Sunday, November 24, 2013

Tylosaurus: Prehistoric Animal of the Week

This week we shall be checking out a true prehistoric sea monster, Tylosaurus!  This is in honor of Nathan Van Vrankan's birthday, who is one of our writers and also works with Tylosaurus

Tylosaurus lived during the Late Cretaceaous about 80 million years ago in a warm, shallow sea that once existed down the middle of North America called the Western Interior Seaway.  There are a few known species belonging to the genus, Tylosaurus.  The biggest, called Tylosaurus proriger, would have been almost fifty feet long as an adult!

Tylosaurus proriger makes a meal out of the prehistoric shark, Cretoxyrhina mantelli A.K.A. the "Ginsu Shark".  That shark would have been about twenty feet long.

Tylosaurus belongs to a family of reptiles called mosasauridae, which are actually a kind of marine lizard, closely related to extant monitor lizards.  Mosasaurs are known in the fossil record only in the Cretaceous period, at the end of the Mesozoic, and likely evolved from terrestrial lizard ancestors.  Despite their late appearance in the oceans, they quickly became extremely successful and some, like in the case of Tylosaurus, would become top predators! 

Tylosaurus skeleton on display at the National Museum in Washington D.C.

Tylosaurus was indeed one heck of a predator.  Many fossils have been uncovered that show evidence of it having preyed on virtually every other animal it shared its habitat with, including plesiosaurs, ammonites, sharks, bony fish, birds and even smaller Tylosaurus.  These fossils include bones with Tylosaurus teeth marks in them to actual remains of other animals found inside the stomach cavity of Tylosaurus skeletons!  To be such a predator, Tylosaurus had more than just size on its side.  Inside this animal's mouth were many sharp, cone-shaped teeth, including two extra rows on the roof of the mouth.  These teeth were backed up by tremendous jaws that no doubt could crush or at least hold on tightly to whatever they got hold of.  Tylosaurus wouldn't have relied on its flippers to propel it through the water.  Instead, Tylosaurus had a long, powerful tail, tipped with a fluke to do this.  Its flippers, which were modified walking limbs from its ancestors, were probably more useful for turning.

Tylosaurus skin impression.  Check out those keeled scales!  Very snake-like.

We know thanks to a wonderfully preserved specimen that Tylosaurus would have had diamond-shaped scales on its body, similar to some modern snakes and lizards.  These scales were even keeled which probably would have helped the animal swim faster by cutting the water around it as it moved.  We also think, thanks to another nicely preserved mosasaur fossil, that Tylosaurus would have had a shallow fluke on the top of its tail.

That's all for this week!  In the weeks to come we will be checking out some newly discovered dinosaurs and one old dinosaur with a new look!   As always comment below or on our facebook page

References

Cope ED. 1869. [Remarks on Macrosaurus proriger.] Proceedings of the Academy of Natural Sciences of Philadelphia 11(81): 123.

Everhart MJ. 2005. Oceans of Kansas - A Natural History of the Western Interior Sea. Indiana University Press, 322 pp.

Snow, F. H. (1878). "On the dermal covering of a mosasauroid reptile". Transactions of the Kansas Academy of Science 6: 54–58.

Lindgren, J.; Caldwell, M.W.; Konishi, T.; and Chiappe, L.M. (2010). "Convergent Evolution in Aquatic Tetrapods: Insights from an Exceptional Fossil Mosasaur". In Farke, Andrew Allen. PLoS ONE 5 (8): e11998. doi:10.1371/journal.pone.0011998. PMC 2918493. PMID 20711249.

Thursday, November 21, 2013

Concept Sketches

Hello!  Today I would like to share with you all some concept sketches.  Concept Art is a form of art meant to visually represent an intended finished product.  When it comes to me illustrating dinosaurs it is a chance for me to play around with different ideas like possible color schemes and poses to see what looks best.  An idea may seem really good in my head but after sketching it on paper I sometimes realize it isn't really that awesome.  This is important since watercolor paper is really expensive and I want to be confident when I make the first marks on a new soon-to-be painting! 

I have two pages from my sketchpad to share.  Each one has multiple concepts on them.  (I am a messy sketcher.)  Many of these sketches have since been turned into full paintings which you may recognize from this blog.  Some I haven't gotten around to going forward with.  Others are scrapped ideas.

Here is the first one...


Recognize anybody?  Take a gander at our list of prehistoric animals to be sure!

Ready for sketch number two?  Here ya go...


This one is a lot more crowded.  There are some interesting poses in there as well!

Between these two pages there are six images that have since become full paintings.  Instead of just telling you how about you guys comment below which ones you recognize.  Then next thursday I can be the big reveal...um well re-reveal since these paintings are totally already on the internet.  Good luck!

Sunday, November 17, 2013

Lythronax: Prehistoric Animal of the Week

As promised last week it is now time to finally take a look at that newly described tyrannosaur from Utah.  Enter Lythronax argestes!  Like its relatives within the tyrannosaurid family, Lythronax was a meat-eater and would have lived during the late Cretaceous about 80 million years ago.  From snout to tail it would have measured roughly twenty six feet long.  The full name translates to "Gore King of the South".  Seriously, between this guy and the "Murderous Monster", Teratophoneus, one would think a slasher movie fan has been naming all the recent tyrannosaurs from Utah! 

Life reconstruction of Lythronax argestes by Christopher DiPiazza.

There have been many kinds of tyrannosaurids discovered from North America over the years.  Lythronax is one of the oldest, however.  Keeping this in mind, Lythronax is also physically the most similar to Tarbosaurus and Tyrannosaurus, both of which were each from about ten to fifteen million years later in time.  The similarity is mostly in the skulls.  All three of these tyrannosaurids exhibit fantastic binocular vision, which means that the eyes face forward and allow for greater depth perception.  Lythronax also had a very robust jaw, especially towards the back of the skull.  In fact, its skull was almost half as wide as it was long!  This, combined with its teeth, which were thick, suggests that Lythronax may have inflicted damage to its prey by crushing rather than slicing, unlike many of its relatives.  Again, these are traits also seen in the much younger and larger Tyrannosaurus and Tarbosaurus.

Lythronax skeletal mount at the Natural History Museum of Utah.

Even though other tyrannosaurids like Teratophoneus, which had more blade-like teeth and a more laterally-streamlined skull, are much closer in time and from the same geographical area as Lythronax, it is likely that they were from different branches on the tyrannosaur family tree.  It could be possible that Lythronax was actually the ancestor of Tyrannosaurus and Tarbosaurus

That's all for this week!  As always please comment below or on our facebook page.  Want to see a particular animal featured on JBHD?  Just let me know and I'll make it happen.

References

Loewen, M. A.; Irmis, R. B.; Sertich, J. J. W.; Currie, P. J.; Sampson, S. D. (2013). "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". In Evans, David C. PLoS ONE 8 (11): e79420.

Thursday, November 14, 2013

Drinks with a Paleontologist: Heinrich Mallison

Last month Gary and I had the pleasure of meeting up with paleontologist and friend of the site, Dr. Heinrich Mallison!  Dr. Mallison has allowed us to interview him and he has also provided his expert input on our Plateosaurus and Kentrosaurus Dinosaur of the Week posts.  Luckily for us he was in the USA all the way from Germany to meet with colleagues at the American Museum of Natural History.  He asked us if we would like to meet up in New York City for some drinks and we promptly cleared our schedules!

From left to right: Heinrich Mallison, Gary Vecchiarelli, Christopher DiPiazza

We had a wonderful time talking about all things paleo as well as some extant animal conversations.  You know it's a good outing when everyone at the table says "Well its getting late.  Better get going." and then ends up staying for an extra few hours having been caught up in conversation again.  He also commented on the fact that we talked with our hands a lot...must be a Jersey thing. 

Who knows?  We may show up for next year's SVP meeting in Germany and have drinks on his turf next time.

Sunday, November 10, 2013

Obdurodon: Prehistoric Animal of the Week

The past few weeks have revealed a lot of new information in the field of paleontology!  First, the worlds largest known species of platypus was discovered in Australia and then a new tyrannosaur was found in Utah!  It seems my facebook newsfeed has been blowing up with posts about this new tyrannosaur named Lythronax.  I, however, would like to check out this giant prehistoric platypus first!  Enter Obdurodon tharalkooschild!

I'm proud of this meme I made.

Obdurodon lived in what is now Queensland, Australia between 5 and 15 million years ago during the Miocene era.  Despite the fact that it is known from only a fossilized tooth, scientists estimate (based on the size of the tooth) that the whole animal would have been about three feet long.  This is more than double the size of a modern platypus. 

Obdurodon tharalkooschild by Christopher DiPiazza

Now you may be thinking "Wait...just one tooth?  How the heck do we know what it was if all we have is a tooth!  I thought platypuses didn't have teeth!"  Well, this tooth is what makes Obdurodon special; it had teeth!  Scientists could tell that this single tooth was from a large platypus because it looks like the teeth of modern platypuses, which are very distinct.  Yes, modern platypuses do have teeth as well, they just loose them before they reach adulthood (like the opposite of us!).  This is also the reason for its genus name, which translates to "permanent tooth".  The species name, ,tharalkooschild, is in reference to a duck from ancient Australian mythology, named Tharalkoos.  Tharalkoos got it on with a rat and then gave birth to the first platypus.  Mythology is weird.

Tooth found from Obdurodon tharalkooschild.

Obdurodon would have been one of the largest animals in it's ecosystem.  Like its modern-day relatives, it was likely a predator, using its unique ability to sense electric fields generated by muscle movements in other animals thanks to tiny structures located at the base of its bill.  It also may have been venomous, like modern platypuses, which posses venomous barbs on each of their back feet.  These weapons are only present in male platypuses.  Also, just to clarify, platypuses are indeed mammals, despite the fact that they lay eggs.  They produce milk with mammary glands which oozes through the mother's skin from the inside to be lapped up by the babies (since platypuses don't  have nipples).

Perry might be an Obdurodon!  Look at the teeth!
 
The discovery of this species is important because it tells us that the evolution of the platypus was not linear.  This is because there are other species of fossil platypus known from the same time period as Obdurodon tharalkooschild.  There are a total of five fossil platypus known, all of were found in either Australia or South America.

That's it for this week!  Join us next week as we take a look at (spoiler) that new Tyrannosaur from Utah!  As always feel leave a comment below or on our facebook page

Works Cited

Pascual, et al. "First discovery of monotremes in South America". Nature 356 (1992), Pages 704-706 (Monotrematum).

Pian R et al. 2013. A new, giant platypus, Obdurodon tharalkooschild, sp. nov. (Monotremata, Ornithorhynchidae), from the Riversleigh World Heritage Area, Australia. Journal of Vertebrate Paleontology 33 (6)

 Proske, Uwe; Gregory, J. E.; Iggo, A. (1998). "Sensory receptors in monotremes". Philosophical Transactions of the Royal Society of London 353 (1372): 1187–98. doi:10.1098/rstb.1998.0275. PMC 1692308.

Australian Fauna". Australian Fauna. Retrieved 14-05-2010.

Thursday, November 7, 2013

Paintings by Larry Felder: Up Close and Personal

A few months ago I shared with you all Gary and I's outing with paleo-artist, Larry Felder.  One of the many highlights of that outing was when Larry generously gave Gary and I each an original oil painting of a dinosaur that was used for an exhibit currently on display at the Boston Museum of Science.  Although I included photos of us holding our beloved gifts, I received a few requests afterwards to show close-up photos of the paintings themselves without us holding them.  (I get it.  Sometimes my face is just too sexy it can be overwhelming.  No worries.)  So on request here they are close up!

Gary's Compsognathus
Christopher's (my) Pachycephalosaurus

Thanks again, Larry! 

Sunday, November 3, 2013

Gojirasaurus: Prehistoric Animal of the Week

November 3rd is the birthday of possibly the most influential fictional dinosaur of all time, Godzilla!  So in honor of the "King of the Monsters", we shall be looking at a real dinosaur that was named after it.  Check out Gojirasaurus quayi!

Happy Birthday!

Gojirasaurus lived during the late Triassic period about 200 million years ago in what is now the New Mexico, United States.  It was a theropod, very similar to Coelophysis or Liliensternus, and would have measured about twenty feet long from snout to tail.  Gojirasaurus was most likely a meat-eater.

Life reconstruction of...Coelophysis from a larger painting I made earlier this year.  It works for Gojirasaurus too though.

The term "Gojira" is the Japanese name for Godzilla so this dinosaur's name literally translates to "Godzilla Dinosaur".  Wait a minute though...Gojirasaurus was by far not the largest dinosaur at only twenty feet.  So why such a big name?  The reason for this is actually less complicated than you would think.  The paleontologist who discovered it during the late 1990s, Ken Carpenter, is a big Godzilla fan so he jumped at the opportunity to name a real dinosaur after his "hero".  Fair enough!  In its defense, however, Gojirasaurus was amongst the largest theropods from its time.  Some paleontologists believe that the bones belonging to Gojirasaurus were those of an animal that wasn't yet fully grown, making it an even larger kind of animal, and definitely the largest known theropod from the Triassic.

Gojirasaurus model on display at the Mesalands Dinosaur Museum in New Mexico.  Not the prettiest guy.

Some paleontologists believe that Gojirasaurus is undeserving of its own genus and was in reality, just a large Coelophysis.  This idea is highly debatable since the skeleton of Gojirasaurus is so fragmentary and there isn't enough to make solid comparisons other than the fact that Gojirasaurus bones are bigger and more robust than those of Coelophysis.  Hopefully more of the skeleton will be unearthed in the future! 

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

References

K. Carpenter, 1997, "A giant coelophysoid (Ceratosauria) theropod from the Upper Triassic of New Mexico, USA", Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 205(2): 189-208

Nesbitt, Irmis and Parker (2007). "A critical re-evaluation of the Late Triassic dinosaur taxa of North America." Journal of Systematic Palaeontology, 5(2): 209–243.