Geosternbergia: Beast of the Week

 This week we are looing at a famous pterosaur.  Check out Geosternbergia sterngergi!  

I'm going to start this post off with pointing out that Geosternbergia is considered simply a separate species within the genus, Pteranodon, by many experts, which would make its name Pteranodon sternbergi.  That being said, since I already did a post on Pteranodon longiceps, I'm choosing to refer to this pterosaur as Geosternbergia.  (taxonomy is complicated and also subject to change especially with fossils)

Geosternbergia was a large pterosaur that flew over the oceans that covered what is now central United States and southern Canada, during the late Cretaceous period, between 88 and 85 million years ago.  It was huge, the largest individuals sporting wingspans of 20 feet (6m) wide.  When alive they would have eaten meat, most likely primarily fish and other marine prey. The genus name is derived from the name of the paleontologist George Sternberg, who found the first fossils of this pterosaur in the early 1950s.  

Watercolor reconstruction of male and female Geosternbergia by Christopher DiPiazza.

Geosternbergia had a proportionally huge skull, which measured over four feet long in the largest specimens.  Most of this skull comprised of its long, toothless, roughly banana-shaped beak. It likely used this beak to dip into the surface of the ocean as it flew to grab prey.  The top jaw extended past the lower jaw, ending in a sharp point.  The eye sockets were actually proportionally tiny, but it still likely had sharp vision. 

Growing out the top of Geosternbergia's skull was a tall, somewhat triangular crest.  Since only the larger adult specimens possessed this crest, it is likely this pterosaur was sexually dimorphic. In addition the adults with the large crests, likely males, also were overall much larger and have narrower hips than the ones thought to be females.  Even more interesting is the fact that out of the many specimens of this pterosaur that have been found, the number of what are thought to be adult females is almost double the males.  This has led some experts to suggest that they may have exhibited polygynous mating behavior, where each male mates with multiple females.  This also aligns with males being larger and possessing elaborate display structures, since they'd be competing more aggressively with each other for mates. Modern examples of this are many, including lions, chicken, and sea lions, just to name a few. 

Skull of male Geosternbergia on display at the Sternberg Museum of Natural History in Kansas.

Geosternbergia's body is almost comically small, with the torso only a fraction of the skull length.  Like pretty much all pterosaurs, it would have been able to comfortably walk around on all fours, folding its extremely long fourth finger, which formed the wing, upwards while on the ground.  It is likely, however, that Geosternbergia spent most of its life at sea, possibly coming to land mostly just to mate and lay eggs.  Its proportionally huge wingspan also supports this idea, which would have allowed it to stay aloft with without expending too much energy, similar to modern sea birds.

Mostly complete skeleton of what is likely a male Geosternbergia, formerly thought to be a distinct genus, called Dawndraco.  (the short rounded crest is reconstructed)

  When alive, Geosternbergia, would have shared its habitat with many kinds of other pterosaurs and sea birds.  In the water below it would have likely hunted any small fish or mollusk it could snatch.  In turn Geosternbergia would have risked becoming food for larger predators, like sharks and the monstrous marine lizard, Tylosaurus, when it was near or in the water.  

References

Bennett, S.C. (1992). "Sexual dimorphism of Pteranodon and other pterosaurs, with comments on cranial crests". Journal of Vertebrate Paleontology. 12 (4): 422–434.

Bennett, S.C. (1994). "Taxonomy and systematics of the Late Cretaceous pterosaur Pteranodon (Pterosauria, Pterodactyloida)". Occasional Papers of the Natural History Museum, University of Kansas. 169: 1–70.

Martin-Silverstone E., Glasier J., Acorn J., Mohr S., Currie P. (2017). "Reassesment [sic] of Dawndraco kanzai Kellner, 2010 and reassignment of the type specimen to Pteranodon sternbergi Harksen, 1966". Vertebrate Anatomy Morphology Palaeontology. 3: 47–59.

Miller, H. W. (1971). "A skull of Pteranodon (Longicepia) longiceps Marsh associated with wing and body parts". Transactions of the Kansas Academy of Science. 74 (10): 20–33.

Sternberg, G. F.; Walker, M. V. (1958). "Observation of articulated limb bones of a recently discovered Pteranodon in the Niobrara Cretaceous of Kansas". Transactions of the Kansas Academy of Science. 61 (1): 81–85.

Zimmerman, H., Preiss, B., and Sovak, J. (2001). Beyond the Dinosaurs!: sky dragons, sea monsters, mega-mammals, and other prehistoric beasts, Simon and Schuster.

Eocursor: Prehistoric Beast of the Week

This week we are going to check out a little dinosaur that gives us insight into the origins of some of the most iconic dinosaurs, Eocursor parvus!  

Eocursor translates to "Dawn Runner" because it was a very early dinosaur and its extremely long legs show us that it was probably a fast runner.  From snout to tail it only measured about 3 feet (roughly 1m) and was a plant-eater.  It lived about 210 million years ago in what is now South Africa and was discovered in the 1990s but wasn't formally described until 2007.

Watercolor life reconstruction of Eocursor by Christopher DiPiazza.

Eocursor was tiny and had no special armor, horns, spikes, large teeth or anything else that some other extinct dinosaurs had that would make it formidable but it is nonetheless an extremely important discovery.  This is because most other dinosaur we know of from the Triassic are either some sort of theropod, like Coelophysis or a prosauropod, like Plateosaurus.  Very rarely does anyone find a dinosaur like Eocursor which is in the same group as and likely the ancestor of the plant-eating, beaked dinosaurs like ceratopsians, thyreophorans and ornithopods.  We call this group the ornithischian dinosaurs or "bird hipped dinosaurs" (ironic because it's the other saurischian "lizard hipped" theropods that were actually directly related to birds).  It may not look like much, but Eocursor's lineage would evolve into some of the most successful and widespread dinosaurs of the Mesozoic!

Eocursor parvus bones

Like I said before, Eocursor had extremely long legs which would have come in handy(or leggy HA!) when avoiding all those hungry meat-eating theropods and crocodilomorphs of its time.  We can tell this because its tibia(lower leg bone right below the knee) was much longer than its femur (thigh bone) which is a characteristic of swift-runners.  It also would have had strong arms with five grasping fingers on each hand.  This might have aided it when foraging for plants to eat.  Its head was small and possessed small teeth that look like they would have been suitable for cutting leaves and other such plant material.  Even thought the top of its skull was never discovered, I would be willing to bet Eocursor also had large eyes, which is a trait common in small, fast-moving, plant-eating dinosaurs.

References

Butler, Richard J.; Roger M. H. Smith and David B. Norman (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 (1621): 2041. 

Gongshuilong: Beast of the Week

 Today we're checking out a recently described hadrosaur with a unique look, Gongshuilong fanwei!

Gongshuilong lived in what is now eastern China, during the late Cretaceous period, between 68 and 66 million years ago.  From beak to tail it measured about 23 feet (7m) long and would have been a plant-eater when alive.  The genus name translates from Mandarin to "Gong River Dragon" in reference to the Gong River near where its bones were discovered.

Gongshuilong life reconstruction in watercolors by Christopher DiPiazza.

Gongshuilong was a member of the hadrosaurid ("duck- billed") family of dinosaurs.  More specifically it was a saurolophine hadrosaur, which is the group that had broader bills and sometimes had crests made of solid bone structures on their heads.  Maiasaura and Probrachylophosaurus are two examples of close relatives.  Like its relatives, Gongshuilong would have been able to walk on all four legs or just its hind legs if it wanted to.  Its claws would have been hoof-like and the middle three fingers of each hand would have been fused together into a mitt, with one single hoof-like claw on the tip of them.  Like all members of its family it would have possessed a broad beak in the front of its jaws, backed up by rows of small teeth packed together to form what are referred to as "dental batteries".  These teeth were ideal for chewing up tough plants.

Photo of some of Gonghsuilong's bones, zooming in on the tall neural arches on the tail.  Image from the paper by Yao et al. listed below.

What makes Gongshuilong unusual for a hadrosaur is the fact that it had a display structure on its tail, in the form of a tall sail made up of elongated neural arches.  This would have given it a unique profile for a dinosaur, which makes me think of some living species of lizards which also sport similar structures on their tails for display within the species.  (Spinosaurus funnily enough independently had something similar)  It is likely Gongshuilong was doing something similar with its tail, possibly signaling to members of the same species for mating displays or to intimidate rivals.  Perhaps females possessed smaller sails than males?  We would need to find more fossils to have a better idea for sure.  

References

Ibrahim, Nizar; Maganuco, Simone; Dal Sasso, Cristiano; Fabbri, Matteo; Auditore, Marco; Bindellini, Gabriele; Martill, David M.; Zouhri, Samir; Mattarelli, Diego A.; Unwin, David M.; Wiemann, Jasmina; Bonadonna, Davide; Amane, Ayoub; Jakubczak, Juliana; Joger, Ulrich; Lauder, George V.; Pierce, Stephanie E. (May 7, 2020). "Tail-propelled aquatic locomotion in a theropod dinosaur". Nature. 581 (7806): 67–70.

Yao, Han; Qiu, Wenjiang; Yu, Juan; Yang, Ling; Wang, Huimin; Cao, Shenghua; Zhao, Kui; Xu, Mengyuan; Shi, Guo; Lou, Fasheng; Zeng, Cuimin; Lu, Pikun; Wu, Rui; Xu, Xing; Han, Fenglu (2026-03-30). "A new saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the Upper Cretaceous of South China, providing further support for the possible Asian origin of Brachylophosaurini".

Mexidracon: Beast of the Week

 This week we will be taking a look at a unusual theropod.  Check out Mexidracon longimanus!

Mexidracon was a theropod dinosaur that lived in what is now Coahuila, Mexico, during the late Cretaceous period, about 72 million years ago.  From beak to tail it measured about 10 feet (3m) long.  Its genus name translates to "Mexican Dragon" and its species name to "long hand".  It may have been a plant-eater when alive or possibly eaten a mix of both plants and meat.  

Mexidracon life reconstruction in watercolor by Christopher DiPiazza.  This dinosaur may have been an omnivore, using its long hands to reach narrow places where prey might hide.

Mexidracon was a member of the ornithomimid family of dinosaurs, famous for resembling modern ostriches as a result of convergent evolution.  They had long necks with beaks with the later surviving forms lacking teeth.  The skull of Mexidracon was never found so it is difficult to know for sure if this was the case for it, but given its presence in the late Cretaceous and its close relationship to relatives we know were toothless, like Struthiomimus, it may have been as well.  Mexidracon is noted to have slightly shorter, more robust lower leg bones than other ornithomimids, but it was still likely a fast runner in life.  

Photograph of some of Mexidracon's bones with labels (in Spanish) (photo credit: Global Revista)

The most notable and unique feature about Mexidracon, however, is its hands.  The hand bones, called metacarpals (bones that make up our palms), were extremely long, which is where it earned its species name from.  It then also had three average length for an ornithomimid (but still relatively long) fingers, each tipped with a claw on each hand.  It is a total mystery why this dinosaur would evolve such an odd trait but there are a few ideas.  The first is the hands may have helped it get food, perhaps gathering vegetation or reaching into crevices or burrows of small creatures, more effectively.  The other possibility is the elongated hands may have been part of a display for members of the same species.  We know ornithomimids had feathers, so perhaps there were fancy display feathers growing there to impress mates or intimidate rivals?  We may never know.  

Mexidracon came from a habitat that paleontologists are still very much actively investigating and finding new exciting specimens from right now.  Other dinosaurs that have been found in the same area of Mexico include the hadrosaur, Velafrons, and the ceratopsian, Coahuilaceratops.

References

Serrano-Brañas, Claudia Inés; Espinosa-Chávez, Belinda; de León-Dávila, Claudio; Maccracken, S. Augusta; Barrera-Guevara, Daniela; Torres-Rodríguez, Esperanza; Prieto-Márquez, Albert (2025-01-28). "A long-handed new ornithomimid dinosaur from the Campanian (Upper Cretaceous) Cerro del Pueblo Formation, Coahuila, Mexico".

Peloroplites: Beast of the Week

 This week we will be checking out a large tank dinosaur.  Enter Peloroplites cedrimontanus!

Peloroplites was a plant-eating dinosaur that lived in what is now Utah, USA, during the Cretaceous period, between 98 and 93 million years ago.  From snout to tail it would have measured about 20 feet (6m) long.  It's genus name translates to "Giant Hoplite" in reference to hoplites, the ancient Greek soldiers who famously carried spears and large shields.  The species name translates to "Cedar Mountain" in reference of the geologic location in which its bones were found, the Cedar Mountain Formation.

Peloroplites life reconstruction in watercolor by Christopher DiPiazza.

Peloroplites was a member of the ankylosaur group of dinosaurs, famous for their heavy armored bodies.  More specifically within the ankylosaur group, it was in the nodosaur family, which are known for having spiky armor, especially around their necks.  Unlike more iconic ankylosaurs, nodosaurids lacked bony tail clubs.  Gargoyleosaurus and Priconodon are other examples of nodosaurs.

Peloroplites had a particularly boxy skull, with a snout that slopes down at the front.  The beak was broad and had a little notch in the center of it.  It also possessed blunt horns on its cheek bones in addition to thick bony armor on the top of its head. Only one tooth was found for Peloroplites, and it is typical for nodosaurs, proportionally small and leaf-shaped, for cutting plants.  Because of this dinosaur's noticeably wide face, it may have been a generalist feeder, hoovering up any plant material it could reach. 

Pelororoplites skeletal mount on display at the USU Eastern Prehistoric Museum, in Utah, USA.

A good amount of Peloroplites' skeleton is known, including much of its skull and many limb and other body bones, but sadly very little armor.  Because of this the skeletal ad life reconstructions of this dinosaur have the armor and spikes are based on other nodosaurs which we do have the armor of.  (Special thank you to Dr. Kenneth Carpenter, the paleontologist who originally described Peloroplites, for confirming this for me.)

When alive, Peloroplites' habitat would have been seasonally wet/flooded environment on the western shore of the shallow sea that used to be present down the middle of the United States during the Cretaceous.  It coexisted with many other dinosaurs, including the small tyrannosaur, Moros, and the larger theropod, Siats.  

References

 Carpenter, Kenneth; Bartlett, Jeff; Bird, John; Barrick, Reese (2008). "Ankylosaurs from the Price River Quarries, Cedar Mountain Formation (Lower Cretaceous), east-central Utah". Journal of Vertebrate Paleontology. 28 (4): 1089–1101.

Diamantinasaurus: Beast of the Week

This week we'll be learning about a beast that greatly helps us understand how sauropod dinosaurs ("long-necks") looked and lived.  Check out Diamantinasaurus matildae!

Diamantinasaurus lived in what is now Queensland, Australia during the middle Cretaceous period, between 95 and 92 million years ago.  It's considered medium-sized for a sauropod, and would have measured about 52 feet (16m) long from snout to tail. (Yes. 52 feet is only medium for sauropods!) Like all sauropods it would have eaten plants when alive.  It's genus name is after the Diamantina River, near where its bones were initially discovered.  The species name is after the popular Australian song, "Waltzing Matilda".

Watercolor reconstruction of Diamantinasaurus by Christopher DiPiazza.  Fossil evidence shows this dinosaur wasn't a picky eater, eating a wide variety of plants.

Diamantinasaurus was initially known from limb bones, ribs, and pelvis bones.  It's limbs stand out as being particularly robust, even for a sauropod.  Another interesting feature is the fact that its front limbs possessed short little finger bones and a single large claw on each hand.  These are common traits to most sauropods from earlier times, but were lost in most later sauropods that lived during the Cretaceous period. Diamantinasaurus appears to have retained what is otherwise considered this primitive trait.  

Photograph of the bones in Diamantinasaurus' manus(hand).  Note the prominent claw that grew out of the side of the hand.

Later on after its initial discovery Diamantinasaurus' skull was discovered.  This is exciting since the skulls of sauropods notoriously are hard to find. (they appear to have tended to get separated from the rest of the body and destroyed before fossilization, which makes sense how small they are compared to the bodies) Diamantinasaurus' snout sloped downwards, and actually resembles the skull of Brachiosaurus, even thought it is believed to have been more closely related to fellow Cretaceous sauropods, like Saltasaurus.  A few of Diamantinasaurus' teeth were also found still in the jaw that had not grown in yet, which were narrow and rod-shaped with chisel-like tips.  

Front and side view of the skull of Diamantinasaurus.

More recently in 2025, fossilized gut contents of Diamantinasaurus were discovered.  This is amazing since up until this point, even though everyone assumed sauropods ate plants, actual proof in the form of a fossilized last meal had never been found in one.  As it turns out Diamantinasaurus appears to have been a generalist plant-eater, with remains of all sorts of plants, including ferns, pine trees, and flowering plants found in its stomach.  This means Diamantinasaurus wasn't only feeding at the tops of trees, like sauropods are often depicted doing, but rather was using its long neck to reach all sorts of heights to feed.  Like all sauropods, Diamantinasaurus couldn't chew since its teeth were only at the front of its snout for chomping.  Rather it would have swallowed mouthfuls of plants whole and relied likely on fermentation inside its body to digest the meals.  Some believe that sauropods also could have swallowed stones to help aid in digestion, like some birds and other reptiles are known to do today.

References

Poropat, S.F.; Upchurch, P.; Mannion, P.D.; Hocknull, S.A.; Kear, B.P.; Sloan, T.; Sinapius, G.H.K.; Elliot, D.A. (2014). "Revision of the sauropod dinosaur Diamantinasaurus matildae Hocknull et al. 2009 from the mid-Cretaceous of Australia: Implications for Gondwanan titanosauriform dispersal". Gondwana Research. 27 (3): 995–1033.

Poropat, Stephen F; Kundrát, Martin; Mannion, Philip D; Upchurch, Paul; Tischler, Travis R; Elliott, David A (2021-01-20). "Second specimen of the Late Cretaceous Australian sauropod dinosaur Diamantinasaurus matildae provides new anatomical information on the skull and neck of early titanosaurs". Zoological Journal of the Linnean Society. 192 (2): 610–674.

Poropat, S.F.; Mannion, P.D.; Upchurch, P.; Hocknull, S.A.; Kear, B.P.; Kundrát, M.; Tischler, T.R.; Sloan, T.; Sinapius, G.H.K.; Elliott, J.A.; Elliott, D.A. (2016). "New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography". Scientific Reports. 6 34467.

Poropat, S. F.; Tosolini, A.-M. P.; Beeston, S. L.; Enchelmaier, M. J.; Pentland, A. H.; Mannion, P. D.; Upchurch, P.; Chin, K.; Korasidis, V. A.; Bell, P. R.; Enriquez, N. J.; Holman, A. I.; Brosnan, L. M.; Elson, A. L.; Tripp, M.; Scarlett, A. G.; Godel, B.; Madden, R. H. C.; Rickard, W. D. A.; Bevitt, J. J.; Tischler, T. R.; Croxford, T. L. M.; Sloan, T.; Elliott, D. A.; Grice, K. (2025). "Fossilized gut contents elucidate the feeding habits of sauropod dinosaurs". Current Biology. 35 (11): 2597–2613.

Daemonosaurus: Beast of the Week

 This week we will be checking out a unique looking early dinosaur with a very cool name.  Meet Daemonosaurus chaoliodus!

Daemonosaurus was a small meat-eating dinosaur that lived in what is now New Mexico, United States, during the late Triassic period, roughly between 205 and 200 million years ago.  From nose to tail it is estimated to have measured roughly 5 to 7 feet (1.5-2.2m).  These are estimates based on the fact that only the skull and neck were found.  The genus name translates to "Demon Reptile" and the species name translates to "Prominent Tooth" in reference to its unusual front teeth.  

Watercolor reconstruction of Daeomonosaurus by Christopher DiPiazza.

The first thing you notice about Daemonosaurus is its unusual face.  It possessed round, short-snouted skull with huge eye sockets, so it probably had sharp vision in life.  It possessed unusually long curved teeth right in the front of its mouth.  In fact, the very frontmost teeth are the longest overall.  The teeth themselves are mostly rounded in cross section with shallow serrations on the anterior sides only.  It is difficult to exactly know what these extreme teeth were adapted for, but it was likely eating some form of meat.  Perhaps it was a fish and other water prey specialist?  Maybe it was snapping up small fast creatures, like insects?  We may never know.

The identity of what kind of dinosaur Daemonosaurus is somewhat mysterious mostly because simply not that many dinosaurs from the Triassic period are known compared to other times.  The Triassic was also a time when dinosaurs were still not clearly diversified into the more distinct forms we recognize from later times.  Initially, when Daemonosaurus was first published on in 2011, it was identified as a theropod dinosaur, closely related to its contemporary, Coelophysis.  This makes sense since they both had sharp curved teeth with serrations, and they even both possess a notch at the front of the upper jaw, which is a common trait among early theropod dinosaurs.  Later on in 2020, however, those same paleontologists who wrote the first paper identifying Daemonosaurus as a theropod revised their stance based on more information, placing it just outside the theropod group as a kind of very early saurischian dinosaur. To review, the saurischian dinosaurs are the broader group that contains both the bipedal theropods and the long-necked sauropods.  This means Daemonosaurus was closer to older dinosaurs, like Herrerasaurus.  Since only Daemonosaurus' skull and neck have been found, we may still learn new things about it and its identity may change yet again in the future! 

Photograph of all the fossil material that is currently known from Daemonosaurus.  Note the long front teeth and huge eye socket. Photo featured in the 2011 paper by Seus et al. referenced below.

When alive Daemonosaurus would have lived in a environment that swung between extreme aridness and heavy rain and flooding during the year.  In fact, the bonebed it was found in is thought to be the result of a flash flood wiping out a bunch of animals.  Daemonosaurus' most common neighbor appears to have been Coelophysis, which it was surrounded by many skeletons of when it was discovered.  It also would have coexisted with the early crocodilian, Hesperosuchus, and the giant predator Postosuchus, to name a few more.

References

Hans-Dieter Sues; Sterling J. Nesbitt; David S. Berman & Amy C. Henrici (2011). "A late-surviving basal theropod dinosaur from the latest Triassic of North America". Proceedings of the Royal Society B. 278 (1723): 3459–3464.

Nesbitt, Sterling J.; Sues, Hans-Dieter (3 August 2020). "The osteology of the early-diverging dinosaur Daemonosaurus chauliodus (Archosauria: Dinosauria) from the Coelophysis Quarry (Triassic: Rhaetian) of New Mexico and its relationships to other early dinosaurs". Zoological Journal of the Linnean Society. 191: 150–179.

Novas, Fernando E.; Agnolin, Federico L.; Ezcurra, Martín D.; Temp Müller, Rodrigo; Martinelli, Agustín G.; Langer, Max C. (2021-10-01). "Review of the fossil record of early dinosaurs from South America, and its phylogenetic implications". Journal of South American Earth Sciences. 110 103341.