Saltasaurus: Prehistoric Animal of the Week

Enter Saltasaurus loricatus!  Saltasaurus was a sauropod dinosaur that lived in what is now Argentina, during the late Cretaceous period, between 70 and 66 million years ago.  It was small for a sauropod, measuring about forty feet from snout to tail.  Its genus name translates to "Salta lizard/reptile" in reference to Salta, a city near where it was discovered. 

Saltasaurus loricatus reconstruction by Christopher DiPiazza.

Saltasaurus is a pretty well studied sauropod.  There are many bones of it on the fossil record, but its real claim to fame was its skin.  Paleontologists found out, thanks to some beautifully preserved fossil remains, that Saltasaurus would have actually had small nodules of bone embedded in its skin.  We see these same sort of structures, called osteoderms, in modern crocodilians and other kinds of dinosaurs, most notably the ankylosauroids.  Never before had sauropods ever been known to have had armor!  It was always assumed that sauropods could get by with just their size, and perhaps tails as weapons.  It is is theorized that Saltasaurus had this dermal bone armor to help protect itself from predators since it indeed wasn't as large as some of its relatives.

Saltosaurus osteoderm fossil.

Saltasaurus belonged to a group of sauropods called the titanosaurs.  Since the discovery of Saltasaurus, other titanosaurs are commonly reconstructed with osteoderms too.  Like all sauropods, Saltasaurus would have stripped leaves off of branches with its teeth, which were only in the front of its mouth.  Titanosaur teeth were long and rod-shaped.  It also had a rather wide, barrel-shaped body, which probably was used for breaking down and fermenting all that tough plant material it was eating all the time.  Since its teeth weren't designed for chewing, Saltasaurus would have swallowed all its food whole and allowed its huge stomach chamber to do all the digesting for it, which would have required a lot of space and energy.  Just think of modern cattle and how big their stomachs are. (four chambers!)  There is a solid chance that sauropods like Saltasaurus also would have been very gassy animals because of this.  (teehee farts!)

Saltasaurus eggs have also been discovered.  They were almost perfectly round and only measured about five inches long in diameter.  Even more interesting, many clutches of these eggs have been discovered all nearby each other and even on top of each other year after year.  This suggests that like many modern reptiles, like certain turtles and birds, mother titanosaurs like Saltasaurus would have laid eggs at the same time in the same place each season.

Saltosaurus egg on display at the Museum of Ancient life in Utah, USA.

Saltasaurus, as well as titanosaurs as a whole, are important to paleontology because they proved that sauropod dinosaurs persisted successfully up until the very end of the Mesozoic era, 65 million years ago.  Prior to their discovery, it was believed that most sauropods died out at the end of the Jurassic period and were replaced by other plant eaters like the hadrosaurs and ceratopsians.  We now know that this is only true for the northern hemisphere.  In what is now South America, Africa, and Australia, sauropods were still the reigning plant eaters of their time!

That is all for this week!  As always please comment below or on our facebook page.  Have a request?  Let me know!

References


Coria, R.A. and Chiappe, L.M. 2007.Embryonic Skin From Late Cretaceous Sauropods (Dinosauria) of Auca Mahuevo, Patgonia, Argentina. Journal of Paleontology v81(6):1528-1532 doi:10.1666/05-150.1