Tag Archives: Western Interior Seaway

Know Your Bones: April 2015

Last month’s challenge appeared to be no challenge to League of Reason’s resident rockhound Isotelus. She gave the correct answer within a day of the blog going up.


Edmontosaurus annectens. They’re like the cockroaches of Alberta’s fossil megafauna. Dig a hole and you’re probably going to find at least a piece of one. :P


This critter is indeed Edmontosaurus annectens and it is indeed an extremely common fossil.


 photo 2015-02-06 11.39.14_zpsd3bsgwtu.jpg

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


Edmontosaurus lived during the Cretaceous 73 to 65.5 million years ago. They ranged widely across western North America, seemingly living along the Western Interior Seaway. Edmontosaurus belong to the hadrosaurid clade, which are popularly called duck-billed dinosaurs. Edmontosaurus belongs to a crestless group of hadrosaurid, unlike a previous “Know Your Bones” challenge. The specimen used in last months blog is actually famous for having what appears to be a bite mark on its tail from a Tyrannosaurus.


Edmontosaurus reached a length of ~13 meters (the skull alone was ~1 meter long) and could weigh up to 4 tons, making them one of the largest hadrosaurids to have ever lived. As a means of locomotion, Edmontosaurus were likely able to walk on all fours or on just their hind limbs. Edmontosaurus is also famous for having several skin impressions, which allows us to know what most of the skin of this animal looked like in life. Edmontosaurus had teeth that grew in columns of six teeth, and had around 50 columns in each jaw. The teeth were continually replaced throughout the animal’s life. However, the beak of an Edmontosaurus was toothless and was extended by a keratinous material, much like modern birds.


Moving on to next month’s challenge:


 photo 2015-01-09133458_zps29f325f9.jpg

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


Good luck, as always.

Know Your Bones: April 2014

Last month was a really challenging, some might even say diabolical, fossil. After a whole month, no one was able to guess the correct answer. I guess that makes me the winner for stumping everyone. Now I know that showing fossil/bone fragments is the way to go if I want to win at this game.


What was the critter that owned the jaw from last month’s challenge? The jawbone belonged to Deinosuchus, which stands for terrible crocodile.


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


Deinosuchus lived 80-73 million years ago, during the Late Cretaceous, in North America. Fossils of this critter have been found in Canada, Mexico, and several states in the U.S. During this time, North America was cut in half by the Western Interior Seaway. Deinosuchus lived on the coastline of this seaway feeding on large fish and marine reptiles in the sea and large animals (dinosaurs) from the land.


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


The image above shows a lower jaw from a modern American alligator (Alligator mississippiensis) compared with the partial jaw of Deinosuchus. Deinosuchus could reach a length of 12 meters and a weight of 8.5 metric tons. This makes Deinosuchus one of the largest crocodilians to ever live. Although it’s name means terrible crocodile, Deinosuchus was actually an alligator, making it the largest alligator to have ever lived.


Time for next months challenge.



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


Because last month’s was so difficult, I decided to be nice and choose an easy one. I would wish everyone luck, but it is not needed this time.