Kentrosaurus: Prehistoric Animal of the Week

Kentrosaurus aethiopicus was a plant eating dinosaur that lived in what is now Tanzania, Africa during the Late Jurassic Period, 150 to 155 million years ago.  It wasn't terribly large for a dinosaur, only measuring about sixteen feet long from head to tail.  Like its close relative, Stegosaurus, it was adorned with spikes on its tail for defense.  Unlike Stegosaurus, however, the spikes on Kentrosaurus didn't stop there!

Kentrosaurus aethiopicus life restoration by Christopher DiPiazza

 The name Kentrosaurus literally translates to "Prickly lizard/reptile" and boy, was it prickly!  The neck probably had small plates, as in its relative, Stegosaurus, but on the body the shapes of the plates quickly change to broad spikes.  From the hip on towards the tail were rows of narrower, sharp spikes.  The plates and spikes of Kentrosaurus were what is called "handed", i.e., there are left and right versions of them so it is likely they were arranged in two rows down the animal's back.  Additionally there is another kind of spike found with Kentrosaurus that doesn't fit on the back or tail anywhere.  Scientists either think these spikes were on the shoulders or the hips (depending on which scientist you ask).  As in all stegosaurids, the head of Kentrosaurus was tiny in proportion to the rest of the body and possessed a beak at the front of the snout.  Inside the mouth were teeth adapted for crushing plant material but could not finely grind.

Kentrosaurus skeletal mount at the Museum fur Naturkunde in Berlin, Germany.

 Kentrosaurus, like other stegosaurids, is interesting in that its center of gravity was at the hips, farther back towards the tail end than what is normally observed with quadropeds (animals that walk on all fours).  In fact, no other kind of dinosaur has its center of gravity as far back as the stegosaurids.  This allows the animal's front half where the head and arms are to be much lighter.  There would be a number of possible advantages to this.  Firstly, stegosaurids like Kentrosaurus may have had the ability to rear up on their hind legs in order to gain access to more food.  Secondly, being lighter in the front meant the animal could rotate its body sideways more easily.  Since Kentrosaurus'  weapon was its tail, this would allow it to make fast turns to ensure its dangerous end was always facing an attacker.  A study by paleontologist Heinrich Mallison concluded that Kentrosaurus had a pretty wide range of motions when it came to its neck, legs and tail.  It was found that the tail in particular could swing in a 180 degree arc with deadly accuracy if it needed to, delivering deadly blows with the tail spikes.  

Diagram showing range of motion for Kentrosaurus's tail from Heinrich Mallison's study.

Special thanks to Dr. Heinrich Mallison for allowing me to use one of his images and for coaching me on my illustration and information for this week's post!  As always if you would like a particular creature to be reviewed and illustrated simply comment below or on our facebook page! 

References

Hennig, E. (1936). "Ein Dentale von Kentrurosaurus aethiopicus HENNIG" ("A dentary of Kentrurosaurus aethiopcius HENNIG"). Palaeontographica Supplement 7 Part II':311-312 German

Mallison, H. (2010). "CAD assessment of the posture and range of motion of Kentrosaurus aethiopicus HENNIG 1915" Swiss Journal of Geosciences online first

Mallison, H. (subm.). "Defense capabilities of Kentrosaurus aethiopicus HENNIG 1915. Palaeontologia Electronica

New Brunswick Geology Museum 2013

Yesterday's New Brunswick Geology Museum's "Dino Day" had a great turnout!

Myself(Chris) and Gary

As an alum from Rutgers University, I am quite familiar with the New Brunswick Geology Museum.  Some of my artwork is even on display there from a commission given to me in 2010!  It is not the biggest museum but it is still very cool with some unique pieces.  Its also very old which can be seen by some of the architecture in there including a very narrow spiral stair case (spiral stair cases are awesome).

It hasn't changed much since this photo was taken.  The whale skeleton isn't there anymore though. 

 Would you like a small tour before the crowds come in?  Of course you would!  Follow me...

Later in the night none other than the great paleo-artist, Larry Felder stopped by to show us some support!  As you may remember Larry is a good friend of ours and did an amazing interview on this site earlier this year!

Christopher DiPiazza, Gary Vecchiarelli and Larry Felder

We had a great time at my old college's museum and are looking forward to working there in the future.  Didn't get to see us yesterday?  Never fear.  We will be at a few more events this month in New Jersey.  The next is Saturday, April 20th at the Liberty State Park.  More information to come so stay tuned. 

Come see us for Dinosaur Day at Rutgers Geology Museum on April 3rd!

Take a step back in time and come with us to discover the different types of dinosaurs that inhabited the Earth during the Mesozoic.  Both Jersey Boys Gary and Chris will be there! You should be there too! There will be a few more events similar to this at other Museums in the NJ area in the upcoming months.  Please click HERE and join the event page on facebook!  

Oviraptor: Prehistoric Animal of the Week

In honor of Easter Sunday I chose to review a dinosaur that has an interesting association with eggs.  Oviraptor is a bird like dinosaur that lived in what is now Mongolia during the Late Cretaceous Period, about 80 million years ago.  It measures a little under five feet long from head to tail.  It was the first discovered member of its family, Oviraptoridae, characterized by having a short, powerful beak similar in a way to modern day parrots (also dinosaurs but not direct descendants of Oviraptorids).  Although there are no teeth in Oviraptor's beak, it and its relatives have small protruding points growing down from the roofs of their mouths.  This, combined with powerful jaw muscles, may have been a useful feeding tool for cracking...something. 

Oviraptor philoceratops life restoration by Christopher DiPiazza

Oviraptor's diet is somewhat of a mystery.  We know for sure that it at least ate lizards because the bones of one was found in an Oviraptor skeleton's stomach cavity.  It is likely that Oviraptor was eating something else, as well with such a specialized mouth, however.  Maybe it was using its powerful beak like parrots do to crack open nuts and seeds?  Perhaps it could crack open shellfish like clams and muscles?  Or maybe it used its beak to crack open eggs from other dinosaurs? 

Illustration of the first discovered Oviraptor philoceratops skull.  It was badly crushed before being discovered and may have had a larger crest starting at the nose. 

The first Oviraptor bones were discovered in the 1920s nearby a nest of dinosaur eggs.  At the time, the paleontologists were discovering a whole lot of bones from another dinosaur called Protoceratops (a small ceratopsid featured in my sex post back in February) in the same area and assumed the eggs belonged to it and the Oviraptor was stealing them.  Oviraptor was then given its full name, Oviraptor philoceratops, which means "Egg Thief that Loves Cratopsids".  To make the story even more interesting, the Oviraptor's skull had been found crushed.  The scientists imagined that it had been done by the jaws of a parent Protoceratops protecting its nest. 

For decades after that Oviraptor was portrayed as an egg stealer.  Then in the 1990s, a team of paleontologists discovered another nest of eggs almost identical to those presumed to be from Protoceratops back in the 1920s.  This nest had the bones of a kind of Oviraptorid(named Citipati) literally laying on top of it.  Inside the eggs the paleontologists found the bones from unborn babies of this same dinosaur.  Because of this discovery, scientists realized that they were likely wrong about Oviraptor as well.  It wasn't stealing eggs from other dinosaurs.  It was protecting its own! 

That's it for this week!  As always feel free to request a dinosaur or other prehistoric animal on our facebook page or in the comments below and I will definitely review it in an upcoming week!  

References

Osborn, H.F. (1924). "Three new Theropoda, Protoceratops zone, central Mongolia." American Museum Novitates, 144: 12 pp., 8 figs.; (American Museum of Natural History) New York. (11.7.1924).

 Dong and Currie, P. (1996). "On the discovery of an oviraptorid skeleton on a nest of eggs at Bayan Mandahu, Inner Mongolia, People's Republic of China." Canadian Journal of Earth Sciences, 33: 631-636.