Tuesday, December 19, 2017

Squalicorax: Beast of the Week

This week we will be checking out a another prehistoric shark.  Lets look at SqualicoraxSqualicorax was a shark that lived in the oceans that once covered North America, Europe, and Northern Africa.  There were four species of Squalicorax sharks, which between all of them, lived between roughly 84 and 68 million years ago.  Growing up to over sixteen feet long from snout to tail, Squalicorax would be considered a large shark, and a top predator in today's oceans. However, Squalicorax would have shared space with a myriad of other enormous marine animals, including giant marine lizard, Tylosaurus, which was possibly its predator.  The name, Squalicorax, translates to "Raven Shark".  I hypothesize this is due to the fact that there is strong fossil evidence of Squalicorax being a scavenger in life, and ravens are also known scavengers in their ecosystems on land.  (Although I cannot for the life of me find anything explaining the etymology on this animal.  If anyone reading this knows better and has a source, please let me know so I can fix it.)  Like all sharks, Squalicorax was a meat-eater.

Two Squalicorax falcatus feast on the remains of a dead juvenile Tylosaurus.

Squalicorax would have looked like a modern Gray Reef Shark, or possibly a Great White Shark, at a glance when alive.  It had a streamlined body, long triangular pectoral fins, and a tall dorsal fin.  However, its teeth were more similar to those of a modern Tiger Shark's, being shallow, finely serrated, and slightly curved to the side.  This means Squalicorax was adapted to cutting and gnawing at its food, an adaptation seen in sharks that frequently scavenge.  This is backed up by the fact that Squalicorax teeth marks have been found in the bones of other animals that would have been too large for it to have hunted.  Even entire Squalicorax teeth have been found embedded in some of these bones.  Fossil animals that this shark scavenged from include turtles, large fish, mosasaurs, and even a duck-billed dinosaur, which had probably died in a riverbed and washed out to sea.  Of course, there is no reason to assume Squalicorax only scavenged and never hunted live prey, too.  Most modern sharks, including all the species Squalicorax shares resemblance with, will hunt or scavenge depending on what food is available to them.

Squalicorax tooth, note how short and wide it is and the serrations.  When the shark bit into something and turned its head from side to side, these teeth would act like a saw to cut pieces of meat into bite-sized chunks.

Sharks, as you may already know, possess a skeleton that is almost entirely made of cartilage.  This soft tissue does not preserve well and hardly ever fossilizes.  Because of this, many prehistoric sharks are only known from teeth and jaws, leading experts to only hypothesize as to what they looked like by comparing their teeth to those of modern sharks.  Not the case with Squalicorax!  A wonderfully preserved fossil from this shark was unearthed in what is now Kansas that includes a fully fossilized head, spine, and pectoral fins!

Wonderfully preserved Squalicorax skeleton on display at the National Musuem in Washington D.C.

That is all for this week!  As always leave comments below!  Special thanks to paleontologist, Nathan VanVranken for his insight during the making of this article and life reconstruction above.

References

David R. Schwimmer, J. D. Stewart and G. Dent Williams. Scavenging by Sharks of the Genus Squalicorax in the Late Cretaceous of North America. PALAIOS Vol. 12, No. 1 (Feb., 1997), pp. 71-83

Monday, November 20, 2017

Magical Dinosaurs: The Gathering

Many know me for my involvement in science and art.  However, in my free time, sometimes I unwind and socialize with the world's best trading card game, Magic: The Gathering.  Magic is a game where two or more players, each representing a special kind of wizard, called a planeswalker, duel, using spells, which are represented on trading cards.  The thing about Magic that I love the most is every player has his or her own deck and cards.  Since there are literally thousands of different cards, decks vary greatly.  Your deck is unique, like you.  Every card in there was hand-picked by you.  (Unless you are one of those who copies the "top tier" decks from the internet.)  A Magic deck is in many ways an extension of its owner, and every game played is a unique and personal experience for players.  I find that beautiful.

So what does this all have to do with paleontology?  Stay with me!  I'll get there!  The most common way to attack your opponent in Magic is to summon creatures to attack him/her for you.  Being a fantasy game, you can expect to see creatures like dragons, elves, goblins, in addition to lots of lesser known, and even some creature types that are unique to the  game.  One thing that always bothered me was the fact that there were so few dinosaurs in magic.  Only two, to be exact.  To add insult to injury, some time later, the two dinosaurs that did exist, were officially changed to be considered "lizards" to help the continuity of the game.  From that point on every so often a creature was released that was clearly based on a dinosaur, but the typing (which is important sometimes in Magic because rules and effects will be based on "creature type") would always be "lizard" or sometimes "beast".

Pygmy Allosaurus was the only dinosaur card in existence for a long time.  The two-fingered hands, curled lip, and arctic habitat only mildly irked me because hey, beggars can't be choosers!  Then it was officially changed to "lizard".  Artwork by Anson Maddocks.

As a paleontology nut who is very much engrossed in evolution and taxonomy, referring to a dinosaur as a lizard was painful.  But it didn't stop me!  I spent weeks and weeks hunting down all the creatures I could find that were based on dinosaurs, despite them officially being classed as lizards or beasts, and finally put together my very own dinosaur deck!

It's clearly a dinosaur given it was made in the nineties (when feathers were still not widely known on dromaeosaurs).  It's even called "raptor"!  Nope.  lizard.  Artwork by Bob Eggleton.
Gonna be honest, this deck was by no means my strongest.  In fact, it lost more games than it won simply because what I wanted it to do was going against what the game wanted to do at the time.  I was focused on the flavor of the deck rather than the effectiveness.  If dinosaur had been an effective type I wouldn't have had to sacrifice and limited myself in the way that I did since Magic does have cards meant for decks where all the creatures are the same type...but that wasn't the case here, despite what the illustrations showed.
I was so convinced this Hystrodon (labeled "beast") was meant to be a stylized nodosaur of some kind.  Looking back maybe it was really supposed to be a giant pengolin...hmm.  I may have been wrong about that one.  Artwork by Anthony S. Waters.

That is until this year.  2017 was the year of the magic set, called Ixalan, taking place on a mysterious tropical island, inhabited by...dinosaurs.  Actual official dinosaurs!  Not only that, but all the lizard and beast cards that were clearly dinosaurs from before, were officially changed to dinosaurs, too!  Nerd Chris was very happy.

"Magic is finally adding dinosaurs officially!  I hope they have feathe- oh...oh wow..."  Artwork by Simon Dominic.

The comeback of dinosaurs in this set of Magic made ripples that extended beyond the Magic community.  Paleontologists and the like caught wind of it too.  Many had things to say on social media about it regarding the design choices of the dinosaurs in this latest set of of Magic because of the feathers.  This is because every single dinosaur you see in this new set of cards has feathers. Ironically, when dinosaur designs are inaccurate due to feathers, it's almost always because of a lack of feathers where they should be, like on dromaeosaurs and tyrannosauroids.  The designers over at Wizards of the Coast, however, went overboard in the opposite direction of going crazy with feathers.  Sauropods, hadrosaurs, even ankylosaurs are adorned with visible, colorful plumage.  The set also includes pterosaurs that are covered in birdlike feathers!  This did not sit well with many.  Comments like "Why can't they just make them realistic?" were common.  One commenter complained that since Magic does living species of animals realistically, there was no excuse to not treat extinct dinosaurs the same way.  (Which I pointed out was totally false.  Magic stylizes the crap out of living species of animals all the time.)

All you pulling the "They do realistic living animals why not extinct ones" card (no pun intended) this is a rhino.  Sit down.

So why didn't Wizards of the Coast simply just stick to science?  To answer this question we need to look into the flavor and story behind the game.  You see, Magic is a franchise that takes place over many universes, or planes, as they call them.  A creature on one card, within the context of the story, might never meet nor have heard of a creature in another card.  This gives the designers freedom from being bound to a specific style or look for years and years.  For instance, a goblin from the Dominarian plane is green-skinned with pointy ears and a big nose, while a goblin from Kamigawan plane would have red skin, with a wide mouth and a bumpy shell on the back.  They're both different versions of the same type of creature.  They just vary depending on where they're from.  Like I said earlier, dinonsaurs had been in Magic before. (they just weren't called dinosaurs)  Those earlier dinosaurs were pretty typical in design for a fantasy franchise.  Scaly...green...and not particularly accurate. 

The developers at Magic knew the official release of the dinosaur type would be a big deal.  They wanted to make the dinosaurs honor our current scientific understanding, but they also had to make these dinosaurs their own.  The plane of Ixalan is not our universe.  None of the dinosaurs featured are named after real genus, like Tyrannosaurus, and Deinonychus.  Instead, Ixalan has dinosaurs like Regisaurus and Ferocidon, to name a few.  So flavor-wise, a real genus of dinosaur wouldn't belong there, anyway.  Design wise, they decided to make it a requirement that all dinosaurs from this set to have bright feathers.  This ensures that when you look at a dinosaur card from Ixalan, you instantly know it is from Ixalan, and not another plane.  Just like you can tell a Dominarian goblin from a Kamigawan one.  This is also nodding at the fact that we now know many real kinds of dinosaurs were feathered, and is in stark contrast to most other fantasy franchises that feature dinosaurs, which take many steps backwards in their design choices, by making them completely scaly.  The folks over at Magic headquarters weren't being ignorant, they knew exactly what they were doing for the sake of the game, but still wanted to let us know they did their science homework by implementing it where they could.  I respect that.

A toothed Pteranodon-ish pterosaur with bird feathers.  And all the science fanboys' heads exploded.  Artwork by Simon Dominic.

Pterosaurs are included, as well, but they are typed as dinosaurs.  Before you start ranting about how "those people don't even know the difference!"  There was actually an article written about exactly this on Magic's official site, by head developer, Mark Rosewater.  What he had to say regarding this is quoted below.

" It was pointed out very early on when we made flying Dinosaurs that labeling them Dinosaurs was scientifically inaccurate.

We had two problems:

  1. Making the flying "Dinosaurs" something other than Dinosaurs hurt the gameplay. Tribal play revolves around the creatures in your deck all being the same creature type, so taking away the creature type limits options for the tribe.
  2. Most people think of things like pterosaurs as dinosaurs. Before the Wikipedia article states that they aren't dinosaurs, it claims "pterosaurs are often referred to in the popular media and by the general public as 'flying dinosaurs.'" This means that if we made them something other than Dinosaurs, we'd get a lot of complaints because the majority of people believe they are Dinosaurs.
So we were in a rough spot. Call them Dinosaurs and we get complaints for being scientifically inaccurate, or don't call them Dinosaurs and we upset an even larger share of the audience and hurt the gameplay. "

The reason why they ultimately decided to type the pterosaurs as "dinosaurs" is the same reason why my old dinosaur deck, which wasn't officially a dinosaur deck, kept losing games.  Having creatures of the same type within one deck, called "tribal", is beneficial.  By splitting pterosaurs off into their own type, it would make both dinosaurs and pterosaurs less playable.  Since, again, this isn't earth and these aren't real dinosaurs, it is passable.  It wasn't a matter of ignorance, it was a difficult call that had to be made for the sake of the game.  I respect that, too.  Plus, some of their flying designs look more like actual flying theropod dinosaurs than a pterosaurs.  Maybe this was done on purpose? 

On top of this some of the designs are actually pretty much spot on, scientifically anyway!  Science fans are quick to complain about Many of the artworks that are clearly stylized and somehow miss the ones that could easily pass for serious paleoart, going off the dinosaurs, alone.

Artist, Jonathan Kuo, knows how to illustrate real dinosaurs.

Also by Jonathan Kuo.  Just take the armor off, maybe dull the colors a bit, and you've got yourself a scientifically accurate Tyrannosaurus!

If you couldn't tell by this point I am totally behind Magic's choice to finally embrace dinosaurs as an official creature type in the game, excessive feathers and all.  I, for one, already have my new and improved, official dinosaur deck ready to go for the next tournament near my home.  What do you think? Was it wise to sacrifice some accuracy for the sake of the game?  Should all the dinosaurs have just been retro-styled with no feathers instead?  Share in the comments below!

Friday, August 11, 2017

Patagotitan: Beast of the Week

Today I will be reviewing a dinosaur that I have wanted to cover as Beast of the Week since last year.  In fact, I have already written a little mini informative blog post about it, as well as my experience attending its unveiling at the American Museum of Natural History in New York last year.  However, because this amazing dinosaur didn't have a name until a few days ago, I had to hold off on doing an official Beast of the Week post on it...until now!  Make way (No, seriously back up. This guy is huge.) for Patagotitan mayorum!

Patagotitan was a massive plant-eating dinosaur that lived in what is now Argentina during the early Cretaceous Period, about 101 million years ago.  It was gigantic, measuring about one hundred twenty two feet long from snout to tail!  The genus name, Patagotitan, translates to "Patagonia titan" in reference to where it was from in Argentina, Patagonia, and the fact that it was freaking huge...because "titan" means big. The species name, mayorum, is in honor of the Mayo family, the people who owned the land on which this dinosaur was found and excavated.

My watercolor painting of a sick Patagotitan in the place where its bones, and the bones of its kin before it (also pictured) will be dug up by humans 101 million years later.

Patagotitan is an amazing dinosaur.  First of all, it was gigantic, definitely one of the largest land animals (let alone dinosaurs) to ever live.  It was a member of the group of sauropod dinosaurs called Titanosauria.  Titanosaurs were sauropods, that unlike many other kinds of long-necked, large-bodied dinosaurs, like the diplodocids or brachiosaurids, survived into the very end of the Mesozoic.  On top of that, the very largest dinosaurs that we currently know, all happen to be titanosaurs, Patagotitan being near the top of even that list.  Even more specific, all of these largest titanosaurs, including Patagotitan, also happen to have lived in what is now Argentina!  Something about that part of the world during the Cretaceous favored extremely large body size in these dinosaurs.  That something is still very much a mystery to paleontologists.  The knee-jerk reaction to answer this question would be that these dinosaurs evolved so large as a defense against predators.  However, even the largest known meat-eating dinosaurs would stop becoming a threat to a healthy sauropod once it reached a certain size, like say.... seventy feet, like Brontosaurus, or a whopping eighty-five feet, like Giraffatitan.  But Patagotitan was one hundred twenty two feet long!  Seems like overkill, but growing to that size would have taken a lot of nutrients and energy.  Natural selection doesn't cause such extreme cases like this to just pop up randomly.  There were reasons. We just haven't discovered them yet!

The front end of Patagotitan and some paleoartist/teacher guy who is probably a model just sayin.  The skeletal mount at the American Museum of Natural History in New York is so large that the head and tail stretch into the two neighboring halls.  The head is modeled after other sauropods, since the skull of Patagotitan was never actually found.

In order to be so large, Patagotitan had some special features about it that prevented it from simply collapsing under its own bulk when alive.  First of all, its bones, despite being so large (the thigh bone is the size of a couch) were hollow inside with lots of air pockets.  This did two things for the animal.  First, it allowed it to be lighter, therefore raising the ceiling of how large it could become without being too heavy to move.  (Birds have the same feature in their bones for lightness too, but they used it to fly, instead of gaining size.  In fact, since birds are also dinosaurs, it is most likely that having hollow bones was originally an ancestral trait for dinosaurs.)  Second, these air chambers were connected in life to its respiratory system, so when the animal was breathing, it was easier for the oxygen to get to where it needed to go throughout its vast body.  Patagotitan's hips were particularly wide, and its legs were also pretty widespread.  This was to help spread out its weight as much as possible when it was standing or walking.  Being that large would have been taxing on an animal, so almost every part of its physiology had to take part in making sure it could support itself. 

The arm and shoulder blade of Patagotitan on display at the American Museum of Natural History in New York.  These are some of the actual bones and have since gone back home, to Argentina.

Another awesome thing about Patagotitan is that it is actually known from several specimens, six to be exact, not just one, which is what we usually get when we find a gigantic dinosaur.  Between these six individuals, paleontologists were able to put together a pretty accurate skeleton of this dinosaur, only leaving about thirty percent of the skeleton still a mystery.  Sadly, the skull was one of these missing parts, but skulls of sauropods rarely preserve because they are very delicate, compared to the rest of the body.  Another detail is that by looking at the geology of the dig site in which they were found, paleontologists found out that these six Patagotitans all died years apart from one another.  So something about that specific area was attracting dying Patagotitans.  Perhaps it was near a river, that dried up from time to time and thirsty dinosaurs would come there looking for water during the dry season and died?  It's a mystery.

Patagotitan's butt.  Note how wide set the back legs are to support its weight in life.

So what's up with that size?  Was Patagotitan the largest dinosaur ever?  Well, that's a little complicated.  The paleontologists who discovered this dinosaur initially thought so.  They measured the height of one of Patagotitan's back vertebra and compared that number to a back vertebra of the dinosaur that was at that time thought to be largest, called ArgentinasaurusPatagotitan turned out to have a taller vertebra, mostly because of a taller neural arch (the crest-like piece of bone that sticks out of the top of the vertebra.  If you run your finger down the center of your back, you can feel your own neural arches.)  Going on those numbers alone, which is all that was really released to the public at the time, it would appear that Patagotitan was the largest of the two.  But there's more to this story, than vertebra, however.

It turns out that despite having a taller vertebra than Argentinasaurus, many of the other bones of Patagontitan's bones that could be matched and compared to Argentinasaurus' were the less massive of the two.  So While the Patagotitan may have been taller in some areas, Argentinasaurus appears to have been more massive.  So it depends on what your definition of size really means.  It's like comparing a giraffe to an elephant.  The giraffe is certainly taller, but the elephant is definitely more massive.  In addition to this, keep in mind that Argentinasaurus is only known from a few bones, and it is very difficult to get an idea of exactly how long its entire body was.  So it is possible that Argentinasaurus was entirely larger in any sense of the word, than Patagotitan

Another thing about size to keep in mind is that none of the Patagotitan specimens were fully grown when they died.  At the same time it is possible that the fossils we have of Argentinasaurus may not have been from the largest individual of its species either...oh the debate goes on!  See what I mean when I say it's complicated?

THAT BEING SAID...At the end of the day it is important to step back and look at this for what it is.  Patagotitan was a really cool, almost completely known dinosaur that was gigantic!  Worrying too much about if it may have been a little larger than the other known gigantic dinosaurs, as if it were some kind of contest, is pointless when there are way more exciting things to take away with the discovery and now publication of Patagotitan!

That is all for this week!  What do you think about Patagotitan?  Feel free to comment below or on the facebook page!

References

Carpenter, Kenneth (2006). "Biggest of the Big: A Critical Re-Evaluation of the Mega-Sauropod Amphicoelias fragillimus Cope, 1878" (PDF). In Foster, John R.; Lucas, Spencer G. Paleontology and Geology of the Upper Jurassic Morrison Formation. 36. New Mexico Museum of Natural History and Science Bulletin. pp. 131–138.

José L. Carballido; Diego Pol; Alejandro Otero; Ignacio A. Cerda; Leonardo Salgado ; Alberto C. Garrido ; Jahandar Ramezani ; Néstor R. Cúneo ; Javier M. Krause (2017). "A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs". Proceedings of the Royal Society B: Biological Sciences. 284 (1860): 20171219. doi:10.1098/rspb.2017.1219.

Mazzetta, Gerardo V.; Christiansen, Per; Fariña, Richard A. (2004). "Giants and Bizarres: Body Size of Some Southern South American Cretaceous Dinosaurs" (PDF). Historical Biology. 16 (2-4): 71–83. doi:10.1080/08912960410001715132. Retrieved 2008-01-08.

Ortiz, Edward, and Reuven Blau. “Meet Patagotitan Mayorum, the Biggest Beast in the City.” NY Daily News, 9 Aug. 2017, www.nydailynews.com/news/national/meet-patagotitan-mayorum-biggest-beast-city-article-1.3397477.


Thursday, July 13, 2017

That Time I Won a Beer Art Contest Because of Dinosaurs

I won a beer contest because of dinosaurs.  That's a cool sentence I can say now without being a liar.  I'll tell you all about it.  Let's start at the beginning.

I wouldn't call myself a high-level beer expert, but I have learned to appreciate craft beers over the years.  That being said, I must admit the way I sometimes go about choosing a new beer to try, unless something in the description catches my eye...is the title.  If a beer has a cool title I am much more likely to try it.  If the can art is cool I'ma also likely to check it out.  Marketing.


That being said, whenever I find beers that have pictures of dinosaurs on the cans or dinosaur-themed names I'm drawn to them.  Sometimes they turn out to be good.  Sometimes they aren't my thing, taste-wise.  However, I must admit I found one of my all time favorite beers to date thanks to this method.  It all started when my now wife and I were visiting her family in New Jersey a few years ago.  We decided to stop at her favorite wine and beer store, called Spirits Unlimited, to get a bottle of wine to bring.  Fun history lesson; Spirits Unlimited is sort of famous in New Jersey.  The store used to be a Food Circus store during the 1950s.  To help advertise this they built a thirty-foot clown sign out in the parking lot that is still there today.  The clown's name is Calico, he's sort of famous locally, and he's horrifying.   He's supposed to be holding a lit cigar, but because the cigar is white just like his gloves, it looks like he's pointing at you with blood on his finger.  Fun stuff.


His nickname is the "Evil Clown" in case you needed an even more obvious reason to be terrified.

So we were in this store hunting for wines and as usual I wander off to look at the craft beers.  On a shelf off to the side, near the cash register, I find a single large bottle of beer from Brooklyn Brewery, called "Quintaceratops".  Since it was dinosaur-themed I bought it, tried it that very night, incidentally fell in love with its dark, rich taste, and it is still one of my favorites to this day.  Sadly it was part of a limited stock and is no longer in production.

You know what else is sad?  The label art for Quintaceratops.  If the guys from Brooklyn Brewery are reading this, I'm sorry, I love you, but I need to be honest here and say the label looks lame. You see, the name, "Quintaceratops" is in reference to the fact that this beer was made using four times the amount of malt than a standard beer + rum = five + dinosaurs are cool =  Quintaceratops is the name.  Naturally, someone who knows a lot of dinosaurs would immediately think of the ceratopsian, Pentaceratops, which also has a reference to the number, five, in its name.  The designers over at Brooklyn Brewery maybe didn't know Pentaceratops existed and instead opted to put an image of a Triceratops with two extra horns growing out of its face...which is fine by me!  That sounds like a cool fantasy dinosaur and would make for some sweet bottle art.  The problem is the fact that the image that appears on the label is simply a little profile of that mythical Triceratops-like dinosaur surrounded by text.  What a missed opportunity!

Pentaceratops is not amused that its more popular relative, Triceatops, got the role it was born to play upon seeing the bottle label.  Awkward.

Fast forward a few years to last month when my wife and I are living in Philadelphia.  Philly Beer Week, a week in June where bars all over the city hold special events promoting local craft beers, is happening.  I'm on my day off, eating breakfast, when I get a text from my wife at work telling me about this beer can art contest going on that afternoon nearby.  (Check out how proactive she is and how much of a bum I am by the way.  She is at work and manages figure this out in her break time.  Meanwhile I was getting ready to binge watch NETFLIX or pet our cat, Petrie, for most of the day.)  I decided I had nothing to lose and made my way over to the Garage Bar in Fishtown, Philadelphia, and find out that Brooklyn Brewery is one of the breweries sponsoring the art contest.  One of the judges explains to all the participants that we are to draw and color our own design for an already existing beer from one of the sponsoring breweries.  The second that information hits my brain I think to myself "QUINTACERATOPS SHALL GET THE LABEL ART IT DESERVES."


Immediately I get to work.  The design I chose was of Pentaceratops, the real "five-horned" dinosaur, with the Brooklyn Brewery logo on its frill.  (Fun fact; Pentaceratops actually didn't have any more horns than Triceratops since they both had three on the face and two jugal horns.  (I guess jugal horns only count as horns sometimes?  Genus names can be weird.)  I tried my best not to get psyched out by the competition since there were definitely some skilled artists participating.  Sometime during the hour and a half I was working I was given a free beer, which was cool.

Early stages of development.

I was able to finish with plenty of time, luckily, and simply waited for the judges to make their choice.  To my delight, my design ended up winning first place.  The judges apparently think dinosaurs are cool, too, and were thrilled to see one incorporated into a design.  Secondly, they were impressed that I chose a beer of theirs that was discontinued, and therefore not very well-known by most people. It was a good day.  Special thanks to Brooklyn Brewery sales representatives, Ben and Chris, for liking my design enough to give it first place.

Finished design before being wrapped onto the can.  I wanted to keep the color scheme of the original bottle label.

I guess the moral of this story is you never know when constantly thinking about dinosaurs is going to lead to a cool experience and a good story.  If anyone from Brooklyn Brewery is reading this and you need more dinosaurs on any can or bottle art, shoot me an email.  I'd be honored to have your beer grace my artwork. 

Sent this photo to my wife as I walked out, covered in sweet Brooklyn Brewery prize loot and pockets full of beer vouchers.

Wednesday, June 14, 2017

Smilodon: Beast of the Week

This week, thanks to multiple requests, we will be looking at a really popular prehistoric mammal.  Make way for Smilodon!

Smilodon was a prehistoric cat that lived in many parts of what is now North and South America during the Pleistocene epoch (more casually referred to as the "ice age"), from 2.5 million years ago to as recent as only ten thousand years ago.  There are currently three named species of Smilodon.  The most well-understood is Smilodon fatalis, which is known from literally hundreds of specimens found in California, which measured between five and six feet from snout to rump and a little over three feet tall at the shoulder as adults.  Smilodon populator was the largest, with canine teeth that could measure up to eleven inches long. Smilodon gracilis was from the oldest time, likely a direct ancestor of the other two, but only known from very partial remains so details of its anatomy is mostly unknown other than the fact that its teeth were more slender than those of its later relatives.  The genus name, Smilodon, translates to "Smiling Tooth" in reference to the fact that this cat had HUGE top canines that likely would have stuck out of the mouth at least partially even when the jaws were completely closed.  Assuming its diet was the same as modern cats, Smilodon would have been an obligate carnivore, eating only other animals.  (I hear you cat people out there.  "But, Chris!  My cat at home eats grass and other plants all the time!" Ah, yes.  But what does your kitty do after consuming the grass?  BARF!  In fact, because they cannot digest plant material, cats specifically eat grass to induce vomiting when they don't feel well.)

Smilodon fatalis with cub.  Reconstruction by Christopher DiPiazza.  Color scheme inspired by modern pumas.  Because of the vast span of places Smilodon remains have been found, it likely was adapted to living in a multitude of different habitats.  Pumas are known to exhibit the same success today, living in mountains, deserts, forests, and even tropical everglades.  That being said, Pumas aren't particularly closely related to Smilodon over any other modern cat.

Smilodon is a very popular and well-loved prehistoric mammal not just in the paleontology community, but also to the general public in general.  It is certainly up there with Woolly Mammoths, and even popular dinosaurs, like Tyrannosaurus and Triceratops.  However, it is only rarely referred to by its actual name in popular media, often called a "saber-toothed....tiger".   (I'm cringing just typing that.) Word to the wise; never EVER refer to Smilodon as a "saber-toothed tiger" in earshot of a paleontologist. If you do forget the proper genus name, it's always safe to refer to it as a "saber-toothed cat" instead.  This is because Smilodon was not a tiger.  In fact, Smilodon and its closest relatives appear to have diverged from modern cats, including tigers very early in cat evolutionary history, about 23 million years ago.  In other words, despite the fact that Smilodon was a cat, there is no species of living cat that we can say is any more closely related to Smilodon than any other.  The subfamily that Smilodon is part of, called machairodontinae, and the subfamily that includes everything from tigers to housecats, called felinae are as distant as they can be within the cat family.  That being said, could Smilodon have even roared?  Think about it.  Only modern cats in the specific genus, panthera, like lions, jaguars, and tigers, can roar.  Every other cat, including Cheetahs, Pumas (mountain lion), and house cats cannot.  It is very possible, since it was so distantly related, that saber cats, like Smilodon, couldn't roar either.  (Sorry if I killed your nostalgia/childhood there.  Just thinking out loud here.)

Smilodon skeleton on display at the American Museum of Natural History in New York.

Despite how popular Smilodon is, many people don't actually know that much about it, often assuming it was just another big cat that happened to have long front canines.  In reality, Smilodon had lots of really interesting features about it beyond the teeth. On the skull, aside from the front teeth, it had a particularly robust and almost blunt-looking face to accommodate the roots of those huge front canines.  So reconstructions of Smilodon that look like a just lion or tiger with long fangs are wrong.  Smilodon also had proportionally longer arms than those of other known cats, and a short, almost stubby tail.

Overall, Smilodon had a much stockier build than most cats.  This suggests that it relied on strength over speed to capture prey.  It is very possible that in life, Smilodon would have been an ambush predator, surprising animals that get too close to its hiding spot, then relying on its strong arms to overpower and contain struggling prey.  In fact, looking at the arm bones of Smilodon, it was determined that it would have had the strongest arms of any known cat!  Also remember that like all cats (except Cheetahs) Smilodon was armed with hooked, retractable claws on each limb, which were probably great at latching onto into, and immobilizing prey even further.  If you have ever played with a house cat before, you might be familiar with the behavior they do that involves holding on with their front claws, and rapidly kicking with their back feet.  As cute as this behavior is in house cats (my fiance and I endearingly refer to it as "gripp'n and kick'n"), it is actually a really effective disembowel tactic when dealing with actual prey.  Imagine how much damage a Smilodon could have done, digging its hooked front claws, backed up by those extremely powerful arms, and shredding its prey's insides with its hind claws at the same time!  Check out the video below of my cat, Petrie, who was happy to demonstrate this behavior on my foot for you all.  Thanks, Petrie.  (Don't worry.  My foot is still intact from the incident.)



But what about those amazing teeth?  Smilodon's teeth are actually the subject of much debate.  At first glance it seems like a no-brainer that they were simply an extreme stabbing/biting adaptation.  But it's not that simple.  You see, Smilodon's teeth were actually pretty delicate and prone to breaking if put under too much pressure.  So in life, if a Smilodon was just chomping as hard as it could into anything, it was bound to get hurt.  Remember, mammals don't constantly regenerate teeth like reptiles do, either.  So where crocodiles and dinosaurs could afford to be less careful with what they bite, Smilodon can't.  With this in mind, a next logical guess would be that maybe Smilodon's long canines were for sexual display?  Plenty of other animals, living and extinct, have unusually shaped or large body parts, including teeth, for this reason.  The only problem with this hypothesis is the fact that we have literally hundreds of Smilodon specimens on the fossil record, and all of the adults have the same long teeth.  If they were really for sexual display, it is much more likely that they would differ between sexes, likely longer in males than in females.  Because this is not what the data shows us, we are probably safer going back to guessing that Smilodon was using those teeth for something other than looking cool, like dealing with prey, but it probably had to be much more meticulous about how it went about it.  Going back to those unusually powerful front limbs, a strong current hypothesis is that Smilodon used its arms to hold still struggling prey so it could use its canines to carefully stab the perfect spot, likely the jugular vein or the trachea(wind pipe).  The arms would have helped ensure that the teeth weren't damaged by the prey when it was still alive.

Smilodon skeleton on display at the Mesalands Dinosaur Museum in Tucumcari, New Mexico.

Smilodon's jaws can open wider than those of any other cat in order to make clearance for the saber teeth.  Despite this, at first glance, even with some clearance, those canines would get in the way if Smilodon tried to bite a piece of food off a carcass with the front of its mouth.  Looking at house cats eat bite-sized kibble can't help us here as a reference.  For a better clue we need to look at cats that have to bite off chunks of food from larger carcasses.  What you will notice is that when eating off large carcasses, cats actually don't use the front of their mouths that often to bite off smaller pieces.  They use the sides of their mouths, armed with large, sharp teeth, called carnassals, to cut meat like scissors.  This may have been how Smilodon got around its massive canines to feed itself, as well.  Check out the clips of exotic cats eating in this video below.  You will notice that most of the time, they are biting with the sides of their jaws to process food.  (at one point in the video they show a random Binturong, which is not a cat, but a civet.  Cute, but not as relevant.)




La Brea, California, is home to tar pits that are tens of thousands of years old, and is where the majority of Smilodon specimens on the fossil record have been found.  During the Pleistocene, animals would occasionally get trapped and die in these tar pits.  While these unfortunate animals were likely giving off distress calls, they would have attracted meat eating-animals to come and eat them, including Smilodon.  Those meat-eaters in turn would get stuck, themselves, and also die, attracting even more meat-eaters and...well you get the idea.  Hundreds of Smilodons have been unearthed out of these tar pits, as well of lots of other kinds of ice age animals, especially predators.  In fact, most of the remains that are found in these tar pits are of meat-eaters because of stuck animals acting as bait.  Even today, animals are still getting stuck and dying in the La Brea tar pits.

Thanks to all these wonderful specimens, paleontologists were able to learn a lot about Smilodon, including how it grew.  Like most mammals, Smilodon had a set of baby teeth, which would later fall out and be replaced by bigger, adult teeth.  The cool thing about Smilodon, however, is that the adult teeth didn't initially cause the baby teeth to fall out.  In fact, when it came to the famous saber canines, there was a period of about a year in a Smilodon's life where the adult canines were growing in next to the baby teeth.  The specimens that show this are extremely rare, even from La Brea, which suggests that juvenile Smilodons at that age probably weren't going out to hunt, and likely were still having food brought to them by parents.

Underside of juvenile Smilodon skulls.  The left one shows the baby canines alongside the growing adult canines.  These skulls were unearthed at the La Brea Tarpits, and are on display at the George C. Page Museum in California.

That is all for this week!  As always feel free to comment below or on the Prehistoric Beast of the Week facebook page!


References

Antón, M. (2013). Sabertooth (1st ed.). Bloomington: Indiana University Press.

Feranec, R. C. (2004). "Isotopic evidence of saber-tooth development, growth rate, and diet from the adult canine of Smilodon fatalis from Rancho La Brea". Palaeogeography, Palaeoclimatology, Palaeoecology206 (3–4): 303–310. 

Kurtén, B.; Werdelin, L. (1990). "Relationships between North and South American Smilodon". Journal of Vertebrate Paleontology10 (2): 158–169. 

Meachen-Samuels, J. A.; Van Valkenburgh, B. (2010). "Radiographs reveal exceptional forelimb strength in the sabertooth cat, Smilodon fatalis"PLoS ONE5 (7): e11412. 


Mihlbachler, M. C.; Wysocki, M. A.; Feranec, R. S.; Tseng, Z. J.; Bjornsson, C. S. (2015-07-01). "Using a novel absolute ontogenetic age determination technique to calculate the timing of tooth eruption in the saber-toothed cat, Smilodon fatalis"PLoS ONE10 (7): e0129847. 

"Vegetarian Cat?" Vegetarian Cat? – Dr. Sophia Yin. N.p., n.d. Web. 14 June 2017.

Thursday, June 8, 2017

Safari Ltd Review: Coelophysis

It's always exciting when I get verification that Prehistoric Beast of the Week is getting noticed.  I love hearing from friends and family that they take the time to read what I post.  However, hearing it from strangers, especially in person, whether they come to see me at a museum, or other special event, has a certain surrealism to it.

I recently experienced a third kind of excitement when I was noticed by a major toy company that want's me to help spread the word about their dinosaur products.  Safari Ltd, known for making detailed, hand-painted, educational toys of dinosaurs since 1982, sent me an email, saying they would like to partner up with Prehistoric Beast of the Week, in hopes that I would review some of their models on here.  Of course, I said yes, and a few weeks later I got a big box in the mail from them, containing some of there awesome dinosaur figures.  So without further ado, let's get to know Safari Ltd's version of Coelophysis!

If you aren't already familiar with Coelophysis, it was a relatively small, meat-eating dinosaur that lived during the late Triassic period, about 200 million years ago, in what is now the Western United States, especially New Mexico, where it is the official state fossil.  Adults measure about ten feet long from snout to tail.  The genus name translates to "Hollow Form" in reference to the dinosaur's hollow bones, which was a trait common to lots of dinosaurs, actually.  For more detailed information on this dinosaur, be sure to check out my Beast of the Week post on it from 2015.

Full body shot of Safari Ltd's Coelophysis.  In my opinion, it's the best available toy of this dinosaur.

Safari Ltd's Coelophysis is part of their newest line of dinosaur toys for 2017.  When I first saw they were making Coelophysis for this year I excited for a few reasons.  First of all, Coelophysis is very rarely made into a toy, despite how well-known it is.  In fact, before this, I can think of only three or four other instances when Coelophysis was specifically made into a toy (and none this detailed)  The second reason I was pumped for this figure is because Coelophysis was a dinosaur who's bones I had the privilege of excavating  a few years ago with the Mesalands Dinosaur Museum in New Mexico, so it has a special little place in my heart in that respect.

The proportions are great on this model.  Most of Coelophysis' length is tail and neck, which this toy showcases.  The shape of the head matches almost perfectly with some of the real Coelophysis skulls that have been unearthed.  We know, thanks to many well-preserved, and complete individual specimens of this animal, that Coelophysis skulls likely became longer and more slender as they aged, or maybe even differed depending on sex.  Judging by the long snout and two bony ridges on the top of the face, this model is probably supposed to be of an adult.  The legs are not too skinny, which is great.  Yes, Coelophysis was a slender animal, but it still would have needed muscles to get around!

My cast of a Coelophysis skull.  The Safari Ltd model matches this wonderfully.

I am hard pressed to find anything really wrong with the proportions of this model, actually.  If I were to really nitpick, I'd say the lengths of the fingers are off.  In reality Coelophysis' first finger was shortest, middle finger was longest, and the third finger was in the middle.  This toy has the third finger longer than the first two.  On a good note, they did include the tiny, almost unnoticeable vestigial fourth finger.  In fact I only just noticed that fourth finger now as I'm reviewing it.

Note how the third digit is longer than the first and second.  But check out that vestigial fourth finger!

Another tiny note is the fact that Coelophysis would have held its tail out in the air behind it for balance in life, while this model has the tip of the tail resting on the ground.  HOWEVER I completely understand that in order for a model of a dinosaur made of plastic, and not of muscles and a sense of balance, would need the tail as a third point of contact to the ground in order to stand.  Safari Ltd has made other bipedal dinosaurs that balance just on their feet, but the feet had to be proportionally larger and wider, which would be much more noticeable if they tried to do it on a dinosaur as lightly built as Coelophysis.  I have also seen Safari Ltd and other toy companies put bipedal dinosaurs on a platform stand to get rid of the balance issue, but personally, I kind of hate the stands.  It sort of kills the play value of a toy.

I love the fact that the sculptor decided to add texture of feathers to this model.  This model goes all out with an even coat over most of the body except for the feet, hands, and face.  It even has feathers down the whole length of the tail!  We actually have no direct evidence of feathers on Coelophysis, but we have found feathers in a lot of other theropod fossils, as well as a few non-theropod dinosaurs.  Because of this, we have reason to think that basal theropods, like Coelophysis, may have had some kind of feathering on their bodies, too.  Using relatives that surround a kind of organism on a family tree to infer a feature, in this case feathers, is called phylogenetic bracketing.  Coelophyis may have used feathers in a variety of ways.  Feathers could have helped keep Coelophysis' body temperature regulated, keeping body heat in when then environment was cold, and shielding the animal's skin from the sun, when it was hot out.  Feathers could also help parents keep their eggs warm.  Maybe mom/dad sat with their eggs and kept them warm that way, or perhaps parents plucked their feathers out and used them as nest material?  Feathers also can slightly obscure an animal's profile, making it easier for it to hide in certain environments.  So the next time someone tells you a prehistoric dinosaur wouldn't have needed feathers, you can list at least three reasons why it would!

Texture on the face showcases small scales, which is totally plausible, and looks good.  This model has the teeth from the upper jaw sticking out despite the fact that the mouth is closed.  Whether or not certain dinosaurs had visible teeth when the mouth was closed is the subject of a lot of debate among paleontologists and paleoartists right now.  The look that this model chose to go with regarding this is still plausible as far as I know.


The feet show the same wide-rectangular scales that you see on the toes and tarsals of modern birds, which I think is a great touch.  In modern birds, these scales were found to be made of the same material as veined feathers, and is therefore used against artists who depict these scales on featherless dinosaurs, or dinosaurs with basal feathers.  The only problem with this assumption is the fact that crocodilians have similarly shaped scales on their fingers and toes so the structure is totally capable of popping up from different materials...OR crocodilians have ancestors with veined feathers.  Whichever idea you want to go with those kinds of scales are totally fine on any kind of dinosaur reconstruction, feathers or not, including this sculpt.

This toy showcases wide, rectangular scales on the toes and feet, which is totally plausible for this dinosaur.

The colors of this model are pretty, but still believable.  Most of the body is painted orange.  The ventral parts of most of the body are white.  There is a lateral black stripe that separates the orange and white parts on the neck, torso, and tail.  This part of the color scheme reminds me of a Thomson's Gazelle. There are also perpendicular black bands on the end part of the tail.  The hands and feet are greenish gray and the snout is painted pale blue.  The two ridges on the top of the snout are painted red, as are the thin rings around the eyes.  This splash of red could possibly be intended to show a sort of intraspecies display for Coelophysis.  Of course we have no idea what colors Coelophysis was in real life, but what Safari Ltd has going on here is definitely within the wide realm of possibility.

Overall I think this is currently the best toy form of Coelophysis on the market so far.  It's not very often that you can get an accurate toy of a Triassic creature, so this Coelophysis is a much welcomed addition to Safari Ltd's line.  It can be purchased anywhere Safari Ltd toys are currently sold, the Safari Ltd website, or the Safari Ltd Amazon site.

Special thanks to Safari Ltd for shipping this beautiful little model over to me to review.

Tuesday, May 30, 2017

Kaprosuchus: Beast of the Week

This week we shall be looking at a totally unique crocodilian.  Enter Kaprosuchus saharicus!

Kaprosuchus was a prehistoric crocodilian, related to today's alligators and crocodiles, that lived in what is now Niger, Africa, during the Cretaceous period, about 95 million years ago.  Sadly it is only known from one skull, and therefore size estimates for its entire snout-to-tail length vary from anywhere between ten to twenty feet depending on who you ask.  I suppose it depends on how proportionally this beast's head was.  When alive, Kaprosuchus almost certainly ate meat, judging by its teeth, which were enormous and sharp.  Four of these teeth that grew from the lower jaw were so long, in fact, that when Kaprosuchus' mouth was closed, would have stuck out above the top of the snout.  This is how Kaprosuchus earned its genus name, which translates to "boar crocodile" because of the tusk-like appearance of these teeth. 

Life reconstruction of a Kaprosuchus with her nest, by Christopher DiPiazza.  Sadly no fossil eggs or nests from this creature have been found yet.

Kaprosuchus became very popular in the grand scheme of things after it was discovered and published.  A few toy companies made figures of it, it was featured on an episode of the BBC show, Primeval, it even appeared in several electronic games, including the latest Jurassic World game.  When a new fossil creature is discovered, this rarely happens.  It is hard to carve out a niche in popular culture next to Tyrannosaurus, Triceratops, and VelociraptorKaprosuchus was able to do this because it just looks so different.  Not only that but its unique look is also intimidating.  This crocodile has four pairs of super long teeth that extend beyond the snout when the mouth was closed!  How could you not showcase that? 

But what were the teeth actually for?  What is interesting is that Kaprosuchus' teeth were actually pretty different from those of other crocodilians not just in length, but in structure, too.  Kaprosuchus' teeth, especially the longest ones had an edge to them, like blades.  This means that they would have been better at cutting meat, rather than grabbing and holding onto prey, like the teeth are in most of its relatives, which are more cone-shaped, with a round cross-section.  At the same time, however, Kaprosuchus'skull still shows us that it still could have delivered a devastating bite, since the bones surrounding the nostril hole were fused together, forming a structure that could handle pressure better. Kaprosuchus' jaws show us that it could have opened its mouth extremely wide in life, even ensuring that those long teeth totally clear each other, to not get in the way when biting things.  In addition to weapons, I have to wonder if the extremely long teeth on this beast could also have been used for display within the species.  Sadly we only have one skull so far, but I can't help but wonder if the teeth were different sizes in males and females.  Modern male crocodilians are typically larger than the females.  Perhaps Kaprosuchus was similar in a way?  We may never know. 

Kaprosuchus skull.  Note how four (almost five) pairs of teeth extend past the snout when the jaws are closed.  Photo by Carol Abraczinskas originally used for Sereno PC, Larsson HCE (2009)


Kaprosuchus also had eye sockets that were close together, but faced more forward and outward than what we see in modern crocodilians, who's eye sockets face above the skull, so the animal can see while mostly submerged in water.  This has led many to speculate that Kaprosuchus spend more time on land than what we typically see in other crocodilians from that time.  However, the eyes were at about the same level, if not a bit higher than where the nostrils were.  Also, the nostril hole does face upward, like in aquatic crocodilians.  I have heard some who defend the terrestrial hypothesis say that this was an adaptation that left the front of the snout solid to be used as a ramming weapon, but again, modern crocodilians ram too while still being mostly aquatic.  Kaprosuchus may have spent more time out of the water than say a modern alligator or crocodile, but personally, I am not completely sold on the fully terrestrial idea for this animal.  Maybe one day if someone discovers the body of this beast, the placement and length of the legs will tell us more clues as to how it lived!

That is all for this week.  As always feel free to comment below or on the facebook page!

References

Sereno, Paul; Larsson, Hans; Larsson, Paul Sereno, Hans (2009). "Cretaceous Crocodyliforms from the Sahara". ZooKeys. 28: 1–143.

Saturday, May 20, 2017

Postosuchus: Beast of the Week

This week we will be checking out a beast that shows us that evolution is capable of truly amazing things and how deceiving looks can really be.  This creature also helps teach us it's okay to change our perceptions as we learn new things, especially in science.  Enter Postosuchus kirkpatricki!

Postosuchus was a pseudosuchian archosaur, more closely related to crocodilians than to dinosaurs, that lived in what is now the Southern United States, specifically New Mexico, Arizona, Texas, and as far east as North Carolina, during the Triassic Period, between 221 and 203 million years ago.  It was one of the largest animals in its environment, with adults measuring between thirteen and fifteen feet long from snout to tail, and ate meat, probably hunting many of the other Triassic animals from the area, including fellow pseudosuchians, Shuvosaurus and Desmatosuchus, and the dinosaur, Coelophysis.  The genus name, Postosuchus, translates to "Post Crocodile", in reference to Post Town, Texas, where the first Postosuchus bones were unearthed.  The species name is in honor of the Kirkpatrrick family, who helped in Postosuchus' excavation.

Postosuchus life reconstruction in watercolors by Christopher DiPiazza.
 
Postosuchus has gone through a few makeovers over the years since it was discovered.  Because the first group of specimens' bones were not always found articulated, and often times among those of other species, early Postosuchus skeletal reconstructions accidentally were partially made of bones from other kinds of animals.  An example of this would be a the pelvis, hand, and toe bones, which would later be found to have really belonged to Shuvosaurus.  Because of this, Postosuchus was often depicted as being able to walk on four or two legs when alive.  However, we now know that it was much more likely to have been an obligate biped, only able to walk on its hind legs, like most theropod dinosaurs. This is thanks to more complete remains of Postosuchus found more recently, proving that the arms and hands were actually much smaller than previously thought, and were incapable of supporting its weight even if they could reach the ground.  The pelvis was much larger than originally thought, too, meaning the animal's center of gravity was over the hips.

Postosuchus brass skeletal mount on display at the Mesalands Dinosaur Museum in Tucumcari, New Mexico.  This mount is actually outdated.  Parts of the pelvis actually belong to Shuvosaurus, and the four-legged stance is improbable.  The vertebrae, especially behind the skull, would have much shallower neural arches in reality.

Postosuchus' skull was tall overall, but narrow laterally in the front, gradually getting wider towards the back.  It had prominent ridges over the eyes, forming an overhanging shelf, perhaps to help block out sun glare in life.  The eye sockets were relatively large, and partially faced forwards, suggesting Postoscuchus may have relied on its sense of site to hunt.  Due to large hollow areas connected to the nostrils, it likely also had a good sense of smell in life.  Postosuchus' jaws were lined with relatively long, pointed teeth that were serrated, for better cutting meat.  Some of the teeth were much longer than the others in certain parts of the jaws, like the tip of the lower jaw, and the mid-section of the upper jaw.  This would have made Postosuchus' mouth act like a deadly trap if it were to bite into a still-living/struggling animal.

Brass cast of Postosuchus skull at the Mesalands Dinosaur Museum.  Note how the longest teeth are in the middle of the upper jaw, and the front of the lower jaw.

Osteoderms have also been discovered with Postosuchus.  Osteoderms are pieces of bone that grow under the skin of an animal.  Modern crocodilians are most famous for having osteoderms, which they use as armor, as well as for built-in solar panels, to better absorb heat from the sun.  The osteodersm associated with Postosuchus appear to have been growing in two rows down the back.  It is still uncertain as to what their purpose was.

Photographs of Postosuchus foot bones from Karin Peyer's 2008 paper, describing the specimen found in North Carolina.  Note how Postosuchus would have walked on four toes on the ground.  This is different from what you'd see in MOST theropods.  (Therizinosaurs walk on four toes.)

Within pseudosuchia, Postosuchus belongs to the family called rauisuchidae.  Rauisuchians all exhibited fully erect posture, and typically had large heads with sharp teeth.  Not surprisingly, they are often mistaken for meat-eating dinosaurs.  They even possessed hollow bones, a trait normally associated with dinosaurs.  However, Postosuchus, like all pseudosuchians, shows some key differences from dinosaurs that give it away as more closely related to crocodilians.  It's ankles are the biggest giveaway because they could rotate, like those of modern crocodilians, rather than the more rigid, one-way bending ankles all dinosaurs have.  It also would have walked with it's first four digits touching the ground and its outermost fifth digit, which was much shorter, out to the side.  Postosuchus was another amazing example of convergent evolution.  In this case, it evolved the same body design you would see in large meat-eating dinosaurs like Megalosaurus or Allosaurus...before large, meat-eating dinosaurs even evolved!

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

References

Chatterjee, Sankar (1985). "Postosuchus, a new Thecodontian reptile from the Triassic of Texas and the origin of Tyrannosaurs". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 309 (1139): 395–460.

Long, Robert A.; Murry, Phillip. A. (1995). "Late Triassic (Carnian and Norian) tetrapods from the southwestern United States". New Mexico Museum of Natural History and Science, Bulletin. 4: 1–254.

Nesbitt, Sterling J.; Norrell, Mark A. (2006). "Extreme convergence in the body plans of an early Suchian (Archosauria) and Ornithomimid Dinosaurs (Theropoda)"Proceedings of the Royal Society B273 (1590): 1045–1048.

Novak, Stephanie E. (2004). A new specimen of Postosuchus from the Late Triassic Coelophysis Quarry, siltstone member, Chinle Formation, Ghost Ranch, New Mexico (M.Sc. thesis). University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

Peyer, Karin; Carter, Joseph G.; Sues, Hans-Dieter; Novak, Stephanie E.; Olsen, Paul E. (2008). "A new Suchian Archosaur from the Upper Triassic of North Carolina". Journal of Vertebrate Paleontology. 28 (2): 363–381.