Monday, March 28, 2016

Gigantoraptor: Beast of the Week

This week we will be taking a look at a dinosaur that gave paleontologists valuable information about fossil eggs, and the modern bird connections to prehistoric dinosaurs!  Enter Gigantoraptor erlianensis!

Gigantoraptor with nest life reconstruction by Christopher DiPiazza.

Gigantoraptor was an oviroraptorosaur theropod dinosaur that lived in what is now Mongolia, during the Late Cretaceous, about 70 million years ago.  It's name translates to "Giant Thief/Hunter" in reference to the fact that at a whopping twenty six feet long, it was much larger than other members of it's clade, like Oviraptor, Anzu, and CitipatiGigantoraptor is only known from one partial skeleton which was found to be still growing, so this dinosaur could have have been even larger as an adult.

Gigantoraptor skeletal mount on display in Japan.

Like its relatives, Gigantoraptor had a short, but deep and powerful beak, somewhat similar to a parrot's.  We know this thanks to a well-preserved lower jaw.  Sadly no upper skull has been found from Gigantoraptor yet.  What it used this beak to eat is still a total mystery.  It may have used it to crack open nuts or clip vegetation. Perhaps it was a meat-eater, as well, and used it to break bones?  Gigantoraptor also possessed three hooked claws on each hand and stood on two long, powerful legs.  For an animal its size, it was likely a fast runner.  Although there is no direct fossil evidence of it, Gigantoraptor almost certainly had feathers.

Eggs likely laid by Gigantoraptor with embryo skeleton.

Another really interesting thing about Gigantoraptor is the fact that paleontologists also have discovered its eggs! (and if they arent from Gigantoraptor they are from something EXTREMELY close to it.)  The eggs in question are almost cylindrical in shape, and each measure over twenty inches long!  Some of these eggs were carefully opened to reveal the bones of an oviraptorosaur embryo inside.  The eggs were discovered arranged in a ring formation.  This is typical for what we know about oviraptorosaur nest, thanks to relatives like Citipati, which were found actually brooding over the eggs laid in the exact position.  Gigantoraptor also would most likely have sat in the middle of this ring of eggs with its arms (which had feathers in life) spread over them for protection.  Within the ring of eggs, the eggs seem to have been laid in groups of two.  This is really important to know since it supports the idea that Gigantoraptor, along with many other egg-laying animals, possessed two oviducts in life.  Modern birds, and a few very bird-like nonavian dinosaurs are the only ones that have actually lost one of their oviducts as they evolved. (and do not pair their eggs as they lay them)  We used to think that birds developed this asymmetrical trait to become lighter and fly, but that doesn't explain why flightless dinosaurs like the troodontids evolved the same feature.

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

References

Wiemann J, Yang T, Sander PNN, Schneider M, Engeser M, Kath-Schorr S, Müller CE, Sander PM. (2015) The blue-green eggs of dinosaurs: How fossil metabolites provide insights into the evolution of bird reproduction. PeerJ PrePrints 3:e1323

Xu, X.; Tan, Q.; Wang, J.; Zhao, X.; Tan, L. (2007). "A gigantic bird-like dinosaur from the Late Cretaceous of China". Nature 447 (7146): 844–847.

Thursday, March 17, 2016

Interview with Paleontologist: Carl Mehling

Today we get to enjoy an interview with paleontologist, Carl Mehling!  Carl was one of the first people I became friends with since I started my involvement with the American Museum of Natural History.  He even led me on my first behind the scenes tour of the back fossil rooms.

Carl and I at the one of the museum's holiday parties.  He was wearing a Knights who Say Ni shirt...this HAS to be a great interview.

Carl Mehling has been at the American Museum of Natural History since 1990 and is currently a Senior Scientific Assistant taking care of the world’s largest collection of dinosaur fossils plus early synapsids and tetrapods, pterosaurs, crocodiles, turtles and marine reptiles. He is interested in all aspects of paleontology, especially the fringe areas that normally get little attention, including bizarre modes of fossil preservation, anomalous discoveries, and oddities within the history of paleontology. Carl collects fossils of all kinds, globally, and has written or edited a number of pieces on fossils, both scholarly and popular.



Question 1: Let’s start from the beginning.  What was your earliest sign of interest in paleontology that you can remember?

CM: I can remember, when I was maybe 5, my aunt and uncle gave my sister me each a Golden Book for Christmas. She got Dinosaurs and I got Three Little Indians. I remember successfully asking her to trade with me because I felt that dinosaurs were more appropriate for me. Who could argue?

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

CM: My parents. My mom is very meticulous, detail-oriented, and experimental. And my dad was the quintessential armchair naturalist. Loved Nature and the outdoors. Loved exploring. And both Mom and Dad were very supportive of my interests. Lucky me!

Question 4: Was there anything you did or learned as you were on your way to your current career that you feel got you to where you are?  By this I mean any sort of field experience, a class, networking with the right people, or possibly something different or all three?

CM: Probably the most important things I wound up with were insatiable curiosity, a reasonably open mind, and flexibility/tolerance. Can’t exactly say whether I had these qualities innately or acquired and developed them but they have set before me a smooth and fascinating road. But having these in place certainly made field experiences, classes, networking, and all other aspects of my path more enjoyable and easier.



Question 5: Is the field of paleontology different now than from when you started as far as you can tell?  What would your advice be to anyone trying to make a career in paleontology (or science in general for that matter) now?

CM: Absolutely. I sense that it is more rigorous and more integrated and more populated. Or maybe I see it that way because I am growing with it and becoming ever more aware of how it all works. Who can say? But what has certainly changed is all the incredible technology we can throw at the fossils now: CT, synchrotron, lasers, UV, LiDAR, etc. We can see and detect things about which we previously couldn’t even form questions. Certainly the best time to be in paleo. But paleontologists have been saying this from day one. I suspect it is simply always true and true for Science in general. What advice would I give to the next wave? Keep that truth in mind.

Question 6: What was or is your favorite project in paleontology so far?  Would you be able to tell us about some of your current projects?

CM: My favorite project was maybe a bit of meta-paleontology. My first job at the AMNH was as part of the Installation Crew for the Fossil Halls renovation in the 1990s. Our crew was responsible for hanging most of the ceiling specimens in the Hall of Vertebrate Origins. We first crafted accurate cardboard models of what was to be hung. This was used to decide the exact placement and orientation of the exhibit object, which was then brought in, configured accordingly and raised to its display height. Cables were set and we were on to the next thing. Lots of creativity. Lots of varied skills put to work. Excellent people to work with.
As for what I am doing right now I am curating my huge collections of fossil plants and coprolites (fossil poop), plus a few other various things, into the AMNH collections. It’s a huge amount of work with many steps but so cathartic and gratifying.

Question 7: You have traveled to a lot of interesting places around the world for your research, including the deserts in Mongolia, to our backyard in New Jersey!  Do you have a favorite destination when it comes to fossils?  Why?

CM: I guess the Cretaceous of NJ will always be my favorite collecting. I have been digging there since 1988 and it consistently surprises me. And now I know the biota so well that they are all like old friends. But lately my mind has been happily lost in the Permian. I did some collecting this year in TX & OK and am blown away by the diversity and abundance. And so many of the animals we found were icons of the Permian that I knew very well since I was very young and meeting them on their turf was a definite thrill. If I lived closer to these beds I am certain they’d be my favorite. At least until I collected somewhere else…


Question 8: A popular image of paleontologists is that they are constantly out in the field digging up fossils, which is true to an extent.  What people don’t realize sometimes is that a lot of paleontology work is conducted in a lab as well.  In your experience, how much of your projects (in general) take place in the field, and how much are in the lab?

CM: The overwhelming majority is the non-field part. Field work focuses on speed and efficiency: get as much of what you seek in the small amount of time you have and get it “home” as safely as possible. After that you can take your time with the real work: cleaning, preparing, repairing, sorting, comparing, identifying, housing, documenting, labeling, cataloguing, accessioning, musing, etc. Sometimes there is even molding, casting, mounting, displaying, photographing, etc. Any of these steps can take a surprising amount of time but each is satisfying in its own way.

Question 9: I remember you telling me specifically that you have collected lots of small fossils, many times in favor of large “sexy” ones.  What is the reason for this? (other than the fact that they’re easier to carry.)

CM: Very hard to say precisely. Part of it is the absolute beauty of some of the tiny teeth and such you meet under the microscope. There is also a thrill in learning to recognize whole animals from surprisingly small pieces. I have a tiny chip of a tooth from the Cretaceous of NJ, maybe a millimeter or two across, whose enamel is the spitting image of that on a hadrosaur tooth from the same place. This miniscule mote came from an animal around 30 feet long. That kind of cognitive connection delights me. But yes, of course, I also love picking up a tiny, gorgeous fossil, which needs no prep, as opposed to digging something huge up for days or weeks. I am from the camp that enjoys prospecting more than quarrying. But I know plenty of folks who prefer the opposite. Something for everyone.




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

CM: Since most of what I do is non-academic, and what I publish tends to be descriptive rather than postulative, I rarely get criticized for my work in paleo. But if one is in that position within any science, they must take it for what it usually is: the mechanics of Science. For Science to work it has to be a debate so that we can all get closer to the probable truth and not get seduced by our own suppositions.

Question 11: Jurassic Park and Land Before Time (opposite ends of the spectrum, I know) were just two of the programs I remember as a kid that helped fuel my obsession with paleontology.  Did you have favorite shows, movies, or even toys growing up that fueled your passion?

CM: Can’t really say if this influenced me or just fit into an already emplaced obsession, but the 70s Land of the Lost (I’m a bit embarrassed to say) was my go-to escape for a while.

Question 12: One of my pet peeves is when people assume paleontology doesn’t really do any real good in the grand scheme of things and is just a “for fun” science.  Do you think paleontology has a bigger part to than this?  How?

CM: Of course. Paleo is historical and thus as important as any history. Without the context of Life’s history we have no idea how we got here, how we fit in, and how life has dealt with all the slings and arrows of the Deep Past. We would have no idea what we are.


Question 13: Who was the first paleontologist you met?  How was that interaction?

CM: Since a paleontologist is anyone who studies fossils, I will assume you mean professional or academic paleontologist. Yet, I can’t exactly remember who was first. I got a behind-scenes-tour at the AMNH with Dr. John Maisey and Dr. Lowell Dingus in maybe 1989. I remember being dazzled and enthralled with everything I saw. They were very good gatekeepers to meet so early on and they are still good friends.

Question 14: Why do you think prehistoric animals are so influential to us today?

CM: I wrote a 60 page paper on this in college. It’s a surprisingly complex question. But basically fossils fuse fantasy with reality. The organisms they represent certainly existed. We want to know them. But the yawning gulf that separates us from fully knowing them allows is, urges us, to fill in the gaps with our imaginations. Humans are story tellers and fossils are the “One upon a time”s…

Question 15: What is your favorite prehistoric animal?  Was it different when you were younger?

CM: It was certainly different when I was younger because it changes ALL the time. Right now it is Petalodus, a Pennsylvanian shark known only from its especially bizarre teeth. Petalodus is my current favorite because I collected my first Petalodus teeth a couple of months ago. My favorite with certainly change in a flash. I am not loyal to any one organism.

Question 16: If you could use a time machine to go back and pick only one prehistoric animal to bring back from history and observe alive and in person, which would it be and why?

CM: Again, it would be Petalodus because it’s in my head and so secretive. But some recent head scratchers that excited me are Atopodentatus, Deinocheirus, Dimetrodon, the new giant Romanian pterosaur, the new giant Argentine titanosaur, Yi qi, any carpoids or eurypterids, Didymoceras. Why? Because they are mysterious!

Dimetrodon

Question 17: Back to the time machine.  This time you can go back to any place and time period and have a look at what the environment was really like.  Which one would you pick and why?

CM: Right now it would be the Permian since that’s where my head is at the moment. But in general, it would be “older is better.” The less it would look like the familiar biota of today the more excited by it I would be.

Question 18: Which is your favorite museum?  Why?

CM: I do, of course, love the AMNH. It’s huge, has an incredible collection whether you look at its diversity, scope, or sheer numbers. I know the history very well and love the stories and characters. But I also love well done, small, regional museums. One that comes to mind is the tiny but complete Santa Cruz Museum of Natural History.

Question 19: What hobbies do you have?  (Don’t have to be paleo-related.) 

CM: Inside and outside of my job I focus on fossils. But since we’ve heard all about that… I am also a letterer with a special focus on ambigrams. I love linguistics and its evolutionary aspects. I love the outdoors, above and below water. I adore food in all of its incredible variety.


Sunday, March 13, 2016

Acheroraptor: Beast of the Week

This week let's take a look at a mysterious, yet at the same time, very familiar dinosaur.  Check out Acheroraptor temertyorum!

Acheroraptor was a meat-eating dinosaur that lived during the Late Cretaceus Period, about 66 million years ago in what is now the Montana, USA.  It is estimated to have measured about six feet long from snout to tail, but this is mostly based on the proportions of other related dinosaurs that are more completely known, since Acheroraptor is known from very fragmentary remains.  The genus name translates to "Underworld Thief" in reference to the Hell Creek Formation, the geological formation in Montana, from which its remains, along with those of many other dinosaurs, were unearthed.  When alive, Acheroraptor lived alongside very famous creatures, like Tyrannosaurus, Triceratops, and Ankylosaurus, as well as Quetzalcoatlus, Pachycephalosaurus, Dakotaraptor, Anatotitan, and Anzu.

Acheroraptor life reconstruction by Christopher DiPiazza. (Mostly based off Velociraptor)

Acheroraptor was a member of the dromaeosaurid family.  These predatory dinosaurs were known for being relatively small, feathered, and for having a retractable sickle-shaped claw on each foot.  The most famous member of this group, obviously being Velociraptor.  This family of dinosaurs can be tracked back to the early Cretaceous where they proceeded all the way to the very end of the Mesozoic Era, Acheroraptor, being one of the very last, and was likely one of the species to have died out when the meteorite hit the earth, 66 million years ago.

Acheroraptor has been known about for a long time, in the form of isolated teeth scattered around the Hell Creek formation, but was never given a formal name.  Believe it or not, paleontologists who know their dinosaurs can identify a tooth alone as being from a dromaeosaur!  Dromaeosaur teeth tend to be triangular, blade-like, and have serrations on both sides.  It was simply referred to as "That dromaeosaur from the Hell Creek Formation" for years until some fragments of its actual jaws were finally found and it was formally named and described in 2013.

Known Acheroraptor jaw material from Evans' 2013 paper.

What's interesting about Acheroraptor is that, despite the fact that it lived in North America, by closely examining its teeth and the shape of its jaw, paleontologists were able to deduct that it was most closely related to Asian droameosaurids, like Velociraptor, and not other North American dromaeosaurids like Dromaeosaurus or Deinonychus.  This suggests that Acheroraptor's ancestors migrated to North America from Asia when the continents were connected.  This is also thought to have been the case with its contemporary, Tyrannosaurus, which also had earlier, close relatives from Asia.

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

References

Evans, D. C.; Larson, D. W.; Currie, P. J. (2013). "A new dromaeosaurid (Dinosauria: Theropoda) with Asian affinities from the latest Cretaceous of North America". Naturwissenschaften.

Wednesday, March 2, 2016

Aerodactylus: Beast of the Week

This week we will look at a newly discovered (sort of) pterosaur with a really cool name.  Enter Aerodactylus scolopaciceps!

Aerodactylus was a pterosaur that lived in what is now Germany, during the Late Jurassic Period, around 150 million years ago.  It is only known from juvenile specimens with small, roughly one-and-a-half foot wingspans.  Adults would probably have been a bit larger than this, perhaps possessing about three-foot wingspans.  (This is purely based on estimates of adults of similar, more completely-known pterosaurs, like Pterodactylus.  Adult Aerodactylus may have been different.)  Aerodactylus was most likely a meat-eater when alive, using its jaws to snap up small prey.  The genus name, Aerodactylus translates to "Air Finger" but there's more to it than that.  It was really named after Aerodactyl, which is a pokemon...based on a pterosaur.  So to sum that up for you pterosaurs inspired the creation of the fictional character, Aerodactyl, which in turn, inspired the name of the actual genus of pterosaur, Aerodactylus.  I love it!

Life reconstruction of Aerodactylus by Christopher DiPiazza.
Aerodactylus was discovered and described back in the 1850s but it was considered a species of Pterodactylus at the time.  The two were similar in appearance and both lived in what is now Germany during the same time period so it was easy to assume that they were more closely related than they really were at the time.  In 2014 the specimens we now call Aerodactylus, were examined more closely, and were discovered to be different enough to warrant their own genus.  They had a different number of teeth, which were were more sparsely arranged in the mouth, differently shaped skulls and eye sockets, longer tail vertebrae, and slightly differently proportioned wings.  These characteristics seem minimal at first, but they are important.  In fact, Aerodactylus was determined to not even belong to the same family, let alone genus, of pterosaur as Pterodactylus

Aerodactylus, thanks to a few very well-preserved specimens, tells us that it would have had a crest on its skull in life, webbed toes, and a pouch under its throat.  All of these characteristics, combined with the fact that it fossilized in what was a lagoon of some sort at the time of its death, support the idea that Aerodactylus was adapted for living and hunting near the water.  Its long jaws, with pointed teeth concentrated towards the tips could have been for snapping up small fish or invertebrates in shallow water, and its webbed toes could have aided it if it waded or swam on the surface of deeper water. 

Aerodactylus juvenile specimen from Vidovic's 2014 paper.  This famous fossil was referred to as Pterodactylus kochi for a long time.  Note the well-preserved throat pouch and outline of the uropatagium (webbing between inner leg and thigh), neck and shoulders,

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

References

Vidovic, S. U.; Martill, D. M. (2014). "Pterodactylus scolopaciceps Meyer, 1860 (Pterosauria, Pterodactyloidea) from the Upper Jurassic of Bavaria, Germany: The Problem of Cryptic Pterosaur Taxa in Early Ontogeny". PLoS ONE 9 (10): e110646.