that was the case.
Molecular analysis confirms T. Rex’s evolutionary link to birds

Putting more meat on the theory that dinosaurs’ closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein — along with that of 21…

Harvard Gazette