Interview with Paleontologist: Natalia Jagielska

Natalia Jagielska is in her 3rd year of PhD study at University of Edinburgh. Specialising in Jurassic Pterosaurs. Prior to doctorate she worked on synchrotron scanning of avian fossils at University of Manchester. 

Question 1: What was your earliest sign of interest in paleontology that you can remember?

NJ: Watching Jurassic Park 3, I'd take a guess, I really liked the raptors. 

Question 2: Did you have anyone who served as a role model when you were younger? Do you still have any now?

NJ: Not really. I really looked up to Nikola Tesla, a working class East European with thick accent and eccentricities, making his way in the West. While loving pigeons.

Question 3: You primarily work with pterosaurs. Did you choose them or did they choose you. (in a sense) 

NJ: It was purely accidental. There was a PhD opening on research on Skye material, I worked on Skye Jurassic deposits in my undergraduate. Unlikely match. 

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? What sort of field experience, a class, networking with the right people, or possibly something different?

NJ: I did a lot of free volunteering and part time work in various sectors. I did teaching, museum outreach, museum curation, industrial petroleum research, NGO, anything that came my way. I regret it in hindsight, as I missed much on developing my private life & ruining work life balance. But boosted my CV allowing to be rather competitive even without research, palaeontology, field work portfolio. 

Question 5: What would your advice be to anyone trying to make a career in paleontology (or science in general)

NJ: Know what you're getting into. And be aware it's a competitive field, with more graduates than job positions. Keep your options open and don't fall into tunnel vision. 

Question 6: What was or is your favorite project so far?

NJ: Mapping of Lower Jurassic Skye I had to do for my undergraduate thesis. 

Question 7: Do you have a favorite destination when it comes to fossils? Why?

NJ: Regis, I just like working with strata that is fissile. And Dorset is nice. 

Natalia with the fossil of the pterosaur, Dearc, which was described by Natalia in Februrary of 2022.

Question 8: A popular image of paleontologists is that they are constantly out in the field digging up fossils, which is true sometimes What people don’t realize is that a lot of paleontology work is conducted in a lab as well. In your experience how much time have you spend in the lab and in the field? What do you prefer?

NJ:. It's 90% office desk or work at home on computer. Especially during the pandemic. 

Question 9: Are there any fossils you’d like to work with that you haven’t yet?

NJ: Elements from the from Karabastau Formation, which might be really unlikely given sociopolitical situation of things 

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

NJ: It's part of research. Depends on delivery of criticism. If it's constructive peer review, I take on board and value it greatly. If it's someone with too much free time and twitter, I doubt it's in goodwill. 

Question 11: A common idea is that paleontology is just a “for fun” science, with no real impact or noticeable effect that helps the world. Do you think paleontology has a bigger part to play to than this? How?

NJ: It's accessible. Visual. And resonates with general public more than any other research field. It's an excellent vehicle for science communication & magnet to get people into educational spaces, like museums. Especially kids. 

Question 12: Who was the first paleontologist you met? How was that interaction?

NJ: On my first lecture on palaeontology at University, Professor John Nudds. I asked about place for work experience in the field in Manchester. Palaeontologists are just people, it's weird holding them up on some pedestal. 

Question 13: What is your favorite prehistoric animal? Was it different when you were younger? 

NJ: Any Dromaeosaurid, then and now, they're like felines of the Mesozoic world and I love felines. 

Question 14: 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?

NJ: Vast majority of fauna isn't preserved well in fossil record. I'd get something that clearly does not have good potential of preserving & we have no record of it.

Question 15: 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?

NJ: Georgian & Victorian England. I just want to know what kind of person Darwin & Owen really were. And see Crystal Palace before it burned down. 

Question 16: Which is your favorite museum? Why?

NJ: I'm going to be extremely sad, and say Natural History Museum London. It's neogothic cathedral for natural world. You cannot get better than this. It's big, and free. 

Question 17: What hobbies do you have? (Don’t have to be paleo-related.)

NJ: I love city walking & architecture, it's like geology of the human age. I also love to build plane models in my spare time. And KTV (Chinese Karaoke), extreme cheese fest, but I love screaming over ABBA. 

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Atrociraptor: Beast of the Week

 This week we'll be covering a unique predator that will be makes its big screen debut in the movie, Jurassic World: Dominion.  Let's check out Atrociraptor marshalli!

Atrociraptor was a meat-eating dinosaur that lived in what is now Alberta, Canada, during the late Cretaceous period, about 68.5 million years ago.  It is estimated to have measured a little over 6 feet long (2 meters) from snout to tail when alive, but this is based on only some skull pieces and scaling them to more completely known relatives.  The genus name translates to "Atrocious Thief". 

Atrociraptor life reconstruction in watercolors. By Christopher DiPiazza

Atrociraptor was a member of the dromaeosaurid family of dinosaurs.  Dromaeosaurids were famous for being relatively small, relatively fast-moving predators with a long retractable claw on the second toe of each foot.  Deinonychus and Velociraptor are the two most famous members of this group.  There are many dromaeosaurids that were discovered possessing fossilized feathers or direct evidence of feathers, so it is almost certain that being feathered was a universal trait to this group, meaning Atrociraptor likely would have been feathered in life as well.  

Unfortunately Atrociraptor is only known from some skull material, specifically the tips of the upper and lower jaws, and teeth.  Based on this, however, scientists were still able to tell it was a dromaeosaurid by the size and number of serrations on the slightly curved, blade-like teeth, which are diagnostic to the family.  Atrociraptor's teeth weren't as curved as those of some other meat-eating dinosaurs, but they were arranged in the jaw so that the tips were dramatically angled to the back of the mouth, which would have helped the dinosaur get chunks of flesh down faster as it tore them off.  This also would prevent living prey from escaping if it was bitten.  Based on the actual jaws, Atrociraptor would have had an unusually short, but deep snout, which is in contrast to its relative, Velociraptor, known for having a particularly long, narrow one.  

Fossil specimen of Atrociraptor's jaws. (photo by Emily Willoughby)

Despite what is often portrayed in movies, we have no idea if Atrociraptor hunted in groups or alone in life.  Like many meat-eaters today, there is a chance it may have done a bit of both depending on what kind of prey was available.  We may never know for sure! 

Atrociraptor would have shared its habitat with other dinosaurs, like, Anodontosaurus, Hypacrosaurus, and Pachyrhinosaurus, Sphaerotholus?  It also would have been weary of the large tyrannosaurid, Albertosaurus.  

References

Currie, P. J. and D. J. Varricchio (2004). "A new dromaeosaurid from the Horseshoe Canyon Formation (Upper Cretaceous) of Alberta, Canada". Pp. 112–132 in P. J. Currie, E. B. Koppelhus, M. A. Shugar and J. L. Wright. (eds.), Feathered Dragons. Indianapolis: Indiana University Press.

Larson, D. W., Brinkman, D. B., & Bell, P. R. (2010). Faunal assemblages from the upper Horseshoe Canyon Formation, an early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed This article is one of a series of papers published in this Special Issue on the theme Albertosaurus. Canadian Journal of Earth Sciences, 47(9), 1159-1181.

Lü, Junchang; Brusatte, Stephen L. (2015). "A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution". Scientific Reports. 5: Article number 11775.

Turner, A.H.; Makovicky, P.J.; Norell, M.A. (2007). "Feather quill knobs in the dinosaur Velociraptor". Science. 317 (5845): 1721.

Xu, Xing; Zhou, Zhonghe; Wang, Xiaolin; Kuang, Xuewen; Zhang, Fucheng; Du, Xiangke (2003). "Four-winged dinosaurs from China". Nature. 421 (6921): 335–340.

Dearc: Beast of the Week

 This week we'll be checking out a newly described pterosaur.  Make way for Dearc sciathanach!

Dearc (pronounced like jark)was a pterosaur that lived in what is now Scotland during the middle Jurassic period, about 166 million years ago.  The one skeleton found would have had a wingspan of about 8 feet (2.5 meters), but it's possible this taxa could have grown large in life, with wingspans of over 9 feet. (3 meters)  The genus and species name translate from Gaelic to "Flying Lizard". Like many of its relatives, Dearc, was almost certainly a meat-eater when alive, possibly preying on fish.

Watercolor life reconstruction of Dearc by Christopher DiPiazza.

Dearc is special for a few reasons.  It was a member of what is referred to as the rhamphorhynchoid group of pterosaurs, which flourished during the Triassic and Jurassic, but appeared to have gone extinct by the Cretaceous periods.  They are identified by having long, pointed teeth, proportionally short hind legs, and long narrow tails.  Dimorphodon is another example of a rhamphorhynchoid.  The other pattern about this group of pterosaurs is that they are overall smaller when compared to their cousins, the pterodactyloid pterosaurs. (like Pteranodon or Quetzalcoatlus) With this in mind, Dearc is particularly large for a rhamphorhynchoid, with a wingspan that was over eight feet or more given that  the individual specimen unearthed was still growing when it died!  

It is the most well-preserved pterosaur specimen to ever be discovered in the United Kingdom, known from an almost complete skull (missing the top of the head and top tip of the jaw, and almost the entire body.  Only the legs, some of the wing bones, and the tip of the tail are really missing.  This is amazing since pterosaurs, having such delicate bones, are not usually fossilized at all unless in really specific conditions, and when they are, they're usually either highly fragmentary or totally flattened to the point their bones are almost in two dimensions when found. Dearc, on the other hand's skull was so well preserved, that paleontologists were able to scan the inside of it and learn what the shape of its brain and inner ear cavities looked like!  Their findings suggest Dearc had a proportionally tiny brain, except for the optic lobes which were huge. This means Dearc would have had sharp eyesight when alive which makes sense for flying and searching for prey from the air.

Fossil of Dearc. photo from the paper describing the taxa by Natalia Jagielska. (listed below)

Dearc's environment would have been much warmer tan it is in Scotland today, and consisted of a series of small islands surrounded by shallow tidal seas.  Dearc may have used its sharp eyesight to hunt for food while flying in the air, possibly even plucking small fish or other animals from the surface of the water with its long, low skull, and extremely long, interlocking teeth.  I can also imagine it being an opportunistic feeder, going after any marine life stranded on sand bars during low tide.  Unfortunately not much is known about any of Dearc's neighbors since the fossil record of its time is still pretty scarce.  That being said dinosaur tracks, including those from stegosaurs, ornithopods, and theropods, were discovered near Dearc's skeleton from the same time, so it was definitely sharing space with large dinosaurs! 

References

dePolo, Paige E.; Brusatte, Stephen L.; Challands, Thomas J.; Foffa, Davide; Wilkinson, Mark; Clark, Neil D. L.; Hoad, Jon; Pereira, Paulo Victor Luiz Gomes da Costa; Ross, Dugald A.; Wade, Thomas J. (2020-03-11). Fiorillo, Anthony R. (ed.). "Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland"

Natalia Jagielska; Michael O’Sullivan; Gregory F. Funston; et al. (February 2022). "A skeleton from the Middle Jurassic of Scotland illuminates an earlier origin of large pterosaurs". Current Biology. 32: 1–8.

Troodontid (Alaskan): Beast of the Week

 This week we'll be checking out a unique member of the troodontid family of dinosaurs.  Let's check out the mysterious Alaskan troodontid!

The Alaskan troodontid was a likely mostly meat-eating dinosaur that lived in what is now Alaska, in North America, during the late Cretaceous period, about 69 million years ago.  From snout to tail it is estimated to have measured about 13 feet (4meters) long. 

This is the first dinosaur featured on Beast of the Week that doesn't have an official Genus and species name yet.  A formal scientific paper has yet to be published describing it, even though its known remains, consisting of teeth, are widely known.  

My life reconstruction in watercolors of a trio of the mysterious Alaskan troodontid.

Even though the fossil material is extremely scant, we know this dinosaur was almost certainly a member of the troodontid family of dinosaurs, like Pectinodon and Byronosaurus, because the fossilized teeth are curved and have extremely deep serrations, which is diagnostic for that group.  Troodontids were typically smaller, fast-running dinosaurs, that would have looked very similar to birds when alive.  What sets this Alaskan troodontid apart, however, is the fact that its teeth are much larger than those of its known relatives.  Using these teeth to predict the size of the rest of the animal, basing proportions off more completely known relatives, we end up with an unusually massive troodontid at about 13 feet long! To put it into perspective, Pectinodon, a more typically sized member of the family, was only about 6 feet long.  

The reasoning for this troodontid's large size is mostly a mystery.  Scientists predict it may have had something to do with its habitat, which if you might remember, was Alaska today.  During the late Cretaceous, Alaska wasn't as cold as it is now, but it was still significantly cooler for the time, compared to the rest of the world.  It also would have undergone long periods of darkness in the winter, just like it does today.  Perhaps having a larger body was an adaptation to the cold, since animals with larger bodies can retain body heat more easily.  On top of that, the Alaskan troodontid almost certainly had a coat of feathers that could have helped retain heat as well.  We can be fairly confident of this since we have fossils of other species of troodontid that preserved actual feathers and evidence of feathers.  

Skeletal mount on display at the Perot Museum in Texas.  Note the vast majority of this mount is guesswork based on other more completely known troodontids.

Like all known troodontids, this species likely would have had large forward-facing eyes, that would have allowed it to better hunt for small prey, possibly even at night.  We also know that troodontids had a strong sense of hearing thanks to enlarged middle ear cavities in their skulls.  At least some of them even had asymmetrically placed ears, an adaptation also present today in many owl species which allows them to better target moving prey in complete darkness or other situations where sight isn't an option.  

The Alaskan troodontid likely had long legs with a retractable toe, armed with a curved claw, on each foot.  This would have been an adaptation ideal for pinning down smaller prey, like mammals and possibly smaller/baby dinosaurs.  The teeth we know were serrated for slicing meat, although some have suggested troodontids may have supplemented their diet with plant material, too.  If this species was living in an environment that was cold and dark for months out of the year, food would have been scarcer, and more menu options would have been ideal anyway.  

When alive the Alaskan troodontid would have shared its habitat with the gigantic plant-eating dinosaur, Edmontosaurus, the ceratopsian, Pachyrhinosaurus, and it would needed to watch out for the tyrannosaurid, Nanuqsaurus.  

References

Castanhinha, R.; Mateus, O. (2006). "On the left-right asymmetry in dinosaurs". Journal of Vertebrate Paleontology. 26 (Supp. 3): 48A.

Currie, P. J. (1985). "Cranial anatomy of Stenonychosaurus inequalis (Saurischia, Theropoda) and its bearing on the origin of birds". Canadian Journal of Earth Sciences. 22 (11): 1643–1658.

Fiorillo, Anthony R.; Tykoski, Ronald S.; Currie, Philip J.; Mccarthy, Paul J.; Flaig, Peter (2009-03-12). "Description of two partial Troodon braincases from the Prince Creek Formation (Upper Cretaceous), North Slope Alaska". Journal of Vertebrate Paleontology. 29 (1): 178–187.

Nanuqsaurus: Beast of the Week

This week we shall be checking the arctic dinosaur, Nanuqsaurus hoglundi!  Nanuqsaurus was a tyrannosaurid, closely related to Tyrannosaurus, Tarbosaurus and Lythronax, that lived in what is now Alaska, North America, during the late Cretaceous period, about 69 million years ago.  Even though only parts of the skull, a few teeth, and a few other bones have been discovered, it can be estimated that Nanuqsaurus would have measured roughly 22 feet (6.7m) long from snout to tail when alive.  Like all known tyrannosaurids, it would have been a meat-eater.  The genus name, Nanuqsaurus, translates to "Polar Bear Lizard" because it was discovered in Alaska...where Polar Bears live.  


When Nanuqsaurus' fossils were initially published on in 2014, it was described as a "dwarf tyrannosaur" with an adult size estimate at about 18 feet long.  The thinking behind this was that since it lived at a higher elevation in an environment that was at least seasonally colder parts of the year, a smaller size would have aided it in requiring less food to stay alive, especially in the winter, when prey was likely more scarce.  A more recent study, however, suggests Nanuqsaurus was at least a little larger, more like 22 feet long, possibly even closer to 30 feet long as an adult, due to the observation that the original fossil material was likely from a juvenile that wasn't done growing at the time of its death, plus additional teeth found that were clearly from a larger animal.

Nanuqsaurus watches as a family of Edmontosaurus pass through.  Watercolor reconstruction by Christopher DiPiazza

A common misconception is that since Nanuqsaurus was found in Alaska, it must have been adapted to extremely cold temperatures, often depicted by artists with a thick coat of snow white feathers trudging through an icy wasteland.  This would make sense if Alaska was exactly the same during the Cretaceous as it is now...except it almost certainly wasn't.  During the Cretaceous, the global temperature was much warmer than it is today, so even the poles would have been noticeably greener.  That being said, what is now Alaska still would have been coolER at the time, experiencing definite colder seasons during winter and fall months, but probably with only occasional snow.  One thing about that environment that was consistent to today, however, was how the poles would have experienced extended periods of daylight in the summer and extended periods of darkness in the winter.  So winter still would have been challenging for most dinosaurs.    

The known remains of Nanuqsaurus from the paper by Fiorillo and Tykoski.  Despite the fact that it isn't much, they were able to determine after close examination that this is indeed a new genus and species of tyrannosaurid.

So how did a dinosaur like Nanuqsaurus survive in a cooler environment when tyrannosaurids elsewhere at the time thrived in more tropical climates?  We know that tyrannosaurs belonged to the broad branch of dinosaurs called, coelurosaurs, many of which were discovered with feathers.  It is therefore totally plausible to infer that all tyrannosaurs had at least some feathers. (Yes, even T. rex.)  Maybe Nanuqsaurus happened to have a denser coat of feathers for better insulation, much like birds in the arctic do today?  

Nanuqsaurus' size may have helped keep it warm as well.  An animal with a larger body has less surface area to volume ratio and therefore more heat conservation.  This is called Bergman's Rule.  You can see examples of Bergman's Rule today in the largest modern reptiles, like crocodiles, which can remain active for longer periods of time without direct access to heat than smaller kinds of reptiles like most lizards/snakes.  In fact, there is another dinosaur known from Nanuqaurus' habitat, a still unnamed species of troodontid, that was the largest known member of its typically small-bodied family, which probably evolved that way for the same reason.  

Animals that live in colder environments also often have shorter limbs and other extremities, which helps prevent as much heat from leaving the body as possible, called Allen's Rule.  We don't have much of Nanuqsaurus' skeleton past the jaws, but it wouldn't be unreasonable to guess it may have had a stockier build for this reason.  

Allen's Rule states that animals typically evolve shorter limbs and extremities to better adapt to consistently colder environments, as demonstrated with the cold adapted, Arctic Fox (Vulpes lagopus) compared to the more generalist, Red Fox (Vulpes vulpes).

When alive, it is likely Nanuqsaurus was the top predator of its environment.  It would have shared its habitat with the large ceratopsian, Pachyrhinosaurus perotorum, and the hadrosaur Edmontosaurus, and probably at least hunted their young.  It also crossed paths with the unusually large (but still smaller than it) Troodon species mentioned earlier, plus at least two kinds of dromaeosaurs.  

That is all for this week!  Feel free to comment below!

References

Druckenmiller, Patrick S.; Erickson, Gregory M.; Brinkman, Donald; Brown, Caleb M.; Eberle, Jaelyn J. (2021-08-23). "Nesting at extreme polar latitudes by non-avian dinosaurs". Current Biology. 31 (16): 3469–3478.e5.

Fiorillo, A. R.; Tykoski, R. S. (2014). "A Diminutive New Tyrannosaur from the Top of the World". PLoS ONE 9 (3): e91287. doi:10.1371/journal.pone.0091287.

 Fiorillo, Anthony R.; Gangloff, Roland A. (2000). "Theropod teeth from the Prince Creek Formation (Cretaceous) of Northern Alaska, with speculations on Arctic dinosaur paleoecology". Journal of Vertebrate Paleontology 20 (4): 675–682. doi:10.1671/0272-4634(2000)020[0675:TTFTPC]2.0.CO;2.

Rhinorex: Beast of the Week

This week we're checking out Rhinorex condrupus!  

Rhinorex was a plant-eating dinosaur that lived in what is now Utah, USA, during the late Cretaceous Period, about 75 million years ago.  It was a hadrosaurid, in the same family as other broad-billed duck-billed dinosaurs like Maiasaura, Edmontosurus, and Hadrosaurus.  From snout to tail Rhinorex would have measured about 30 feet (9m) long.  The genus name, Rhinorex, translates to "Nose king" in reference to this dinosaur's large, down-turned snout.  Other hadrosaurs had similarly-shaped snouts, but none as extreme as Rhinorex's.  When alive, Rhinorex would have lived nearby other dinosaurs such as Coahuilaceratops, Teratophoneus, and its close relative, Gryposaurus.

Watercolor life reconstruction of Rhinorex by Christopher DiPiazza

It's still not clear as to why some hadrosaurs, like Rhinorex, had such downturned snouts.  They may have been an adaptation for a specific feeding strategy, or possibly a display for attracting mates or intimidating rivals.  It may have even enabled Rhinorex to make certain sounds.  Lambiosaurine hadrosaurs like Parasaurolophus, possessed crests that grew from their snouts, but often extended to the tops of their heads for display and sound purposes.  It is possible that the lineage Rhinorex was from just applied the strategy in a different direction. 

Reconstruction and photograph of Rhinorex skull.  Image from the paper by Terry Gates and Rodney Scheetz.

Rhinorex was the only well preserved dinosaur fossil found from its specific area thus far.  In addition to it's skull there was also some skin impressions found, which look similar to other known hadrosaur skins; fine pebble-like scales.  All other dinosaur fossils in Utah from the same time period were found hundreds of miles away and would have likely been adapted to at least a slightly different kind of habitat.  Rhinorex helps fill in gaps previously unknown about Late Cretaceous ecosystems in Utah. 

That's all for this week!  As always feel free to comment below or on our facebook page!  Have a request?  Just let me know and I'll make it happen!

References

T.A. Gates & R. Scheetz (2014): A new saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the Campanian of Utah, North America Journal of Systematic Paleontology. doi: 10.1080/14772019.2014.950614

Tianyulong: Beast of the Week

This week we'll be checking out a fascinating little creature that changed the way we imagine dinosaurs.  Let's get to know Tianyulong confuciuci! 

Tianyulong was a plant-eating (or maybe omnivorous) dinosaur that lived in what is now Northeastern China, during the late Jurassic period, between 158 and 159 million years ago.  It was tiny, only measuring a little over two feet long from beak to tail. (about 70cm) The genus name translates to "Tianyu Dragon", named after the Tianyu Museum of Nature, where the first discovered skeleton of this dinosaur is housed. 

Tianyulong life reconstruction in watercolors by Christopher DiPiazza.

Tianyulong was a member of the heterodontosaurid family of dinosaurs.  Heterodontosaurids were small, plant-eating or possibly omnivorous, dinosaurs that flourished during most of the Jurassic period.  They are widely thought of being from the base of the ornithiscian branch of dinosaurs, which later includes ceratopsians (like Triceratops), ornithopods (like Iguanodon), and the armored thyreophroans (like Stegosaurus and Ankylosaurus).  More recently it was suggested that heterodontosaurids were more closely related to marginocephalian dinosaurs (group that includes more ceratopsians and pachycephalosaurs) than other ornithiscians.

We know more about what Tianyulong looked like in life, compared to most prehistoric animals, because there are more than one full skeletons on the fossil record.  Tianyulong had a proportionally large skull and short neck.  It also had very long legs with long foot bones, implying it was a fast runner in life.  The tail was more than double the length of the rest of the body.   

Cast of the holotype of Tianyulong on display at the American Museum of Natural History in New York in the temporary Dinosaurs Among Us exhibit.

In its skull, Tianyulong had small flattened teeth in the back of its jaws that appear to have been ideal for shearing plants.  In the front of its mouth, just behind its beak, it had two pairs of long canine-like teeth, a trait present in all known heterodontosaurids.  It is still unclear as to exactly why this unusual trait evolved, especially in small plant-eating dinosaurs.  It is also worth noting that individuals that appear to have been not fully mature still have these long teeth, so they may not have been an adaptation for sexual selection.  There is also no evidence they were only present in one sex and not the other.  Some have suggested they had something to do with the dinosaur's diet.  Others have suggested that both males and females could have used these teeth to participate in intraspecies combat or display over territory.   

Tianyulong skeleton, including the outline of feathers, currently at the Beijing Museum of Natural History.  Note how most of the body is covered in feathers.  Also check out that cute tail tuft!

Possibly the most amazing thing that we know about Tianyulong is the fact that many of the skeletons found preserved feathers! The exact arrangements of these feathers varies slightly among the known individuals, but they all at least appear to have had long bristle-like structures growing from their backs.  One individual also shows a shorter, but extensive coat of feathers over most of the rest of the body with a tuft of longer feathers at the tip of the tail.  Another still undescribed individual (mentioned by paleontologist, Dr. David Hone) had what appears to be the long bristles in a mohawk arrangement running from the head down almost the entire length of the animal's body.   It is possible these variations could be based on the sex or maturity of the animals. It's also possible they all looked the same in life but fossilized in different stages of decomposition, resulting in some with more feathers than others. Regardless, the presence of these feathers on Tianyulong, an ornithiscian dinosaur and not a theropod (dinosaur group that includes birds), strengthens the argument that feathers may have been more extensive among dinosaurs than originally thought.  

References

Butler, Richard J.; Smith, Roger M.H.; Norman, David B.(2007). "A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia". Proceedings of the Royal Society B: Biological Sciences. 274 (published online): 2041–6.

Butler, Richard J.; Upchurch, Paul; Norman, David B. (2008). "The phylogeny of the ornithischian dinosaurs". Journal of Systematic Palaeontology. 6 (1): 1–40. 

Liu Y.-Q. Kuang H.-W., Jiang X.-J., Peng N., Xu H. & Sun H.-Y. (2012). "Timing of the earliest known feathered dinosaurs and transitional pterosaurs older than the Jehol Biota." Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication).

Zheng, Xiao-Ting; You, Hai-Lu; Xu, Xing; Dong, Zhi-Ming (19 March 2009). "An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures". Nature. 458 (7236): 333–336.