Sunday, May 31, 2015

Dimetrodon: Beast of the Week

This week we have a creature that is no doubt very popular even in popular culture, but is sadly very poorly understood by the majority of people out there.  Let's get to know Dimetrodon!

Dimetrodon was a synapsid (same wide group that includes us, mammals) that lived during the early Permian Period, between 295 and 272 million years ago (Several species of Dimetrodon spanned this time range.) in what is now the Southwest United States, in Texas and Oklahoma.  Some fossils of Dimetrodon have also been unearthed in Germany.  It was a meat-eater, and the biggest individuals measured about ten feet long from snout to tail.  The name, Dimetrodon, translates to "Two Kinds of Teeth".  Despite this, Dimetrodon more accurately had three kinds of teeth. (womp-womp)

Dimetrodon grandis with the amphibian, Diplocaulus, as prey.  Reconstruction by Christopher DiPiazza.

If you ever had dinosaur toys as a child (or as a totally awesome not-boring adult, like myself) you might recognize Dimetrodon.  It stands out with it's lizard-like body and enormous fin along its back.  What many people don't realize is that Dimetrodon wasn't a dinosaur.  In fact, it was much more closely related to you, me, and my Yorkshire terrier than it was to any dinosaur.  Dimetrodon is oftern referred to as a "mammal-like reptile".  So it's still considered a reptile to a degree, but it was evolving characteristics that would eventually allow its relatives to become true milk-producing, hairy mammals by the time actual dinosaurs appeared on the earth, and eventually the many mammals we are familiar with today.


First of all, like I said above, Dimetrodon came and left (went extinct) about 40 million years before the first dinosaurs ever evolved on the planet.  In addition, Dimetrodon gives us good clues to what it really was in the bones alone.  The teeth, as the name implies, were differentiated, instead of uniform (what you would see in most other reptiles.)  As mammals, we too have different kinds of teeth in our mouths.  In the front of Dimetrodon's mouth, it had short teeth, similar to incisors.  On the sides it had long, canine-like teeth for slashing, and in the back the teeth were shorter, probably good for breaking up and processing chunks of other animals to be swallowed.  If you look at the rest of the skull, you would notice that it has nostril holes in the front, eye sockets towards the back, and another hole behind the eye sockets, called the temporal fenestra.  ("fenestra" means "window": fun fact)   This hole is present in all mammal skulls, as well.  (Yes, even yours.  We even call them "temples") Dinosaurs and their closest relatives,  have an additional hole between the eye socket and the nostril on each side, called the antorbital fenestra.

Dimetrodon grandis skull.  Note the differences in teeth and the temporal fenestra behind the eye socket.

Dimetrodon's legs were relatively short compared to its long body and large head.  The limbs could have been held erectly as it walked and ran, but it would have had to rest on its belly with them sprawled out to the sides, like a lizard or crocodilian.  Because of this, Dimetrodon probably wasn't capable of running very fast for long distances, but it wouldn't have needed to since all the animals it coexisted with were either just as slow, or slower.  When alive, Dimetrodon would have been the top predator of its environment (that we know of) and it probably would have regularly preyed upon other reptiles, amphibians, like Eryops, and even prehistoric sharks, like Orthacanthus.

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

The most striking feature about Dimetrodon was its amazing fin, or sail, we call it, growing from its back.  This structure was made up of very long, thin extensions of its neural arches,  Neural Arches are the little top parts of the vertebrae bones.  You can feel your own if you run your finger down the middle of your back.  In life, these rod-like bony structures would have been covered with a thin layer of skin, giving it the sail appearance.  One reason why scientists think this structure evolved was to help regulate Dimetrodon's body temperature.  If there were blood vessels in the skin part of this sail in life, the blood would more easily be warmed when exposed to the sun, circulating to warm up the rest of the body faster, or the opposite if Dimetrodon was getting overheated and decided to go into the shade to cool off.  Since all of the other animals it coexisted with would have also been ectothermic, and would have needed time to heat up in the sun each morning, Dimetrodon's sail could have served as a good adaptation to give it a head start at becoming active each day, allowing it to hunt prey, which would have still been in an inactive state.  It's the same reason why it is always easiest to catch frogs and reptiles in the morning, when they are still warming their bodies up and can't move around as quickly as they would be able to midday. (Although I don't condone going out and trying to grab wild animals!)  Others question if the sail would really have been that effective at thermoregulation and suggest it was more likely just an adaptation for display within the species.  There are actually more than one recognized species of Dimetrodon, each sporting variances in the shapes of their sails.  That being said, there is a chance at least some of these variations, especially the ones that coexisted with one another, could have been different sexes and/or ages of the same species.

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

References

Angielczyk, K. D. (2009). "Dimetrodon is Not a Dinosaur: Using Tree Thinking to Understand the Ancient Relatives of Mammals and their Evolution". Evolution: Education and Outreach 2 (2): 257–271.

Baur, G.; Case, E.C. (1899). "The history of the Pelycosauria, with a description of the genus Dimetrodon, Cope".Transactions of the American Philosophical Society 20 (1): 5–62.

Florides, G.A.; Wrobel, L.C.; Kalogirou, S.A.; Tassou, S.A. (1999). "A Thermal Model for Reptiles and Pelycosaurs".Journal of Thermal Biology 24 (1): 1–13.

Olson, E.C. (1966). "Community evolution and the origin of mammals". Ecology 47 (2): 291–302.

Sunday, May 24, 2015

Dryptosaurus: Beast of the Week

This week we will be looking at another extremely important, yet sadly underrepresented dinosaur.  It is also a dinosaur that is native to my home state and in some ways the unofficial mascot of this website. (It's featured on the banner above.)  Check out Dryptosaurus aquilunguis!

Dryptosaurus was a meat-eating dinosaur that lived in what is now New Jersey, on the East coast of the United States during the Late Cretaceous Period, 67 million years ago.  From snout to tail it measured about twenty five feet long.  The genus name, Dryptosaurus, translates to "Tearing Lizard/Reptile" and the species name, aquilunguis, translates to "Eagle Claw" in reference to this dinosaur's huge, curved claws, which it possessed on its hands.  Dryptosaurus was a tyrannosauroid, closely related to Eotyrannus, from England, Guanlong, from China, and to a lesser extent, Tyrannosaurus rex, from Western North America.

Dryptosaurus life reconstruction by Christopher DiPiazza.

 Dryptosaurus was one of the first prehistoric dinosaurs to be recognized by science in the United States.  Discovered only eight years after America's first discovered dinosaur, Hadrosaurus, which was also a resident of what is now New Jersey, it was originally given the genus name, Laelaps, which is the name of a dog from Greek mythology that always succeeded in catching its prey.  Despite being a really cool name, it was soon realized that the genus name, Laelaps was already assigned to...a mite, and thus the dinosaur was changed to Dryptosaurus instead.

Dryptosaurus skeletal mounts on display at the New Jersey State Museum.

Dryptosaurus is interesting because it was a more basal kind of tyrannosauroid, like Guanlong and Eotyrannus, yet it lived much later, during the very end of the Mesozoic, at the same time as the more specialized short-armed, two fingered, tyrannosaurids, like TyrannosaurusDryptosaurus was sort of a relic of it's time, exhibiting adaptations of predators from long before.  Other than it's three-fingered hands already discussed, Dryptosaurus also possessed lighter, blade-like teeth which is in contrast to the more robust teeth of its relatives like Tyrannosaurus.  These ancestral features could have had something to do with the fact that when alive, Dryptosaurus lived isolated from the western dinosaurs of the late Cretaceous, like Tyrannosaurus and Triceratops, by a shallow sea running longitudinally down the center of what is now the United States, called the Western Interior Seaway.  Since it wasn't in competition with its western relatives due to geographic isolation, it may have retained its the more generalist adaptations of its ancestors. 

Dryptosaurus stands out among tyrannosauroids because its claws, especially the ones on the first digit of each hand, were the longest in proportion to the rest of the body.  It's arms were also not quite so long when compared to more basal tyrannosauroids, but still were certainly longer than those of more specialized tyrannosaurids, like Tyrannosaurus.  Despite the fact that it is only known from bones, Dryptosaurus likely had feathers.  We can assume this thanks to fossilized feathers on other tyrannosauroids, namely Yutyrannus and Dilong.

Baby Dryptosaurus (based on bones of other kinds of baby theropods) investigates a horseshoe crab.  Sea creatures may have been familiar cohabitants to Dryptosaurus.

Not much is known about Dryptosaurus' environment since the east coast of the United states has lots of human development, and therefore is more difficult to excavate for fossils now.  However, there are known fossils of duck-billed dinosaurs and armored dinosaurs from the same area.  Since its environment was coastal, Dryptosaurus also may have taken advantage of aquatic animals as food like beached fish, or perhaps turtles coming to shore to lay eggs. 

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

References

Brusatte, S. L. and Benson, R. B. J. and Norell, M. A. (2011) The Anatomy of Dryptosaurus aquilunguis (Dinosauria: Theropoda) and a Review of its Tyrannosauroid Affinities. American Museum Novitates, 3717 . pp. 1-53. ISSN 0003-0082

Cope, E.D. (1866). "Discovery of a gigantic dinosaur in the Cretaceous of New Jersey." Proceedings of the Academy of Natural Sciences of Philadelphia, 18: 275-279.

Thursday, May 21, 2015

Interview with Paleontologist: Susan Drymala


Today we have the treat of hearing from paleontologist, Susan Drymala!  Susan Drymala is a graduate student in vertebrate paleontology at North Carolina State University (now working towards her PhD) and the North Carolina Museum of Natural Sciences. Susan has a BS in geology from the University of Maryland and a MS from NCSU. She took a brief hiatus from academia between her BS and MS due to illness and ended up working for an aggregate mining company for a year and began the blog The Forgotten Archosaurs. Susan studies crocodile-line archosaurs (pseudosuchians), specifically Paracrocodylomorpha, and terrestrial ecosystems of the Triassic. She has done field work in the Triassic of Arizona, New Mexico, Maryland, and North Carolina and the Cretaceous of Utah and recently named a new species of large crocodylomorph.



 Question 1: Who did you admire growing up?

SD: I actually don’t remember having any major role models while growing up, other than the occasional teacher. I was a pretty shy kid.

Question 2: At what age did you get inspired to pursue a career in paleontology?

SD: I knew quite early on that I wanted a career in the natural sciences. I vividly remember visiting places like Yellowstone National Park and Dinosaur National Monument at age 5 and hanging on every word of the park rangers. I pretty much always envisioned a career in geology or biology and things slowly solidified over the years until sometime in high school when I was quite certain that paleontology was definitely the path I wanted to take.

Question 3: You are best known for working with pseudosuchians (as oppose to dinosaurs) from the Triassic.  Was this a part of the field that you had more interest in before you started research, or did the research choose you?

SD: When I started to really pursue paleontology as a possible career, there two things that I was certain of: I wanted to work on animals that were unusual/ poorly understood and I was really interested in mass extinctions. I DID NOT want to do Dinosaurs, since it seemed like everyone was working on them and I figured that there must be a lot of other cool critters that were even more mysterious out there to be studied. I knew that I didn’t want to do anything with humans, which for me meant that mammals were out of the question too; they’re too recent and too familiar. I wanted to explore further back in time. By the time I was a freshman at the University of Maryland, taking Historical Geology with Tom Holtz, my interest in extinction events and the less familiar side of paleontology brought my attention to the Triassic and to the pseudosuchians that dominated that time.

Question 4: What was your favorite prehistoric animal growing up?  Which is your favorite now?

SD: I never really had a particular favorite of much of anything while growing up. I’ve always been drawn to big predators though, so I’ve always liked big cats and theropods. Once I started reading about pseudosuchians, I was immediately drawn to the “rauisuchians”. I’m still not sure I have a favorite per se, but since my MS thesis and first publication were all about Carnufex, it will always hold a special place in my heart.

Life reconstruction of the pseudosuchian, Carnufex, by Christopher DiPiazza.

 Question 5: Paleontology is such a diverse field these days involving many disciplines.  What advice would you give to an aspiring paleontologist today?

SD: Paleontology can be a very difficult field to be in because it’s a field that so many are drawn to – I think because it is so interdisciplinary and it stirs our imaginations – and yet there is so little funding and so few jobs. When I first meet a lot of young people interested in going into paleontology, the conversation is often begun with one of the many paleo clichés such as “I’ve wanted to be a paleontologist since I was a kid” or “I really like theropods”. Although there’s nothing specifically wrong with that, I’ve noticed that a lot of profession paleontologists are turned off by these sorts of statements, so I try to get aspiring paleontologists to expand that childlike wonderment into the wonderment of a scientist and this includes a number of questions and bits of advice:

1.)   Are you a researcher? A lot of aspiring paleontologists don’t realize just how many different career paths you can take and still work in paleontology. And not all of them require a PhD. Sure, lots of paleontologists are professors and curators, but there are also preparators, collections managers, and paleo artists, to name just a few, and all require different skill sets and very different career paths. It’s important to get to know the field of paleontology as a whole before deciding on a career.

2.)   What do you want to study? Don’t just say “T. rex”. If you are a researcher – if you’ve got a lot of questions and ideas on how to answer them - there are three things to think about as far as area of study: time period, taxon, and methodology. If you want to go into research, you’ll need to choose a specific field from each of these areas. For example, I study the phylogenetics and paleoecology (methodology) of Triassic (time period) paracrocodylomorphs (taxon). You don’t have to choose just one topic per area and you can certainly focus more on one area than the other – plenty of paleontologists focus almost entirely on a certain methodology and will apply it to pretty much any taxon, while other will apply a whole host of methods to understand one particular taxon – but all three are important for budding paleontologists to consider.

3.)   In paleontology, you need to be both the jack of all trades (in order to land a job) and the foremost expert in one narrow field (to remain relevant as a researcher). Well trained paleontologists are employed in all sorts of areas, from teaching med school anatomy to managing the geological resources at a national park. Having a good understanding of a lot of different areas of study keeps you marketable but also makes you a better scientist, since you’ll have more tools to approach research questions with. I’ve made sure to get a good education in both geology AND biology for this reason. Being an expert in one area is also important though, because it makes the “foremost expert” in something, which means other scientists will come to you on that topic.

Question 6: Going to college these days and then on to grad school has become a daunting task.  Many people are unaware of how long it takes to make it to the finish line.  The rewards are great, but what would you say to someone pursuing professional studies after college?

SD: The question of “are you a researcher” that I discussed in the last question is really important here. There are plenty of ways into paleontology that do not require advanced degrees. Becoming a fossil preparator, collections manager, museum display designer, or paleo artist does not necessarily require a PhD. If you do want to go the academic route though, it is important to have those qualities of a researcher, that “spark” of inquiry and imagination found in a good scientist, but also a lot of energy. The road through grad school is hard and you have to learn a lot more just how to do good science. Like I said, you’ve got to be a jack of all trades. You’ve got to learn a lot of different sciences, but also a lot of other skills, like scientific communication (from writing scientific literature and grants to public outreach). 

 

Question 7: What was or is your favorite project?  Would you be able to tell us about some of your current projects?

SD: Carnufex has been my baby for the last 3 years. I’ve really enjoyed working on this animal because it really is helping to make sense out of the various carnivorous pseudosuchians of the Triassic. Because of Carnufex, I’ve been working pretty heavily on the phylogenetics and evolution of that area of the pseudosuchian tree. I’m hoping to have a new paracrocodylomorph tree out in the next year or two and I’ll definitely be talking about some of the modifications within the basal crocodylomorph part of the tree at SVP.

Question 9: Do you ever get criticized on any of your work?  How do you handle it?

SD: So far, I haven’t had any major criticisms of my science. I’ve been pretty fortunate to have some pretty big names as mentors and I’ve got a lot of great people rooting for me. I’m sure that once I get more of my phylogenetic work out there I might start to stir some things up, but that tends to happen a lot with phylogenetics. I generally just try to remind people of what the science says and how science works; I’m putting hypotheses out there and the data that’s available to support it, that’s all. I really think that it’s important to not let things get personal in science. People are equal; ideas are not. If the data doesn’t support a hypothesis, we should let go of that hypothesis.
Some people did react somewhat negatively to the implication that Carnufex might have been bipedal and there are two things that I’ve tried to address with this: (1) we never explicitly said that Carnufex was bipedal, but the media seems to have taken the artists reconstruction (which is more of a rearing pose than true bipedality) and ran with it, but also (2) we haven’t explicitly ruled out that Carnufex was bipedal because it’s not outside the realm of possibilities given the large skull, short forelimb, and the fact that plenty of other Triassic paracrocs were likely bipedal. I just try to remind people of what the science says, and what it doesn’t.
With the recent publicity of Carnufex, I’ve gotten a little bit of personal criticism, especially focused on my voice, which has been very interesting. When it comes to personal attacks, I generally prefer to not “feed the troll” and just turn the other cheek. However, I also don’t tolerate bullies and especially not those perpetuating negative stereotypes, so I will sometime respond to negative criticism, but I always try to stay civil. And fortunately, as I learned on Twitter recently, there are a lot of great paleontologists out there on social media willing to back me up.

Question 10: Jurassic Park and Land Before Time (opposite ends of the spectrum I know) were the movies I remember as a kid that fueled my passion for dinosaurs.  What was your most memorable movie, book or TV program that inspired you with regards to paleontology?

SD: I think that we probably grew up in the golden age for dinosaurs in the media. Not only did the late 80s and early 90s have some great dino movies (Jurassic Park, the Land Before Time, We’re Back! A Dinosaur’s Story, Prehysteria!) and TV shows (Dinosaurs, of course), but the Discovery Channel was also still showing real documentaries then too. Walking with Dinosaurs and the other associated documentaries were great to have around as I considered a career in paleo. I think all of these had a bit of a snowball effect on me.

Question 11: I remember meeting my first professional paleontologist.  Do you remember the first paleontologist you ever met?  Were you a nervous wreck? 

SD: I remember emailing Matt Carrano when I was in high school and thinking about becoming a paleontologist. I was so excited to get a reply. I kept a pint-out of that email for years. My next real encounter with a “real” paleontologist was when I met Tom Holtz at an open house for University of Maryland. At first I was nervous, but he was such a nice and energetic person who I had so much in common with that we became pretty fast friends and the nerve went right out the door.
I still get a little nervous when I meet some of the big names in paleontology. Even though I know I shouldn’t, it’s hard to not get a little nervous when you’ve seen these people on TV and you know that they’re such an important part of the community. I tend to be a shy person anyway.

Question 12: Dinosaurs and the animals that lived at the same time as them were amazing creatures.  Why do you feel they continue to fascinate us?

SD: From my own experience, I think that they speak to the innate explorer in all of us. Our imaginations love the unfamiliar and the prospect of discovery. And in a time when our world seems to be shrinking, prehistoric creatures remind us that there are still new things out there to be discovered. Paleontology is currently the only form of time travel.



Question 13: What is your favorite time period?

SD: I adore the Triassic. I could probably gush about it for hours. It begins and ends with two of the biggest mass extinctions of all time. It’s the time of Pangea, the only time in the history of life on land that all the continents were connected. It is a time when the holdovers of the ancient Paleozoic ecosystems (like synapsids, temnospondyls, and cycads) are still abundant and when most of the modern clades we are familiar with first appear, including turtles, mammals, and archosaurs. It’s a time when dinosaurs are around, but they have not risen to dominance yet. It’s the time of the pseudosuchians.

Question 14: What hobbies do you have? (not necessarily paleo-related) 

SD: I certainly adore science to no end, and although I don’t have much time for hobbies these days, I am fortunate that a lot of my hobbies are related to paleontology. Most of my hobbies involve travel, the outdoors, and art (of varying types). I get outdoors as much as possible to hike, camp, or rock climb (although I don’t have much time these days except for when doing field work). I’ve been to the 48 contiguous United States, 7 foreign countries, 5 tectonic plates, 3 hot-spot volcanoes, and a whole host of national parks and monuments. I enjoy just about all forms of art and have engaged in almost all except for music and the performing arts. I used to do a lot of painting with acrylics and oil paints, but have shifted to focus mostly on drawing. I also really enjoy sculpture and sewing.

One of Susan's acrylic paintings.
 
One of Susan's graphite sketches.


Question 15: Have you ever been to New Jersey? 

SD: Being from Maryland originally, I’ve been to NJ a number of times. Most of my experiences with the Garden State have involved to turnpike, but as an undergrad at UMD, I helped organize a geology club trip to the Franklin mine to collect minerals and we camped in a nearby state park, which was beautiful. It was a really great trip. 

Thank you, Susan!  To learn more, please check out her website, the forgotten archosaurs, and follow her on twitter.  Farewell until next time!  

Sunday, May 17, 2015

Deinonychus: Beast of the Week

Today we will be looking at a well-loved, and extremely important dinosaur.  Check out Deinonychus antirrhopusDeinonychus was a meat-eating dinosaur that lived in what is now the United States, including Wyoming, Montana, Oklahoma, and even parts of the East coast, including Maryland, during the Early Cretaceous Period, between 115 and 108 million years ago.  It was relatively small, measuring about eleven feet long from snout to tail.  The name, Deinonychus, translates to "Terrible Claw" in reference to the second digit on each of its feet, which possessed an enlarged, crescent-shaped talon, which was retractable, like a switchblade.

Deinonychus about to get you.  Reconstruction by Christopher DiPiazza.

Starting in the 1800s, when the first dinosaur was seriously recognized by science, the image of dinosaurs was that of hulking, oafish lizard-like creatures.  That all changed when the bones of Deinonychus were unearthed in the 1960s, however.  It was the first dinosaur that really made paleontologists stop and reassess their views on the way dinosaurs lived, by showing signs of being a fast-moving, light-weight predator that shared more characteristics with birds than it did with other reptiles, like lizards and crocodiles.  Since then, many more bird-like dinosaurs have been discovered, of course.  Most people now, especially younger dinosaur lovers, would see small, bird-like dinosaurs as a commodity in their books and toy collections, but one shouldn't forget that Deinonychus was society's first taste of this amazing kind of dinosaur.

Deinonychus skeletal mount on display at the American Museum of Natural History in New York.

When alive, despite its size, Deinonychus possessed weapons which would have made it a formidable predator.  The most obvious were the feet, each possessing a second digit with an almost five inch long "killer claw" which could be held above the ground when not in use to prevent wear, and swung forward for stabbing, when attacking.  Each of the hands was equipped with three long fingers, each tipped with a hook-shaped claw, as well.  Inside the mouth, Deinonychus had many small, blade like teeth, which were serrated.  The jaws of this dinosaur were designed for slicing off bite-sized pieces of meat.  Deinonychus' tail was long (took up about half of its total body length) and had small bony rods running down its length.  We call these structures ossified tendons, which are present in a lot of different kinds of dinosaurs.  They would have made the tail stiff, like a fishing pole, and would have helped the dinosaur make sharper turns while running.  Although only bones have ever been found, it is likely Deinonychus was covered in feathers just like a bird, based on more well-preserved remains of other dinosaurs which were extremely closely related to it. 

Deinonychus food diagram

There are a few ideas as to exactly how Deinonychus hunted.  The first, and most well-known is that Deinonychus hunted in groups to kill larger prey.  The idea is that these predators could have used their powerful hind legs to jump onto larger prey and clung on using their front claws and used tails for balance.  Then they would have used their deadly claws on their feet to bicycle kick into their prey's body, essentially disemboweling it until it collapsed.  This pack-hunting theory is further supported by an amazing discovery of dinosaur fossils which includes the bones of the larger plant-eating dinosaur, Tenontosaurus, with Deinonychus teeth marks on its bones.  One could argue that there is a strong chance the Tenontosaurus was already dead and that the Deinonychus were merely scavenging it, but bones from Deinonychus were found nearby as well!  This suggests that the smaller meat-eaters may have indeed attacked it, and in self defense the larger plant-eater managed to take out some of its attackers before it died.  It's a cool idea, and has been recreated in art countless times, (Seriously, poor Tenontosaurus' whole identity has been reduced to "Deinonychus food" in most books and other media.) but still really can't be totally proven.  Some who oppose this idea argue that perhaps the Deinonychus were not pack hunters, were all drawn to the plant-eater's dead body, and killed a few of each other as they fought over the meat.

The second idea of Deinonychus' hunting behavior delves into its killer claw more deeply.  Believe it or not, many modern birds also actually have an enlarged second digit talon on their feet.  The ones that do, like most hawks and eagles, use this claw to pin down prey (alive or dead) to stabilize it as they tear bite-size chunks of meat off with their sharp beaks.  It is very possible that dinosaurs like Deinonychus could have hunted mostly smaller prey, and used their talons for the same purpose. The video below I took at my job of our Eurasian Hawk demonstrating this technique on a dead mouse.  



Eggs that are believed to have belonged to Deinonychus have also been discovered.  It all started when the rock from which a Deinonychus skeleton was extracted were examined more closely.  It was discovered that they contained dinosaur eggshells.  The next question was whether or not the Deinonychus was eating the eggs, which could have belonged to another dinosaur, or if it the eggs were its own and it was protecting them.  Soon after, tiny bones, called gastralia, were discovered with the eggshells.  Gastralia, or belly ribs, as they are sometimes called, are found on the underside of a dinosaur's torso.  This suggested that the Deinonychus' chest and belly were in contact with the eggs, and it very well may have been incubating them, much like parent birds do today.  Not only does this support the idea that Deinonychus was guarding its own eggs, it also suggests that Deinonychus was endothermic! ("warm-blooded")  Think about it.  Only an animal that gave off its own body heat would brood eggs to keep them warm.  Ectothermic ("cold-blooded") animals, like lizards and crocodiles, rely on the sun, decomposing nesting material, or other outside sources of warmth to incubate their eggs. (There are exceptions, like some pythons who incubate their eggs, creating warmth with muscle friction, but this is an exception, not a norm.)  What a great find!

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

References

Fowler, D. W.; Freedman, E. A.; Scannella, J. B.; Kambic, R. E. (2011). Farke, Andrew Allen, ed. "The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds". PLoS ONE 6 (12): e28964. doi:10.1371/journal.pone.0028964. PMC 3237572. PMID 22194962.

Makovicky, P.J.; Grellet-Tinner, G. (2000). "Association between a specimen of Deinonychus antirrhopus and theropod eggshell". In Bravo, A.M. and T. Reyes. First international symposium on dinosaur eggs and babies,Isona i Conca Dellà Catalonia, Spain, 23–26 September 1999. pp. 123–128.

Maxwell, W. D.; Ostrom, J.H. (1995). "Taphonomy and paleobiological implications of TenontosaurusDeinonychus associations". Journal of Vertebrate Paleontology 15 (4): 707–712. doi:10.1080/02724634.1995.10011256.

Ostrom, John Harold (1970). "Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana". Bulletin of the Peabody Museum of Natural History 35: 1–234.

Ostrom, J. H. (1969). "Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana". Peabody Museum of Natural History Bulletin 30: 1–165.

Ostrom, J.H. (1976). "On a new specimen of the Lower Cretaceous theropod dinosaur Deinonychus antirrhopus". Breviora 439: 1–21.

Turner, Alan H.; Makovicky, Peter J.; Norell, Mark A. (2007). "Feather quill knobs in the dinosaur Velociraptor". Science 317 (5845): 1721. doi:10.1126/science.1145076. PMID 17885130.

Xu, X.; Zhou, Z.; Wang, X.; Kuang, X.; Zhang, F. & Du, X. (2003). "Four-winged dinosaurs from China". Nature 421 (6921): 335–340. doi:10.1038/nature01342. PMID 12540892.

Monday, May 11, 2015

Beast of the Week Reviews Jurassic World: the Game

Jurassic World is only a month away and I am getting pretty excited to see it in theaters.  Yes, I know, the dinosaurs are not really accurate...at all.  But, as a movie it looks like it will be a lot of fun!  Just a few days ago I stumbled upon an add on facebook advertising a Jurassic World game for the iphone or ipad.  It was free so I decided to download it and see what it was like.  Let's check it out!

dan daaan dan DAAAN dandanDAAAANdandandanDAAAAAAN! (Don't even try to tell me you didn't get that.)

Jurassic World: the Game is sort of like a combination of Zoo Tycoon and Pokemon, as far as games go.  The main premise is that you are building the dinosaur park, managing money, food for the dinosaurs, DNA to create more dinosaurs, and you also need to level up the dinosaurs by feeding them.  Throughout the game you are faced with challenges to fulfill, which earn you experience points, advancing you to further levels.

If this zoo were real I'd have a problem with the size of some of those enclosures.

The other part of the game is based on fighting the dinosaurs against other dinosaurs for prizes!  Now, if this were real life I would not condone this at all...but just like pokemon, my all time favorite game, it's not so I can freely say it is a lot of fun.  (Shut up, PETA.) I am a big pokemon veteran, so this style of gameplay of turn-based combat I was able to pick up pretty easily.  Also like pokemon, the animals in Jurassic world each fall into a "type", carnivore, herbivore, pterosaur, or amphibious.  Each one of these types is strong to one other type, weak to another, and neutral to the third.  This makes combat with teams of up to three require a bit more strategy than just simply bashing as hard as you can over and over.  I learned that even though my dinosaur may be a much lower level than the opponent's, if it has a type advantage it can still easily win that match.  Fighting computer dinosaurs is required to advance in the game, but you can also play a random real person, who also has the game, for a quick match any time you like.


When you feed your dinosaurs food, they will gain levels, just like in pokemon.  The higher the level a dinosaur is, the stronger it will be in battle.  As you level a dinosaur, it will "evolve", changing its appearance slightly twice.  Then the third and last time it "evolves" it changes its appearance drastically, ending up looking like an a complete monstrosity.

My Triceratops ended up looking like Armadon from Primal Rage.
 
I know what all you geeks are wondering.  "But, Chris!  Are the dinosaurs SCIENTIFICALLY ACCURATE?"  I must say I had low expectations for the accuracy of the animals in this game, it being Jurassic Park World and all.  The animals in this game are actually very hit or miss, depending on the individual creature model you are looking at, and there lot of them!  It isn't like all the pterosaurs are inaccurate and all the sauropods are accurate, either.  There is no pattern at all.  It makes me wonder if different artists were doing different individual models or something.  Let's look at one example I found after playing the game for a few days.  Also keep in mind I am referring to the dinosaurs BEFORE they evolve for the last time, since these forms are clearly meant to be for fun.

This Ornithocheirus (referred to as Tropeognathus in the game) looks really good!  The wings are really long, the shoulders, chest, and arms are proportionally beefy, and the posture is good too!  It even has the fuzzy texture worked in!  Is this Jurassic Park???

Not bad at all, JP!

But then I saw this monstrosity...


Terrordactile alert!

Tapejara with teeth, no fuzzy covering, and bat wings.  It's mildly frustrating how the same game can get one animal really spot on, but another, which is so closely related, totally messed up.  This sort of accuracy inconsistency pops up a lot more in the game, too. 

What about feathers?  Jurassic Park is notorious for ignoring the fact that many theropods had feathers.  When I opened this game I was totally expecting to see naked theropods all over the place.


Lots of the theropods are feathered!  Jurassic Park game...with feathered theropods!  Is this real life?  I'm not just talking about a few wisps of plumage on the head, either.  These guys have plumage all over their bodies!  Now, mind you, not ALL of the dinosaurs have feathers that probably should, like Tyrannosaurus, for instance.  But when it comes to dromaeosaurs, and even Guanlong, and ornithomimids, the feathers are totally there.

My Pyroraptor...with accurate feathers.  This is actually a Jurassic Park game?
Even this Utahraptor, despite lacking primary feathers on the arms, has feather texture on its body you can see. If that isn't enough for you...

...here is Utahraptor past level 30.  Happy now?

What about shrinkwrapping?  For those of you who don't know, shrinkwrapping, in reference to dinosaur reconstructions, is a term coined a few years ago, which is used to describe when an artist basically just draws the dinosaur's skeleton with skin draped over it.  It was very common for a long time (still is sometimes) and was the result of artists doing their homework so intensly by copying the actual bones, they forgot that living animals don't actually look like that.  Well, the dinosaurs in this game aren't shrinkwrapped either.  In fact, many of them are as beefy as ever!

A very healthy-looking Argentinosaurus.

Of course there are still plenty of flaws.  The wrists on the theropods are pronated the wrong way, the azhdarchids have wings that are too long, and the number of fingers and toes on a lot of dinosaurs is wrong, too. (the two-fingered Allosaurus was particularly upsetting)  Overall, however, it is far from terrible, especially considering it is part of the Jurassic Park franchise.

What's my final verdict?  This is a really fun game.  It is easy to play, not at all time consuming (you can get a lot done in literally a minute if you wanted), and it includes a great variety of prehistoric animals including lots that don't normally get any pop-culture appearances.  It is also free!  As you play the game it WILL ask you to spend money to buy booster packs of supplies and dinosaurs.  Whether or not you pay is up to you.  It is totally possible to play through the game successfully and get rarer dinosaurs without spending money, it just takes a little longer.  Like all things Jurassic Park, it isn't perfect with regards to scientific accuracy, but this game does come really close on some of the animals, which is saying a lot considering educational franchises like Discovery and Animal Planet get stuff way worse than some of this, and they are actually trying to educate you.

If you end up downloading it let me know your thoughts in the comments below!  I'd love to hear them!

Sunday, May 10, 2015

Parasaurolophus: Beast of the Week

This week we will be taking a look at a very popular duck-billed dinosaur.  Say hello to Parasaurolophus!  Parasaurolophus was a plant-eating, duck-billed dinosaur that lived in what is now North America during the Late Cretaceous, about 77 to 73 million years ago.  Parasaurolophus measured about thirty one feet long from beak to tail, but certain incomplete specimens show evidence of having been a bit larger.  Parasaurolophus is most well-known for its long, curved crest that grew from the back of its head, giving it one of the most iconic profiles of any dinosaur.  The name Parasaurolophus translates to "Near Crested Lizard/Reptile" and is in reference to it being compared to another duck-billed dinosaur with a smaller crest, called Saurolophus (just "crested lizard/reptile"), which was discovered earlier.  Turns out that Parasaurolophus and Saurolophus, although both hadrosaurids (duck-billed dinosaurs), weren't really that closely related.  Parasaurolophus belongs to what is called the lambeosaurine branch of hadrosaurs which had hollow crests and narrow beaks, which Saurolophus did not have.  Parasaurolophus was much more closely related to CorythosaurusVelafrons, and Tsintaosaurus, to name a few examples.

Parasaurolophus walkeri pair by Christopher DiPiazza.  The short-crested female is based on speculation.


There are actually a few different named species of Parasaurolophus.  The most well-recognized is called Parasaurolophus walkeri, and it lived in what is now Alberta, Canada, and would have coexisted with other well-known dinosaurs like Styracosaurus, Chasmosaurus, Struthiomimus, Corythosaurus, and Eouplocephalus.  From the southwestern United States, however, there was also Parasaurolophus tubicen, which is incompletely known, but was probably the largest species, and Parasaurolophus cyrtocristatus, which had a much shorter, more curved crest, and would have coexisted with (and ran away from) Teratophoneus.  

Parasaurolophus walkeri skull on display at the American Museum of Natural History in New York City.

At one time, some paleontologists made a hypothesis that Parasaurolophus cyrtocristatus was actually a female of one of the other two species, due to its smaller crest, but further research concluded this was probably not true since they did not live during the exact same time period.  This being said, it is not unreasonable to guess that the Parasaurolophus females could have had shorter crests anyway, since we can observe similar trends of sexual dimorphism (males and females look different) in other lambeosaurine hadrosaurids that are known from a bigger pool of specimens, like Corythosaurus.

Parasaurolophus cyrtocristatus skeleton on display at the Field Museum of Natural History, in Chicago.

Recently, in 2013, a specimen of a baby Parasaurolophus was published by scientists at the Raymond M. Alf Museum of Paleontology in California, shedding more light on the growth and development of this interesting dinosaur.  The specimen, which was just under six feet long from beak to tail (small when you consider the animal we are talking about!), is estimated to have only been one year old when it died.  Paleontologists could tell this by looking at the cross-section of a the dinosaur's bone and counting the ring-like patterns on the inside, similar to a tree. This specimen hadn't developed any rings yet at the time of its death.  Despite this, the tiny dinosaur's crest had already started to grow from the front of  its skull, almost between its eyes.  At the age that it dies, that specimen would have likely still been under it's mother's care, according to the information and evidence on the fossil record about other hadrosaurid mothers.

Fossil remains of the baby Parasaurolophus published in 2013.  Photograph is from Dr. Andrew Farke's paper, cited below.

So what was the crest for, anyway?  At first some people thought that hadrosaurids, like Parasaurolophus, were amphibious, and spent a lot of their time in the water because the skin that preserved around the toes of one specimen (an Edmontosaurus) that looks like webbing at first glance (it turned out to have been more like padding for walking) and the fact that they had flat bills like ducks (which weren't really that similar to a duck's bill!)  To go with this incorrect idea, some proposed the crest of Parasaurolophus was a snorkeling adaptation, since it was hollow on the inside and would have connected to the animal's airways.  A more likely reason for this crest, however, is to help the animal to produce a distinctive sound.  the dinosaur would inhale through it's nose, the air would pass through the tubes inside the crest and become amplified, then released through the mouth as a loud bellow.  The mechanics would have been very similar to playing a trombone, actually.  With the help of some more modern technology, scientists were able to scan the inside of a Parasaurolophus crest and reproduce what they might have sounded like based on their findings.  According to what they came up with, the sounds of Parasaurolophus would have been pretty eerie!  Check out the audio below!


The fact that Parasaurolophus probably used its crest to make sounds, combined with the fact that we know the young had short crests, leads us to the undeniable fact that the young and adults must have sounded different.  (young would have been more higher pitched)  This makes sense for communication reasons.  A mom would have an easier time finding her babies by their calls if they ever became separated.  You can actually observe very similar baby to parent vocalizations in modern dinosaurs, the birds, and also crocodilians.  The sounds were also probably a good way for adults to attract mates and establish dominance, which can also be seen in a myriad of modern animals.

There was more to Parasaurolophus than just the crest, remember.  In the front of its mouth, it had a flat, and relatively narrow beak, which would have been good for selectively foraging its favorite plants to eat.  This is different from the widened, bills of other hadrosaurids, like Anatotitan's, which were probably more adapted for a generalist plant diet.  Like all hadrosaurids, Parasaurolophus had hundreds of tiny teeth in the back of its mouth, which were tightly packed together to form what we call a dental battery.  these structures were perfect for chewing tough plants much like the molars that plant-eating mammals use to chew with today.

Parasaurolophus had relatively long arms and could have walked on four or two limbs depending on how fast it wanted to move.  Its vertebrae had tall neural arches, especially on its back, which would have given it a hump-like profile in life.  Like all hadrosaurids, Parasaurolophus' tail was especially thick, and also pretty rigid.  The tail would have probably been its weapon of choice if it needed to defend itself or its young.

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

References

Barden, Holly. "Sexual dimorphism in dinosaurs: a review of the evidence and approaches" (PDF). APS 402 Dissertation. University of Sheffield.

Currie, Phillip J.; Koppelhus, Eva, eds. (2005). Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Bloomington: Indiana University Press. pp. 312–348. ISBN 0-253-34595-2.

Evans, David C. "Nasal Cavity Homologies and Cranial Crest Function in Lambeosaurine Dinosaurs." Paleobiology 32.1 (2006): 109-25. Web.

Farke, Andrew A., Derek J. Chok, Annisa Herrero, Brandon Scolieri, and Sarah Werning. "Ontogeny in the Tube-crested Dinosaur(Hadrosauridae) and Heterochrony in Hadrosaurids." PeerJ 1 (2013): E182.

Sullivan, R.M.; Lucas, S.G. (2006). "The Kirtlandian Land-Vertebrate "Age"-Faunal Composition, Temporal Position, and Biostratigraphic Correlation in the Nonmarine Upper Cretaceous of Western North America". In Lucas, S.G.; Sullivan, R.M. Late Cretaceous vertebrates from the Western Interior (PDF). New Mexico Museum of Natural History and Science Bulletin 35. pp. 7–23.

Weishampel, D.B. "Acoustic Analysis of Vocalization of Lambeosaurine Dinosaurs." Paleobiology 7.2 (1981): 252-61. 

Wilfarth, Martin (1947). "Russeltragende Dinosaurier". Orion (Munich) (in German) 2: 525–532.