Sunday, September 28, 2014

Chunerpeton: Prehistoric Animal of the Week

This week we honor a prehistoric amphibian that has ties to animals that are near and dear to my heart today.  Check out Chunerpeton tianyensisChunerpeton is one of the first known salamanders to ever appear in the fossil record.  It lived during the Jurassic Period, about 160 million years ago, in what is now China.  It measured about seven inches long on average, and like its living relatives, would have been a predator, capturing and swallowing whole any small animal it could fit in its mouth.  The genus name, Chunerpeton, translates to "Early Creeper".  When alive, Chunerpeton would have lived nearby some dinosaurs like Anchiornis and Eosinopteryx.

Life reconstruction of Chunerpeton tianyensis by Christopher DiPiazza. I opted for no gills since all its living relatives don't have them as fully grown adults.

Chunerpeton is known from hundreds of well preserved fossils.  During the Jurassic, the lake in which these Chunerpeton lived was buried under a layer of ash when a nearby volcano erupted, preserving them all to eventually become wonderfully preserved fossils.  Many specimens retain skin, eyes, stomach contents (included small shrimp in case you were wondering) and external gills.  The fact that Chunerpeton is known from all the way back during the Jurassic is amazing.  Before its discovery only a few years ago, the oldest known salamander fossils were from only about 65 million years ago, not long after the great Mesozoic extinction that wiped out most of the dinosaurs.  Of course other kinds of amphibians have been around since MUCH earlier, but Chunerpeton was the first occurrence of a true salamander like we see around us today. 

Chunerpeton fossil.  You can see where external gills would have been just behind the skull.

What kind of salamander was Chunerpeton though?  Scientists identified it as a member of the salamander family, cryptobranchidae.  Modern examples of cryptobranchids are the largest living amphibians, like the Chinese Giant Salamander. (Andrias davidianus)  The highly endangered Hellbender (Cryptobranchus alleganiensis) from North Eastern United States is also a cryptobranchid.  Chunerpeton is also closely related to another family of modern salamander, called hynobidae.  Both hynobids and cryptobranchids spend most of their time in cool, clean water, and are voracious predators, snapping up any kind of prey that wanders too close to their mouths.  Like most amphibians, they start out as a fully aquatic larval form with gills.  As they age they lose the gills and gain the ability to breathe air but still prefer to spend most of their time in the water.  It is likely Chunerpeton was the same way.  Many Chunerpeton fossils, like I stated earlier, preserved external gills.  This leaves many to believe that Chunerpeton retained its gills into adulthood, which is exhibited in some kinds of modern salamanders.  These fossils could also just be of juveniles, however.

My pet Hynobius dunni begging for food at the front of the tank.

 Like I shared a few days ago, I personally keep many salamanders in my home as pets.  Amongst them I do have one kind, a hynobid, that is closely related to the ancient Chunerpeton.  It is called a Japanese Oita Salamander. (Hynobius dunni)  Quite a little cutie!  He eats worms and crickets right from my fingers too!

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

References

Ke-Qin Gao & Neil H. Shubin (27 March 2003). "Earliest known crown-group salamanders". Nature 422 (6930): 424–428. doi:10.1038/nature01491.

Roach, John. "China Ash Yields Salamander Evolution Secrets." National Geographic. National Geographic Society, 28 Oct. 2010. Web.

Steyer, Sebastien. Earth before the Dinosaurs. Bloomington: Indiana UP, 2012. Print.


Thursday, September 25, 2014

Salamander Power: A Tale of Regeneration

It's almost my birthday and you know what that means!  I only write about what I want to and totally ignore your requests for a few days!  (I'm pretty darn good at accommodating you folks the rest of the year.  Let me enjoy myself.)  This week we shall be focusing on one of my all time favorite extant animals with a really interesting prehistoric story twist.  We are going to talk about salamanders.

My pet Kaiser's Spotted Newt. (Neurergus kaiseri)  In my opinion this genus is one of the most beautiful species of amphibian.  It gives dart frogs solid rivalry.

Salamanders one of my favorite living animals.  I'm not exactly sure specifically why but I do know that I decided they were one of my favorites at a very young age.  I remember I found my first Red Back Salamander when I flipped a dead log over in the woods near my house.  I was hooked ever since I suppose.  In fact, I keep several different species of salamanders in my home as pets.  They are not necessarily the most popular kind of pet amongst the masses (even in the reptile/amphibian pet trade) but they are certainly my favorite.  Oh and for the record, please don't confuse salamanders with lizards.  They have the same body shape but are totally different animals.  Salamanders are amphibians (soft, absorbent skin, related to frogs, mostly lay squishy eggs that need to stay wet) and lizards are reptiles. (dry scaly skin, related to snakes, mostly lay shelled eggs on land)  Totally different animals.

Red Back Salamander (Plethodon cinereus) I caught near my house one time years ago.  I named her Mitsy...

One amazing thing about salamanders is that they are the only tetrapod that can regenerate limbs and other parts throughout their entire lives.  (A tetrapod is a vertebrate that has four limbs, or evolved from ancestors with four limbs.  This includes amphibians, reptiles, birds, and mammals.  Yes, snakes and whales count as tetrapods.)  Certain kinds of lizards can regenerate tails but salamanders can regenerate tails, legs, arms, eyes, organs...pretty much anything that doesn't kill the animal.  It is because of this that salamanders are currently the subject of much medical research.  Imagine in the future if we could regrow our body parts thanks to an amphibian!

Axolotl.  A large fully aquatic salamander native to Mexico.  They are pretty much extinct in the wild due to habitat loss.  They are extremely common in captivity, however.  This is one species that is currently being researched for medical purposes.

Well, paleontologists in Germany discovered that this ability to regenerate body parts goes back a lot farther than we previously thought.  It turns out that amphibians were regenerating arms and legs 300 million years ago!  They weren't salamanders, either, but a now extinct kind of amphibian, called a temnospondyl.  The genus of the animal, itself, is MicromelerpetonMicromelerpeton is known from many wonderfully preserved fossils.  Scientists noticed that some of these individual fossils showed strange arrangements and proportions in the hands and feet.  When compared to data about modern salamanders, it was discovered that these odd bones (some were too small, some were fused, some were too numerous in the hand) actually reflect an animal that is in the process of, or recently regenerated that limb.  This also means that the ability to regenerate these body parts evolved much earlier on the amphibian family tree and was lost by all the modern kinds except for salamanders.  Frogs, for instance, can only regenerate body parts when they are tadpoles and lose the ability once they reach their adult forms.  Salamanders, however, can do it throughout their entire lives.

image from Frobisch's paper showcasing fossilized remains of Micromelerpeton hands in the process of regeneration.

As if that wasn't interesting enough, before I go I want to share with you something amazing!  Like I stated, I keep many salamanders for pets.  Amongst them I have two Hong Kong Newts. (Paramesotriton hongkongensis)  They are beautiful little creatures.

Hey, guys.  (Paramesotriton hongkongensis)

A few months back I noticed something was wrong with one individual's left arm.  It was turning white and appeared to be deteriorating.  I was worried this might be the result of an infection of some sort.  Infections are bad for amphibians because they spread especially fast and can be passed to other individuals as well.  Luckily, since I work at a zoo, I already know a great veterinarian who works with exotic animals and immediately set up an appointment one afternoon.  He examined the little fellow and told me that luckily it was not an infection, just trauma. (Probably from a fight with his tankmate.  They go into frenzies during feeding time and tend to bite anything that moves, including a neighbor's arm.)  He decided to amputate the whole arm.  I was then on antibiotic duty (lol dooty) for several weeks.

At that point I was aware that salamanders could regenerate limbs, but I honestly didn't really consider that this guy could.  Well only a few weeks later I noticed what looked like loose flap of skin coming off of my newt's arm stump.  I looked more closely and was amazed to see a teeny tiny baby-sized hand had emerged from where the stump was!  He was regenerating!  I had never witnessed it in person before and always assumed the new arm grew back to match the size of the animal.  It was cool to learn that it actually starts as a very small, basically fetal stage, and grows to match the rest of the body!  How cool is that?!?!?!  Here are some photos I took of his regenerating hand. 




From now on they are each fed in separate containers and given time for their feeding modes to wear off to prevent any future biting incidents.  That's all for today!  Hope you enjoyed a little peek into my somewhat private life of amphibian keeping.  Stay tuned for Sunday for a beloved Prehistoric Animal of the Week! 

References

Frobisch, Nadia B., Constanze Bickelmann, and Florian Witzmann. "Early Evolution of Limb Regeneration in Tetrapods: Evidence from a 300-million-year-old Amphibian." Proceedings of the Royal Society 281 (2014): n. pag. Web.

Friday, September 19, 2014

Jamie Oliver's Diner: Jersey Boy in England

As you may know I made a trip to London back in May.  One of the places I made a point to visit was an American style restaurant just opened earlier this year by famous chef, Jamie Oliver.  Now why would an American visit an American style diner in a foreign country?  There is no fun in that!  Well there is actually a lot of fun because the whole place is freaking dinosaur themed.


The place is covered literally from ceiling for floor with dinosaur-themed art.  Some of it is really clever.  My favorite was the giant feathered theropod suspended from the ceiling over the stairs as you walk in.  Couldn't quite figure out which genus it was supposed to be.  Eotyrannus perhaps?  Below are the photographs I took with my thoughts about them.  Hope you enjoy!  If you ever get a chance to visit downtown London, make a point to stop in for a milkshake if you like being surrounded by zany dinosaur stuff.  I was bummed they weren't selling T-shirts yet.

Upon walking in the door visitors are greeted with an inspiring last supper parody featuring dromaeosaurs dining upon a disembodied sauropod head and neck.

This is the giant hanging feathered theropod.  The wrists are wrong but everything else is pretty up to date-looking!

Yay feathered ornithomimid!

Spanish Triceratops fighting.  I actually did this in college but the uniform looked too good on me so they made me quit because I was making all the other matadors feel depressed about their bodies.  Also bull/triceratops fighting is sort of inhumane if you think about it.

Can't have an American-themed dinosaur place without oil jokes!

I'm expressing disapproval at the fact that the Tyrannosaurus is sitting on top of the sick Triceratops from Jurassic Park without offering her any of his herbal tea.  She clearly needs it more than him.

These stitched dinosaur scenes were very pretty.

Jurassic Park Spinosaurus Dino Lube should be in every garage.

There was this mounted, racing striped theropod head over the bar.

Gotta love the Oviraptor ribbon dancing in the nude.

My other occupation back in college but the jeans on me...same deal.

Like I said the place was literally decorated with dinosaur art from ceiling to floor.

Close up of some of the ceiling art.  Wish I knew the story here.

We will end it with some nice graffiti art of a Papo dinosaur toy.  The dinosaur oil signs were also inspired by papo toys.

Hope you enjoyed my little photo tour of the place.  Like I said if you are ever in London and want your dinosaur fix and eat some good fries and a shake at the same time, try out Jamie Oliver's Diner!

Sunday, September 14, 2014

Dreadnoughtus: Prehistoric Animal of the Week

This week we will be looking at a recently discovered behemoth of a dinosaur.  Make way for Dreadnoughtus schrani!  Dreadnoughtus was a huge plant-eating dinosaur that lived in what is now Argentina, during the Late Cretaceous, roughly 77 million years ago.  It was one of the largest land animals of all time, measuring eighty five feet long from snout to tail.  It is considered a titanosaur, which was a kind of sauropod (long-necked dinosaurs) that survived all the way to to the end of the Mesozoic Era.  The genus name, Dreadnoughtus, translates to "fears nothing".  This is in reference to this animal's immense size and that it probably had no predators to fear once it reached adulthood.  Dreadnought is also the name of a kind of giant, armored battleship which were first launched during the early 1900s.  Two of these massive ships were also in the Argentine navy making this dinosaur's name that much more appropriate. (and badass) 

life reconstruction painting of Dreadnoughtus schrani by Christopher DiPiazza.

Dreadnoughtus is an exciting discovery for a few reasons.  One reason is between the two individual animals found, a lot of bones were unearthed, more than what is typical for large dinosaurs.  In fact, going by types of bones (Once you have the left humerus, for instance, you can safely assume the right one is the same, just mirrored even if it was never found.), over 70% of Dreadnoughtus' anatomy is known.  This is extremely rare for a large dinosaur since in order for fossilization to take place, the animal's remains need to be buried rapidly after death.  This is more common with small animals. Its more likely for mud or sand to completely cover a dead pigeon-sized Anchiornis' entire body, for instance, within a matter of minutes.  But what are the chances eighty five feet of dead dinosaur would have been rapidly buried?  Normally when large animals, especially sauropods, die, the remains would have sat there for a while, scavengers would pick at them, maybe even scatter them around to different places.  Millions of years later, paleontologists are lucky to find one vertebra that fossilized to study.  (Doesn't stop scientists from naming new species though!)  Because of this Dreadnoughtus is considered the largest, well understood, dinosaur known to science.  What I mean is that there are other dinosaurs that have been discovered that may have been bigger than Dreadnoughtus, but they are only known from highly fragmentary remains and scientists tried to hypothesize their full sizes by scaling imaginary skeletons around the few bones that were actually found.

Image from the 2014 paper by Kenneth Lacovara, referenced below.  Note the size compared to an average human diagram and how many bones (shown in white on the diagram) were actually discovered!

Dreadnoughtus' bones gave scientists a lot of answers as to how large titanosaurs would have looked and possibly walked.  Its front limbs were shorter than its hind legs, so it is likely that its neck was held more parallel with the ground nomrally.  It could have raised its neck for short periods of time for eating the tops of trees or displaying for members of its own species possibly, however.  Dreadnoughtus' neck was extremely long and was about half the animal's total length.  The tail, however, was relatively short, only thirty feet long.  (only a thirty-foot tail...I feel weird saying that.)  Most Titanosaurs, like Dreadnoughtus' smaller cousin, Saltasaurus for instance, had a pretty wide stance with reference to to their legs and bodies.  Dreadnoughtus, however, although having a still pretty wide stance, held its legs more underneath its body in comparison to its kin.  We know this because of the angles at which the leg and arm bones attach into their sockets.  These extremely powerful limbs would have acted like pillars, supporting Dreadnoughtus' immense bulk as it walked, and stood and...did pretty much everything I guess.  Other titanosaurs, like Saltasaurus, are known to have had bony armor embedded in their skin.  There is not evidence that suggests this in Dreadnoughtus so it is a mystery as to whether or not it had such a defense adaptation.  It wouldn't surprise me, however, if an animal as large as Dreadnoughtus, lacked armor as its size alone (as an adult, at least) would have made it impossible to kill for any known predator.

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

References

Lacovara, Kenneth J.; Ibiricu, L.M.; Lamanna, M.C.; Poole, J.C.; Schroeter, E.R.; Ullmann, P.V.; Voegele, K.K.; Boles, Z.M.; Egerton, V.M.; Harris, J.D.; Martínez, R.D.; Novas, F.E. (September 4, 2014). "A Gigantic, Exceptionally Complete Titanosaurian Sauropod Dinosaur from Southern Patagonia, Argentina". Scientific Reports. doi:10.1038/srep06196. Benson, Roger B. J.; Campione, Nicolás E.; Carrano, Matthew T.; Mannion, Phillip D.; Sullivan, Corwin; Upchurch, Paul; Evans, David C. (May 6, 2014). "Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage". PLOS Biology. doi:10.1371/journal.pbio.1001853.

Wilson, Jeffrey A.; Carrano, Matthew T. (June 1999). "Titanosaurs and the origin of "wide-gauge" trackways: a biomechanical and systematic perspective on sauropod locomotion". Paleobiology 25 (2): 252–267. Retrieved 31 August 2014.

Wilson, J. A. (February 2006). "An Overview of Titanosaur Evolution and Phylogeny". III Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno: 169–190.

Sunday, September 7, 2014

Euoplocephalus: Prehistoric Animal of the Week

Sorry for the delay.  (Not really though because I had no choice in the matter.)  This week we will be looking at a well studied, but until recently not so well understood armored dinosaur.  Check out Euoplocephalus tutus!

Euolpocephalus tutus life reconstruction by Christopher DiPiazza.

Euoplocephalus was a heavily-armored, plant-eating dinosaur that lived in what is now Canada, during the late Cretaceous period, about 77 to 75 million years ago.  It belonged to the ankylosaurid family, which also includes the larger, "more famous", Ankylosaurus.  (I say "more famous" because many depictions in pop culture or in toy form that are labelled as Ankylosaurus are usually based on Euoplocephalus because it is more completely known.)  The genus name, Euoplocephalus, translates to "well-armed head" and the species name, tutus, translates to "safely protected" because this dinosaur had a LOT of armor.  It was twenty feet long from snout to tail and would have co-existed with many other dinosaurs like Chasmosaurus, Styracosaurus, Parasaurolophus, and Corythosaurus

Euoplocephalus mount on display at the Senkenberg Museum of Natural History in Germany.

Euoplocephalus' body had a series of bone chunks embedded in the skin, separate from its actual skeleton, called osteoderms.  Osteoderms have been discovered in a number of other kinds of dinosaurs like the titanosaurs, and stegosaurs.  They can also be observed in modern animals, like crocodilians.  Ankylosaurs, however, were the most heavily armored.  This armor most likely would have protected the animal from predators or possibly from rivals of the same species if they ever did engage in such behaviors over dominance, territory, and/or mating rights.  Some of the armor on Euoplocephalus took the form of small osteoderms, along the back and sides, but other osteoderms were keeled, and almost blade-like, higher up on the back.  Euoplocephalus also had two rings of keeled osteoderms on its neck, called cervical rings, and a flat, wide sheet of bone covering the entire dorsal portion of its extremely wide pelvis, called a sacral shieldEuoplocephalus's head was armored, too, including the eyelids, and it had horns on the back of its skull and its jugal bones (under the eyes).  Although armor from the tail was never found, it is likely that Euoplocephalus had rows of osteoderms down there, as well, since they are known from a related ankylosaur from Asia, called Pinacosaurus.  As if all that armor wasn't enough, Euoplocephalus was armed with a mass of solid bone on the tip of its tail that it could have swung around as a serious weapon against other dinosaurs.  The tail just in front of this bony club was stiffened and fortified to support it and absorb shock when it smashed into things like wimpy theropod legs.  The base of the tail was not stiffened to give the weapon some range, and would have been supported by large muscles.

Euoplocephalus possessed a wide, flat beak which was a good adaptation for grasping low vegetation.  Because of the broadness of the beak, it wasn't likely a picky eater and probably acted like a giant, reptilian lawnmower, just sucking up any plants it walked in front of.  The plants would then be shredded by its small teeth, located farther back on the jaws.

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

 Inside the skull, Euoplocephalus had a series of long passages running through its skull which were attached to it's nostrils.  It was first believed that these had something to do with a heightened sense of smell.  It was later found out that Euoplocephalus had an inner ear that was capable of picking up extremely low-frequency noises.  Because of this, it is also possible that Euoplocephalus used these hollow passages inside its skull to make ultra-low sounds to communicate with members of its own species.  This behavior can be observed in animals alive today, like Elephants.  Euoplocephalus also had tiny eye sockets, but this doesn't mean it would have had poor vision.  In fact, it is likely it could see pretty darn good.  Remember, all of those spikes, horns, and armor were likely just as much for display within the species, as they were defense against predators, so being able to see them on a rival/potential mate was important to Euoplocephalus.

Another Euoplocephalus skull.  This one is from the University of Alberta.  Photo was taken and provided by Victoria Arbour for her latest paper on ankylosaur taxonomy.  (more on that soon!)

That is all for this week!  Special thanks to Dr. Larry Witmer and Victoria Arbour for providing their expertise for the information and life reconstruction in this post.  Feel free to comment below or on our facebook page!  

References

Arbour V.M. and Currie P.J. (2013). "Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA". PLoS ONE 8 (5): e62421. doi:10.1371/journal.pone.0062421.

Arbour, V. M. (2009). "Estimating Impact Forces of Tail Club Strikes by Ankylosaurid Dinosaurs". PLoS ONE 4 (8): e6738. doi:10.1371/journal.pone.0006738. PMC 2726940. PMID 19707581..

Coombs W. (1972). "The Bony Eyelid of Euoplocephalus (Reptilia, Ornithischia)". Journal of Paleontology 46 (5): 637–50. JSTOR 1303019..

Coombs W. (1979). "Osteology and myology of the hindlimb in the Ankylosauria (Reptilia, Ornithischia)". Journal of Paleontology 53: 666–84. JSTOR 1304004.

K Carpenter (1982). "Skeletal and dermal armor reconstruction of Euoplocephalus tutus (Ornithischia: Ankylosauridae) from the Late Cretaceous Oldman Formation of Alberta". Canadian Journal of Earth Sciences 19 (4): 689–97. doi:10.1139/e82-058.

Miyashita T, Arbour VM, Witmer LM, Currie PJ, (2011). "The internal cranial morphology of an armoured dinosaur Euoplocephalus corroborated by X-ray computed tomographic reconstruction". Journal of Anatomy 219 (6): 661–75. doi:10.1111/j.1469-7580.2011.01427.x.

M. K. Vickaryous, A. P. Russell (2003). "A redescription of the skull of Euoplocephalus tutus (Archosauria: Ornithischia): a foundation for comparative and systematic studies of ankylosaurian dinosaurs". Zoological Journal of the Linnean Society 137 (1):

Thursday, September 4, 2014

Reunited: Pleistocene Texas

I actually forgot I made a lot of paintings featuring animals that have been individually featured on here for Prehistoric Animal of the Week.  Today we will be reuniting some mammals!  Remember Bison latifrons from last month? 


How about Neochoerus


Well if you read each of my posts about them you would have noticed that they actually coexisted with each other.  Nowadays, capybaras, known from tropical regions, and bison, known from dryer, cooler areas, wouldn't really seem to go together, but these two did thousands of years ago!  Here they are in the full painting.  There are also prehistoric muskox in the background, and a dinosaur and the giant prehistoric beaver, called Castoroides, in the foreground. 


If you go by these animals' modern relatives, the proportions in this painting are going to seem off.  Remember, however, these creatures were different!  The capybaras were man-sized (six feet), the bison had a seven-foot wide skull (including the horns), and the beaver was about eight feet long. 

This painting was commissioned to me for the Dallas Paleo Society's Occasional Papers and will be the cover for volume 11.