Tag Archives: archosaur

Know Your Bones: August 2014

Last month’s challenge brought in a few good guesses, but only one correct answer. Once again, Isotelus guessed correctly, and within hours of the posting of the challenge.


 While it looks like a Wiener dog T-rex, I’m going to guess: 


This prehistoric wiener-dog is indeed Postosuchus.


(Taken at the Dinosaur Museum and National Science Laboratory)


During the late Triassic (288 to 202 million years ago), Postosuchus roamed across most of what is now North America. During this time, it was one of the largest predators on earth. It could have hunted and killed any of the dinosaurs that were alive at the same time. Postosuchus could reach a length of ~4 meters, stood ~2 meters tall, and could have weighed 250 to 300 kilograms. Postosuchus possessed a skull that was 55 cm long and 21 cm across.


Postosuchus had protective plates that covered their back, neck, and tail. These plates are something they share with their closest living relative the crocodilians. However, Postosuchus was a terrestrial predator and walked with its legs directly under the body. This armor probably protected them from other Postosuchus. During the late Triassic, there were not many other critters in the world that could challenge a full-grown and healthy Postosuchus, except another Postosuchus.


Moving on to this month’s challenge:



(Taken at the New Mexico Museum of Natural History and Science)


Good luck and thanks to everyone that reads and guesses.

Know Your Bones: February 2014

Last month, I tried to throw a hard ball your way, because the month before was so easy. However, Isotelus easily identified this critter within a day of the blog being posted.


I love me some Aetosaurs! My guess: Originally Desmatosuchus haplocerus, now thought to be D. smalli.


Isotelus is correct, this specimen is an Aetosaur called Desmatosuchus. Whether this is D. haplocerus or D. smalli is unknown to me (way to make me look bad Isotelus).


(Taken at the New Mexico Museum of Natural History and Science)

Desmatosuchus lived 201 – 252 million years ago, during the late Triassic. As one can see from the skeleton, Desmatosuchus, as well as all Aetosaurs were armored creatures. The armored plates found on the back were most likely used as defense against larger predators that existed during the late Triassic. Something that might be less obvious is that Desmatosuchus, like all Aetosaurs, were most likely vegetarians. Another thing that is also not immediately obvious is that the closest living relative to Aetosaurs are crocodilians.


(Taken at the New Mexico Museum of Natural History and Science)

This means that not only is Desmatosuchus a member of the diapsid clade, but also a member of the archosaur clade. This clade includes everything you see in the image above. Aetosaurs make up an early example of armored archosaurs, something archosaurs will do again in the centuries to come.


Moving on to this months challenge:


(Taken at the New Mexico Museum of Natural History and Science)

Good luck to everyone. I also want to say that I like the fact that people are posting their answers as hidden.