Anatotitan: Prehistoric Animal of the Week

Today we are checking out one of the largest and most well studied of the duck-billed dinosaurs.  Enter Edmontosaurus annectens!  This plant eating dinosaur grew to be almost forty feet long from head to tail and lived 68 to 66 million years ago during the late Cretaceous in what is now the western United States of America.   Specifically, its remains have been found in Montana, South Dakota and Wyoming.  When alive this dinosaur would have co-existed with other famous animals such as Ankylosaurus, Triceratops, Pachycephalosaurus and Tyrannsoaurus. 

Life reconstruction of Edmontosaurus annectus by Christopher DiPiazza.

Yes, I put a different genus name for the title.  This dinosaur has gone through a bit of an identity crisis over the years having its genus name changed more times than something that typically changes a lot (I'm off my game with analogies today okay?...or with ANAT-ogies OH YEAH! My pun ability is just fine though).  In the past this dinosaur has been named Anatosaurus, Trachodon, Anatotitan and now has been lumped with the genus previously thought to be separate, Edmontosaurus.  I would like to do a different species of Edmontosaurus in the future so I figured no harm in using Anatotitan for this post.  Anatotitan translates to "titan duck" (way cool) and Edmontosaurus translates to "Edmonton reptile/lizard" (because another species of this genus was first discovered there.  Appropriate, but not as cool sounding).

Skeletons on display at the American Museum of Natural History in New York City.  These tail-dragging poses are not considered accurate anymore.

Out of all the duck billed dinosaurs, also known as hadrosaurs which are characterized by having wide, flat bills in the front of their mouths, Anatotitan had the "duckiest" bill.  It was particularly wide and almost angular to a degree.  This is a great adaptation for an animal that needed to eat a lot of plant material.  The wider an animal's mouth, the more foliage it can get in each bite.  To be honest, the bill of a hadrosaur, even Anatotitan, isn't really all that similar to that of an actual duck's (which is adapted for sifting through water and lined with ridges on the inside).  Beyond the bill there were hundreds of tiny teeth all packed together to form a solid unit called a dental battery.  This was a great adaptation for grinding and chewing the tough pine needles which it would have eaten (at least its breath was probably fresh!).  Anatotitan would have walked on all fours but was capable of rising up and running on its hind legs if it wanted to move more quickly.

Fossilized skin from "Dakota".

There has been a mummified specimen of an Anatotitan found!  Back in the early 2000s a high school student named Tyler Lyson discovered a beautifully preserved Anatotitan fossil that still had muscle and skin.  Shortly after, paleontologist, Phillip Manning, was responsible for excavating and studying this amazing find.  We now know thanks to this mummy (which had turned into fossilized rock) that Anatotitan would have had a thick, powerful tail and neck.  It was also probably able to run faster than what most scientists had previously thought (faster than a T. rex even...how convenient).  The scales on this specimen, nicknamed "Dakota" because of where it was found, were like tiny mosaics of differing sizes.  The different sizes formed patterns that may reflect a color pattern the animal would have sported when alive.  Assuming this is true, this dinosaur would have had darker bands going down its tail.

That's all for this week.  As always feel free to comment below or on our facebook page!

References

Brett-Surman, Michael K. (1979). "Phylogeny and paleobiogeography of hadrosaurian dinosaurs". Nature 277 (5697): 560–562

Campione, Nicolás E.; and Evans, David C. (2011). "Cranial growth and variation in Edmontosaurs (Dinosauria: Hadrosauridae): implications for latest Cretaceous megaherbivore diversity in North America". PLoS ONE 6 (9): e25186. 

Lambe, Lawrence M. (1917). "A new genus and species of crestless hadrosaur from the Edmonton Formation of Alberta" (pdf (entire volume, 18 mb)). The Ottawa Naturalist 31 (7): 65–73. Retrieved 2009-03-08.

Lambe, Lawrence M. (1920). "The hadrosaur Edmontosaurus from the Upper Cretaceous of Alberta". Department of Mines, Geological Survey Memoirs 120: 1–79. 

Ostrom, John H. (1964). "A reconsideration of the paleoecology of the hadrosaurian dinosaurs". American Journal of Science 262 (8): 975–997