Friday, December 18, 2015

Happy 100th Anniversary to 5027!

I'm biased.  I'm not afraid to admit it, especially when it comes to my home.

I grew up in New Jersey and traveled New York City frequently for my entire life.  One tradition when I was tiny was to visit the American Museum of Natural History with my family every Mother's Day.  My mother enjoyed looking at the exhibits about human cultures from around the world but naturally all that mattered to me was seeing the dinosaur hall on the fourth floor.  (The dioramas of modern animals were pretty cool too...and the hall of ocean life.)  This is not uncommon and since working there this summer I have witnessed many children with the same mindset.  For example, the following is an actual line I overheard a little boy (I estimate about five years old) say as his mom walked him in through the museum's main entrance one day.

"If I don't see the dinosaurs right now I am going to punch every person here in the face."

Although I am firmly against violence, I can't help but respect that little guy just a little.

So naturally my favorite dinosaur exhibit is there and my favorite Tyrannosaurus specimen is the one that has been on display there for one hundred years as of this month.  Unlike other famous Tyrannosaurus, that have been found more recently, like "Sue", "Stan", "Jane", and now "Tristan" (We will talk more about Tristan soon), the New York Tyrannosaurus was never given a name.  It is referred to as its official specimen number, AMNH 5027. (AMNH stands for American Museum of Natural History)  Simple, but no less iconic to those who know it. 5027 isn't the largest Tyrannosaurus on the fossil record (a little under forty feet long), nor is it the most complete. (although it was for a while)  What it does have to its name is being the first T. rex to ever be put on display in a museum which I think is really neat.  (Like I said, I'm biased.)  It was discovered in the early 1900s by American paleontologist, Bernum Brown in Montana.  At the time it was the most complete Tyrannosaurus on the fossil record, particularly when it came to the skull.  Other interesting things to note is this particular specimen of Tyrannosaurus has several bones, including neck vertebrae and ribs, that appear to have been broken and then healed in life.  This supports the idea that dinosaurs like Tyrannosaurus were leading potentially violent/dangerous lifestyles and could bounce back from seemingly devastating injuries.  (Not unlike some of their modern relatives, crocodilians)

When it was to be first mounted in the museum, it was done so in an upright position with its tail dragging on the ground.  This made sense at the time since scientists hadn't really started connecting larger dinosaurs to birds yet and based most of their reconstructions on lizards and crocodilians.  The mount itself is actually a combination of two specimens of Tyrannosaurus that were discovered around the same time in the early 1900s, AMNH 5027, which makes up the majority of the skeleton, and AMNH 973, which was discovered first but is less complete.  The rest of the skeleton that they still didn't have anything of they used the more completely known Allosaurus for a reference, which is why it originally had three fingers on each hand, instead of two.

AMNH 5027's original pose at the museum.  That Triceratops next to it is also there today, but hasn't changed at all and is thus, really outdated in a few catagories.  This photo is available to see along with many others at the AMNH research library.

Flash forward to the 1994 which is when AMNH 5027 received a makeover and was reposed in a more horizontal position to go along with updated information about how dinosaurs carried themselves with their tails above the ground for balance.  Along with it, the Apatosaurus/Brontosaurus mount in the same hall  was reposed in the same way, and the mind-blowingly dynamic Barosaurus vs. Allosaurus display was debuted in the museum's main entrance.  This is the exhibit I have known since I was little, since before that they were either renovating it (so it was closed to the public) and before that I was too young to remember/wasn't born yet.  One vivid memory I remember when I was extremely young was seeing the Allosaurus mount intended for the entrance hall being wheeled into a back room as I passed by a hallway intended for employees only.  It has stayed with me to this day.

If you visit AMNH 5027 now, this is what you will meet.

So why talk about all this now?  Well, like I stated earlier, December 2015 marks AMNH 5027's one hundredth anniversary of being on display at the American Museum of Natural History.  I consider myself SO LUCKY to have started working there the same year and thus, was able to be present for the museum's paleontology department's birthday party for it!  Every department at the museum actually has it's own holiday party in December, but paleontology's sort of doubles as an anniversary since the T. rex was erected in December anyway.  Convenient!

The baker we used obviously doesn't know the proper way to write T. rex...or what a T. rex looked like...  It tasted good.  Photo courtesy of Rosa Luna who is the digital marketing manager at the museum.

Below are a few more pictures that were taken from that night.  It was so much fun and was a great opportunity to meet and get to know better, other people with the same passion as myself.


Follow the toothy fliers to get to the party!
Dustin Growick, host of The Dinosaur Show, and I...did not plan this.  We both have the same sense of paleofashion is all.
It was awesome to meet Dr. Mark Norell, a paleontologist I had seen on television since childhood.  It was even more awesome to hear about Dr. Norell's exciting most recent dinosaur project!

References

Dingus, Lowell. The Halls of Dinosaurs: A Guide to Saurischians and Ornithischians. New York: American Museum of Natural History, 1995. Print.

Osborn, H.F. 1913. Tyrannosaurus, Restoration and Model of the Skeleton. Bulletin of the American Museum of Natural History vol 32, pp. 9-12.

Sunday, December 6, 2015

Probrachylophosaurus: Beast of the Week

This week we will be checking out a newly described plant-eating dinosaur.  Let's welcome Probrachylophosaurus bergei!  Probrachylophosaurus was a hadrosaurid (duck-billed) dinosaur that lived in what is now Montana, USA, during the late Cretaceous, 79 million years ago.  From beak to tail, an adult measured about twenty nine feet long.  The genus name translates to "Before the Short-Crested Lizard".  Who is this later "short-crested" guy?  We'll get to that...

Probrachylophosaurus by Christopher DiPiazza.

Probrachylophosaurus, as stated above, was a hadrosaurid, so it was related to dinosaurs like Anatotitan and Hadrosaurus, to name only a few.  That being said, it would have comfortably walked on all fours, but could have stood or ran on its powerful hind legs when needed.  It's tail would have been thick and stiffened with bony rods inside the body in life, making a nice counterbalance to it's front half, and possibly even an effective club-like weapon against predators and rivals.  With its broad beak, it would have been able to scarf down as much vegetation as possible to be pulverized thoroughly with its hundreds of tightly-packed teeth in the back of its mouth.  (Hadrosaurs had the most teeth in their mouths of any known animal!)

Probrachylophosaurus skull material from Fowler's 2015 description.

Brachylophosaurus is an important fossil because it gives us a clearer picture of a very specific instance of dinosaur evolution taking place.  In this case, Probrachylophosaurus strongly indicates that it was the direct ancestor of a different, yet closely-related kind of hadrosaur called (You guessed it!) Brachylophosaurus.  These two dinosaurs lived in the same area of North America but Probrachylophsoaurus was excavated from rocks about one million years older than Brachylophosaurus.  They both had flat, bony crests on their heads, above their eyes but Probrachylophosaurus' was shorter, telling us that natural selection shifted these animals towards longer crests as time went on.  The purpose of these crests is not totally clear, but it's always safe to say they were for display within the species, specifically mate selection.

One of the things scientists did with Probrachylophosaurus was cut open its leg bone to reveal how old it was when it died.  (You can count the rings on the inside of a femur or rib to see how many years old a dinosaur was, just like on the inside of a tree trunk.)  Turns out the Probrachylophosaurus specimen was fourteen when it died, which is still considered a juvenile, but past sexual maturity and very close to being full size going off what is known about hadrosaurs in general.  (Thanks Maiasaura!)

Cross section of Probrachylophosaurus' bone, showing the growth rings, which ultimately revealed that it was fourteen years old when it died.

So how old was the biggest known Brachylophosaurus when it died?  This could disprove the original idea that nature was selecting for longer crest lengths within that million years, if Brachylophosaurus was an older adult when it died, suggesting that the later juvenile Probrachylophosaurus simply had more crest-growing to do.  This is a question I asked Dr. Liz Freedman Fowler, who was one of the paleontologists who studied and ultimately described Probrachylophosaurus.  Turns out the original theory holds true.  Dr.Fowler explained to me that the biggest specimen of Brachylophosaurus with a longer crest, was found to have been younger than Probrachylophosaurus, with a shorter crest, when it died.  Both dinosaurs may have had a little bit more growing to do, but the crests still would have been longer, regardless, as generations moved on between 79 and 78 million years ago.

Quick doodlegram I did comparing the two.

It's always exciting when a new find ads a puzzle piece to a mystery.  Technically most organisms can be considered in the process or evolving somewhat, but rarely do we get such a clear picture of it taking place at different stages like this.  This is why paleontology is so important to biology.  It gives us a clear demonstration of evolution at work, a process that normally takes millions of years!

That is all for this week!  As always feel free to comment below or on our facebook page!  Special thanks to Dr. Fowler for talking to me before and during the making of this post!

References

Fowler, Elizabeth A. Freedman, and John R. Horner. "A New Brachylophosaurin Hadrosaur (Dinosauria: Ornithischia) with an Intermediate Nasal Crest from the Campanian Judith River Formation of Northcentral Montana." PloS one 10.11 (2015): e0141304.

Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Osm√≥lska, Halszka; and Dodson, Peter (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561. ISBN 0-520-06727-4.




Wednesday, December 2, 2015

Behind the Painting: Therizinosaurus

I've done several behind-the-scenes posts on here about art.  Today I will give you a brief play by play of how I came to finish my Therizinosaurus painting featured on here last weekend.

Many times, if I depict a creature doing something other than just standing there, it was inspired by the behavior of a living animal I observed. (Then again, sometimes living animals just stand there too so I suppose it's always inspired by living animals at least a little bit!)  In this case, it was a Two-Toed Sloth, named Eugene, I work with.  Sloths are known for being relatively slow-moving mammals that live in trees.  This guy was no exception.  One evening as I was on my way out, I witnessed him sleeping upside down...with a half-eaten piece of lettuce in his claw that he had been munching on before spontaneously dozing off.  It was pretty cute.

Here's a photo  I snapped of Eugene munching on a nice, juicy.... ZZZZZZzzzzzzzzzz

I witnessed this years ago, but it always stuck with me.  It wasn't until I decided I wanted to paint a Therizinosaurus for the last Prehistoric Beast of the Week (actually a re-do of a post from back when I worked on the Jersey Boys Hunt Dinosaurs blog), when I thought to myself "Wouldn't it be neat to show it dozing off mid-meal just like the way Eugene did that one time?"  It seemed appropriate.  It is actually no coincidence that therizinosaurids are often compared to the now extinct, ground sloths, that used to live merely thousands of years ago, in appearance and proposed behavior.  The two kinds of animals may have filled similar niches in life.  The fact that a living sloth was my inspiration was just coincidence. 

Megatherium, a kind of giant ground sloth, skeleton on display at the London Museum of  Natural History.  These heavy mammals may have behaved similarly to therizinosaurids that lived millions of years before them.

During my lunch breaks at work I usually doodle in my monthly planner.  Many of these doodle-sketches eventually get turned into full paintings, as was the case here.

I really liked the idea of a sitting pose, with one leg partially stretched out. 

Currently, I do a lot of travelling between New Jersey and New York City, often spending nights over one place or the other.  I always pack a shopping bag with my pallet of paints, jug for water, brushes, paper, rags, and pencils (watercolor painting supplies) when I make one of these trips.  One of these days I spent working on this painting at my girlfriend's apartment in Astoria.  While there, her roommate's cat insisted on..."helping" me.  Apparently this well-meaning feline believed that giving me a close-up view of her anus was in some way a source of inspiration.

Maybe she saw the mug I was drinking from and assumed I just really liked looking at butts.

Finally, about a week later, a few hours per day, I had my finished product!  I decided to make the feathers a reddish brown color, which looks good and plausible for a large, shaggy animal.  I also made the skin and scales on the face and feet blue, with small red waddle under the neck for display.  (This individual is a male.)  This was inspired by various large ground birds like Cassowaries and turkeys.

Mmmmmmm....Ginkgooooooo

Sloths, turkeys, and Cassowaries weren't the only animal references I used for Therizinosaurus, either!  When it came to doing that quick sketch of the mating display via claws, I i turned to a living animal in which the males are characterized by having longer front claws than the females, and use those claws in courtship displays, as well.  Fresh water turtles!



Another huge coincidence is the fact that when Therizinosaurus' claws were first discovered they were thought to have been from...a turtle!

I hope you enjoyed this little post.  I sure enjoyed making the painting leading up to it!  When I remember I try to take photos of my sketches and unfinished paintings to share with you on here.  Farewell until next time!