Just emailed it to you!

I forgot image credit, I apologize! This is by Andrey Atuchin, courtesy the Cleveland Museum

Thanks to all our collaborators, the taggable ones are @ashpoust.bsky.social , @mfabbri.bsky.social , @rileysombathy.bsky.social ! Extra thanks to the Cleveland Museum, the Yale Peabody Museum, and the LA Natural History Museum for allowing crucial sampling of their specimens (12/12)

Really nice work by @jgn-paleo.bsky.social & Zanno reached this same conclusion from independent lines of evidence/specimens just a few weeks ago. Our papers converge on the same conclusion, mutually bolstering each other (11/12)
www.nature.com/articles/s41...

We have uploaded all high-resolution, whole-slide images in all light regimes onto Dryad, available for anyone to download, study, and compare (10/12)

doi.org/10.5061/drya...

So the Nanotyrannus type specimen is full-size, or nearly so. We discuss more in the paper why we don’t find it likely that this is simple intraspecific variation in T. rex, sexual dimorphism, or a congenital dwarfism. The best explanation is that Nanotyrannus is distinct from Tyrannosaurus (9/12)

This is especially apparent when we compare to a juvenile T. rex hyoid from the LACM. Despite being smaller in size, the Nano hyoid shows a close package of external growth marks that is the classic indicator of skeletal maturity (8/12)

All that was left was to test the Nanotyrannus type specimen, the skull that formally defines the species Nanotyrannus lancensis. At the time, it was the general consensus that Nano was a juvenile T. rex, so we were surprised to find every indication of maturity in the hyoid (7/12)

Then, we had to establish that it worked in extinct dinosaurs, especially large theropods. Running the size gamut from Coelophysis to Allosaurus to two definitive Tyrannosaurus individuals, we showed that hyoid microstructure works well! Not quite as precise as limbs, but it gets the job done (6/12)

First, we had to establish that hyoid histology worked to gauge maturity in living relatives of dinosaurs of known growth stages. We showed that it did, in a growth series of Ostrich, Alligator, and even a Dwarf Caiman. Step one, done! (5/12)

The Nano skull does have ‘hyoids’, tubular throat bones. During a visit to the Cleveland Museum of Natural History, curator Caitlin Colleary and I wondered if these might also contain a record of growth, and allow us to directly test maturity in the name-bearing specimen (4/12)

The best way to tell a dinosaur’s maturity is by looking at the bone microstructure (histology) of limb bones. However, the type specimen of Nanotyrannus is an isolated skull, so this method wasn’t viable. This difficulty resulted in the longest-running current debate in dinosaur paleontology (3/12)

There has been a debate since the skull’s discovery in 1942: whether Nano was a small-bodied tyrannosaur that lived with Tyrannosaurus, or just a juvenile T. rex. This has major implications for how we understand T. rex growth and carnivores within last ecosystems to host non-bird dinosaurs (2/12)

Hess Postdoctoral Fellow Steph Lechki speaking about energetic fitness models to finish out the last day of SVP!

PhD student @lnwilson.bsky.social showing new methods for imaging embryonic bird tissues in 3D