Happy Thought for 31 October 2025

 Have a Happy Thought:

People that study bones have long understood that at a certain age, the growth plates close over, and the bones don’t get any longer. In humans, this happens sometime in the late teens or early 20s. In other words, early adulthood.

This pattern – bone growth stopping in early adulthood – is common to pretty much all animals.

Including… dinosaurs.

Palaeontologists have put this knowledge to use as they study fossilised bones – yes, apparently you can see in a fossil whether the growth plates are closed or not!

In fact, this has very recently led to a discovery… or at least a naming… of (say this in a scary/dramatic voice in your head): the Nanotyrannus.

Image: a pack of Nanotyrannus hunt a juvenile T. rex. Art by Anthony Hutchings.

Yep, that’s right. There were mini-Tyrannosaurs running around the late Jurassic.

For years, palaeontologists just figured that these were juvenile T. Rex, or even a “teenage” of the species.

But now, by looking at several skeletal features, including growth plates, these scientists can confirm that this is actually a different species. Or, as one of the authors of the paper says, “For Nanotyrannus to be a juvenile T. rex, it would need to defy everything we know about vertebrate growth.”

Image: Nanotyrannus snout. N.C. Museum of Natural Sciences

 

And while the image of a mini T-rex may sound adorable, they would probably still have been pretty vicious predators. In fact, the skeleton that led to this discovery is of one of these Nanotyrannus in battle with a full-grown Triceratops!

 

Lindsay Zanno, associate research professor at North Carolina State University and head of paleontology at the North Carolina Museum of Natural Sciences, with the Dueling Dinosaurs fossil. Credit: N.C. State University

 

In fact, this isn’t even the only announcement of new Archosaur species recently. A team of biologists recently discovered that what we thought was one, very adorable, penguin species is actually three separate sub-species. (or, as one article puts it: One Of The World’s Rarest Penguins Is Actually Three Subspecies In A Trench Coat.)

 

You can read the original study (or just look at the pretty diagrams) here:

Image: (a) Map of Aotearoa New Zealand indicating the geographic distribution of yellow-eyed penguins and proposed new subspecies designations. From Population genomics of yellow-eyed penguins uncovers subspecies divergence and candidate genes linked to respiratory distress syndrome by Guhlin et. al, bioRxiv 2025.10.20.683354

 

 

Thanks to phys.org for the tipoff: Nanotyrannus confirmed: Dueling dinosaurs fossil rewrites the story of T. rex