...is not a dinosaur.

This blog is a result of an erroneous mistake; one day I referred to Dimetrodon as a mammal-like reptile in front of a vertebrate paleomammalogist. These animals are not at all members of Reptilia; they are Synapsids - four-legged, back-boned animals that span back 315 million years on a completely different evolutionary branch on the tree of life.

Since then, I've found Dimetrodon partying with members of Dinosauria across the pages of coloring books and frolicking in the aisles of toy stores, surrounded by lifeforms which evolved some 66 million years after those ancient mammalian relatives.

Submit your photos of any number of creatures - Synapsids, Pterosaurs, Ichthyosaurs - that have been tragically mislabeled. For funsies.

Jurassic mini golf including T-rex (which ruled during the Cretaceous, not the Jurassic period), and Allosaurus, which although IS from the Jurassic, shouldn’t be hanging out with Dimetrodon from the early Permian.

Seriously where is this? Because I would go to Jurassic mini-golf, scientific inaccuracies aside. 

A drawer full of tiny, tiny sadness at the local zoo. (They are cute, though!)


Found this on a cup that said “Dinosaurs of North America” at the Museum of the Rockies at Montana State University. The exhibits however are extremely accurate and make sure they establish the difference between things like Dimetrodon and dinosaurs. Plus, they have feathered dinosaurs!

You win some, you lose some. 

Dimetrodon even looks kinda dog-like here. 

My 9 year old future Paleontologist Sydney just brought this to our attention. Um, Dimetrodon what are you doing in this Animal Planet Dino Tube? You no live there.

Sydney is super unimpressed. 

I guess in this case we can just eat the mistake?

I wish all mistakes in life were as easy tasty to absolve. 

I guess in this case we can just eat the mistake?

I wish all mistakes in life were as easy tasty to absolve. 


Spotted in the gift shop at Perth Museum in Western Australia.

wait does that 6’ = six feet? if so sign me up 


Diagram of synapsid evolution from Palaeoswhich is probably from T. S. Kemp’s 1982 Mammal-Like Reptiles and the Origin of Mammals. Unfortunately, it’s been a while since I’ve had access to that book and the only copies available cost princely sums.

Compared to the evolution of, say, birds and whales, the evolution of synapsids doesn’t really seem well-known to the public. It’s a shame since I think this is one of the best documented and most fascinating examples of major evolutionary change around. It doesn’t help that there isn’t even a decent name for this group of animals; ‘Non-Mammalian Synapsid’ is beyond clunky; ‘Protomammal’ and ‘Stem-Mammal’ would probably be better for therapsids alone; and of course, ‘Mammal-like Reptile’ is misleading anachronistic nonsense. 


(via scientificillustration)

A Dimetrodon, Plesiosaur and a Teleosaurus were hidden in this spot the difference book.

ummmmm alslo Plesiosaurs don’t have human arms

what is this

For the record, I think you are being too hard on people with this, but if you look at the pictures on the box, it looks like this qualifies…

Theeeere he is. Sneaky Dimetrodon

And you’re probably right. I’ll try to not be such a jerk.