Tuesday, March 21, 2017

Livyatan: Beast of the Week

This week we will be voyaging back to the Miocene to observe an amazing whale.  Make way for Livyatan melvillei!

Livyatan was a large, toothed, whale that swam in oceans that covered what is now South America and Australia (likely most of the southern hemisphere given that range) during the Serravalian stage of the Miocene epoch, between thirteen and twelve million years ago.  However, teeth that appear to be from Livyatan, found in Australia are dated at only between five and six million years old, pushing this animal's success much further through time. (If it is, in fact, the same genus, and if not it's still from an extremely close relative.)  Only teeth and parts of the skull have been found, but based on this, experts have estimated the animal's body length to have been between forty four and fifty seven feet long from snout to tail.  The genus name is the Hebrew spelling of the word, Leviathan, which was an enormous sea monster from biblical mythology.  The species name, melvillei, is in honor of Herman Melville, the author of the classic novel, Moby Dick...which is about a huge whale...in case you didn't know.

Livyatan immobilizing a young megalodon shark.  Painting by Christopher DiPiazza.

Livyatan was in the same major family of whales as the modern Sperm Whale.  Sperm whales (which Moby Dick was based on) are the largest living toothed whales.  However, they only have teeth on the lower jaw.  Sperm Whales eat almost exclusively giant squid.  Unfortunately we don't know exactly how they hunt because a Sperm Whale has never been observed in the act due to the fact that they dive down too deep, where the squid live, for us to observe the hunting behavior.  We know large squid make up most of their diets, however, because humans used to hunt Sperm Whales for their oil and during dissection/butchering, squid have always been found upon cutting open the stomach.  We also see scars and marks from giant squid tentacles on the faces of many Sperm Whales from their prey fighting back before being consumed.


Livyatan, on the other hand, despite being a close relative to Sperm Whales, may not have behaved, let alone, hunted the same way as their modern family members.  One very striking difference is that Livyatan had proportionally larger, more robust teeth, and a full set of them at that, on the lower and upper jaws.  Some of these teeth measure fourteen inches long!  This suggests it was not a squid specialist.  The fact that the teeth are so large and thick, points to Livyatan being more of a hunter of larger, more general prey that it would utterly pulverize via monstrous bites.  This makes sense, since we know Livyatan coexisted with plenty of other large sea creatures, including seals, sea lions, sharks, dolphins, and slightly smaller whales.  That's right, Livyatan, may have been a hunter of other whales!  (Which isn't unheard of. Orcas do it all the time.)   I find it worth noting that Carcharodon megalodon, (the giant predatory shark that is most certainly NOT still alive today, despite what Discovery Channel's idiotic shows suggest) was a contemporary of Livyatan's.  It is likely that the two were competitors, being similarly-sized predators.  They may have even preyed on each other depending on the circumstances!

Cast of Livyatan's skull on display at the Museo di Storia Naturale e del Territorio, in Italy.

The rest of Livyatan's skull was shaped similarly to that of a modern Sperm Whales.  This suggests that in life it had a large mass of soft tissue taking up most of the front of it's head, called a spermaceti organ.  This body part is full of oil and fat that helps whales use echolocation to navigate underwater.  Because of this it is likely Livyatan could do the same.  It also probably used complex vocalizations to communicate to members of its own species, as well.

I did this quick sketch just to show how much of a whale's head can be soft tissue compared to the skull.  The Sperm Whale's (pictured on the left) iconic rectangular profile is due to soft tissue mostly. (I actually botched the Sperm Whale's profile.  The shaded blue soft tissue part should go beyond the tip of the jaws even.)  It is likely, judging by the skull, that Livyatan, pictured left, had something similar. 

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

References

Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; de Muizon, Christian; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle (1 July 2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru Nature466 (7302): 105–108. 

Norris, K.S. & Harvey, G.W. (1972). "A theory for the function of the spermaceti organ of the sperm whale". In Galler, S.R; Schmidt-Koenig, K; Jacobs, G.J. & Belleville, R.E. Animal orientation and navigation. NASA, Washington, D.C. pp. 397–417.

Tuesday, March 14, 2017

Sphaerotholus: Beast of the Week

This week we shall be checking out a relatively small, but successful round-headed dinosaur.  Say hello to Sphaerotholus!

Sphaerotholus, was a pachycephalosaurid dinosaur, related to the much more famous, Pachycephalosaurus, that lived in what is now North America, including New Mexico and Montana, USA, as well as Alberta and Saskatchewan, Canada, during the late Cretaceous period.  The genus includes three species, that together, spanned from 76 to 66 million years ago.  When alive, Sphaerotholus would have been a plant-eater and could have measured roughly six feet from beak to tail, based on the very fragmented fossil material that is actually known from it. (basically just the top of the skull.) We can also guess roughly how large it was by comparing it to more completely-known, similarly-sized pachycephalosaurids, like Prenocephale and StegocerasSphaerotholus' genus translates to "ball dome" in reference to the top of it's head...which was quite spherical.

Sphaerotholus goodwini, from New Mexico, life reconstruction by Christopher DiPiazza.

Unfortunately not too much is known from this dinosaur.  Despite the fact that there are three named species, all the specimens consist of fragments of the top of the skull and very little else.  What we do know, is that even for a pachycephalosaurid, it had a particularly rounded and thick skull.  The arrangement of nodes (small horns/bumps surrounding the dome) were arranged in a unique way, as well.  Interestingly, pachycephalosaurids actually exhibit quite a bit of variation amongst species when it comes to head ornamentation, and Sphaerotholus was at the derived end of this family tree, when it came to cranium thickness. Some experts have suggested that Sphaerotholus is should really be sunken into the same genus as a more completely known, close relative, called Prenocephale, which was native to what is now Mongolia, but so far the material from Sphaerotholus has proven to be different enough to hold this off for now.

Dorsal view photo of a Sphaerotholus buchholtzae dome, from Canada, held at the American Museum of Natural History, from Paterson's 2013 paper.  Arrows are pointing to injuries possibly from head-butting behavior.

So why such a thick skull?  This question has been asked and debated by paleontologists since the first pachycephalosaurid was discovered.  The knee-jerk conclusion was that these dinosaurs were using their heads as weapons to ram each other with, similar to the behavior seen in many horned mammals today, like goats and muskox.  In fact, the skulls of many of these pachycephalosaurids, including Sphaerotholus, have been found with injuries on them, in the form of small lesions on the tops of their domes that became infected and possible healed in life, suggesting they were, indeed smashing their noggins together.  However, some other paleontologists think that if these dinosaurs actually rammed their skulls in that way, it would seriously injure, or even kill both animals.  It is possible they still used their heads as weapons, but rather aimed for softer parts of their rivals' bodies, like the flanks, or maybe at shorter range, swinging their necks around like clubs, instead of ramming with a running start.  It is also possible the skulls were at least partially for display within the species, as signs of sexual maturity, or even sex. (Although we have no idea if the males and females actually looked different from each other at this time.  Remember, we only have dome tops!)

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

References

Carr T. E.; Williamson T. D. (2002). "A new genus of highly derived pachycephalosaurian from western North America". Journal of Vertebrate Paleontology. 22 (4): 779–801.

Longrich N. R.; Sankey J. T.; et al. (2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA". Cretaceous Research. 31: 274–284.

Mallon Jordan C.; Evans David C.; Tokaryk Tim T.; Currie Margaret L. "First pachycephalosaurid (Dinosauria: Ornithischia) from the Frenchman Formation (upper Maastrichtian) of Saskatchewan, Canada". Cretaceous Research. 56: 426–431.

Peterson, Joseph E., Collin Dischler, and Nicholas R. Longrich. "Distributions of Cranial Pathologies Provide Evidence for Head-Butting in Dome-Headed Dinosaurs (Pachycephalosauridae)." Docs.com. N.p., 16 July 2013. Web.

Tuesday, February 28, 2017

Platypterygius: Beast of the Week

This week we will be looking at a successful ichthyosaur.  Enter Platypterygius!

Platypterygius was a relatively large ichthyosaur, group of marine reptiles that converged with fish in their body shape, that could grow to be about twenty three feet long from snout to tail.  The genus encompasses several species that have been found around the world, including Australia, United States, Russia, Colombia, and Argentina.  That, alone, makes this creature a success story in the grand scheme of things.  However, it is when Platypterygius lived that makes it truly impressive.  Most ichthyosaurs lived during the Triassic and Jurassic.  It is thought by most that by the time the Cretaceous came around, the poor ichthyosaurs were outcompeted by newer forms of large marine reptiles like pliosaurs and mosasaurs.  But not Platypterygius!  This gritty reptile persisted all the way through to the late Cretaceous, 131 to 91 million years ago!

Platypterygius sp. native to what was once Texas, USA, life reconstruction by Christopher DiPiazza.  This genus is known to have eaten turtles in life.

Like its closest relatives, Platypterygius had the telltale ichthyosaur profile, which superficially resembles a combination of a tuna and a swordfish at first glance.  It had a long pointed snout, lined with sharp teeth.  It had four flippers that evolved from walking limbs millions of years prior.  The back flippers were proportionally much smaller than the front ones.  It likely had a tail fluke of some kind and dorsal fluke, as well.  It's eye sockets were relatively large so they were likely comfortable hunting in deep water where there was less light and/or during the night.  Platypterygius is defined by having more finger bones than what is typical of ichthyosaurs in its front limbs.  These bones are especially flat and widened to form the broad paddle appendage it used for swimming in life.  It is because of this specific morphology it earned its genus name, which translates to "flat wing".

Platypteregius americanus skeleton at the Royal Tyrrell Museum in Canada.  Photo by By Roland Tanglao

The earlier forms of Platypterygius that lived during the early Cretaceous were specialist hunters as far as we can tell, preferring to hunt fish and cephalopods. (like squid and ammonites)  These species, like Platypterygius hauthali, from South America (lived between roughly 131 and 125 million years ago), had relatively streamlined bodies and longer pectoral (front) flippers.  These are adaptations for fast swimming so they could pursue their quick-moving prey.  Millions of years later, however, we see a shift in strategy.  Species of Platypterygius that lived towards the end of the Cretaceous, like P. americanus (time range of 112 to 91 million years ago), were bulkier, with proportionally shorter flippers. Their teeth were also slightly larger and more robust.  In addition to differences in morphology, the later forms of this genus show evidence of hunting differently, too. Paleontologists have discovered remains of different kinds of prey in their stomach cavities, including bones from birds, and even sea turtles.  This paints a picture of an ichthyosaur that was less picky about what it considered prey, and was able to afford pursuing this wider menu with a little extra muscle at the price of speed.  Platypterygius managed to carve out a more generalist niche when its relatives were going extinct in reaction to increasing competition from other kinds of marine reptiles that were appearing during the Cretaceous, like pliosaurs and mosasaurs.

Platypteregius sp. tooth.  Photo by Nathan Van Vranken.

That is all for this week!  Special thanks to paleontologist, Nathan Van Vranken, who is currently finishing a new scientific publication on ichthyosaurs, including Platypterygius, for lending his brain to this post.  As always leave a comment below or on our facebook page!

References

Arkhangel’sky, M. S., Averianov, A. O., Pervushov, E. M., Ratnikov, V. Yu, and Zozyrev, N. Yu., 2008, On ichthyosaur remains from the Cretaceous of the Voronezh region: Paleontological Journal, v. 42, n. 3, p. 287-291.

Van Vranken, Nathan, 2017, Texas Cretaceous Ichthyosaurs: A Glimpse of Their Last Days in the Early Late Cretaceous.

Sunday, February 12, 2017

Bulbasaurus: Beast of the Week

This week we will be looking at a newly described reptilian relative of mammals.  Check out BulbasaurusBulbasaurus was a dicynodont, a wildly successful group of plant-eating reptiles that shared characteristics with mammals.  It lived during the late Permian, between 260 and 252 million years ago, in what is now South Africa.  From beak to tail it would have roughly measured two feet long...maybe a bit less.  (Only the skull has been found, which was about six inches long.)  The genus name, "Bulbasaurus", tranlsates to "bulbous reptile" in reference to the bony mass above its nose.  The species name, "phyloxyron", translates to "leaf razor", in reference to how it may have cut leaves to eat with its beak. 

Life reconstruction of Bulbasaurus, by Christopher DiPiazza.

Bulbasaurus, as stated above, was a dicynodont.  Dicynodonts were interesting reptiles that looked like a combination of a few different animals alive today.  I have heard many compare them to pigs...but I never really saw that.  They had proportionally large heads, and broad beaks.  Many kinds had two tusks protruding downwards from their top jaw.  They would have walked in a squat, semi-sprawling posture on four, stout legs.  So if I were to describe a dicynodond in terms of modern animals...I'd say just imagine a French Bulldog...with beak...yeah...yeah, that's perfect. 

Bulbasaurus was an important find because it was a member of the family within dicynodonts, called geikiidae.  Until its discovery, geikiids were only known from significantly later times in the Permian and Triassic.  Bulbasaurus sets the first geikiids back millions of years than what was previously thought, however.  Geiikid dicynodonts typically had particularly large, robust heads, curved beaks, and longer tusks, which Bulbasaurus had when compared to its contemporary family members. 
 

Bulbasaurus skull from the paper recently published by Christian Kammerer and Roger M. H. Smith.

SO WHAT ABOUT THAT NAME?!  Was Bulbasaurus named after the pokemon, Bulbasaur? It certainly looks similar.  In fact, Bulbasaur, the pokemon's design was almost certainly based off dicynodonts, as I explained in a post last year.  According to interviews with Dr. Christian Kammerer, one of the paleontologists who worked with, and lead author of the paper that describes Bulbasaurus, it's insisted the name is a coincidence, and it really is just in reference to it's nose...and the species name...."leaf razor" in reference to it's beak, despite the fact that any pokemon fan can tell you one of Bulbasaur's signature attacks is called razor leaf.  I guess we will just have to believe them just like you should just believe my illustration of Bulbasaurus in no way is in reference to Bulbasaur, the pokemon's, color scheme, nor is the pose and setting inspired by the artwork on Bulbasaur's first pokemon card...

Stop looking for things that aren't there!  Definitely no connection here.  Total coincidence.

References

Kammerer, C.F.; Smith, R.M.H. (2017). "An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa". PeerJ. 5. doi:10.7717/peerj.2913. ISSN 2167-8359.

Kammerer, C.F.; Angielczyk, K.D.; Frobisch, J. (2011). "A Comprehensive Taxonomic Revision of Dicynodon (Therapsida, Anomodontia) and Its Implications for Dicynodont Phylogeny, Biogeography, and Biostratigraphy". Journal of Vertebrate Paleontology. 31 (sp1): 1–158.

Saturday, February 4, 2017

Plateosaurus: Beast of the Week

This week we will be going over a well-known and popular dinosaur, Plateosaurus!

Plateosaurus was a plant-eating dinosaur that lived in what is now Germany, Switzerland, Greenland, and France, during the late Triassic Period, between about 214 and 210 million years ago.  As an adult it would have averaged about twenty feet long from snout to tail, although certain specimens suggest it was capable of growing even larger than that in some instances.  The name, "Plateosaurus" translates to "Broad-Build Lizard" most likely in reference to the dinosaur's robust bones.

Two rival Plateosaurus engelhardti duel for mating rights by Christopher DiPiazza.  The behavior was inspired by the intraspecies combat of many lizards and is purely speculation.

Plateosaurus is classified as a basal sauropodomorph, or "prosauropod".  These plant-eating dinosaurs were related to the much larger, and more iconic sauropods, like Brontosaurus and Apatosaurus, but tended to live in the late Triassic and early Jurassic periods.  In fact, a branch of basal sauropodomorphs actually gave rise to the first true sauropods.  Unlike sauropods, prosauropods typically walked on their hind legs.  Many of them, including Plateosaurus, were obligatory bipeds, meaning they could only walk on their hind legs, like modern birds, and other theropods.  HOWEVER...That being said...Plateosaurus was likely able to walk on all fours when it was a baby, based on what we know about a close relative, Massospondylus, which we know were quadrupedal as babies, thanks to skeletons, then became obligatory bipeds as they grew up.

Plateosaurus had a relatively long neck, which it would have used to help it feed on vegetation above and below it without without having to move its body much.  It had a long, almost rectangular skull, with the tip of its snout sloping slightly downwards.  Within the mouth it possessed many small, leaf-shaped teeth with serrations, which would have been ideal for eating plants, like horsetails, which lived at the same time as it.   The back of Plateosaurus' jaws also sloped downwards, implying there was more muscle there for biting through tough vegetation.

Plateosaurus mounted skeleton on display at the American Museum of Natural History in New York City.  The dinosaur would have likely walked with its tail above the ground in life, as this was mounted before that idea.

Plateosaurus also had robust, powerful arms, each tipped with five fingers.  The first three fingers possessed curved claws, the first digit's being the largest.  These claws may have helped to manipulate branches while feeding, defend against predators, or fight rivals of the same species. (or all three.)  The hind legs were also powerful, each foot ending in four long, broad claws.  The long, muscular tail would have helped Plateosaurus keep its balance as it walked around on its hind legs.

Left hand of Plateosaurus.  Note the large claw on digit 1.

Fortunately, Plateosaurus is known from many individual specimens, so scientists have been able to learn a lot about this dinosaur.  By looking at certain bones closely, it can be determined how an individual dinosaur was growing.  Plateosaurus, it turns out, went through a period of rapid growth when it was young, then slowing down when it reached a certain age or size.  However, the sizes of different individual Plateosaurus seemed to vary at the same age. For instance a sixteen-foot long Plateosaurus could have been the same age as an almost thirty foot Plateosaurus.  We see this today in modern reptiles and it depends on how many resources are available to animals as they are growing.  The more food an animal has, the larger and more rapidly it will grow.

Plateosaurus mounts on display at the University of Tübingen, in Germany.

Looking at the mobility of the ribs of Plateosaurus, and how they could change positions depending on if the dinosaur was inhaling or exhaling, it could also be hypothesized that this dinosaur was endothermic, like birds, and would have had the same kind of one-way breathing system that they do.  This form of respiratory system, only currently known today in birds and a few reptiles, makes it so that the animal is constantly taking in fresh oxygen with every inhale and exhale.  If humans could breathe like that track events would be a lot more intense!

That is all for this week!  Special thanks to Dr. Heinrich Mallison, who lent his expertise on Plateosaurus for the making of this post.

References

Creisler, Ben. "Plateosaurus: The Etymology and Meaning of a Name." Plateosaurus: The Etymology and Meaning of a Name. Dinosaur Mailing List, n.d. Web. 

Huene, F. von (1926). "Vollständige Osteologie eines Plateosauriden aus dem schwäbischen Keuper" [Complete osteology of a plateosaurid from the Swabian Keuper]. Geologische und Paläontologische Abhandlungen, Neue Folge (in German). 15 (2): 139–179.

Jaekel, O. (1911). Die Wirbeltiere. Eine Übersicht über die fossilen und lebenden Formen [The Vertebrates. An overview of the fossil and extant forms] (in German). Berlin: Borntraeger.

Mallison, H. (2010). "The digital Plateosaurus II: an assessment of the range of motion of the limbs and vertebral column and of previous reconstructions using a digital skeletal mount". Acta Palaeontologica Polonica. 55 (3): 433–458. 

Sander, M.; Klein, N. (2005). "Developmental plasticity in the life history of a prosauropod dinosaur". Science. 310 (5755): 1800–1802. Bibcode:2005Sci...310.1800S.

Tuesday, January 17, 2017

Shonisaurus: Beast of the Week

This week we will be looking a HUGE seabeast!  Make way for Shonisaurus popularis!  Shonisaurus was an ichthyosaur, in the same group as the more famous, Ichthyosaurus.  Like it's relatives, Shonisaurus' body was shaped similarly to that of a fish, despite the fact that it was an air-breathing reptile.  (This evolutionary strategy would pop up again, millions of years later with mammals in the form of whales.) Shonisaurus stands out because it was so large, measuring about 50 feet from snout to tail as an adult.  It lived in the ocean that covered what is now Nevada, in the USA, during the late Triassic Period, about 215 million years ago.  The name, Shonisaurus, translates to "Shoshone Mountain Lizard" in reference to the mountains in which it was found.  When alive, Shonisaurus would have eaten mollusks and fish.


Shonisaurus was an earlier form of ichthyosaur, so it did not possess all of the telltale characteristics you might see in later, more famous kinds, like Icthyosaurus.  For one thing, Shonisaurus presents no evidence of having possessed a dorsal flipper when alive, nor a full tail fluke.  So it wouldn't have had the distinct tuna-like profile other, later ichthyosaurs had.  Its lower flippers, that had evolved from walking limbs of its ancestors, were relatively long and narrow, while later relatives had more rounded ones.  One feature it had that did pass on to the rest of the ichthyosaur group was the fact that it had exceptionally large eyes, even proportional to its immense body size.  This suggests that Shonisaurus could see where there was little light, and may have spent at least part of its time in very deep waters.

Shonisaurus skull cast on display at the 2015 "Mega Dinosaur Exhibition" in Tokyo, Japan.

Shonisaurus was large.  It was one of the largest marine reptiles known to science, in fact.  So what and how did it eat?  Well, luckily, along with over thirty adult skeletons on the fossil record of this beast, paleontologists have also identified coprolites (fossilized poop) from it.  Turns out, according to the poop, Shonisaurus was eating squid, belemnites (like a squid but with an internal shell) and soft fish.  Interestingly enough, however, these prey items were all small, so it means that Shonisaurus must have been devouring huge quantities of them in order to grow and stay alive.  In order to better understand this, we can take a look at modern marine giants that prey on small animals.  Balene whales come to mind first, but as their description suggests, they had balene, an adaptation that helps them devour krill and other small prey in a very specific fashion.  Shonisaurus had small, almost nonexistent teeth that faced somewhat sideways in the mouth.  In fact, it appears that Shonisuarus' lineage was on its way to doing away with teeth altogether. (Which makes sense since there are many kinds of later ichthyosaurs that were toothless.)  I feel an even better modern analogue than whales would be the Basking Shark and Whale Shark.  These two kinds of sharks, in addition to also being very large, have no teeth in their mouths, but they can open them extremely wide as they filter feed on small prey.   Having been a reptile, Shonisaurus would have been able to open it's jaws relatively wide, as well, and could probably achieve similar feeding feats.

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

References

Kosch, Bradley F. (1990). "A revision of the skeletal reconstruction of Shonisaurus popularis (Reptilia: Ichthyosauria)". Journal of Vertebrate Paleontology10 (4): 512–514.

Mcmenamin, Mark A.s., Meghan C. Hussey, and Lydia Orr. "Ichthyosaur Coprolite With Nautiloid: New Data On The Diet Of Shonisaurus." (2016): n. pag. Web.

Nicholls, Elizabeth L.; Manabe, Makoto (2004). "Giant Ichthyosaurs of the Triassic—A New Species of Shonisaurus from the Pardonet Formation (Norian: Late Triassic) of British Columbia". Journal of Vertebrate Paleontology24 (4): 838–849.


Saturday, January 14, 2017

Mongolian Paleo Drama: Year in the Making

When I paint life reconstructions.  Unknown to the viewers, there is almost always a story behind every painting.  There are usually never any hints, or givaways, or any sign of a bigger picture, but as I'm working on the piece, I try to think of what that particular dinosaur or other prehistoric creature has gone through up until the exact second in time that I choose to capture it's image, as well as what might happen to it after that second is over.  In fact, if you were to ask most artists, they will probably tell you the same thing.  If you turn on Netflix and check out Bob Ross, you will see that he is a prime example of this, narrating his own story as he works along through his piece.  I strongly feel like if it wasn't for the artist's imagination and ideas behind the paintings, the products, themselves wouldn't have as much life.

That penguin, for instance...he's gonna make it.  He just is.

Well, sometimes I do give hints as to what is about to happen, or happened in the past of my subjects.  In the case that I'm about to show you, most people wouldn't have noticed there was a bigger story, because the two paintings in question were painted, and therefore shared with the world a year apart from one another.  But they are connected.  Let's look at the first one below.


It's my Therizinosaurus, a plant-eating theropod that lived in what is now Mongolia.  I was inspired by sloths while painting this fellow.  Back when I was working at zoos, I witnessed one of our male sloths, Eugene, fall asleep with a piece of lettuce in his hand.  Minutes later he woke up from his spontaneous nap to continue feasting.  I thought it would be cute to show a dinosaur doing something similar.  However, falling asleep can be dangerous, especially if you have predators...


Jump forward in time one year to November of 2016 when I finished this painting of a mother Tarbosaurus feeding her young.  Tarbosaurus was also from Mongolia and would have coexisted, and possibly hunted Therizinosaurus.  Now look closer at what exactly it is that she's feeding her baby...


That's right.  The hunk of meat that is being fed to her baby is the disembodied arm of Therizinosaurus, who likely was ambushed by the tyrannosaurid during his nap.  But there's a twist here.  Look closely at the mother Tarbosaurus again.  Not all that blood is coming from the disembodied arm.


Therizinosaurus managed to get a few hits in with his enormous claws before he was killed.  One nice slash to the face and another, deeper stab, to his attacker's neck and shoulder.  This Tarbosaurus is bleeding, and judging by the second wound, she might not have much time left.  Let's hope her baby can learn to hunt on his own quickly!