And the skull goes to…

 

Will Carlson!

Earlier this month, we posted a picture of two 3D printed skulls and asked our readers to identify which dinosaur they belonged to for a chance to win their own copy! 
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This ten year old kid was able to identify the 3D printed skull of Deinonychus all by himself, with help only from his Dinosaur books at home. Most adults couldn’t do that!

 

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For his prize, we not only gave him the 3D printed skull, but I also led him on a tour of our Morian Hall pf Paleontology. I’ve showed a lot of people around that hall, but few have displayed the level of enthusiasm for, and knowledge of, the subject of Paleontology like Will did. 

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Congratulations Will!!

 

Now let’s talk a little about the skull.  “Deinonychus? What?” you may say… “Who….?”

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Photo courtesy of Dallas Krentzel

 

Most people haven’t heard of Deinonychus, but they have probably seen them. The “velociraptors” in the Jurassic Park movies were basically Deinonychi. In reality, Velociraptor was a small dinosaur, about the size of a turkey. They were terrifying, and a pack of them could probably kill us all if they broke into the marketing offices here at HMNS, but small nonetheless

 

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Photo courtesy of the University of Michigan Museum of Natural History

 

Deinonychus, on the other hand, was quite large, much larger than the Velocitraptors that have been discovered so far. Deinonychus grew to about 13 feet long and between 4 and 5 feet tall, similar proportions to the “Velocitraptors” you see in the movies. The name Deinonychus means “terrible claw” in greek, referring to the large second toe claw of the animal, most likely used to pin down its prey as it tore away at their flesh.

 

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Photo courtesy of James St. John

 

Deinonychus is important in the history of paleontology because its initial scientific description by Dr. John Ostrom of Yale ignited the classic debate over how active Dinosaurs were. Up to that point, dinosaurs had been generally regarded as “sluggish lizards”, wallowing in shallow water or competing in stop-motion style fights. However the similarities between the skeletons of Deinonychus that had been discovered and that of modern birds led Dr. Ostrom to theorize that these animals were active hunters who were agile enough to take down prey that was much larger than they were.

Dino-chores at HMNS

The last three evenings have been spent doing a dinosaur cleaning. Three times a year staff and volunteers give up a few of their evenings to dust the mounts in the Hall of Paleontology. We clean the mounts using a variety of tools ranging from low tech dust clothes and soft brushes to pretty fancy vacuums and air guns. We give everything a thorough inspection.

It’s not all that different from dusting your home. Excepting that a fair amount of the work takes place high above the cement floor maneuvering a multi ton hydraulic lift in and around delicate bones. In some places the clearance between exhibits is just a few inches. Paleo volunteers regularly help with the task.

Our digging volunteer crew is adept at this and I completely trust them,the quarry skills involved in chipping rock away from bones and being able to account for your hands and feet naturally translate to dusting the mounts when they are out of the rock as well.
Another benefit is to see the exhibits and specimens from an entirely alien perspective.

 

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Tales of the Continental Divide: The Adventures of Mesosaurus

Mesosaurus was an unusual reptile. It looked kind of like crocodiles do today, with a long, thin body, eyes located on top of the skull, webbed feet, and an average length of about 16 inches. It also lived kind of like many crocodiles do today, in freshwater environments. Possibly one of the weirdest things about mesosaurus is that it did all of these things during the Permian period, 320-280 million years ago. That’s 130 million years before crocodiles (and dinosaurs as well) even existed!

 

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Mesosaurus, next to an Ichthyasaur of a much later age, photo courtesy in the Internet Archive Book Images

 

                In fact, Mesosaurus is was one of the earliest reptiles discovered to have made the transition back into a marine environment. The earliest reptiles appear in the fossil record around 340 million years ago, so it seems that after a mere 20 million years, this retile was done with terra firma. In fact, one of the mesosaurus skeletons that have been discovered is the earliest reptile found with amniote embryos fossilized with it, meaning these are one of the ealiest animals known to have laid hard-shelled eggs. So we’re talking about the early history of reptiles here.

 

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Lower Permian Mesosaurus, photo courtesy of elrina 753

 

But speaking of reptiles, it should be pointed out that mesosaurus is not like most of the reptiles we see today. Ancient reptiles can be divided into different categories, based partly on the number of holes they have on either side of their skull. Snakes and lizards are diapsids, defined by two particular holes on either side of their skull, but mesosaurus was an anapsid, which means that it lacks these holes. Anapsids are very primitive reptiles, and in fact some scholars classify them as “parareptiles”. The only species of anapsids living today are turtles and tortoises, who have a fascinating history of their own.

 

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Mesocaurus in matrix, photo courtesy of Museo Civico di  Historico Naturale Milano

 

The most common type of large reptiles found in the Permian were synapsids, like the dimetrodon in the Permian section of our Hall of Paleontology, and the Edaphasaurus in the great mural featured in that hall. The only synapsids that exist today are, well, all mammals. That’s right, that big, fin-backed lizard in our hall is more closely related to us than to a dinosaur. But of course he’s still a distant relative, like an old uncle.

 

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Recreation of a Dimetrodon, photo courtesy of Rick Hebenstreit

 

But back to Mesosaurus… There’s another reason that this animal is notable, and that’s the 7,772 mile journey some of its fossils made after their deposition! During the Permian, when mesosaurus was doing its thing, Pangea, the ancient Super Continent, was still forming. Pangea formed around 270 million years ago, ushering in the end of the Permian Period and the extinction of the great synapsids, and making way for the reign of the dinosaurs. It was actually the formation of Pangea and the resulting environmental changes (helped by volcanic activity and climate change) that caused this extinction, which was the worst extinction event in Earth’s history.

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Photo Courtesy of David Smith

 

Around 200 million years ago, Pangea began to break apart. The continents that are now called Africa and South America separated, drifting away from each other and carrying the already fossilized bones of Mesosaurus with them. In the early 20th century, Continental Drift was a hotly debated topic, and it was the fossils of mesosaurus that helped to validate the theory. The remains of this fresh water-dwelling reptile, can be found in Eastern South America and Western Africa, separated be 7,000 miles of ocean. We are sure mesosaurus lived in fresh water, because the rock that its fossils have been discovered in specifically forms in that environment. So, either some of these little guys hopped a tramp steamer, or they were dragged with their respective continents. This, along with numerous other bits of evidence, like the mid-Atlantic Ridge, have helped to validate the theory of Continental Drift.

 

Win a 3D printed Dinosaur Skull! If you can identify it…

Alasaurus skulls

These 3D printed skulls were made here at HMNS, in preparation for a larger project we are planning for one of our rare specimens, which will eventually be placed in our Hall of Paleontology. The 3D prints that we will create when everything is up and running will be used to further our knowledge of Permian life from what is present day West Texas.

But until then… Let’s have some fun! The first person who can comment the correct identity of what dinosaur these skulls belong to will win their very own 3D printed copy and 4 tickets to see our Hall of Paleontology!

The winning entry will be contacted on Monday, September 5.