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!

Masiakasaurus: Beast of the Week

This week we shall be looking at an awesome little dinosaur with teeth unlike any other!  Check out Masiakasaurus knopfleri!  Masiakasaurus was a meat-eating dinosaur that lived in what is now Madagascar during the late Cretaceous period, about 70 million years ago.  From snout to tail an adult would have measured between six and seven feet (2m) long.  The genus name, Masiakasaurus, translates to "Vicious lizard/reptile" and the species name, knopfleri, is in honor of singer/songwriter/guitarist, Mark Knopfler, who's music the paleontologists who found this dinosaur's fossils were listening to during their time in the field.

Life reconstruction in watercolors of Masiakasaurus by Christopher DiPiazza.

Masiakasaurus belonged to the family of dinosaurs called noasauridae.  They are a branch of the broader group of theropods, called ceratosaurs, which also includes the larger, more well known, Ceratosaurus and Carnotaurus, to name just a few.  Noasaurids, specifically were much smaller and more gracile than their relatives, with proportionally small heads and long legs.

The most prominent feature about Masiakasaurus, is its teeth.  Unlike the teeth of most theropods, which angle perpendicular to the jaw, the teeth of Masiakasaurus were angled forward in he front of the mouth.  This striking appearance was what earned its name as "vicious".  Despite its appearance, however, was Masiakasaurus was probably only truly vicious towards much smaller animals.  Its tooth arrangement may have been an adaptation for grasping small, fast moving prey, like a moveable cage.  The environment Masiakasaurus lived in did have many prey animals in it at the time, thanks to a great fossil record from Cretaceous Madagascar, including frogs, mammals, small crocodilians, and even small birdlike dinosaurs.  Another idea that some people have proposed is that Masiakasaurus was a fisher.  In fact, we see similar, unrelated examples of teeth like this in many fish-hunting marine reptiles, like Plesiosaurus.  The teeth in the back of Masiakasaurus' mouth were more similar to those of other theropods, and would have been for cutting food to be swallowed. 

Masiakasaurus skull, featuring the unique teeth and jaws.  CLEARLY it lived during a time before orthodontists.

In addition to its teeth, some other notable features about Masiakasaurus would be its neck, which was long and actually not very flexible, which is not the norm compared to other kinds of long-necked theropods.  Its hands each had four fingers, but only the first three digits on each had claws.

Masiakasaurus skeleton on display at the Royal Ontario Museum in Toronto, Canada.

Masiakasaurus is a great find by paleontology standards because it is known from more than one specimen, so almost all of its anatomy is known.  Another interesting thing about Masiakasaurus, is that paleontologists were able to study what they think was its growth pattern based on individual specimens of different sizes that have been found.  Based on what the pool of specimens available to work with and by closely examining the kind of bones Masiakasaurus had compared to those of other dinosaurs, it is hypothesized that Masiakasaurus was actually a relatively slow-grower, and would have attained adult size by the time it was about eight years old.  This is indeed pretty slow compared to other non-avian dinosaurs that have been studied in the same way and even modern animals that are related to it, like birds, which reach adulthood, in general, much more rapidly.  (Anyone who has ever raised a baby chick knows exactly what I'm talking about.  Seriously, one minute they are fluffy yellow peeps... blink once and BAM...adult chicken.)

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

References

Carrano, M.T.; Sampson, S.D.; Forster, C.A. (2002). "The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar". Journal of Vertebrate Paleontology 22 (3): 510–534.

Carrano, M.T.; Loewen, M.A.; Sertic, J.J.W. (2011). "New materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and implications for the morphology of the Noasauridae (Theropoda: Ceratosauria)". Smithsonian Contributions to Paleobiology 95: 53pp.

Andrew H. Lee & Patrick M. O’Connor (2013) Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri. Journal of Vertebrate Paleontology 33(4): 865-876.

Sinosaurus: Beast of the Week

This week we will be looking at one of the first large predatory dinosaurs.  Make way for Sinosaurus triassicus!

Sinosaurus triassicus life reconstruction in watercolors by Christopher DiPiazza

Sinosaurus was a meat-eating dinosaur that lived in what is now Southwest China during the early Jurassic period, between 201 and 196 million years ago.  From snout to tail it measured 18 feet (5.5 meters) long. It's genus name translates to "Chinese Lizard/Reptile" and the species name is in reference to the Triassic period which is when it was first believed to have lived upon its discovery. (We now know it was in the Jurassic.)

Sinosaurus is a dinosaur that underwent a few identity changes as paleontologists discovered more fossils and learned more about it over the years.  Most prominently it was believed to be an Asian species of the more popular North American theropod, Dilophosaurus, and was originally named Dilophosaurus sinensis.  This makes sense at first since both of these dinosaurs are known for having two bony crests on the top of their snouts.  They both also even have a similar notch towards the front of their upper jaws.  However, as more material from Sinosaurus was unearthed over the years, it was determined that it was more closely related to later kinds of theropods, called the tetanurans, and therefore was given its own genus name, Sinosaurus.  Tetanurans are a broad group of theropods characterized by how their tails were stiffened in life thanks to how their tail vertebrae interlock together.  Tetanurans are also all more closely related to birds than to other dinosaurs, including other kinds of theropods.  According to this updated idea, Sinosaurus was particularly closely related to another crested theropod from the early Jurassic, Cryolophosaurus.  

Sinosaurus skeletal mount on display at the Maryland Science Center in Baltimore, Maryland, USA.

Sinosaurus had curved serrated teeth that would have been ideal for slicing through and stripping off chunks of meat from bodies.  The upper jaw notch towards the front of its snout may have been an adaptation for hooking into and ripping through the skin of other dinosaurs to get into the meat inside, similar to the hooked beaks of modern carnivorous birds, like hawks, eagles, and vultures.  Sinosaurus is probably most known for its bony crests which adorned the top of its skull.  These crests had holes in them, making them lightweight, and may have served as visual display adaptations within the species or even possibly could have helped absorb impact, allowing Sinosaurus to bite harder without injury.

Sinosaurus skull from in Zhang's 2023 paper. (listed below)

Sinosaurus shows evidence of tooth injury in life in the form of what is called alveolar remodeling.  This means that it experienced a broken tooth and the ridge of bone in the jaw that includes the tooth sockets, called the alveolar bone, changed shape in the healing process following the loss of the tooth.  Dinosaurs losing and replacing teeth is common in the fossil record, but this is the only recorded instance of an actual tooth related injury that healed in this way known so far for a dinosaur.  

Sinosaurus lived during a time when predatory dinosaurs were first starting to get truly large.  Prior to this most meat-eating dinosaurs were much smaller and more gracile, like Coelophysis, and even the biggest plant-eaters, like Plateosaurus, weren't that huge compared to what would later evolve.  At 18 feet long, Sinosaurus was likely the top of the food chain in its environments.  

References

Chung-Chien, Young (1940). "Preliminary Notes on the Lufeng Vertebrate Fossils*: Young:-Lufeng Vertebrate Fossils". Bulletin of the Geological Society of China. 20 (3–4): 235–240.

Dong, Z.M. (2003). "Contribution of New Dinosaur Materials from China to Dinosaurology" (PDF). Memoir of the Fukui Prefectural Dinosaur Museum. 2: 123–131.Xing, L.D.; Bell, P.R.; Rothschild, B.M.; Ran, H.; Zhang, J.P.; Dong, Z.M.; 

Rauhut, O.W.M. (2003). "The interrelationships and evolution of basal theropod dinosaurs". Special Papers in Palaeontology. 69: 215.

Zhang, W.; Currie, P.J. (2013). "Tooth loss and alveolar remodeling in Sinosaurus triassicus (Dinosauria: Theropoda) from the Lower Jurassic strata of the Lufeng Basin, China". Chinese Science Bulletin. 58 (16): 1931–1935.

Zhang, Z.-C.; Wang, T.; You, H.-L. (2023). "A New Specimen of Sinosaurus triassicus (Dinosauria: Theropoda) from the Early Jurassic of Lufeng, Yunnan, China". Historical Biology. in press.

The Paleontology Behind Pokemon: Part 3

 It is time for my third installment of Paleontology Behind Pokemon, a post where I delve into the design choices behind pokemon based on dinosaur and other prehistoric animals.  If you have not seen the first two pokemon posts you can check out part one here and pat two here.

Walking Wake

The newest generation of pokemon yielded a few exciting new desings that are clearly based on dinosaurs.  Possibly the most surprising is the new look of the legendary pokemon, Suicune, called Walking Wake.  Suicune was originally based on a dog or a generalized mammal, but Walking Wake is very clearly based on a theropod dinosaur.  It has a proportionally smaller head, long legs, and short arms with three fingers on each hand.  At first it looks like it could be a dromaeosaur but it doesn't have the signature giant toe claw on each foot and I feel that if a pokemon were to be based on a dromaeosaur that would be the one feature that would be included, if not emphasized.  

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

My realistic assumption is Walking Wake isn't based on any particular taxa or even group of dinosaur beyond theropod, but in my headcannon it is a tyrannosauroid, like Dilong, Moros, or Dryptosaurus.  I named mine "Drypto" for that reason. (plus it's water type and drypto sounds like drip which is a thing water does.)

Frigibax, Arctibax, and Baxcalibur

Walking Wake wasn't the only dinosaur introduced in the newest wave of pokemon.  We also have the evolution line of dragon/ice pokemon, Frigibax, Arctibax, and Baxcalibur.  All three of these pokemon also appear to be based on theropod dinosaurs and all three sport a blade-like fin or ridge on their backs.  At first Spinosaurus seems the most likely source of inspiration, but they lack the long snout of a spinosaur and pokemon is usually pretty good about using up to date looks when they do use specific dinosaurs for references.  I have also read they are based on Concavenator, which also has a more isolated fin-shaped hump on its back.  Part of me can't help but wonder if their names are playing off of dinosaurs, like Altispinax and Becklespinax, both of which also had high ridges on their backs, but are known from much less complete fossil material.  

Concavenator skeleton on display at the Fukui Prefectural Dinosaur Museum.

As always it is also always safe to assume these pokemon could be inspired by all or many of the above fossils, resulting in a more generic, but no less cool, design.  I also want to note that Arctibax looks the most like an actual dinosaur, due to its posture, and the fully evolved Baxcalibur looks more like Godzilla than a real dinosaur due to its proportions and more upright posture.

Tropius

Tropius is a pokemon introduced in the third wave of pokemon games.  It is a grass/flying type and is clearly based on a long-necked sauropod dinosaur.  I have also read it is more specifically inspired by the cryptid, Mokele-mbembe, a sauropod dinosaur said to live in the Congo River according to legend.  The grass typing and incorporating banana trees into the design is pretty clever, but the flying typing is just bizarre in my opinion.  A sauropod seems like the least likely animal that would be flying, especially with wings made of leaves!  I also always found it odd how Tropius has no tail.  

Chikorita, Bayleef, and Meganium

Speaking of grass type sauropods, we can't forget Chikorita and its evolutions.  Introduced in the second generation of pokemon as one of the starters, Chikorita's design isn't obvious at first.  But once it evolves, gaining a long neck, it becomes pretty clear this little pokemon is a sauropod. 

Giraffatitan skeleton on display in Berlin.

The final evolution, Meganium is even more obvious.  I can't help but think of them as brachiosaurs, since Meganium has a shorter tail and more upright neck posture.

Great Tusk

Another new pokemon introduced in the latest generation is the ancient form of the second generation pokemon, Donphan, called Great Tusk.  Donphan was based on elephants and Great Tusk appears to be mostly based on Mastodon or Mammoths, based on its tusk shape.   

Mastodon skeleton on display at the Rutgers Geology Museum.

It also looks like actual dinosaur features were incorporated into it as well with its armored back, spikes, and reptile-like tail. 

Breloom

Breloom is a grass/fighting type pokemon that evolves from Shroomish, a literal mushroom.  But Breloom appears to take the mushroom theme and apply it to a dinosaur shape, standing on two digitigrade feet, having short arms, a beak, and a long tail.  

Stegoceras skull.  Breloom's head resembles the flared out and domed skulls of many pachycephalosaurs.

Specifically Breloom looks to be most similar to pachycephalosaurs, with the wide mushroom cap on its head resembling a domed skull.  

Tyranitar

Tyranitar is a pokemon released in the second generation of pokemon.  It is a rock/dark type and has always been one of the most popular pokemon based on its cool design and strength in battle.  Tyranitar is also the first pokemon I've written about here that isn't actually based on anything from paleontology directly but I kept getting requests on social media to include it since I started writing these posts so I figured I'd finally set the record straight here.  At first Tyranitar seems like it would be based on a Tyrannosaurus, but I'm convinced this is based on its name only and little else.  In fact, nothing about its actual design is directly based on any real dinosaurs beyond anything extremely general.  Tyranitar DOES however appear to be directly based on a kaiju (Japanese giant monster traditionally represented by an actor in a costume) from the Ultra Man franchise, named Bemular.  

Bemular, the monster Tyranitar appears to be the most based on.

Habrosaurus: Beast of the Week

 This week we'll be checking out a prehistoric amphibian.  Make way for Habrosaurus!

Habrosaurus was a salamander that lived in what is now Alberta, Wyoming and Montana, during the late Cretaceous period into the early Paleocene (surviving the asteroid that wiped out most of the dinosaurs), from 68 to 58 million years ago.  From snout to tail Habrosaurus is estimated to have been over five feet (1.6 meters) long, making it one of the largest salamanders of all time.  When alive Habrosaurus likely would have likely preyed on smaller aquatic animals, like shrimp and mollusks. (all amphibians are predators at least as adults) The genus name translates to "Graceful Reptile" even though it was and amphibian, not a reptile.

Life reconstructions in watercolors of Habrosaurus dilatus by Christopher DiPiazza.

There are currently two species of Habrosaurus known on the fossil record.  Habrosaurus prodilatus is the older species, lived in what is now Alberta, Canada, and would have shared its habitat with dinosaurs like Styracosaurus, Parasaurolophus, and Gorgosaurus.  Habrosaurus dilatus is the later species and lived in what is now Western United States, and would have shared its home with dinosaurs, like Triceratops, Ankylosaurus, Pachycephalosaurus, and Tyrannosaurus.

Habrosaurus was a member of the siren (sirenidae) family of salamanders which have numerous species still alive today, all native to the southern United States.  Sirens are characterized by having extremely long, eel-like bodies, front limbs only (no back legs), gills, and live their entire lives in freshwater but can also burrow into the mud if they need to.  Unlike many amphibians, sirens do not undergo metamorphosis, but rather stay fully aquatic their entire lives, simply growing larger as they age.  

Teeth and jaw fragments from Habrosaurus dilatus from Gardner's 2003

 paper linked below.

Fossils of Habrosaurus dilatus' teeth indicate that it specialized in eating hard-shelled prey, like snails and shrimp.  Both species also may have been preying on fish and other animals small enough to fit in their mouths if they wandered too close.  Living sirens are some of the few kinds of amphibians known to actually be omnivores as adults, supplementing their mostly meat diet with water plants, as well.  There is no way to know if Habrosaurus may have eaten some plants as well when it was alive.  iLike living sirens, Habrosaurus likely spent its time on the muddy bottom of swamps and other bodies of fresh water, where it relied on secrecy to ambush prey.  I wonder how many unsuspecting large dinosaurs were bitten on the nose by an angry Habrosaurus, as they tried to take a drink?

That's all for this week!  Leave a comment below!

References

Gardner, James D. (November 2003). "Revision of Habrosaurus Gilmore (Caudata; Sirenidae) and relationships among sirenid salamanders". Palaeontology. 46 (6): 1089–1122.

Hill, R. L., Mendelson, J. R. & Stabile, J. L. 2015. Direct observation and review of herbivory in Sirenidae (Amphibia: Caudata). Southeastern Naturalist 14, N5-N9.

K. Roelants, D.J. Gower, M. Wilkinson, S.P. Loader, S.D. Biju, K. Guillaume, L. Moriau, F. Bossuyt (2007) Global pattern of diversification in the history of modern amphibians. Proc. Natl. Acad. Sci. USA, 104: 887-892

Coelophysis: Beast of the Week

This week we will be taking a look at another very well-studied dinosaur.  Check out Coelophyis bauri!  Coelophysis was a relatively small, meat-eating dinosaur that lived during the late Triassic period, between 215 and 200 million years ago, in what is now the Western United States.  Fully grown, adults measured about ten feet long from snout to tail.  Coelophysis bones are mostly known from New Mexico (where it is the official state fossil), but evidence of this dinosaur has been found as far as the east coast, as well, in the form of tracks.  The genus name, Coelophysis, translates to "Hollow Form" in reference to the dinosaur's hollow bones, a trait actually common to many dinosaurs, not just Coelophysis.  When alive Coelophysis would have coexisted with creatures like crocodilian relatives, Typothorax, Shuvosaurus, and Postosuchus.

Group of Coelophysis bauri of varying ages gathering in a dried river bed.  Fossils suggest large groups of Coelophysis died at about the same time relatively quickly due to harsh environments.  Watercolor reconstruction by Christopher DiPiazza.

Coelophysis lived during a time in history when dinosaurs were obviously around, but had not become as diverse and large as most people know them to be just yet.  During the Triassic, the biggest, most formidable animals were actually other kinds of archosaurs like pseudosuchians (group that includes modern crocodilians) like Typothorax, Postosuchus, and Shuvosaurus, as well as the crocodile-looking-but-not-really-close-to-crocodiles, the phytosaurs, like Rutiodon.  In fact, actual dinosaurs were somewhat of a rarity during the Triassic. If you would like the full story on how reptiles were evolving and going extinct during this time, please go read my post about my work in New Mexico excavating the fossils of these creatures.  It was a fascinating time in earth's history.

This is a fossil I found that has been split right down the middle, showcasing how hollow it is.  It is most likely from a Coelophysis. 

Coelophysis likely specialized in hunting small prey by using speed and agility.  It was very lightly built, most of its ten-foot length consisting of its neck and tail, and would have been able to run quickly on its hind legs, which were slender, but strong.  It had a long, narrow snout with a slight notch at the tip of the upper jaw, which could have helped it hold on to struggling prey.  Inside the mouth were many small, serrated teeth, for slicing meat.  Originally it was believed that Coelophysis was cannibalistic, since one specimen in New Mexico was discovered with what looked like baby Coelophysis bones inside where its stomach used to be.  Under further inspection, however, it was decided that these bones were in fact belonging to one of the small species of land crocodilians that would have been common back then.  However, small broken bones and teeth that were confirmed to be from baby Coelophysis were found in the stomach cavities and around the mouths of other adult specimens, showing that cannibalism of smaller individuals still was probably taking place.  In turn, Coelophysis would have needed to be weary of becoming prey to the bigger predators alive back then, like Postosuchus or Redondasaurus.

Coelophysis cast on display at the Mesalands Dinosaur Museum, in Tucumcari, New Mexico.  You can see the bones of what was originally believed to be a baby in the stomach cavity.

Coelophyisis is one of the few prehistoric dinosaurs that paleontologists can pretty much completely map out as far as its skeleton and growth is concerned.  This is because of a fossil site in New Mexico, called the Ghost Ranch Formation, which was discovered with literally hundreds of individual specimens of Coelophysis, including fully-grown adults down to small babies.  Nobody knows for certain why so many of these dinosaurs died at this location, but it is likely that the Ghost Ranch area used to be a river during the Triassic.  Animals, like Coelophysis would have come to the river bed to drink during the dry season, died from thirst, then their bodies would have been buried under mud to be fossilized when the water did come through.  Another possibility is that they all gathered to hunt a common food source, like spawning fish (which Coelophysis' long snout and neck could have been adaptations for) and were wiped out by a flash flood.

A team of paleontologists, lead by Dr. Daniel Barta, recently investigated how Coelophysis grew by making thin slices in Coelophysis bones and looking at ring-like patterns on the inside, each ring indicating a year of the animal's life. (much like the growth rings of a tree) They determined that not all individual Coelophysis grew at the same rate.  Some very large individuals turned out to actually be very young when they died, while other relatively small individuals were actually much older.  This implies that Coelophysis' growth was probably more based on how much an animal was eating, which is similar to how many modern reptiles grow today.  This may have been a helpful trait for animals that lived in harsh environments where food wasn't consistently available over time where animals with more consistent growing patterns might starve.

There is evidence that Coelophysis may have also lived on America's east coast of North America, including parts of my home state, New Jersey!  Although no bones were ever found there, we do have lots of theropod dinosaur tracks that are from the exact time that Coelophysis was alive, and match the size of its feet.  Because it cannot be proven 100% (no bones) that these dinosaurs were actually Coelophysis, however, they were given their own name, Grallator.  

Grallator (most likely Coelophysis) tracks that were unearthed in New Jersey.  These slabs are on display at the Rutgers Geology Museum in New Brunswick, New Jersey.

Coelophysis is an important dinosaur, not only because scientists are able to study it so extensively, but also because it represents a turning point in dinosaur evolution.  Coelophysis lived during a time where many other kinds of reptiles, like the phytosaurs and most pseudosuchians, were about to go extinct, but dinosaurs were not.  Coelophysis' lineage would later flourish even more and radiate into the many theropod dinosaurs everyone knows and loves and eventually the birds, which are still successful today!  

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

References

Barta, D.E., Griffin, C.T. & Norell, M.A. Osteohistology of a Triassic dinosaur population reveals highly variable growth trajectories typified early dinosaur ontogeny. Sci Rep 12, 17321 (2022). https://doi.org/10.1038/s41598-022-22216-x

Gay, R.J. (2002). "The myth of cannibalism in Coelophysis bauri". Journal of Vertebrate Paleontology 22 (3): 57A.

Nesbitt, S. J.; Turner, A. H; Erickson, G. M; Norell, M. A (2006). "Prey choice and cannibalistic behaviour in the theropod Coelophysis". Biology Letters. 22 2 (4): 611–614. doi:10.1098/rsbl.2006.0524. PMC 1834007. PMID 17148302.

Rinehart, L.F.; Lucas, S.G.; Heckert, A.B.; Spielmann, J.A. & Celesky, M.D. (2009). "The paleobiology of Coelophysis bauri (Cope) from the Upper Triassic (Apachean) Whitaker quarry, New Mexico, with detailed analysis of a single quarry block". New Mexico Museum of Natural History & Science, a division of the Department of Cultural Affairs Bulletin 45: 260.

Schwartz, Hilde L.; Gillette, David D. (1994). "Geology and taphonomy of the Coelophysis quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico". Journal of Paleontology 68 (5): 1118–1130. JSTOR 1306181.