Aquilonifer: Beast of the Week

This week we will be looking at a tiny creature that gives us insight to how some of the earliest mothers raised their young.  Check out Aquilonifer spinosus!  Aquilonifer was a small arthropod (same group of animals that includes insects, arachnids, and crustaceans) that lived in what is now Hertfordshire, England, during the Silurian Period, about 430 million years ago.  It measured only about a centimeter long as an adult and would have scuttled around on the ocean floor. We are unsure as to what it ate but it may have been a scavenger, sifting through the sand, and eating any tiny morsel of organic material it could find.  Judging by its mouthparts it may also have been a predator, subduing and eating smaller animals it came across.  The genus name, Aquilonifer, translates to "Kite Carrier" and the species, name spinosus, translates to "spiny".  It was also referred to as "The Kite Runner" by paleontologists who found and studied it for the fashion in which it cared for its young.

Life reconstruction by Christopher DiPiazza

This little creature was found with ten even tinier arthropod organisms attached to its body via fine threads.  At first it was hypothesized they may have been some sort of parasite, but that doesn't make much sense since all known parasites would need to be much closer to their hosts in order to survive, not floating behind it on a string.  It was then determined, upon looking at them more closely, that they were most likely offspring.  This creature would have dragged its kids around like little parasailers underwater!  Even though no animal known today does anything quite like this, many arthropods do carry their young around with them via other means.  Many spiders carry their eggs and young in a silk pouch attached to the abdomen, and mother scorpions pile their liveborn offspring onto their backs.  Considering how old and distantly related Aquilonifer is to these modern creatures, to say this was indeed a method of parenting isn't really unreasonable.  Parasites, on the other hand, tend to be pretty consistent across the board in wanting to be on or inside their hosts.

Basically this, but with less character-building experience.

Aquilonifer was also interesting in that beyond being an arthropod...scientists can't quite figure out exactly where it belongs on the family tree.  It may have been an extremely early branch of the arthropod phylum, that would eventually radiate into the forms that you see today.  When alive it may have crawled around on the ocean floor similar to a centipede does on land with its 26 legs.  It had a long pair of feelers in the front, what appear to be mandibles in the front, and ...get this....no eyes.  This isn't that crazy if you think about it.  This creature probably relied mostly on feeling in an environment where having a sense of sight wouldn't have benefited it.

High power 3D scanning of the tiny fossil allowed scientists to get a more detailed view of its anatomy.

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

References

Siveter, David J, Siveter, Derek J, Sutton, MD and Legg, D, 2016, Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care, PNAS Online 

 Jonathan Webb, BBC News, 4 April 2016, Bizarre fossil hauled its offspring around 'like kites'

Confuciusornis: Beast of the Week

This week we will be checking out possibly one of the most well-understood of all the prehistoric dinosaurs.  Check out Conficiusornis sanctus!  Confuciusornis was a prehistoric bird, that lived in what is now China, during the early Cretaceous Period, between 125 and 121 million years ago.  From beak to tail it measured about a foot and a half long, and had a wingspan of a bit over two feet wide.  When alive, Confuciusornis would have eaten meat but also probably ate plant material, possibly seeds, as well.  Its name translates to "Confucius Bird Sage", in reference to Confucius, the famous Chinese philosopher.

Confuciusornis is known from literally thousands of fossilized specimens, which is unheard of when it comes to other dinosaur fossils.  Because of this we know quite a bit about its anatomy and lifestyle.

Confucius fossil pair.  Possibly a male and female. (note the long tail feathers)

First of all, many of the Confuciusornis specimens preserved soft tissue, including feathers.  It had long, narrow primary feathers on the wings and certain individuals had a pair of extremely long, ribbon like feathers growing from their tails.  It has been suggested that Confuciusornis was sexually dimorphic, the males possessing the long ribbon feathers for display.  It is also possible that both sexes had these feathers, and certain individuals were molting (shedding old feathers) at the time of their deaths.  The presence of these feathers also didn't have any correlation with body size, so if it was sex-related, the males and females were the same size as adults.  These tail feathers are interesting in that only the tips demonstrate the classic feather structure with a central shaft, branching off into barbs on either side.

Confuciusornis possessed a large, toothless beak, like modern birds.  However, there were other prehistoric birds that lived after Confusiusornis had gone extinct that still had teeth.  This proves that Confuciusornis evolved its beak independently of those that we see in modern birds.  The beak would have been relatively powerful in life, and many scientists suggest it could have been a seed-eater.  Modern seed-eating birds, like cardinals and sparrows, have similarly shaped beaks.  However, some doubt this since no gastroliths, small rocks swallowed by animals to help digest hard food, like seeds, were ever found in any Confuciusornis specimen. (and we HAVE found them in many other dinosaur fossils) We know Confuciusornis  at least ate small fish, since the remains of one was found in the neck region of one specimen.  This could have been the crop, a pouch in the throat region of birds, used for storing food before swallowing.

The wings of Confuciusornis tell us that this dinosaur probably could fly, but it wouldn't have been as agile in the air as many modern birds are, especially for long periods of time.  We hypothesize this because Confuciusornis doesn't have a very large breastbone, or keel as it's called in birds, for wing muscles to attach.  Keel bones in many modern birds are proportionally huge.  Even the ones on domestic chickens and turkeys are large. (Next time you eat a rotisserie chicken check this out.  It's where the breast meat attaches to the skeleton.)  Confuciusornis also didn't have as wide of a range of motion in its shoulder joints as modern flying birds do, which would have made flapping a bit more difficult for it.  Finally, it's tail lacked the broad steering feathers found in modern birds.  The hands of Confuciusornis had three distinct fingers, tipped with curved claws, which is something else not common in modern birds.

Confuciusornis life reconstruction showing some display behavior by Christopher DiPiazza.

Lastly, scientists may have figured out what color Conficiusornis' feathers were!  Since the fossilized feathers were so well preserved, scientists were able to look at them under a powerful microscope and see the shapes of melanosomes, organelles that give color to a feather.  Even though the color, itself, wasn't visible, the shape of the organelle would reflect the pigment that would have been there in life.  By comparing these shapes to those of modern bird feather melanosomes, they were able to conclude that Confuciusornis likely had a dark gray body, black tail feathers, and possibly white primary feathers.  However, it should be noted that not ALL kinds of melanosomes necessarily preserved, so an overlapping of different kinds of these organelles may have yielded a different coloration in certain areas.

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

References

Chiappe, Luis M., Shu-An, Ji, Qiang, Ji, Norell, Mark A. (1999) "Anatomy and systematics of the Confuciusornithidae (Theropoda:Aves) from the Late Mesozoic of northeastern China" "Bulletin of the American museum of Natural History no.242 89pp.

Elzanowski, A. (2002) "Biology of basal birds and the origin of avian flight". In: Zhou Z., Zhang F. (eds) Proceedings of the 5th Symposium of the Society of Avian Paleontology and Evolution, Beijing, 1–4 June 2000. Science, Beijing, pp 211–226

Wogelius, R.A., Manning, P.L., Barden, H.E., Edwards, N.P., Webb, S.M., Sellers, W.I., Taylor, K.G., Larson, P.L., Dodson, P., You H., Da-qing L., and Bergmann, U. 2011. Trace metals as biomarkers for eumelanin pigment in the fossil record. Science, 333(6049): 1622-1626.

Zhou Z. and Farlow, J.O. (2001) "Flight capability and habits of Confuciusornis". In: Gauthier and Gall (eds). New perspectives on the origin and early evolution of birds: proceedings of the international symposium in honor of John H. Ostrom. Peabody Museum of Natural History. Yale University, New Haven. pp. 237–254

Yutyrannus: Beast of the Week

This week we will be checking out a dinosaur that changed the way we think about feathers.  Enter Yutyrannus huali!

Yutyrannus was a meat-eating dinosaur that lived in what is now China during the early Cretaceous Period, about 125 million years ago.  It was large, measuring about thirty feet from snout to tail as an adult.  The genus name, Yutyrannus, translates to "Feathered Tyrant" because, as you're about to learn, it had feathers!

Yutyrannus life reconstruction by Christopher DiPiazza.

Yutyrannus belonged to the tyrannosauroid group, and was closely related to other dinosaurs like Guanlong, Eotyrannus, and Dryptosaurus.  Like them, it had characteristic curved, serrated teeth, and strong front arms, each tipped with three hooked claws.  It's later relatives would eventually develop the well-known two-fingered front limbs, best known in its slightly more distant relative, Tyrannosaurus.  Adult Yutyrannus also possessed a short horn in front of each eye and a ridge-like bony crest running down the top of its snout.  These features may have been used for combat or display within its species.  Yutyrannus had strong legs, but its foot bones were relatively short compared to those of some other theropods, suggesting it wasn't an extremely fast runner in life. It may have been better at ambushing, and then using its size and power to take down prey, rather than chasing it very far.

Yutyrannus cast mounted at the American Museum of Natural History in New York.

Yutyrannus' real claim to fame, however, is the fact that we know for certain it had feathers.  This is due to actual visual presence of fossilized feathers found on the remains of the three specimens that were found.  Because of the placement of these feathers, which includes the bottom of the pelvis, the tail, the arms, and the ankle, it is likely that Yutyrannus had a more even coat of plumage over most of its body in life.  This evidence makes Yutyrannus the largest dinosaur known to date with actual fossilized feathers.  (Other large dinosaurs, like Deinocheirus, show evidence of having had feathers by having a pygostyle, but not actual fossilized feathers found with its bones, which is what we have with Yutyrannus.)  These feathers weren't preserved well enough to tell exactly what kinds of feathers they were, but they most likely would have been somewhat shaggy in life, similar to those on modern ground birds, like emus or kiwis.

Shaggy kiwi.  If you're even in Washington D.C., check these guys out at the National Zoo.

So why feathers?  This is the first question that many people ask when learning about Yutyrannus.  A better question might be "why not feathers?"  Feathers are a versatile adaptation.  They can keep an animal warm when the environment is cold, but also cool when the environment is too hot.  They also serve as protection against the elements like precipitation or the sun, can help camouflage by obscuring the animal's basic body shape, and can aid with communicating to other members of the same species in a visual and/or behavioral way.  Thanks to finding Yutyrannus, we now think it is possible, and maybe even likely that tyrannosauroids all had feathers in some form, including T. rex.

Preserved feathers on the ankle (you can see the bones on the left) of Yutyrannus on display at the American Museum of Natural History in New York.

If you live in the New York / New Jersey area you can come see a  cast of the famous Yutyrannus fossil, as well as remains (casts and real fossils) of many other important feathered dinosaurs at the American Museum of Natural History's seasonal Dinosaurs Among Us exhibit, which closes in January, 2017.  Maybe I'll see you there!  That is all for this week.  As always feel free to leave a comment below or on the facebook page.

References

Xu, X.; Wang, K.; Zhang, K.; Ma, Q.; Xing, L.; Sullivan, C.; Hu, D.; Cheng, S.; Wang, S.; et al. (2012). "A gigantic feathered dinosaur from the Lower Cretaceous of China" Nature 484 (7392): 92–95.

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 Citipati.  Gigantoraptor 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 https://doi.org/10.7287/peerj.preprints.1080v1

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.

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.

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, 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.

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.