Short version: paleontologists do not yet agree. The current weight of published evidence leans toward Nanotyrannus being a juvenile Tyrannosaurus rex, based on bone-histology growth studies. A minority of recent work argues for a distinct genus on the basis of tooth count, skull shape, and forelimb proportions. As of 2026, the debate is open.
The longer story of how tyrannosaurs grew, why their biology is so contested, and what 250 million years of survival pressure looks like in the fossil record is the whole conversation behind Surviving Climate and Chaos.
Read more about the book →Evan Jevnikar
Reading tyrannosaur bone histology like tree rings, and what it tells us about growth, age, and size.
Read →
Ontogeny, taxonomy, and the slow process of resolving look-alike specimens.
Read →
A running list of the most interesting fossil descriptions of the year, with context on why each one matters.
Read →