Furcatoceratops: Beast of the Week

 This week we'll be checking out a newly described ceratopsian, Furcatoceratops elucidans!

Furcatoceratops was a ceratopsian dinosaur that lived in what is now Montana, USA, during the late Cretaceous period, between 76 and 75 million years ago.  From beak to tail it measured about thirteen feet (4 meters) long.  The genus name translates to "Forked-horned Face" and the species name, elucidans, means "enlightening".  Like all known ceratopsians, Furcatoceratops likely ate plants when it was alive.

Watercolor life reconstruction of Furcatoceratops by Christopher DiPiazza.  The crossed horns is speculation based on the fact that there would have been keratin growing over the fossilized horn cores (which are very close together) in life.  

Amazingly, Furcatoceratops is known from an almost complete skeleton, which is rare for dinosaur fossils.  As is the case with most ceratopsians, its most notable feature is its horns.  Furcatoceratops had two horns growing from above its eyes that are quite close together, basically parallel to each other. This is unusual compared to the brow horns of other ceratopsian dinosaurs, which tend to grow angled away from each other.  Furcatoceratops also had a series of small, triangular horns growing from the perimeter of its frill.  Many ceratopsians also have a horn on the snout over the nostrils but since that portion of Furcatoceratops' skull was one of the few parts not found, it is unclear if it also had a horn there in life.  

As which all ceratopsians, the exact evolutionary purpose of Furcatoceratops' horns is unknown, but display within its species or defense against potential predators are possibilities.  Lower on the skull, Furcatoceratops had a sharp beak backed up by many small teeth that would work together like shears for processing mouthfulls of plants when alive. 

Furcatoceratops skeleton on display at the National Museum of Nature and Science in Tsukuba, Japan. (photo credit: "eight heads serpent")

Within the ceratopsian group (dinosaurs known for their horns and bony frills) Furcatoceratops is part of the centrosaurine branch of the family tree.  Centrosaurines are known for having robust, tall snouts, and proportionally shorter frills.  Within this group, Furcatoceratops appears to be particularly closely related to Nasutoceratops, which was alive during almost the same time as Furcatoceratops in what is now Utah, USA.  

That is all for this week!  As always feel free to comment below!

References

Ishikawa, H.; Tsuihiji, T.; Manabe, M. (2023). "Furcatoceratops elucidans, a new centrosaurine (Ornithischia: Ceratopsidae) from the upper Campanian Judith River Formation, Montana, USA". Cretaceous Research. 105660.

Visiting the Pokemon Fossil Museum

 I was fortunate enough to take a trip to Japan this past summer with friends and family. We are all big Pokemon fans, my wife and I having played the games since the late 90s, and my daughter enjoying the anime, so we naturally had a lot of fun visiting several of the official Pokemon centers and other attractions throughout the country during our three weeks in the country.  One of the must-sees was to visit the Pokemon Fossil Museum, a traveling exhibit that showcases fabricated skeletons and models of prehistoric Pokemon alongside casts of the real dinosaur and other prehistoric animal fossils they're based on.  

Model of what the skeleton of the Pokemon, Tyrantrum, might look like on display in the main hall of the museum, before entering the exhibit. My daughter and I for scale.

Upon entering the exhibit visitors are greeted by a model of the pterosaur Pokemon, Aerodactyl, being ridden by a Pikachu (because of course there's Pikachu) dressed like a paleontologist. Pikachu was never one of my favorite Pokemon but I must admit this version of the electric mouse was very cute.  "Paleontologist Pikachu" would be portrayed several more times throughout the exhibit acting as a sort of guide, and was shown interacting with various prehistoric Pokemon.  Regarding Aerodactyl, despite being one of the original fossil Pokemon from the first generation of the franchise, there is no actual skeleton of it in the exhibit.  It is mentioned and depicted again alongside a cast of a Pteranodon, Dimorphodon, and Pterodactylus, demonstrating pterosaur anatomy, however. 

Aerodactyl and Paleontologist Pikachu are the first pokemon models you meet upon entering.  Sadly there was no Aerodactyl skeleton on display anywhere. 

Casts of the skeletons of Pteranodon and Dimorphodon hanging from the ceiling.

Two more of my favorite Pokemon, Cranidos and Rampardos, based on pachycephalosaurs, were also not featured as models or skeletons, but they are mentioned alongside casts of two different Pachycephalosaurus skulls.  

Pachycephalosaur section of the exhibit.  It was cool to see two different Pachycehpalosaurus specimens on display next to each other.  Sadly there were not models or skeletons of Cranidos or Rampardos on display anywhere.

The exhibit showcases quite a few ceratopsian pieces, including a (real?) Protoceratops skull and a baby Triceratops skull cast that appears to have been filled in quite a bit.  It doesn't match the other baby Triceratops skulls I've seen in photos of and in person at other museums.  They also have a model of what I'm pretty sure is the Triceratops prorsus skull, from the Yale Peabody Museum.  These pieces are showcased alongside a full skeleton model of the ceratopsian Pokemon, Bastiodon.

Protoceratops and baby Triceratops skull cast.  You can tell what parts of the Triceratops are reconstructed by the smooth texture.

The ceratopsian part of the exhibit, flanked by skeleton of the pokemon, Bastion in the background, and model of Triceratops prorsus skull in the foreground.

The main hall of the exhibit showcases full skeletal mounts of the sauropod Pokemon, Aurorus, and the real dinosaur it's based on, Amargasaurus, opposite each other where visitors can compare them side by side.  Amargasaurus is known for the long, bony extensions growing from the top of its neck vertebrae, which may have formed a sail or hump in life. Aurorus design took this feature and turned it into an aurora borealis-like structure that ripples like a flag.  The signage explicitly mentions that the structure on the Pokemon has no bones supporting it, but the skeletal model has pieces for it.  I'm assuming to keep the skeleton recognizable especially to younger visitors.  Makes me think of how some skeletal mounts of real dinosaurs include physical outlines of soft parts, like wings or even attach real arm feathers to the bones to showcase structures that would have been present in life. 

The Pokemon, Aurorus, and dinosaur, Amargasaurus were the two largest pieces in the exhibit.

Beautiful Amargasaurus.  This was my first time seeing a skeletal mount of this dinosaur in person.

Aurorus is one of my all time favorite Pokemon so it was a delight to see this model skeleton.

There was of course a theropod section, with a cast of the original Megalosaurus jaw discovered in the 1800s, alongside a cast of what is labelled as a baby Tyrannosaurus skull.  I was unfamiliar with this specimen so I reached out to paleontologist and tyrannosaur expert, Dr. Thomas Holtz, who was kind enough to share that it appears to be of a two-year old Tyrannosaurus specimen housed in Los Angeles.  The actual specimen is only known from the very front of the snout and lower jaw, and a part of the top of the cranium, so most of the skull on display here is reconstructed.  These are showcased alongside a model skeleton of the tyrannosaur Pokemon, Tyrunt.  I appreciate how the design of the Pokemon shows the teeth as part of the actual jaw, instead of in sockets, like the Pokemon's design suggests. 

Megalosaurus jaw cast and the mostly reconstructed baby Tyrannosaurus skull cast.

Skeleton model of the tyrannosaur pokemon, Tyrunt.

The link between theropod dinosaurs and modern birds is also addressed with a skeleton model of the feathered dinosaur Pokemon, Archen, alongside a standing skeletal mount and cast of the famous Archaeopteryx specimen, housed in Berlin.

Check out that beautiful Archaeopteryx art by Hitoshi Ariga.

Archen, which is mostly based on Archaeopteryx, skeleton on display.

I was impressed by how much attention was given invertebrate fossils in this exhibit, particularly ammonites.  In fact, the most extensive collection on display in the exhibit was of ammonites, which were of course shown alongside their Pokemon counterparts, Ammonite and Omastar.  

This exhibit showcased an extensive collection of real ammonite fossils packed with information.

Other invertebrate Pokemon were represented, including the flying bug-type Pokemon, Yanmega, alongside casts of the real prehistoric flying insect, Meganeura.  Fossils of crinoids alongside models of the Pokemon Lileep were present, and of course horseshoe crabs alongside the Pokemon, Kabuto and a skeleton of its evolved form, Kabutops.  

Comparing the Pokemon, Kabuto, to horsehoe crabs.  I love how the eyes on the model appeared to be glowing.

Kabutops skeleton model.  I'm assuming it's meant to represent a fossilized exoskeleton?  I remember seeing a little pixelated image of this in the museum part of the old Pokemon gameboy game.

One very entertaining aspect of this exhibit for Pokemon fans was the models of the fossil items obtained in the video game that can be turned into Pokemon on display.  My favorite example of this is the "old amber" fossil item, used to resurrect Aerodactyl in the game, displayed alongside real pieces of fossil amber.  

"Old Amber" from the Pokemon games alongside some real fossilized amber.

I've seen museum exhibits based on fictional entertainment franchises before, but the first thing that I noticed about the Pokemon exhibit, was how the visitor is immersed between two worlds, the real world, and the fictional Pokemon world.  The signage talks to you from both places, so you can imagine yourself as a real Pokemon trainer in that fictional world part of the time.  The biggest example of this was how the exhibit acknowledges the difference in the meaning of the word "evolution" between the real world and the Pokemon world.  They explain how actual evolution is a process that typically takes many generations or millions of years to observe and how fossils play a part in our understanding of it.  Then they compare to how in pokemon "evolution" is more like metamorphosis, individual animals changing their form drastically at specific points during their life.  Below is a translation from the signage for this section of the exhibit.

"As your Charmander accumulates experience in battles and other tasks, it evolves into a Charmeleon, and eventually into a winged Charizard.  It becomes a different kind of Pokemon with a very different appearance, but as an individual it is still the same you got from Professor Oak.  It may sound a lot like 'growth' in our world, although the change is perhaps more than just growth, and it is seemingly not related to the passage of time.

In our world, 'evolution' doesn't happen to an individual, but occurs as a group, over the course of generations.  For example, we say 'life evolved from fish to amphibians, and eventually began to live on land' to describe an evolutionary course.  But this does not mean that one fish acquired feet instead of fins and began to walk on the ground.  First, amongst fish there were some individuals that had 'slightly harder fins'. These were advantageous for survival in certain circumstances, so later generations had more individuals with those 'slightly harder fins'.  This was repeated over a long enough time to reach individual obtained 'much harder fins' that we would consider a different species."

This was probably my favorite piece of signage in the museum for educational value.  I love how gracefully they explain real evolution compared to how it works in the Pokemon games.

Lastly the gift shop was full of all sorts of exclusive goodies.  This was of course dangerous for my wallet.  The haul you see her was me showing restraint.  I especially love the skeletal art keychains.  

Paleontologist Pikachu plush, skeleton keychains of Aerodactyl and Aurorus, postcards, sticker, and magnet of Hitoshi Ariga's art, and finally a break apart chocolate bar of one of several randomly assorted prehistoric pokemon. (a popular candy in Japan, normally featuring real dinosaurs) This haul was me showing restraint. Still kinda wish I grabbed the Rampardos plush and the fossil Pokemon bandana.

Overall I'm thrilled I finally got to visit this delightful exhibit after only reading about it for years.  It was a once in a lifetime experience that my whole family thoroughly enjoyed.  I especially appreciated how it was not short on real fossil displays or actual science education, despite the Pokemon theme, so even people who aren't fans of the franchise could enjoy it.  I highly recommend visiting for any Pokemon or paleontology fan.  If you want more prehistoric Pokemon content from me or want more info on the various Pokemon mentioned in this post, make sure to check out when I broke down which real animals all the prehistoric Pokemon are based on in three parts 1 through 3.  Here, here, and here.

The walls of the gift shop were covered in skeletals of fossil Pokemon. I love them.

Venetoraptor: Beast of the Week

This week we'll be checking out a recently described creature that looks as natural in a space fantasy franchise as it does in the late Triassic.  Say hello to Venetoraptor gassenae!

Venetoraptor gassenae life reconstruction in watercolors by Christopher DiPiazza.

Venetoraptor was a small archosaur(reptile group that includes dinosaurs, pterosaurs, and crocodilians) that lived in what is now southern Brazil during the late Triassic period, between 237 and 227 million years ago.  From beak to tail, it measured a little over three feet (96cm) long.  It's genus name translates to "Vale Veneto Hunter/Thief" after the the area of Brazil near where its fossils were found, Vale Veneto.  

Venetoraptor was a member of the lagerpetid family of archosaurs.  Lagerpetids were generally small animals with proportionally long, slender limbs that exhibited fully erect posture, like dinosaurs and pterosaurs have.  Many were quadrupeds, but some, like Venetoraptor, were thought to walk on their hind limbs.  Lagerpetids are also interesting because they at one time were thought to be the group that gave rise to the first dinosaurs.  It is more recently thought, however, that lagerpetids were actually more closely related to pterosaurs.  It is plausible that lagerpetids, like Venetoraptor, were covered in feather-like structures in life, since both pterosaurs and some dinosaurs are also known to have had them.

3D printed Skeletal mount of Venetoraptor on display at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires.  photo credit: CONICET

Venetoraptor had a hooked beak, similar to modern birds of prey, on the tip of its mouth.  Unfortunately the rest of its jaws past the tips were never found so it is unclear if it had teeth or not.  It also would have had proportionally large eye sockets, suggesting it had sharp eyesight in life.  The hooked beak suggests Venetoraptor may have been a meat eater, hunting insects and other small animals, but at this point its exact diet is still mostly guesswork.  

Venetoraptor possessed long slender limbs, its legs were especially long, suggesting it was capable of bipedal locomotion in life.  It also had noticeably long, hooked claws, leading some think it may have been a good climber, possibly spending considerable time in, or even living in trees.  

I'm just going to come out and say it.  Venetoraptor looks like the Kowakian Monkey-lizards from Star Wars.

That is all for this week!  As always feel free to leave a comment below.

References

Kammerer, Christian F.; Nesbitt, Sterling J.; Flynn, John J.; Ranivoharimanana, Lovasoa; Wyss, André R. (2020-07-28). "A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry". Proceedings of the National Academy of Sciences. 117 (30): 17932–17936.

Müller, R. T.; Ezcurra, M. D.; Garcia, M. S.; Agnolín, F. L.; Stocker, M. R.; Novas, F. E.; Soares, M. B.; Kellner, A. W. A.; Nesbitt, S. J. (2023). "New reptile shows dinosaurs and pterosaurs evolved among diverse precursors". Nature. 620 (7974): 589–594.

Medusaceratops: Beast of the Week

 Medusaceratops lokii was a plant-eating dinosaur that lived in what is now Montana, USA, during the Late Cretaceous period, between 78 and 77 million years ago.  Medusaceratops measured about twenty feet long from beak to tail and was a member of the ceratopsian family of dinosaurs, most known for their horns, beaks, and frills. The genus name, Medusaceratops, translates to "Medusa Horn Face" in reference to the horns over the eyes and around the frill of this dinosaur, which curved downward, and were almost serpentine in shape.  This reminded paleontologists of the mythical creature called a gorgon, the most famous of which was named Medusa, who had snakes for hair and could turn people to stone if they looked at her.  The species name, lokii, is in reference to Loki, the Norse god of trickery.  This is because the bones of Medusaceratops were believed to have belonged to other, already known ceratopsian dinosaurs for years, and in a sense, tricked paleontologists into thinking it was a different taxa before finally being recognized in 2010.

Medusaceratops life reconstruction by Christopher DiPiazza.

So why did Medusaceratops have those horns, anyway?  Unlike the horns of some other ceratopsians, which face up our outwards, this dinosaur's horns point downwards.  Unless it was fighting the monsters from Tremors, I doubt they would have been much good as weapons against predators.  Part of me still thinks that the horns, despite this, still could have deterred a predator from hurting vital areas on Medusaceratops' body, like the eyes or neck, simply by just being in the way.  This idea doesn't really hold up since there were so many different kinds of ceratopsains, each with unique horn arrangements, however.  If they were purely for defense, we would more likely see ceratopsian horns converge to a defensive arrangement across the family.  The more likely answer to these horns is that they were display adaptations, meant to intimidate and/or impress members of the same species.  If a would-be predator happened to break at tooth or two on a horn in a failed attempt to hunt Medusaceratops then it was icing on the ceratopsian cake...which that predator would never get to taste.

Medusaceratops skeletal mount on display at the Wyoming Dinosaur Center.

Medusaceratops was originally thought to be the oldest known chasmosaurine ceratopsian dinosaur on the fossil record.  Chasmosaurine ceratopsians typically had longer horns over their eyes, and proportionally long frills.  Chasmosaurus, Triceratops, Mercuriceratops, Coahuilaceratops, and Vagaceratops are all examples of other chasmosaurines.  More recently found material and further inspection of its bones, however, reveal that Medusaceratops was actually a member of the centrosaurine group of ceratopsians, known for having proportionally shorter frills and taller snouts, like Styracosaurus, Stellasaurus, Wendiceratops, and Nasutoceratops.  

That is all for this week!  As always feel free to comment below.

References

Kentaro Chiba; Michael J. Ryan; Federico Fanti; Mark A. Loewen; David C. Evans (2018). "New material and systematic re-evaluation of Medusaceratops lokii (Dinosauria, Ceratopsidae) from the Judith River Formation (Campanian, Montana)". Journal of Paleontology. 92 (2): 272–288.

Ryan, Michael J.; Russell, Anthony P., and Hartman, Scott. (2010). "A New Chasmosaurine Ceratopsid from the Judith River Formation, Montana", In: Michael J. Ryan, Brenda J. Chinnery-Allgeier, and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press, 656 pp.

Dakotaraptor: Beast of the Week

This week we will be revisiting an unfortunately very confusing dinosaur.  Let's check out Dakotaraptor steini.  Dakotaraptor was originally published on in 2015 and was claimed by the head author to be a very large dromaeosaur, in the same family as Deinonychus and Velociraptor.  It would have lived in what is now South Dakota, United States, during the very late Cretaceous Period, 66 million years ago.  From snout to tail it was estimated to measure about eighteen feet long, which would have made it one of the largest dromaeosaurs known. Other dinosaurs that would have been from the same environment include Tyrannosaurus, Triceratops, Pachycephalosaurus, Edmontosaurus, Anzu, and Acheroraptor.  The genus name, Dakotaraptor, translates to "Dakota Thief/Hunter" in reference to where it was found.

Life restoration of what the creature associated with Dakotaraptor MAY have looked like if it was indeed an unenlagiine. (I included it's other misidentified parts too if you know what to look for!)

Since the initial discovery and publication, many the fossils associated with Dakotaraptor have, under more close examination, turned out to be from other animals.  The original bones weren't found articulated in any sort of death position, but were more jumbled up in what likely used to be the bottom of a body of water, so it makes sense that multiple different dead animals ended up there over time and were eventually fossilized.  Some of the bones turned out to belong to the large oviraptorosaur, Anzu, as well as Tyrannosaurus, and even a prehistoric Soft-shelled turtle, called Axestemys.  

Photograph of what was originally thought to be the "killer" retractable toe claw of Dakotaraptor that has since been recognized as possibly being from a Tyrannosaurus hand.

That being said there are still a few bones that were associated with Dakotaraptor that as of now appear to be from some kind of large dromaeosaur.  More recent peer reviewed research suggests Dakotaraptor may actually belong to the unenlagiine branch of dromaeosaurs, the group known for having very long narrow snouts, based on what little material there is.  Until these bones can be formally studied further, we may never know for sure.

References

Arbour, V.M.; Zanno, L.E.; Larson, D.W.; Evans, D.C.; Sues, H. (2015). "The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra". PeerJ. 3: e1957.

DePalma, Robert A.; Burnham, David A.; Martin, Larry D.; Larson, Peter L.; Bakker, Robert T. (2015). "The First Giant Raptor (Theropoda: Dromaeosauridae) from the Hell Creek Formation.".Paleontological Contributions (14).

Jasinski, Steven E.; Sullivan, Robert M.; Dodson, Peter (2020-03-26). "New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous". Scientific Reports. 10 (1): 5105.

Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247.

Unenlagia: Beast of the Week

 This week we will be checking out an amazing little bird-like dinosaur.  Check out Unenlagia comahuensis!

Unenlagia was a bird-like theropod that lived in what is now Argentina during the late Cretaceous period, roughly 89 million years ago.  From snout to tail Unenlagia may have measured about seven feet (2.1m) long, but estimates vary since it's known from fragmentary remains.  When alive it likely ate meat, possibly specializing in smaller prey or fish.  The genus name translates to "Half-bird" due to the dinosaur's limbs which were particularly similar to those of modern birds.  In fact when it was first discovered in 1986, it was thought by paleontologists studying it to be a kind of prehistoric bird.  More recently Unenlagia was determined to be more closely related to dinosaurs like Velociraptor, being a member of, or very closely related to the family of dinosaurs called dromaeosaurids.

Watercolor reconstruction of Unenlagia comahuensis by Christopher DiPiazza.

Sadly Unenlagia is only known from several bones, so we aren't positive about how it looked in life exactly.  The bones we do have, however, have an interesting history to them regarding how paleontologists think about dinosaurs and their relationship to birds.  The upper arm bone and shoulder blade of Unenlagia was originally thought to be adapted for flapping by paleontologists studying it.  This is what led them to believe that Unenlagia may have been either a kind of prehistoric bird extremely closely related to birds.  Some even hypothesized that Unenlagia may have been capable of flight.  More recently, however, it was determined that Unenlagia's arms were positioned more similarly to those of dromaeosaurids, like Velociraptor and Deinonychus, and did not have the range of motion of modern bird wings, thus implying it was indeed flightless.  

Photograph of Unenlagia's bones from Gianechini's 2011 paper.

Since Unenlagia's discovery, dinosaurs that are more complete than, yet extremely similar to the parts of Unenlagia we do have, give us a better idea of how it looked in life.  These dinosaurs have been given their own subfamily, called unenlagiinae, named after the earliest discovered member.  Based on more complete members of this group, we can guess that Unenlagia may have had long, slender legs and a long, narrow snout, lined with cone-shaped teeth. Because of these features some hypothesize unenlagiines may have specialized in hunting small prey and/or fish in life.  Unenlagiines also tended to have proportionally smaller arms than those of other dromaeosaurids.  

That is all for this week!  As always feel free to comment below!

References

Agnolin, F.L.; Novas, F.E. (2011). "Unenlagiid theropods: are they members of the Dromaeosauridae (Theropoda, Maniraptora)?". Anais da Academia Brasileira de Ciências. 83 (1): 117–162.

Carpenter, K. 2002. "Forelimb biomechanics of nonavian theropod dinosaurs in predation". Senckenbergiana Lethaea 82: 59–76

Gianechini, F. A.; Apesteguía, S. (2011). "Unenlagiinae revisited: Dromaeosaurid theropods from South America". Anais da Academia Brasileira de Ciências. 83 (1): 163–95.

Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247.

Matías J. Motta; Federico L. Agnolín; Federico Brissón Egli; Fernando E. Novas (2020). "New theropod dinosaur from the Upper Cretaceous of Patagonia sheds light on the paravian radiation in Gondwana". The Science of Nature (journal). 107 (3): Article number 24.

Norell, M.A.; Makovicky, P.J. (1999). "Important features of the dromaeosaur skeleton II: information from newly collected specimens of Velociraptor mongoliensis". American Museum Novitates (3282): 1–45.

Novas, F.E.; Puerta, P.F. (1997). "New evidence concerning avian origins from the Late Cretaceous of Patagonia". Nature. 387 (6631): 390–2.

Novas, F. E.; Pol, D.; Canale, J. I.; Porfiri, J. D.; Calvo, J. O. (2008). "A bizarre Cretaceous theropod dinosaur from Patagonia and the evolution of Gondwanan dromaeosaurids". Proceedings of the Royal Society B: Biological Sciences. 276 (1659): 1101–7.

Stegouros: Beast of the Week

This week we will be checking out a recently described, and very unique little armored dinosaur.  Say hello to Stegouros elengassen!

Watercolor life reconstruction of Stegouros elengassen by Christopher DiPiazza.

Stegouros was a plant-eating dinosaur that lived in what is now Chile during the late Cretaceous period, between about 75 and 72 million years ago.  It was a member of the ankylosaur group of dinosaurs, known for sporting bony armor all over their bodies, but it was extremely tiny for that group, only measuring about six feet from beak to tail.  The genus name, Stegouros, translates to "roofed tail" in reference to the bony structures growing from the top of its tail (more about that in a bit) and the species name, elengassen, is the name of a mythical creature known for its armor from Aonik'enk folklore, the indigenous people of the area in which Stegouros' bones were unearthed. 

Photograph of the known skull parts of Stegouros. Image from the paper by Scoto-Acuna Et al.

Stegouros is known from an almost complete skeleton.  Almost the entire rear half of the body is known, plus armor plates, and even an almost complete skull. Stegouros had a slightly curved beak which could have been used for clipping vegetation to eat.  It also had small teeth in the back of its mouth with serrations, ideal for shredding plant material before being swallowed.  It had  relatively small osteoderms on most of the upper part of its body, but the real impressive armor was on its tail.  Unlike some of its relatives, like Ankylosaurus, which are famous for having bony clubs on the tips of their tails, Stegouros had a series of wide flat pieces of bone growing from the sides of the tail and eventually fusing together to form a solid flat piece of bone at the end of the tail, forming an almost plant-like shape.  The whole structure is best described as being similar to the Aztec weapon, called a macuahuitl.  Stegouros may have used this amazing tail to defend itself from potential predators, or perhaps even to fight members of its own species for dominance or over territory, mates, or resources.

Photograph of the tail of Stegouros.

Paleontologists have determined that Stegouros evolved separately from the two other major groups of ankylosaur dinosaurs, the narrow-snouted nodosaurids, and the club-tailed ankylosaurids, forming a third major branch of armored dinosaurs, called Parankylosauria that split off earlier from the other two.

References

Soto-Acuña, Sergio; Vargas, Alexander; Kaluza, Jonatan; Leppe, Marcelo; Botelho, Joao; Palma-Liberona, José; Gutstein, Carolina; Fernández, Roy; Ortiz, Hector; Milla, Verónica; Aravena, Bárbara; Manríquez, Leslie M. E.; Alarcón-Muñoz, Jhonatan; Pino, Juan Pablo; Trevisan, Cristine; Mansilla, Héctor; Hinojosa, Luis Felipe; Muñoz-Walther, Vicente; Rubilar-Rogers, David (2021). "Bizarre tail weaponry in a transitional ankylosaur from subantarctic Chile". Nature. 600 (7888): 259–263.

Mystipterus: Beast of the Week

This week we'll be checking out a newly described prehistoric mammal that I was privileged enough to help introduced to the world.  Let's look at Mystipterus austinae!

Watercolor reconstruction of Mystipterus living in what is now north Dakota, 32 million years ago.  It would have shared its home with land snails, a legless burrowing lizard, and the early canid, Hesperocyon.

Mystipterus was a prehistoric mole that lived in what is now North Dakota during the middle Oligocene period, about 32 million years ago.  Known from mostly just a lower jaw, its body length is estimated at only a few inches long (about 7 centimeters) from nose to tail.  Like its living relatives, it was likely a meat-eater, sniffing out and devouring most invertebrates and possibly other kinds of smaller animals it came across.  The genus name translates to "Impossible to Identify" because of its dubious identity after it was first discovered. It was initially interpreted as a bat, but has since been more accurately identified as a mole.

Mystipterus one of the earliest known moles.  By comparing the fossils that have been found to those of modern kinds of moles, paleontologists have predicted that Mystipterus would not have resembled the more specialized moles, with their enlarged front limbs for digging.  Rather it was most similar to moles in the genus Uropsilus, which are more generalized.  The common name for this group is the shrew-moles, since they in many ways resemble shrews.  It may have even had a long, trunk-like nose, like some shrews have.  

Jaw and teeth from Mystipterus featured in the 2023 paper, by Korth Et al. referenced below.

Like its modern relatives, Mystipterus likely spent most of its time underground, possibly coming out at night to hunt. It may also have been a strong swimmer in life, like many modern moles and shrews are, especially since the rocks its bones were found in indicate it would have inhabited a wet environment with lots of slow-moving rivers and streams.  Since it was so small, it would have needed to avoid predators, especially while above ground, like the early canid, Hesperocyon, whos bones were found in the same area as Mystipterus'.

References

Korth, W. W.; Boyd, C. A.; Emry, R. J. (2023). "Additional small mammals from the Oligocene Brule Formation (Whitneyan) of southwestern North Dakota". Paludicola. 14 (2): 57–74.

Maryland Dinosaurs: Major Discovery!

 As you probably know, if you have been reading this blog for a while or follow me on any social media, I was born in and spent the majority of my life in New Jersey. What you may not know, however, is that I moved down to Maryland several years ago.  It was pretty sad because that means I'd be farther away from some of my favorite things, like the American Museum of Natural History, Hadrosaurus, Dryptosaurus, and good pizza.  One positive thing of the move, however, is it means I'm now living extremely close to a unique dinosaur fossil site, called the Arundel Formation, where some amazing dinosaur bones have been unearthed.

Photo of the Arundel formation I took while at the press release.  Just out of frame in both directions there are parking lots and warehouses.

The Arundel Formation used to be a mining area during the late 1800s, but now is surrounded by warehouses and office buildings.  Fossils have been discovered there for decades, including many tree and other plant fossils, like pinecones and even pollen, as well as bones from several kinds of dinosaurs, like Maryland's official state dinosaur, Astrodon.  All the fossils here are from the early Cretaceous period, about 115 million years ago, in what was a slow-moving river with surrounding swamps at the time.

Dr. Thomas Holtz speaking at the press conference about the kinds of dinosaurs that have been found at the Arundel formation.

Earlier this week a press conference was held at this site with exciting news.  Teams of paleontologists and volunteers, led by John-Paul Hodnett, just this year started uncovering many bones from not one, but several different species of dinosaurs, some of which are previously only known from teeth and other very tiny fragments, as well as at least one completely new taxa!  As stated, this site has been yielding fossils for many decades, but this many bones from this many different species at once is a first.

Below is a breakdown of the newest dinosaur discoveries shared from this press release.

Leg bone from a very large theropod

Watercolor reconstruction of Acrocanthosaurus, which may have lived in what is now Maryland.

The largest theropod bone on the eastern side of the country was discovered at the Arundel Formation just this year.  Based on the size of the tibia, the whole dinosaur is estimated to have been roughly thirty eight feet long from snout to tail.  

John-Paul Hodnett speaking about how the fossils formed at the press release from within the Arundel formation.  The big bone still in the ground at his feet is a tibia from a very large theropod.

Based on fragmentary material found at this sight in the past, as well as the time period the formation is from, this leg could belong to Acrocanthosaurus, but it could also be something entirely new depending on what further examination shows.  

Astrodon bones and a claw.  

Watercolor life reconstruction of Astrodon, Marylands state dinosaur.

Astrodon is Maryland's official state dinosaur.  It was a sauropod, related to Brachiosaurus and Camarasaurus, and was likely the largest animal in its community when it was alive.  This past year more bones from Astrodon, including a foot claw, have been discovered, giving us a more complete picture of this dinosaur's skeleton.  

Recently unearthed Astrodon fossils from the Arundel site.

It is possible these bones are from the same individual, which was a subadult when it died, that we already have an incomplete skeleton of on the fossil record, based on the size and location in the site they were found.

Priconodon bones.  

Very rough sketch of what Priconodon may have looked like.

Priconodon was a plant-eating armored dinosaur, from the nodosaur group of ankylosaurs, characterized by usually sporting long, thorny spikes running down their flanks.  For years, Priconodon was only known from teeth and very small bone fragments.  

Gigantic Prictonodon tail vertebra unearthed recently at the Arundel site.  My hand for scale.

Just this year, however, whole bones, including some truly massive vertebra, have been discovered.  Based on the size of these vertebra, Priconodon could very well have been one of the largest, if not THE largest armored dinosaur ever found!

New species of tyrannosauroid teeth

Watercolor reconstruction of a generic early Cretaceous tyrannosauroid, with three fingers on each hand, long legs, and feathers.

Teeth from what appear to be a tyrannosauroid have been discovered this year at the site for the first time at this location.  

Tyrannosauroid tooth recently unearthed from the Arundel formation.

Unlike giants like Tyrannosaurus rex, which lived at the very end of the Cretaceous, tyrannosauroids during the early cretaceous were usually relatively small, but likely fast-moving and covered in feathers.

Dromaeosaur teeth

Deinonychus, which may have lived in what is now Maryland.

Dromaeosaur fossils have been unearthed at this site, possibly belonging the famous, Deinonychus, based on size and time period.  This year more teeth that match this dinosaur were unearthed.

Ornithomimosaur bones and claw

Bones from an ornithomimosaur, group of dinosaurs that connvergently resembled ostriches, have been found at this site, including a bone unearthed just this year.  

watercolor reconstruction of a generic early cretaceous ornithomimid.  They tend to have proportionally larger heads and small teeth, compared to their toothless later relatives.

Like the dromaeosaur bones, ornithomimosaur bones have been uncovered at this site before, but having new material will add to how much we can actually learn about them and hopefully help us create a more accurate picture of them in this part of the world. 

Ornithomimid fossils recently unearthed from the Arundel formation.

Small coelurosaur theropod

A few very small bones and teeth from some kind of small bird-like theropod have been found at the Arundel site.  Unfortunately they aren't diagnostic enough to narrow it down any more than being from a coelurosaur, the broad group of theropods that includes tyrannosaurs, dromaeosaurs, and birds.  The teeth appear to be straight and pointed, however, which is unusual.  (I wonder if it was a kind of unenlagiine) Hopefully we'll learn more soon.

In addition to all these dinosaurs, the fossils of several other animals, including crocodiles, turtles, stingrays, and mussels were unearthed this year.  Furthermore, fossils from other dinosaurs and other animals have been found here in the past and may come up again as digging continues, including mammals and a small early ceratopsian, similar to the western US contemporary, Aquilops.

Watercolor reconstruction of Aquilops, which lived at the same time as the dinosaurs unearthed at the Arundel formation.

The news of so many bones being pulled out of this sight is extremely exciting.  Not only because they will vastly increase our understanding of previously very mysterious dinosaurs, but also because we have at least one totally new species. Even more exciting perhaps, is the fact that its all taking place on the east coast, an area not normally associated with major dinosaur fossil sites.  I can't wait to see what else is uncovered in the coming days!