Sunday, February 23, 2020

Suuwassea: Beast of the Week

This week we will be looking at an exciting long-necked dinosaur that I actually was lucky enough to help prep bones of during my time at the Academy of Natural Sciences in Philadelphia.  Let's check out Suuwassea emilieae! 

Suuwassea was a plant-eating dinosaur that lived during the late Jurassic period, about 145 million years ago, in what is now Montana, USA.  Its genus name translates from the Native American Crow language to "Ancient Thunder", one of the coolest dinosaur genus names out there.  From snout to tail, Suuwassea would have measured between 45 and 50 feet long.

Suuwassea emilieae reconstruction in watercolors by Christopher DiPiazza

Suuwassea was a member of the sauropod order of dinosaurs.  Sauropods were the iconic group of dinosaurs that are defined by their large bodies, long necks, and small heads.  North America during the late Jurassic was literally shaking with sauropod dinosaurs.  Giants such as Apatosaurus, Brontosaurus, Barosaurus, Diplodocus, Camarasaurus, and Brachiosaurus, all were thriving there.  Suuwassea stands out among them based on where it falls in the sauropod family tree, however.  It belonged to the family within sauropods, called dicraeosauridae.  Dicraeosaurids have mostly been discovered in South America and Africa.  Suuwassea is the only known member from North America.  Dicraeosaurids also tended to be smaller compared to other sauropods with proportionally shorter (relatively speaking) necks.  Despite living among many other sauropod relatives, Suuwassea may have utilized these differences in anatomy to exploit slightly different foods, like lower-growing plants that may have been more cumbersome for something like the much larger Diplodocus or Brachiosaurus to easily get to.

Neck vertebra from Suuwassea on display at the Academy of Natural Sciences in Philladelphia, PA.

Suuwassea possessed vertebra on its neck and back that had longer neural arches than what is typically seen in other groups of sauropods.  This would have given it a slight hump-like appearance in life.  Some of the later dicraeosaurids, like Amargasaurus and Bajadasaurus, would push that feature to extremes, sporting long spine-like structures growing from their vertebra!

That is all for this week!  As always feel free to comment below!

References

Harris, J.D. and Dodson, P. (2004). "A new diplodocoid sauropod dinosaur from the Upper Jurassic Morrison Formation of Montana, USA." Acta Palaeontologica Polonica 49 (2): 197–210.

Sander, P. Martin; Christian, Andreas; Clauss, Marcus; Fechner, Regina; Gee, Carole T.; Griebeler, Eva-Maria; Gunga, Hanns-Christian; Hummel, Jürgen; Mallison, Heinrich (2011-02-01). "Biology of the sauropod dinosaurs: the evolution of gigantism"Biological Reviews of the Cambridge Philosophical Society86 (1): 117–155.

Sereno, Paul C.; Wilson, Jeffrey A.; Witmer, Lawrence M.; Whitlock, John A.; Maga, Abdoulaye; Ide, Oumarou; Rowe, Timothy A. (2007-11-21). "Structural Extremes in a Cretaceous Dinosaur"PLOS ONE2 (11): e1230.


Wednesday, February 12, 2020

Prehistoric Dinosaur Mimics

Mimicry is one of the most well-recognized forms of defense in the animal kingdom.  For those who need a refresher, mimicry is defined in biology as the very close resemblance of one organism, or part of an organism, to a different species of organism.  This is usually meant to trick would-be predators.  Common examples are caterpillars with patterns to look like large snakes, or butterflies with spots on their wings that make them look like owls.

A snake!  Actually it's just an upside-down caterpillar.  But frogs, lizards, and songbirds, frequent predators of caterpillars and prey to snakes, might hesitate when attacking this it. Photo: Andreas Kay

How likely do you think mimicry in prehistoric animals was?  Given how vast biodiversity is, I have no doubt that some sort of mimicry took place millions of years ago, but to what extent? And in which species?  Did large non-avian dinosaurs mimic?

Recently on social media I have noticed a slight trend in artists posting images of ceratopsians and hadrosaurs with coloration on their frills and crests meant to mimic the faces of tyrannosaurs.  At first, this might seem like a plausible defense strategy.  Tyrannosaurs, from what we know, were usually the top predators in any community they inhabited during the late Cretaceous.  In fact, it is often said that the only animal that a tyrannosaur would ever need to fear was a larger tyrannosaur!

An adult Lambeosaurus already doesn't have much to fear from any of the other creatures that would be scared off by a tyrannosaur anyway.




But that phrase is exactly why I am highly skeptical of this being a likely mimic strategy.  The sight of a tyrannosaur would no doubt send every other animal in the area running...except for possibly another tyrannosaur.  The problem with this on a ceratopsian or a hadrosaur is the fact that we know tyrannosaurs were the main predators of both of these kinds of dinosaurs.  An adult Chasmosaurus or Lambeosaurus already doesn't have much to fear from any of the other creatures that would be scared off by a tyrannosaur anyway.  Ironically, their only real predator is the only one that wouldn't be scared by it.  In some cases they may even attract the very predator they would hope to repel!

There's two reasons why a tyrannosaur might be outright drawn into the image of its own species.  The first is like many vertebrates, tyrannosaurs needed to find a mate in order to reproduce.  So it is likely that at least during certain parts of the year, a tyrannosaur would mistake a mimicking Lambeosaurus as a potential partner only to discover that it's a meal upon closer inspection.

It is likely that at least during certain parts of the year, a tyrannosaur would mistake a mimicking Lambeosaurus as a potential partner only to discover that it's a meal upon closer inspection.

The second reason is that we have substantial fossil evidence that at least some tyrannosaurs engaged in intraspecies combat, specifically in the form of biting each other on the face, thanks to healed teeth marks in some skulls.  Plus, territorialism is very common across many kinds of large meat-eaters in general so this makes sense.  So a tyrannosaur might see a ceratopsian with its likeness on its frill, mistake it for a rival, and charge in for a challenge only to discover that it is once again a meal upon closer inspection.

A tyrannosaur might see a ceratopsian with its likeness on its frill, mistake it for a rival, and charge in for a challenge only to discover that it is once again a meal upon closer inspection.

Lastly, and perhaps this is best reason why visual mimicry wouldn't work for repelling tyrannosaurs, is the fact that we have very strong evidence that tyrannosaurs had excellent senses of smell.  So even though these plant-eating dinosaurs would look like a fearsome predator, a tyrannosaur would be able to identify them as what they truly were before they even saw them assuming the wind was blowing in the right direction.

That being said, I highly doubt mimicry in large plant-eating dinosaurs of large meat-eating dinosaurs (their direct predators) was very likely in real life.  And to be fair, most of the artists I witnessed producing these pieces admit that it was just for fun, which is fine.  However, it still got me thinking a lot about mimicry in general and I decided it was an interesting enough subject to cover for this post.

So I wonder if there was a more likely form of mimicry in prehistoric dinosaurs.  To explore this further we need to look at mimicry today and how it works.  In general, if an animal exhibits mimicry to ward off predators, it will typically mimic the likeness of an animal at least two levels above them on the food chain.  This way, they are mimicking a predator that will almost definitely scare away their direct predators, but at the same time the higher predator they are mimicking usually won't view them as a regular food source, as well.

A butterfly mimicking an owl is specifically doing so to scare away smaller birds, which themselves are regularly preyed on by real owls.

For example, butterflies that mimic the face of an owl with yellow spots on their wings are specifically trying to scare away their main predator, smaller birds, which themselves are regularly preyed on by real owls.  At the same time, real owls very rarely, if ever, eat butterflies.  So the butterfly isn't really taking a risk looking like an owl.

In general, if an animal exhibits mimicry to ward off predators, it will typically mimic the likeness of an. animal at least two levels above them on the food chain.

So back to the idea of mimicking a tyrannosaur.  I came up with a fun little idea of a much smaller plant-eater that may not find itself in direct contact with tyrannosaurs as often due to it living in more dense underbrush, but does have to worry about being preyed on by smaller predators, like dromeosaurs. So what if they had some sort of mimicry of a large, toothy monster on their bodies?  I'm not saying it's a true hypotheses of mine, but it's less unlikely than the imagery on a larger plant-eater.

Smaller plant-eating dinosaurs may not have been regularly be preyed on by adult tyrannosaurs.  So looking like one may have helped it survive attacks by more direct predators, like dromeosaurs.  

Another form of less specific mimicry is coloration to form generalized eyespot patterns that don't particularly mimic any specific species.  This is actually already commonly depicted by paleoartists, especially when it comes to ceratopsian frills.  Bold, circular patterns to give the illusion of eyes is common in a lot of animals alive today.

Are these Butterfly fish looking at you?  Which end is the head and which is the tail? Photo credit: Chris Huss

The first way this can help an animal is to draw attention from the place where the real eyes are, the head.  This can throw a predator off when attacking, and might save the animal's life.  Being directly chomped on the head is usually a death sentence.  But being bitten elsewhere might be a better chance of survival.

The second way general eyespots can help an animal is to suggest to a predator that it is being watched when in fact, it very well may not be.  A ceratopsian with eyespots could be completely oblivious as it munches away on plants while a tyrannosaur is taking a few extra seconds deciding if it's even worth it to try and ambush.  In nature, a few seconds can be more than enough time for the prey animal to realize it is being stalked and give it a start in running away or defending itself.

A dinosaur sporting eyespots could be completely oblivious while a tyrannosaur is taking a few extra seconds deciding if it's even worth it to try and ambush.

Mimicry is a widely successful form of defense that can be observed across many kinds of organisms alive today.  It was very likely also utilized in prehistoric species, but to what extent and in which species is still mostly a mystery.  What do you think?  Do any other kinds of prehistoric animals seem likely candidates for mimicry?


References

Bona, Sebastiano De, et al. “Predator Mimicry, Not Conspicuousness, Explains the Efficacy of Butterfly Eyespots.” Proceedings of the Royal Society B: Biological Sciences, vol. 282, no. 1806, 2015, p. 20150202.

Peterson, J. E.; Henderson, M. D.; Sherer, R. P.; Vittore, C. P. (2009). "Face Biting On A Juvenile Tyrannosaurid And Behavioral Implications". PALAIOS. 24 (11): 780–784. Bibcode:2009Palai..24..780P. doi:10.2110/palo.2009.p09-056r. Archived from the original on August 11, 2013.

Tanke, Darren H.; Currie, Philip J. (1998). "Head-biting behavior in theropod dinosaurs: paleopathological evidence (PDF)Gaia15: 167–184. Archived from the original (PDF) on 2008-02-27. [not printed until 2000]

Witmer, L. M.; Ridgely, R. C. (2009). "New Insights Into the Brain, Braincase, and Ear Region of Tyrannosaurs (Dinosauria, Theropoda), with Implications for Sensory Organization and Behavior". The Anatomical Record292(9): 1266–1296.

Sunday, February 9, 2020

Globidens: Beast of the Week

This week we will look at a prehistoric sea monster with teeth unlike any other.  Check out Globidens!

Globidens was a mosasaur, a kind of meat-eating marine lizard, that was about twenty feet long from snout to tail.  Fossils of different species within the genus have been found in the United States, Morocco, Angola, and Indonesia which flourished throughout the late cretaceous period from 85 to 66 million years ago.  The genus name, Globidens, translates to "Globe Teeth" because of its unusual sphere-shaped teeth.

Globidens phosphaticus cracking the shell of an ammonite.  Watercolor life reconstruction by Christopher DiPiazza.

Globidens is most known for its teeth, which were unlike those of any other mosasaur, most of which had cone-shaped teeth, like Tylosaurus, or blade-like teeth, like Platecarpus.  Globidens, on the other hand, had teeth that weren't sharp at all, but had wide bulbous crowns.  The skull looks like this beast had a mouth full of big, round mushrooms growing out of its jaws!  These blunt, teeth were ideal for crushing hard objects, leading paleontologists to hypothesize that it specialized in hunting prey with shells, like mollusks, crustaceans, and possibly even turtles.  In addition to the teeth, Globidens had a robust lower jaw, which would have been controlled by enormous muscles in life, giving it an extremely powerful bite.  Paleontologists suspect it may have had one of the strongest bite forces of any mosasaur, despite not being the largest-bodied member of the family.  After the discovery of it's teeth, a Globidens skeleton with shell fragments of large prehistoric bivalves in the stomach cavity proved the already strong hypothesis of its preferred food.

Skull of Globidens phosphaticus, which lived in what is now Angola, on display at the Smithsonian National Museum of Natural History in Washington D.C.

Other than the jaws, Globidens had other notable features.  Its snout was relatively short for a mosasaur.  A shorter snout, allows for a higher concentration of pressure when biting down, so this was likely another adaptation that supported its strong biting pressure.  The eye sockets were large and housed wide scleral rings (a disc-shaped bone that supports the eyeball in life) which supports the idea that this creature had good vision, and likely could see well in low light, like the seafloor where much of its prey would have dwelled.  Lastly, Globidens' bones were dense which this is another adaptation of an animal that wants to be able to dive deeper underwater.  In addition to wanting to dive into deeper waters to find its preferred food, Globidens would also be avoiding other species of mosasaurs that it shared its habitat with that were even larger than it, like Tylosaurus, which was more of a surface predator.

Amazingly, Globidens wasn't the last lizard to evolve strange round teeth for crushing shells.  A kind of lizard alive today, called a Caiman Lizard (genus Dracaena) native to central and South America, has teeth almost exactly like those of Globidens, just on a smaller scale, which it uses to crush the shells of snails.  Even more interesting is the Caiman Lizard is from a totally different family of lizards from mosasaurs, so the shell-crushing teeth evolved convergently.  Evolution is amazing!

The modern day Caiman Lizard independently evolved similar feeding adaptations to that of Globidens because it also eats hard-shelled prey. (photo credit: Reptiles Magazine)

That is all for this beast!  Can you think of any other animals (alive or extinct) that have similar crushing adaptations?  As always feel free to comment below!

References

LeBlanc, Aaron; Mohr, Sydney; Caldwell, Michael (2019). "Insights into the anatomy and functional morphology of durophagous mosasaurines (Squamata: Mosasauridae) from a new species of Globidens from Morocco". Zoological Journal of the Linnean Society.

Martin, J. E. and Fox, J. E. 2007. Stomach contents of Globidens, a shell-crushing mosasaur (Squamata), from the Late Cretaceous Pierre Shale Group, Big Bend area of the Missouri River, central South Dakota. Geological Society of America Special Papers, 427:167-176.

Massare, J. A. 1987. Tooth Morphology and Prey Preference of Mesozoic Marine Reptiles. Journal of Vertebrate Paleontology, 7(2):121-137.

Russel, Dale (1975). "A new species of Globidens from South Dakota, and a review of globidentine mosasaurs". Fieldiana Geology33 (13): 235–256.

Friday, January 31, 2020

Prehistoric Beast at the Smithsonian National Museum of Natural History: Deep Time

Even though I was born and raised in Northern New Jersey, I have always had a close relationship with Maryland and Washington D.C. because a large part of my family lives there.  That being said I have been to the Smithsonian National Museum of Natural History several times over the years.  I wrote about it here back in 2016 and then again more recently for its seasonal exhibit, The Last American Dinosaurs.  This past June, however, the main fossil hall was opened to the public again after being renovated and I was finally able to visit it for myself.  Let's check it out!

The David H. Koch Hall of Fossils takes place in an open hallway on the main floor of the museum.  Large dinosaurs are of course a focal point, but the overall exhibit is meant to explore the concept of deep time, and all the different life forms that have existed and what they can teach us, not just the most popular ones.  A popular question is "How does paleontology benefit humanity?" Personally, I find this question a bit egocentric and closeminded.  Nature shouldn't be directly paying us in order to be valued.  Despite this truth, studying deep time does in fact provide us with valuable information to better ourselves.  This exhibit does a good job addressing this question by forcing us to look at prehistoric animals in new ways, their direct relationships with life today, and of course, the concept of extinction.  Understanding extinctions from the past can tell us information about current extinctions (of which there are unfortunately many occurring) and how we can best prevent them. The earth has changed climate patterns many times throughout history and resulted in many observable extinctions in the fossil record, but never as rapid as the one caused by humans now.  Looking back and seeing the consequences of catastrophic events in the past can give us insight on how to best combat the crisis that is currently happening.

Diplodocus (left) and Camarasaurus (right) re the two largest dinosaurs on display.

The first fossil you see when approaching the exhibit is the first ever discovered specimen of the beloved spike-tailed dinosaur, Stegosaurus.  This is a wonderfully complete specimen, showcasing all the plates, the tail spikes, and even the bony throat armor, which many people don't realize this iconic dinosaur had.  Because this specimen was partially disarticulated, however, it posed as a sort of puzzle for paleontologists as to exactly how the plates were arranged and how the animal stood and carried itself in life for a long time.  The specimen is right there in the hallway at eye level behind a wall of glass so visitors can get very close to it and see all the details and textures on the bones.

Stegosaurus holotype on display.

The other side of the hall is the museum's active paleontology lab.  You can watch employees and volunteers behind glass prepping fossils for study or display.  This is a really great feature for educational purposes.  So many kids go into museums with dreams of working with real fossils one day.  This gives them a chance to see up close what that really entails.  It also is a chance for people of all ages to see that fossils aren't simply yanked out of the ground, perfectly complete and ready to display.  Fossils are often encased in excess rock on all sides from being taken out of the field and require sometimes years of careful work to remove all that rock until the fossil is ready to be studied. Sometimes we can't even identify what creature a fossil is from until much or all of the prep work is done!

One thing I always appreciated about the Smithsonian was that it makes a point to give you a sense of what it might have been like to actually step into the prehistoric environments from all sides by surrounding you with all kinds of elements, not just the biggest, most charismatic animals.  This newest version of the fossil hall was no exception.  There are many displays that show you what the smaller animals, invertebrates, and plants would have looked like from the same community.

The Smithsonian has lots of exhibits starring smaller fossil organisms that would have coexisted the more charismatic giants everyone already knows and loves.

Another great feature of this exhibit is the presence of several free-standing miniature dioramas of various reconstructed environments across time.  These are complete with scale models of land formations, bodies of water, plants, and of course the animals that are featured in the environments.  The fact that they can be viewed from all sides lets more visitors enjoy them at once, and also makes small details more visible.

Miniature diorama showcasing early Permian life.  Note how guests can view from both sides.

Of course the big skeletons of dinosaurs draw the most attention regardless of all the other wonderful features included in this exhibit.  That being said, many of the most iconic species are posed showcasing behaviors that are less common in art and other popular media, forcing visitors to think of their favorite prehistoric beasts in ways they never have before.

A perfect example of this is the Smithsonian's Allosaurus.  Allosaurus is widely known as a predatory dinosaur, often depicted attacking/killing/threatening/eating other dinosaurs.  It's hard not to with teeth and claws like that!  This Allosaurus, however, is posed in a resting position, tenderly guarding a nest of eggs.  Dinosaur eggs and families are no stranger to museum exhibits, but it's hardly ever the top predators who are shown tending to them.  This mount forces us to remember that ALL dinosaurs, even the most fearsome hunters, started tiny and helpless.

Parent Allosaurus.

Another unusual mount that is much more dynamic is their Stegosaurus in the process of knocking the meat-eater, Ceratosaurus, to the ground with its tail.  Just like the case with the nesting Allosaurus, this is a scenario that likely could have happened but is not often portrayed.  People naturally expect the predator to win the fight, even though they likely didn't more than half the time.  Being a predator is dangerous because it forces an animal to confront and kill other animals or starve trying.  Other animals don't want to be eaten so they do everything in their power to escape, or in the case of the Stegosaurus, fight back with formidable defensive weapons.  It is because of this that predators of most species typically have higher mortality rates.

Stegosaurus in the process of knocking over Ceratosaurus.  Notice all the bony throat armor included on this mount.

For those out there who just can't survive without seeing some good old fashioned predatory carnage, look no further than the Smithsonian's mount of the world's favorite carnivore, Tyrannosaurus rex.  T. rex is posed standing over a defeated Triceratops', separating the poor horned dinosaur's head from the rest of its lifeless body.  This scene was inspired by relatively recent studies regarding unhealed Tyrannosaurus bite marks on the frills of Triceratops skulls, suggesting that the meat-eaters would pull the heads off their ceratopsian victims in order to get to the neck meat when feeding.  The same Triceratops skeleton was previously displayed in a walking position in the previous American Dinosaurs exhibit as well as the main fossil hall before renovations.

Tyrannosaurus with Triceratops.

Nestled in the heart of all these massive dinosaurs is a beautiful section on the relationship between modern birds and other dinosaurs.  It points out the fact that birds ARE dinosaurs, as well as going into how they achieved flight.  There is a gorgeous mechanical model of a bird suspended from above guests that provides a moving visual demonstration of the mechanics of dinosaur flight compared to that of pterosaurs and other flying animals.

Say it with me.  BIRDS. ARE. DINOSAURS.

There is of course so much more to see in this hall I just can't fit into one post.  Of course the best way to enjoy this exhibit is seeing it in person.  If you're ever in the DC area, make the Smithsonian your first priority!

References

Kaplan, Matt. “How to Eat a Triceratops.” Nature, 2012, doi:10.1038/nature.2012.11650.

Monday, January 20, 2020

Ceratosaurus: Beast of the Week

This week we shall be looking at a popular meat-eater with some truly unique features.  Enter Ceratosaurus!

Ceratosaurus nascornis life reconstruction in watercolors by Christopher DiPiazza.

Ceratosaurus was a meat-eating dinosaur that lived during the late Jurassic period, about 150 million years ago, in what is now the United States, specifically Utah and Colorado.  Bones thought to be from Ceratosaurus have also been unearthed in Portugal.  As an adult it would have measured about twenty feet from nose to tail but one specimen suggests it may have grown even larger in some cases.  The genus name, "Ceratosaurus" translates to "Horned reptile/lizard" and refers to the horn-like protrusions on the animal's snout and over its eyes.

Bronze cast of a Ceratosaurus skull on display at the Mesalands Dinosaur Museum in Tucumcari new Mexico.

The most notable feature about Ceratosaurus is the presence of its "horns".  These bony structures aren't really horns as much as they are crests, however, since they were extremely thin and delicate.  Whereas the horns of certain other dinosaurs, like Carnotaurus, were robust enough to have been effective weapons in life, the "horns" of Ceratosaurus would have easily broken if they were used in any sort of violent activity.  They were most likely used for display within the species, rather than for physical fighting.  Keep in mind that these crests would have had a layer of keratin growing over them, so they might have appeared even longer and possibly even a slightly different shape in life.  A juvenile Ceratosaurus skeleton that was discovered showcases proportionally smaller crests on its skull, supporting the idea that they were for display, possibly helping individuals within the species to identify others as sexually mature or not.

Juvenile Ceratosaurus skull on display at the North American Museum of Ancient Life. Note the smaller crests on the nose and above the eyes. (Photo credit: Jens Lallensack)

The crests weren't Ceratosaurus' only unique feature.  This dinosaur also had a row of small bony plates, called osteoderms, running down the center of its back.  This is a feature common in certain groups of dinosaurs, like the thyreophorans, like Stegosaurus, but is extremely rare in theropods.  The exact purpose is a mystery, but we can make some educated guesses.  As with the head crests, these bony structures may have aided in display within the species.  Perhaps males had longer plates than females?  Perhaps they were absent in juveniles?  Maybe they helped camouflage Ceratosaurus slightly by breaking up its basic body shape?  We may never know for sure.

Neck of the Ceratosaurus skeleton on display at the Smithsonian National Museum of Natural History in Washington D.C.  I circled a group of the osteoderms in yellow.

Ceratosaurus' tail was particularly deep and flattened laterally. This lead some to hypothesize that Ceratosaurus may have been a decent swimmer and specialized in hunting aquatic prey. (although there is little other evidence that suggests this)  Ceratosaurus also had short, but fully functional arms each tipped with four fingers and three claws.

Lastly, Ceratosaurus had the longest teeth proportional to its body of any known dinosaur.  The teeth were curved and serrated, like steak knives.  They look to be ideal for slashing chunks of flesh from bone, rather than crushing armor and bone.  This is further supported by the fact that Ceratosaurus' lower jaw was rather thin, and therefore wouldn't have been capable of applying too much force or withstanding too much pressure before being injured.

Almost-complete(no arms!) Ceratosaurus skeletal mount on display at the National Museum in Washington D.C. 

Ceratosaurus bones have been found in the same formations as other, larger Jurassic meat eaters, like Allosaurus and Torvosaurus.  Most scientists agree that Ceratosaurus may have specialized in hunting a different kind of prey than its larger contemporaries, perhaps going after smaller animals, rather than giant sauropods and heavily-armed stegosaurs.  This is further supported by the fact that Ceratosaurus bones are particularly less common than most of the other dinosaurs known from the Late Jurassic of North America.  This could mean that Ceratosaurus typically dwelled in habitats slightly different from the rest of those dinosaurs where fossilization didn't take place as easily.

Sometimes I wonder what exactly prevented Ceratosaurus from existing close to the other megapredators of it's time...

They said it couldn't be done but I managed to make a cartoon merging Late Jurassic megapredators with Mean Girls.  It wasn't even that hard.

That's all for this week!  As always feel free to comment below!  Want to see a particular prehistoric beastie reviewed?  Let me know and I'll make it happen!

Works Cited

Carrano, M.T.; Sampson, S.D. (2008). "The Phylogeny of Ceratosauria (Dinosauria: Theropoda)". Journal of Systematic Palaeontology6 (2): 183–236.

Foster, John (2007). "Gargantuan to Minuscule: The Morrison Menagerie, Part II". Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 162–242. ISBN 0-253-34870-6.

Gilmore, C.W. (1920). "Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus". Bulletin of the United States National Museum 110: 1–154.

Marsh, O.C. (1884). "Principal characters of American Jurassic dinosaurs, part VIII: The order Theropoda". American Journal of Science 27 (160): 329–340.

Rowe, T.; Gauthier, J. (1990). "Ceratosauria". In Weishampel, D.B.; Dodson, P.; Osmólska, H. The Dinosauria. University of California Press. pp. 151–168. ISBN 0-520-06726-6.

Wednesday, January 15, 2020

The Paleontology Behind Pokemon: Part 2

Since the last time I talked about Pokemon on here many more interesting Pokemon have been created and added to the franchise, many of which are, indeed based on prehistoric animals.  In addition, there were many older Pokemon that I simply didn't have the space to cover in one post. (and I was made well aware of it in the comments section!) So after four years here is the sequel of the paleontology behind Pokemon! (If you don't know what Pokemon are, or haven't read the first post, you can access it here before reading this one.)

Read it?  Good!  Let's get started with part 2!

Lapras


Lapras is from the first generation of Pokemon to be released, and is a long-standing fan-favorite Pokemon design.  Although quite a few creative liberties were added, its general appearance is clearly based on a plesiosaur.  The wide body, four flippers, short tail, and long neck, are all telltale characteristics of this iconic group of prehistoric marine reptiles.  If anything, Lapras may have been more based on legends of lake cryptids, like the Loch Ness Monster, which are mostly based on people's visions of plesiosaurs anyway.  

Plesiosaurus skeleton on display at the London Museum of Natural History.

Unlike real plesiosaurs, Lapras carries its head upright in a swan-like pose most of the time, which was how plesiosaurs were depicted for a long while before more recently when paleontologists figured out they more likely held their necks horizontally in front of them.  Also, Lapras sports a turtle-like shell on its back, a horn in the middle of its forehead, and external ears like a mammal, which are all unique to it, and not to any real plesiosaur.  

Yanmega
Yanmega is the second life stage of the dragonfly Pokemon, Yanma.  Yanmega, however is probably based on the giant prehistoric insect, Meganeura, and not simply a bigger dragonfly, based on the name.  

Meganeura fossil.  This insect differs from modern dragonflies because the patterns on its wings are less complex.

Despite this, Meganeura, wasn't actually a dragonfly, but a different kind of insect that was similar, but still had a few different characteristics, setting it apart, like the structure of the wings.  It lived during the Carboniforous Period, about 300 million years ago, and the largest individuals had wingspans of over two feet.

Lileep and Cradily


Lileep and its evolution (second life stage) Cradily are based on prehistoric crinoids.  Crinoids are a group of invertebrates related to sea stars, also known as sea lilies, that attach themselves to rocks and feed on particles of food that come to them via their feathery appendages.  

Fossil crinoids.

Despite being animals, they superficially look like underwater flowers. (and the Pokemon based on them even have the grass type)  Fossils of ancient crinoids date back to the Ordovician Period, 485 million years ago.

Tirtouga and Carracosta


Tritouga and its evolution Carracosta are fossil Pokemon, which means that in the Pokemon game a fossil needs to be dug up, then revived into a living Tirtouga, in order to have one.

Archelon skeleton on display at the Canadian Museum of Nature

Because of this they are most likely based prehistoric sea turtles, like Archelon, and not simply a generic modern sea turtle.  Sea Turtles thrived during the Cretaceous Period alongside dinosaurs, pterosaurs, and other marine reptiles, like plesiosaurs and mosasaurs, that are now extinct.  

Dragapult


Dragapult and its earlier forms are the among the newest wave of Pokemon to be added to the franchise.  They are dragon and ghost typing, which at first confused me.  I get that a dragon type could be literally anything remotely reptilian or amphibious looking, which certainly fits here, but the ghost I didn't quite understand.  I noticed it had a transparent tail and floated around like a ghost, but anyone who knows a lot about Pokemon, understands that very few of the designs are truly random, and usually have a deeper, not always obvious inspiration.  For sure there had to be a more specific meaning than simply "floaty ghost dragons are cool".  Then I read the official flavor text in the game for the first stage, Dreepy, and I realized what it was.  

"After being reborn as a ghost Pokemon, Dreepy wanders the areas it used to inhabit back when it was alive in prehistoric seas."

This is a Pokemon based on the concept of long dead prehistoric creatures coming back as ghosts.  Now look at the shape of this guy's head...

Diplocaulus skull on display at the American Museum of Natural History in New  York.

These guys are based on the prehistoric amphibian, Diplocaulus.  Diplocaulus lived during the Permian period, and is known for its wide, boomerang-shaped head.  Diplocaulus also would have had a tail that was flattened from side to side for swimming in fresh water which is also included in Dragapult's design.  (Although Diplocaulus would have swam in fresh water, not the sea.)  It's a wonderful model for a Pokemon design, and adding in the element of it being a ghost, nodding at the fact that this is a creature that normally wouldn't be alive in modern times, is very creative.  

Arctozolt and Dracozolt


The newest wave of Pokemon games also feature prehistoric Pokemon that need to be revived from fossils as well.  However, the game designers attempted to make it different this time by having players revive two of four available fossils together (one front end and one back end) to make one hybrid Pokemon.  This is a nod to the occurances of paleontologists occasionally accidentally assigning certain bones to the bodies of different species, creating a sort of "Frankenstein fossil" if you will.  The Pokemon designers exaggerated this point by purposefully making sure that each Pokemon that resulted from this method of revival looks as lopsided as possible.  

Velociraptor skeleton on display at the Dublin Zoo.

In the case of Arctozolt and Dracozolt, it appears the head and arms are from a small theropod dinosaur, possibly Velociraptor.  Dracozolt even has lightning bolt-shaped wings on the arms, which may be based on how Velociraptor and its relatives had primary feathers on their forearms in life.  The back ends are harder to pinpoint, but they're likely some sort of marine reptile, like an ichthyosaur, and a large dinosaur, possibly a thyreophoran.  

Arctovish and Dracovish



The other two Pokemon resulting from this method of revival have the same two back ends, but the head of a prehistoric fish, no doubt based on Dunkleosteus.  Dunkleosteus was a massive prehistoric fish from the extinct placoderm group of fish, which had bony plates covering their bodies.  Dunkleosteus didn't have teeth, but rather wide, blade-like sheets of bone forming a mouth that worked like a bear trap.  

Arctovish has the fish head on a marine animal body, which would in theory flow fine design-wise, but they made it so the poor Dunkleosteus head is upside down.  To my knowledge there have been no instances of any paleontologist accidentally completely flipping an animal's head in the final reconstruction, but there have been cases where certain skulls were initially a puzzle of exactly how they would have been held on the body, for sure.

Dunkleosteus skull on display at the Vienna Natural History Museum in Austria

As for Dracovish, one might argue that a Dunkleosteus head on a dinosaur body would be really cool, but the Pokemon designers must have really wanted it to look silly and less intimidating, so they stuck the head on the tip of the tail instead.  This might be nodding at the original reconstruction of the famous plesiosaur, Elasmosaurus, by Edward Drinker Cope, who wrongly placed the animal's skull on the wrong end in his first reconstruction, mistaking the long neck for a long tail.  

Edward Drinker Cope's original illustration of Elasmosaurus with the head placed on the wrong end.

That is all for this week!  I know there are certainly more Pokemon that are based on prehistoric beasts.  Can you list any below?  I may do a part three one day if there are enough!

References

Anderson, P.S.L.; Westneat, M. (2009). "A biomechanical model of feeding kinematics for Dunkleosteus terrelli (Arthrodira, Placodermi)Paleobiology35(2): 251–269.

Clarkson, E. N. K., 1979, Invertebrate Palaeontology and Evolution, 3rd Edition: London, Chapman and Hall, 434 p.

Dudley, Robert (April 1998). "Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotion performance". The Journal of Experimental Biology201 (Pt8): 1043–1050.

Friday, January 10, 2020

Interview with Paleontologist: Dana Ehret

Dr. Dana Ehret was born and raised ‘Down the Shore’ in Spring Lake Heights, New Jersey. His interest in paleontology started at a young age, when his dad and uncles would take him shark tooth collecting.  Dana attended Stockton University where he received a B.S. in Marine Biology. While at Stockton, Dana was mentored by paleontologist Dr. Roger Wood who introduced him to paleontology as a career and fossil turtles. Dana then attended the University of Florida where he received a M.S. in Geology with a minor in Wildlife Ecology and Conservation and his Ph.D. in Interdisciplinary Ecology. His Master’s work focused on growth and skeletochronology in extinct tortoises from the Nebraska Badlands, while his Ph.D. looked at the macroevolution of body size in the megatoothed sharks. Dana has worked as the Curator of Paleontology at the University of Alabama and is now the Assistant Curator of Natural History for the New Jersey State Museum. His research focuses on the evolution and taxonomy of lamniform sharks and turtles, particularly in the Eastern US.



Question 1: What was your earliest sign of interest in paleontology that you can remember? 

DE: I grew up in Spring Lake Heights, New Jersey and my parents were from Wall Township. Going back to the 1960s my family went fossil shark tooth collecting at Shark River Park. My uncles first took me when I was about 5 years old. I still have those teeth on my office desk! Finding prehistoric shark teeth in a river just down the road from my grandparent’s house was mind boggling!

My second memory was my grandmother. She drove a school bus and in the summers she would take special needs students to Princeton. Sometimes I would tag along and she would take me to the Princeton University museum. The Cervalces scotti skeleton on display there was the first fossil skeleton I ever remember seeing in person. It’s now at the NJ State Museum, where I work, so I see it every day!

Question 2: Did you have any professionals or family members who served as role models when you were younger? Do you still have any now?

DE: My family was VERY supportive of my interests but didn’t have any formal training in the sciences. I credit two elementary school teachers with fostering my love of science. First, my second grade teacher, Ms. Ardythe Wright. She taught me how to grow avocado trees from pits and gave me a deep respect for natural history. The second was Mr. Rich Muhlenbruck, my 7th and 8th grade science and history teacher. He was AMAZING! We are still good friends and go to lunch whenever we can get together.

Growing up, I never dreamed that I could actually be a paleontologist. I went to Stockton University (then The Richard Stockton College of New Jersey) for undergrad and one of the first classes I took was a general studies ‘Dinosaurs’ class taught by Dr. Roger Wood. He was also assigned as my undergrad advisor. During our first meeting he asked what I wanted to do with my life and I said, “I’d love to be a paleontologist but that’s what old guys on tv do.” He laughed and said, “If that’s what you want to do, then do it.” 13 years of college later, I did it.


Helping tag a Nile Crocodile in St. Lucia, South Africa

Question 3: Was there anything you did or learned as you were on your way to your current career that you feel got you to where you are? By this I mean any sort of field experience, a class, networking with the right people, or possibly something different or all three?

DE: I was VERY lucky with my school choices. Undergrad work and field trips really prepared me for my career. I credit Roger Wood and Dr. Margaret Lewis at Stockton University for really giving me a leg up as an undergraduate student. Roger comes from paleontology ‘royalty’, both his father, Albert Wood, and his uncle, H.E. Wood were well-known and respected paleontologists. I did an undergrad research project with Roger on fossil turtles from the Cretaceous of Wyoming and he took me to the Academy of Natural Sciences, the American Museum of Natural History, and the Smithsonian and taught me the proper research methods.

Question 4: Is the field of paleontology different now than from when you started as far as you can tell?  What would your advice be to anyone trying to make a career in paleontology (or science in general for that matter) now?

DE: YES!! I was very lucky with my career trajectory. I went to Stockton to study Marine Biology and met two AMAZING paleontologists that took me under their wing. For graduate school I was accepted into the Geological Sciences program at the University of Florida without an advisor. I was very fortunate to have Dr. Bruce MacFadden accept me as his Masters student after I started. If I had to do it all over again, there is NO way I would’ve done it the same way! These days, I feel that undergraduate students really need to reach out to potential graduate advisors well in advance. My first couple of SVP meetings, there were very few undergrad presentations (and they were all posters.) Today, I see AMAZING talks by undergrad researchers and I’m just blown away! When I talk to undergraduate students, my advice is: get involved! Volunteer, find internships, do a senior thesis project! Anything you can do to set yourself apart. I was lucky enough to be a co-author on a paper as an undergrad because I did an internship and I definitely think it set me apart.


Showing visitors fossils at the Alabama Museum of Natural History for National Fossil Day

Question 5: What was or is your favorite project so far?  Would you be able to tell us about some of your current projects?

DE: My favorite, hands down, was my work on white shark evolution. This was the majority of my PhD work at the University of Florida. I was honored to be asked to describe an extinct species of white shark from the Miocene of the Pacific Basin, Carcharodon hubbelli. It was based on a set of articulated jaws, teeth and vertebrae from Peru that had been in the private collections of Dr. Gordon Hubbell, but donated to the Florida Museum of Natural History. I described the anatomy, growth and paleobiology of this shark, took two trips to Peru and had three papers (two featured articles) come out of the research. I also survived an 8.0 earthquake during one Peruvian trip!

As for current research, my ‘pet project’ now is a new genus of Cretaceous sea turtle from Tennessee. This new turtle is VERY weird and I have a very fun scientific name picked out! I can’t tell you anymore quite yet.


Studying the fossilized jaws of the late Miocene shark, Carcharodon hastalis, at the Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos in Lima, Peru

Question 6: Do you have a favorite destination when it comes to fossils?  Why?

DE: I have to say, I worked at the University of Alabama/Alabama Museum of Natural History for five years. The late Cretaceous outcrops in Alabama are AMAZING!! The museum owns 140 acres of Campanian chalk called the Harrell Station Paleontological Site. The region has produced fossils including sharks, fishes, mosasaurs, dinosaurs, pterosaurs, and lots of invertebrates. The southeastern Gulf Coast of the United States is an overlooked source of amazing fossils.

Searching for late Cretaceous fossils with students at the Harrell Station Paleontological Site in Dallas County, Alabama

Question 7: A popular image of paleontologists is that they are constantly out in the field digging up fossils, which is true to an extent.  What people don’t realize sometimes is that a lot of paleontology work is conducted in a lab as well.  In your experience, how much of your projects (in general) take place in the field, and how much are in the lab?

DE: While collecting fossils is fun and exciting, you then need to prepare, catalogue and describe the specimens. Even though probably 75% of my job duties are in a museum; in the lab, doing outreach, designing exhibits, working on papers, I try to get out in field at any chance I get. Many times I go after work, on weekends and on vacation. When people ask me what I do for fun, I say: Go fossiling! While my job title is Asstistant Curator, paleontology is also my passion. Paleontologists typically have a ‘field season’ which is typically in the spring/summer months. The rest of the year is spent writing, prepping, cataloguing, etc. I would also argue that outreach is an essential part of our field. I’m very, very active on social media, giving talks, working in our public lab, etc.


Question 8: You are most known for your work on turtles and sharks.  Did you choose these subjects for your work or did it “choose you” in a sense?

DE: Most of my colleagues that study both fossil and living turtles can trace their love of turtles back to their earliest memories. My background in turtles came from my undergraduate advisor, Dr. Roger Wood. Roger is a legendary turtle researcher, having described arguably the largest turtle ever, Stupendemys geographicus. When I arrived at the University of Florida, Dr. Bruce MacFadden had a project involving fossil tortoises and I was a perfect fit. My background in turtle conservation also lead to many other seasonal jobs in state and federal agencies. I always joke that I became interested in fossil sharks for ‘the money’. Dr. MacFadden had an NSF grant to study evolution of ‘Megalodon’ and the megatoothed sharks and needed a PhD student. I was available, and he and I worked well together. My background in Marine Biology and my early interest in fossil sharks made me a natural fit!


Studying a female Great White Shark, Carcharodon carcharias, at the Kwazulu Natal Sharks Board, South Africa

Question 9: Is there a subject you’d like to work on that you have not yet?

DE: I like to joke that I want to cover as many taxonomic groups as possible in my career. But I definitely recognize that I specialize in certain groups of organisms and cannot be an expert in all groups. Thus far I’ve been an author or co-author on papers and research including fossil sharks, turtles, pterosaurs, lungfishes, toothed birds, mosasaurs and even rudistid clams. I’d like to dip my toe into Appalachian dinos at some point though.


Dana posing with Ornithomimus at the New Jersey State Museum in Trenton, New Jersey.

Question 10: Do you ever get criticized on any of your work?  How do you handle it?

DE: Of course! That is how science works! One proposes a hypothesis and puts it forward for others to test. I would say the most controversial idea I have proposed in a paper was reassigning ‘Isurus’ or ‘Cosmopolitodushastalis, the broad toothed ‘mako’, to the genus ‘Carcharodon’. Like most people, it can be tough to be criticized, but scientists are mostly respectable and that is how it works. Peer-review to be heart-wrenching when you get a bad review. But at the end of the day, I remember that science is always about questioning and testing the ideas proposed by others. When I review manuscripts I keep in mind that harsh comments can really hurt and I always approach my reviews with sensitivity.
  
Question 11: A common idea is that paleontology is just a “for fun” science, with no real impact or noticeable affect that helps the world.  Do you think paleontology has a bigger part to play to than this?  How?

DE: Of course it does! As a grad student (along with my fellow lab members) we used to practice talking to the public about our research and why it is important. I always include the importance of our work in my talks as well. Why is studying giant, extinct sharks important? Well….. by studying fossil sharks and how they respond to changes in climate, food resources, ecology, etc we can better understand and model what will happen to living species in the future. We are in an unprecedented time of drastic climate change. By learning more about how organisms responded to drastic, sudden changes in their environments through time, we can model how animals may or may not react going forward.

Question 12: Who was the first paleontologist you met?  How was that interaction?

DE: I was REALLY lucky!! As a freshman in college I had Dr. Roger Wood as a professor and advisor. By the time I was a junior in college I knew Dr. Margaret Lewis and Dr. Albert Wood. During my senior year of undergrad I had met Drs. Ted Daeschler (Academy of Natural Sciences) and Gene Gaffney (American Museum of Natural History). With regards to Roger Wood, I think we hit it off right away. He was approachable and easy to talk to. As I mentioned previously, Roger really propelled me on my career path!

Question 13: What is your favorite prehistoric animal?  Was it different when you were younger?

DE: Stegosaurus is my all-time favorite prehistoric animal and it hasn’t changed since I was little. I REALLY wanted to work on stegosaurs in grad school. When I got to the Univ. of Florida and first met with Dr. Bruce MacFadden he asked me, ‘What do you want to work on” and I replied, ‘Dinosaurs’. After he stopped laughing he said, NO! Florida has no dinosaurs. In hindsight, I am very happy with my career path.

Stegosaurus in watercolors by Christopher DiPiazza

Question 14: If you could use a time machine to go back and pick only one prehistoric animal to bring back from history and observe alive and in person, which would it be and why?

DE: That’s easy, and it isn’t prehistoric. The Thylacine! Research and news these days are focused on bringing back mammoths or creating dinosaur chickens via reverse genetic engineering. But if we can’t protect and keep the living species of elephants safe, why bring back ones that went extinct thousands of years ago?  The Thylacine went extinct in the 1930s and it was likely due to humans. Think about it, a marsupial wolf!! A large carnivore with a pouch!! There are many taxidermied specimens and skins in collections around the world, this is doable!

Question 15: Back to the time machine.  This time you can go back to any place and time period and have a look at what the environment was really like.  Which one would you pick and why?

DE: I’m sure a lot of my colleagues would say the Cambrian Explosion, to see all of the wild innovations that organisms were trying out. But not me, the Miocene of Peru and Chile, what we know as the Pisco Formation today would be my choice. What a time! Giant sperm whales (Livyatan melvillei), sharks (Carcharodon hubbelli), whales with walrus-like tusks (Odobenocetops), sloths that swam in the ocean and ate sea grasses (Thalassocnus)…. WOW! The environment was teeming with amazing creatures (I just named a few) and highly productive.

Question 16: Which is your favorite museum?  Why?

DE: Collections-wise I’m biased, the Florida Museum is amazing! As a biologist and paleontologist the Herpetology, Ichthyology and Paleontology collections combined are unparalleled. This museum is a national treasure, both in terms of collections and staff. Exhibit-wise, the American Museum is my favorite. The cladistic approach to fossil life along with the most amazing specimens is my go to museum. I’ve taken my nephews multiple times and subjected them to my own personal tours!

Question 17: What hobbies do you have?  (Don’t have to be paleo-related.)

DE: Where to begin? I am a COLLECTOR! I started working on cars when I was 13 years old. I have a 1970 Dodge Dart, which I’ve owned for 20 years. But I also helped restore a 1963 Pontiac LeMans convertible with my dad before that. I’m also a motorcycle enthusiast and own two bikes. Another hobby is music. I LOVE going to shows! I play some banjo (clawhammer-style), and have some beautiful instruments. I am also a HUGE vinyl collector. I have close to 2000 LPs, 1000+ 45s and am now getting into 78s. When I’m not collecting fossils you’ll see me at flea markets and yard sales throughout New Jersey!


Dr. Ehret entertaining the idea of growing antlers like the famous "Elk-Moose" on display at the New Jersey State Museum.

Thank you Dr. Ehret!  If you are ever in New Jersey, make a trip to Trenton and you might see Dr. Ehret in the fossil labs.  Farewell until next time!