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.

Elasmosaurus: Beast of the Week

 This week we will be checking out a sea beast who's proportions were so outrageous, it confused even scientists! Check out Elasmosaurus platyurus.

Elasmosaurus was a large reptile that lived in he sea that covered what is now central part of the United States during the late Cretaceous period, between 80 and 77 million years ago.  From snout to tail it would have measured about 34 feet (7.1m) and would have eaten meat when alive.  Its genus name translates to "plate reptile" in reference to how wide and flat some of its hip and chest bones were.  

Watercolor life reconstruction of Elasmosaurus by Christopher DiPiazza.

The first thing you notice about Elasmosaurus is its extremely long neck.  Plesiosaurs, the group of marine reptiles it belonged to, are famous for having long necks, but Elasmosaurus stands out even among them.  Proportionally one of the longest necks of any animal that ever lived, it accounts for more than half of its total body length.  Unlike many other kinds of long-necked animals, like giraffes or the sauropod dinosaurs, which evolved their necks by elongating the individual vertebrae, Elasmosaurus' ancestors appeared to have simply increased the number of vertebra instead, resulting in a whopping seventy two vertebra in just the neck! Because of this, Elasmosaurus' neck would have been relatively flexible, at least when it moved its head side to side.  (I like to compare it to one of those wooden snake toys that you can hold by the tail to make it move around.)  Because the neural arches on the tops of the neck vertebra were pretty tall, Elasmosaurus' vertical range of motion would have been much more limited.  This means that the iconic swan-like neck pose many older depictions of plesiosaurs, as well as most images of the Loch-Ness Monster and other lake cryptids based on plesiosaurs, are anatomically wrong.  

Cheap and surprisingly lifelike, this snake toy has limited movement in an up and down motion but pretty flexible side to side, similar to how Elasmosaurus' neck likely was.

The neck of Elasmosaurus is so unusually long, it even tricked scientists at the time of its discovery.  The first skeletal mount of Elasmosaurus accidentally has the head placed on the end of the tail, instead of the neck, since a reptile with a super long tail seemed more logical at first. (at least to the scientist who drew it)

Drawing of the initial interpretation of Elasmosaurus with the head incorrectly placed at the tip of the tail and has what was really the neck as a long tail.

So why such a long neck?  This is something paleontologists are still contemplating and we may never truly know the answer.  One strong hypothesis is the long neck would have allowed Elasmosaurus to get its head closer to fish, which it would have hunted, without scaring them away with its huge body, essentially tricking them into thinking it was smaller and less threatening, than it really was.  Another idea is the neck may have enabled Elasmosaurus to pursue prey that may have hidden between rocks or other difficult to reach places.  A third idea is that Elasmosaurus evolved such long neck due to sexual selection, being a sign of genetic fitness and therefore attractive as a mate.  Maybe rival Elasmosaurus settled disputes by showing off who had a longer neck?  We may never know for sure.

Elasmosaurus skeletal mount (with the head on the right end) on display at the Academy of Natural Sciences in Philadelphia, USA.

Elasmosaurus had a proportionally tiny head which was flattened top to bottom. Like most long-necked plesiosaurs, its eyes were positioned on the top of its head and its jaws were lined with long cone-shaped teeth that interlocked when its jaws were closed.  The longest teeth were in the front of the mouth, likely an adaptation to hold onto slippery fish prey. 

The body of Elasmosaurus is wide and almost turtle-like in shape and function, with virtually no flexibility, since some parts of its pelvis and shoulder blades were fused together at the midline of its torso, forming wide plate-shaped structures.  This would have made its body stable when swimming at higher speeds.  Like all plesiosaurs, its limbs were modified into long rigid flippers, with upper limb bones and joints suggesting they would have been able to move them like the oars of a boat as they swam for sustained periods of time. Similar to modern sea turtles, Elasmosaurus' front flippers appear to have been where most of its power for swimming came from while the hind flippers would have been more for steering.  It's tail was proportionally short and flattened from side to side like a rudder. 

Elasmosaurus' habitat was a shallow warm sea that existed in the middle of what is now the United States during the late Cretaceous, dividing the continent into two landmasses.  Many marine fossils have been unearthed and studied from there.  When alive Elasmosaurus would have shared its habitat with many kinds of fish, ammonites, turtles, seagoing birds, the pterosaur, Pteranodon, and of course, mosasaurs(marine lizards), including Tylosaurus, Globidens, and Prognathodon.

References

Cope, E. D. (1869). "Synopsis of the extinct Batrachia, Reptilia and Aves of North America, Part I". Transactions of the American Philosophical Society. 14: 44–55. 

Houssaye, A. (January 1, 2013). "Bone histology of aquatic reptiles: what does it tell us about secondary adaptation to an aquatic life?". Biological Journal of the Linnean Society. 108 (1): 3–21.

O'Gorman, J. P. (2016). "A Small Body Sized Non-Aristonectine Elasmosaurid (Sauropterygia, Plesiosauria) from the Late Cretaceous of Patagonia with Comments on the Relationships of the Patagonian and Antarctic Elasmosaurids". Ameghiniana. 53 (3): 245–268.

Sachs, S. (2005). "Redescription of Elasmosaurus platyurus Cope, 1868 (Plesiosauria: Elasmosauridae) from the Upper Cretaceous (lower Campanian) of Kansas, U.S.A". Paludicola. 5 (3): 92–106.

Diplodocus: Beast of the Week

 This week we will be looking at an iconic dinosaur.  Make way for Diplodocus!

Perhaps one of the most widely known dinosaurs, Diplodocus was a sauropod that lived in what is now Western United States, most notably Colorado and Wyoming, during the Late Jurassic period, between 154 and 152 million years ago. Like all sauropods, it was a plant-eater, and like many sauropods, it was notably huge.  Diplodocus could grow to between 80 to 90 feet (about 24-27 meters) on average, but some specimens imply it could grow to even longer, exceeding 100 feet (30.4 meters) in some cases.  The genus name translates to "Double Beam" in reference to the upside-down "T" shaped projections growing from the underside of its vertebrae.  Currently two species of Diplodocus are recognized.  Diplodocus carnegii, which was described first, and Diplodocus hallorum, which appears to have been the larger of the two species.

Life reconstruction of Diplodocus (the big one) in watercolors by Christopher DiPiazza. 

Diplodocus is an important dinosaur because although it was not the first ever discovered sauropod dinosaur (that goes to Cetiosaurus, discovered in 1842 in England), it was the first sauropod discovered with enough bones to get a decent idea of what sauropods actually looked like, showing scientists just how bizarre these animals truly were.  No other kind land animal got close this large, let alone had these kinds of proportions.  You could argue giraffes come somewhat close with long necks, but theirs aren't nearly as proportioally long, nor do they have the insanely long, whiplike tails of many sauropods. 

Tail vertebra of Diplodocus on display at the Natural History Museum in London.  Note the upside down "T" projections on the underside of each bone.

 Diplodocus was a member of the more specific family of sauropods called the diplodocidae. (which is named after Diplodocus, itself.) Diplodocids are known for having more elongated faces than those of other sauropods, had peg-shaped teeth concentrated at the front of their jaws, and front limbs that were slightly shorter than their hind limbs.  The teeth were likely adaptations for stripping or clipping leaves off of trees.  The leg proportions means the dinosaur's center of gravity would have been around its hips, and therefore it could have probably stood up on its hind legs at least for short periods, maybe to display, scare predators, or reach higher leaves to eat.  

Probably the most notable trait of diplodocids, however, is their incredibly long, whiplike tails, which consisted of 80 vertebrae and could make up more than half the length of the entire animal's body.  The base of the tail was flexible and backed up by huge muscles, which would have allowed the dinosaur to move the end of this tail around extremely fast and with a lot of concentrated force.  Most experts suspect this would have been an effective weapon against potential predators.  Despite not having any spikes or other bony protrusions on its tail like many other kinds of dinosaurs had, since the tip of Diplodocus' tail could have hit so hard, it likely would have been able to seriously injure, and possibly lacerate the bodies of its enemies. 

Diplodocus skeleton on display at the National Museum of Natural History in Washington DC.

Like all sauropods, Diplodocus had an extremely long neck, made up of vertebra that had huge hollow spaces in them.  These were the attachment sites for air sacs which connected to the dinosaur's respiratory system, which allowed the huge body to be as light as possible as well as more effectively distribute oxygen throughout.  The neck bones also had bony ribs growing out of the bottom which overlapped.  In life these structures would have stiffened and therefore structurally strengthened the neck, making it easier for the dinosaur to keep its head up. 

In addition to huge adults, paleontologists have also uncovered bones from more than one small juvenile Diplodocus.  Experts think it is unlikely huge sauropods, like Diplodocus, cared for their eggs and young, but the skeletons of these small individuals, which were all found in the same area, suggest babies may have banded together for extended periods of time as they grew up.  At smaller sizes sauropods would have been extremely vulnerable to predators when young, so being part of a larger group, with more sets of senses alert for danger could have been a strategy to minimize the likelihood that each baby Diplodocus would be eaten by a predator.  (Fun trivia: During my time working and volunteering at the Academy of Natural Sciences in Philadelphia I helped prep some of the bones from these Diplodocus specimens!)

These young Diplodocus remains also preserved skin impressions, showing us that these dinosaurs had scaly skin that varied in pattern and texture on different parts of the dinosaur's body.  This is not a surprise, since most modern reptiles exhibit this on their skin in various ways, but it's still extremely exciting to get confirmation of it for a dinosaur like Diplodocus, especially since preserved skin is so rare in fossils.  

Fossilized skin impression from young Diplodocus from Gallagher's paper referenced below.  Note how they vary in shape and form.  

When alive, Diplodocus would have shared its environment with many other dinosaurs, including fellow sauropods, Apatosaurus, Brontosaurus, Brachiosaurus, Barosaurus, Camarasaurus, and Suuwassea.  Other plant-eating dinosaurs, like Stegosaurus, Gargoyleosaurus, and Camptosaurus were also present.  Predators that would have hunted young Diplodocus include Allosaurus, Ceratosaurus, and Torvosaurus. 

References

Carpenter, Kenneth (2006). "Biggest of the big: a critical re-evaluation of the mega-sauropod Amphicoelias fragillimus". In Foster, John R.; Lucas, Spencer G. (eds.). Paleontology and Geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin, 36. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 131–138.

Foster, J.R. (2003). Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A. New Mexico Museum of Natural History and Science:Albuquerque, New Mexico. Bulletin 23.

Gallagher, T; Poole, J; Schein, J (2021). "Evidence of integumentary scale diversity in the late Jurassic Sauropod Diplodocus sp. from the Mother's Day Quarry, Montana". PeerJ. 9: e11202. 

Holland WJ (1915). "Heads and Tails: a few notes relating to the structure of sauropod dinosaurs". Annals of the Carnegie Museum. 9 (3–4): 273–278.

Upchurch, P.; Barrett, P.M. (2000). "The evolution of sauropod feeding mechanism". In Sues, Hans Dieter (ed.). Evolution of Herbivory in Terrestrial Vertebrates. Cambridge University Press.

Wilson JA (2005). "Overview of Sauropod Phylogeny and Evolution". In Rogers KA, Wilson JA (eds.). The Sauropods:Evolution and Paleobiology. Indiana University Press. pp. 15–49.

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.

Beipiaosaurus: Beast of the Week

 Beipiaosaurus inexpectus was a theropod dinosaur that lived in what is now Liaoning, China, during the early Cretaceous period, 125 million years ago.  From snout to tail it measured about 7 feet (2.2 meters) long and would have eaten plants when alive.  The genus name means "Beipiao Reptile" which is in reference to the city, Beipiao, near where its fossils were discovered.  

Watercolor reconstruction of Beipiaosaurus by Christopher DiPiazza.  Note the combination of shorter, shaggy feathers and long, quill-like feathers.

Beipiaosaurus was an early member of the therizinosaur group of theropods, which are famous for being herbivores in an otherwise mostly meat-eating group.  They are also known for having proportionally short legs and long arms, equipped with three extremely long claws on each hand.  Later therizinosaurs, like the more famous, Therizinosaurus, are known for having long, slender necks with proportionally tiny heads, but Beipiaosaurus actually had a very large head, with a skull the same length as its femur.  Beipiaosaurus also had three weight-bearing toes on each foot, while its later relatives had four. 

Beipaosaurus had a long, narrow skull, with a small beak at the tip that was also lined with small leaf-shaped teeth, ideal for shredding plants.  It had long, powerful arms, each equipped with three extremely large, hooked claws.  Since Beipiaosaurus appears to have been a plant-eater, these claws could have been for manipulating branches as it ate, or possibly even for defense against predators.  Thanks to beautifully preserved remains, we know that Beipiaosaurus was mostly covered in shaggy, fur-like feathers that could have been an adaptation to keep the dinosaur warm. (the climate where it lived during the early Cretaceous could get cold at times)  Beipiaosaurus also had a second kind of unusual long, quill-like feather that appear to have been growing out of its body amongst the shorter, shaggier feathers.  We don't know exactly what these quill-like feathers were for. Perhaps they helped keep the animal dry by wicking off rain, or possibly they were for some kind of display among members of the same species? It's difficult to tell without seeing the animal alive. Beipiaosaurus also had a bone on the tip of its tail, called a pygostyle, which modern birds also have where their tail feathers attach.  Beipiaosaurus doesn't show any evidence of those kinds of feathers, however, so the bone, itself, must have evolved first.

Fossil Beipiaosaurus.  Note the feathers that preserved around the neck.

Perhaps the most amazing discovery about Beipiaosaurus, however, is that scientists were able to figure out what colors its feathers were in life.  Be examining the fossilized feathers from Beipiaosaurus' neck under a special kind of microscope, they were able to see cell structures, called melanosomes, which can determine the color of a feather according to the their shape.  Then they compared the shape of Beipiaosaurus' melanosomes to those of living birds and looked for matches.  The modern bird feathers that matched Beipiaosaurus' melanosomes the most were brown, so we can confidently assume that at least some Beipiaosaurus had brown feathers on their necks in life.  

Scientists also found patches of Beipiaosurus' skin!  By looking at its skin under a microscope and then comparing it to other animals, they were able to determine by the amount of keratin (material that feathers, hair, and nails are made of) in the cells, that Beipiaosaurus' body wouldn't have radiated as much heat as many modern birds.  They also were able to determine that Beipiaosaurus would have shed its skin more like modern birds, as dandruff, rather than other kinds of reptiles, like lizards, which shed skin in large pieces or flakes.  (fun fact: modern crocodilians also shed their skin as dandruff!)

Close up of a patch of Beipaosaurus skin from McNamara's 2018 paper.

Before Beipiaosaurus was discovered in 1996, the exact placement of therizinosaurs on the dinosaur family tree was more debated.  Originally, some paleontologists thought they were late-surviving descendants of the early sauropodomorphs from the Triassic and early Jurassic, like Plateosaurus, based on similarities with their small leaf-shaped teeth, long necks, wide bodies, and robust legs.  The discovery of Beipiaosaurus, however, which has more obvious theropod traits while clearly showing a direct connection to the more outlandish, later therizinosaurs, confirms therizinosaurs were indeed theropods.  

That's all or this week!  As always feel free to comment below!

References

Li, Q.; Clarke, J. A.; Gao, K.-Q.; Zhou, C.-F.; Meng, Q.; Li, D.; D’Alba, L.; Shawkey, M. D. (2014). "Melanosome evolution indicates a key physiological shift within feathered dinosaurs". Nature. 507 (7492): 350–353.

McNamara, M. E.; Zhang, F.; Kearns, S. L.; Orr, P. J.; Toulouse, A.; Foley, T.; Hone, D. W. E; Rogers, C. S.; Benton, M. J.; Johnson, D.; Xu, X.; Zhou, Z. (2018). "Fossilized skin reveals coevolution with feathers and metabolism in feathered dinosaurs and early birds". Nature Communications. 9 (2072): 2072.

Xu, X.; Tang, Z.-L.; Wang, X. L. (1999). "A therizinosauroid dinosaur with integumentary structures from China". Nature. 339 (6734): 350–354.

Xu, X.; Cheng, Y.; Wang, X.-L.; Chang, C. (2003). "Pygostyle‐like Structure from Beipiaosaurus (Theropoda, Therizinosauroidea) from the Lower Cretaceous Yixian Formation of Liaoning, China". Acta Geologica Sinica. 77 (3): 294–298.

Xu, X.; Zheng, X.; You, H. (2009). "A new feather type in a nonavian theropod and the early evolution of feathers". Proceedings of the National Academy of Sciences. 106 (3): 832–834.

Lambeosaurus: Beast of the Week

 This week we will be checking out another amazing hadrosaur.  Make way for Lambeosaurus!

Lambeosaurus was a hadrosaur ("duck-billed" dinosaur) that lived in what is now Canada during the late Cretaceous period, 75 million years ago.   Adults measured 23 feet (7 meters) long from beak to tail.  The genus name translates to "Lambe's Lizard" in honor of the paleontologist, Lawrence Lambe.  Like all hadrosaurs, Lambeosaurus would have eaten plants when alive.

Lambeosaurus lambei life reconstruction in watercolors by Christopher DiPiazza.

Lambeosaurus was a member of the lambeosaurine group of hadrosaurs, which are characterized by having more narrow snouts and often elaborate, hollow, bony crests on their heads.  Corythosaurus and Hypacrosaurus are two other members of this group which were particularly closely related to Lambeosaurus.  Within the Lambeosaurus genus there are actually two distinct species, Lambeosaurus lambei and Lambeosaurus magnicristatus.  Lambeosaurus lambei was discovered first, lived earlier by a few million years, and had a crest that jutted out in the front accompanied by a solid, bony, rod-like structure growing out of the back of its head.  Lambeosaurus magnicristatus lived slightly more recently, and had a larger, rounder crest that grew forward out of the top of its skull. 

There are two species of Lambeosaurus.  Lambeosaurus lambei (left) and Lambeosaurus magnicristatus (right). 

The exact function of Lambeosaurus' crest may always be a mystery, but many experts agree it most likely evolved for some sort of display within the species.  The front portion of the crest was also hollow, and attached to the nasal cavities of the animal, so it is commonly suggested they had a role to play in making unique sounds, as well.  Among Lambeosaurus lambei specimens, there seems to be a variety in crest size between individual adults.  Some paleontologists believe that this represents sexual dimorphism, the males with slightly larger crests than the females.  Babies and juveniles are also known from Lambeosaurus, which had tiny crests that start in the front of the skull, and expanded backward as the animals matured. 

Skull cast of Lambeosaurus lambei on display at the Academy of Natural Sciences in Philadelphia.

Lambeosaurus had a very long, slender snout that was tipped with a rounded bill.  This feature would have been ideal for clipping tough vegetation that would then be ground up by many small teeth in the back of the mouth, which acted together as a unit, called a dental battery.  Like all reptiles, Lambeosaurus would have been able to regenerate teeth continuously as they became worn or lost.  

Baby Lambeosaurus skull on display at the Royal Tyrrell Museum. (photo credit: Roland Tanglao)

Like all hadrosaurs, Lambeosaurus would have been able to walk on all fours or just its hind legs, as a biped, depending on what suited it.  Its front limbs were relatively the middle three fingers on each hand were fused together and tipped with a large hoof-like claw.  Its tail was long and extremely robust, and would have served as a counterbalance for the animal if it walked or ran on its hind legs.  The tail also could have served as an effective weapon to keep predators away or even knock them over if swung hard enough, if needed.  

References

Dodson, Peter (1975). "Taxonomic implications of relative growth in lambeosaurine dinosaurs". Systematic Zoology. 24 (1): 37–54.Simpson, D.P. (1979). Cassell's Latin Dictionary (5th ed.). London: Cassell Ltd. p. 883. 

Evans, David C.; Reisz, Robert R. (2007). "Anatomy and relationships of Lambeosaurus magnicristatus, a crested hadrosaurid dinosaur (Ornithischia) from the Dinosaur Park Formation, Alberta". Journal of Vertebrate Paleontology. 27 (2): 373–393.

Horner, John R.; Weishampel, David B.; Forster, Catherine A. (2004). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria(2nd ed.). Berkeley: University of California Press. pp. 438–463.

Hypacrosaurus: Beast of the Week

This week we're checking out an important and well-studied plant-eater.  Make way for Hypacrosaurus!

Hypacrosaurus was a hadrosaurid ("duck-billed" dinosaur) that lived in what is now North America during the late Cretaceous period, between 75 and 67 million years ago.  When alive, like all members of its family, it would have eaten plants.  The largest adults measured about 30 feet (9.1 meters) from beak to tail.  The genus name translates to "Near the Highest Lizard" which is a seemingly odd genus name.  It's because the first Hypacrosaurus fossils uncovered were soon after the first Tyrannosaurus (the "highest" of dinosaurs at the time) fossils, and the two were similar in size, T.rex being a bit larger.  (This comparison made more sense at the time when we knew about WAY fewer dinosaurs.)

Hypcrosaurus altispinax life reconstruction in watercolors by Christopher DiPiazza.

Hypacrosaurus was a member of the lambeosaurine group within the hadrosaur family.  Lambeosaurines are known for having hollow bony crests growing from the tops of their skulls.  Parasaurolophus, and Hypacrosaurus' especially close relative, Corythosaurus are more famous members of this group.  Hypacrosaurus' crest was similar to Corythosaurus' in that it shaped almost like a sort of round helmet that starts about midway up the snout and ends at the base of the skull, behind the head.  Hypacrosaurus' crest was a bit shorter and wider than Corythosaurus', however.  Like its relatives, the crest was hollow and could have aided it in making specific kinds of sounds meant to communicate with members of its own species.  The crest also could have very well aided in visual display, since we know these dinosaurs grew the crests as they matured.  Different-sized and shaped crests would indicate the maturity of an individual when viewed by its peers.

Hypacrosaurus altispinax skull on display at the American Museum of Natural History in New York.

Hypacrosaurus, the genus, actually includes two distinct species that lived during different times.  Hypacrosaurus altispinax was discovered first and was found in Alberta, Canada.  Hypacrosaurus stebingeri was slightly smaller and had a lower crest than H.altispinax and was discovered in Montana, USA.

Hypacrosaurus is one of the few kinds of fossil dinosaurs scientists were able to find lots of eggs and babies from.  So much so, that they were able to study how these dinosaurs grew and aged throughout their lives.  Hypacrosaurus babies had only tiny, barely noticeable crests, and grew extremely fast for animals their size.  In fact, according to studies that examined multiple specimens of various sizes and looking at markings on the inside of their limb bones, paleontologists suggest Hypacrosaurus was sexually mature between only two to three years of age.  They didn't reach full adult size, however, until they were about ten to twelve.  The reasoning why an animal would have grown so quickly could have something to do with a need to avoid predation.  As the dinosaur grew, the variety of predators able to hunt it diminished.  The ability to reproduce early in life also probably played a part in its relationship with predators, since most dinosaurs likely never made it to adulthood.  

Skull of a baby Hypacrosaurus on display at the Museum of the Rockies in Montana.

Lastly, scientists were able to find preserved cells in beautifully preserved cartilage of a baby Hypacrosaurus specimen.  Not only that, but they were able to observe that these cells were in the process of dividing when the dinosaur died, and ultimately were able to extract traces of genetic material from it!  Not only was this cool for finding dinosaur genetic material, but it also proved that genetic material can survive MUCH longer than previously thought if the conditions are specific enough.

References

Bailleul, A. M.; Zheng, W.; Horner, J. R.; Hall, B. K.; Holliday, C. M.; Schweitzer, M. H. (2020). "Evidence of proteins, chromosomes and chemical markers of DNA in exceptionally preserved dinosaur cartilage". National Science Review. 7 (4): 815−822.

Cooper, Lisa N.; Lee, Andrew H.; Taper, Mark L.; Horner, John R. (2008). "Relative growth rates of predator and prey dinosaurs reflect effects of predation". Proceedings of the Royal Society B. 275 (1651): 2609–2615.

Erickson, G.M.; Zelenitsky, D.K.; Kay, D.I.; Norrell, M.A. (2017). "Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development" (PDF). Proceedings of the National Academy of Sciences. 114 (3): 540–545.

Horner, John R.; Currie, Phillip J. (1994). "Embryonic and neonatal morphology and ontogeny of a new species of Hypacrosaurus (Ornithischia, Lambeosauridae) from Montana and Alberta". In Carpenter, Kenneth; Hirsch, Karl F.; Horner John R. (eds.). Dinosaur Eggs and Babies. Cambridge: Cambridge University Press. pp. 312–336.

Interview with Paleontologist: David Wilcots

David Wilcots is a geologist, paleontologist and artist living in Philadelphia where he grew up.  Mr. Wilcots is a registered professional geologist in Pennsylvania and Delaware.  He earned his Bachelor’s degree in geology at Temple University in Philadelphia, and Master’s degree in geology from Fort Hays State University in western Kansas. His master’s thesis was entitled, “Functional Morphology, Phylogeny and Paleoecology of the North American Miocene Rhinoceros, Aphelops”.  

Wilcots has over 29 years experience working as an environmental geologist and has worked for several environmental/engineering consulting companies in the Philadelphia region.  Currently David is the senior geologist for Sci-Tek Consultants, Inc., an engineering and environmental consulting company in center city Philadelphia.  

Mr. Wilcots is also a volunteer paleontologist at the Academy of Natural Sciences museum in Philadelphia in its Dinosaur preparation lab. For nine days each summer David is an expedition paleontologist in Wyoming for the Burke Museum of Natural History and Culture of Seattle, Washington.

David has also been an expedition paleontologist for the: 

 • Utah Geological Survey, Salt Lake City, Utah 

• The University of Utah Museum, Salt Lake City, Utah, and the 

• American Museum of Natural History, New York, NY.

He has given presentations about fossils at schools and has presented at S.T.E.M. programs for young people.  In 2012 David was featured on the Discovery Channel Global Education Partnership DVD entitled “Life in the Age of the Dinosaurs”.  In December of 2014 David launched the website for Dinosaurs Fossils and Adventures; DinosaursFA.com which is an on-line paleontology website for ages 8 to 18. In February 2020 he was a S.T.E.M. presenter for the Franklin Institute’s Color of Science Symposium.

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

DW: When I was four my parents took me to the American Museum of Natural History in New York City.  I saw the dinosaurs there and was just transfixed.  It was out of this world for me. I've been excited about dinosaurs and fossils ever since.  

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

DW: I did not have anyone that served as a role model for paleontology or geology.  I had role models in my parents when it came to how to learn and talk to people and overall how to be professional.  They were both very supportive of my interests- my brother too.  I did not grow up wanting to be like a certain paleontologist who was out there, though.  In my teenage years I didn't know any geologists or paleontologists except for Louis Leakey in in National Geographic Specials.

Question 3: You are a geologist full time.  Tell us more about your work and what its all about. 

DW: I am an environmental geologist.  I work for an engineering/environmental consulting firm. (Sci-Tek Consultants, Inc.)  In my capacity at this firm I manage environmental projects, which includes environmental site assessments, soil and groundwater sampling, borehole drilling supervision, and sometimes air and rock sampling.  I sample these media for environmental quality to test for potential contamination and to report on site contidions.

Question 4: How much of your work in geology and paleontology overlap?

DW: My job as an environmental geologist does not overlap with paleontology.  However, when I'm doing paleontology, I need my knowledge and experience as an geologist to do it effectively.  Geology allows me to read the rocks and strata that I see.  

Question 5: Was there anything you did or learned as you were on your way to your current career that you feel got you to where you are?  What sort of field experience, a class, networking with the right people, or possibly something different?

DW: My interest in geology probably kicked in during my teenage years.  Going on field trips and stopping along the highway to look at rocks fueled my fire and inspiration for geology going.  I also made a point to go to a lot of museums and as I learned more, my interests in both geology and paleontology grew.  I also watched a lot of science-based TV, like National Geographic, NOVA, Wild Wild World Animals, Marlin Perkins' Wild Kingdom, Jacques Cousteau, and several other shows kept me inspired.  

Question 6: Are the fields of paleontology and geology different now than from when you started as far as you can tell?  What would your advice be to anyone trying to make a career in paleontology (or science in general)

DW: As for geology, ground-penetrating radar technology has improved. Paleontology, however, has some newer technology, like 3-dimensional printing that has really changed the field.  You can shrink giant specimens down or expand tiny specimens up.  You can also make copies of specimens.  Twenty or thirty years ago, making copies of specimens was a long and arduous process.  3D printing has made is much easier to study fossils as well as communicate and work with a team.  You can simply send a file to someone on the other side of the world and they can reproduce it.  

Question 7: What was or is your favorite project so far? (geology or paleontology)

DW: For paleontology it would be when I was working summers in southwestern Wyoming with John Alexander with the AMNH and later the Burke Museum in Seattle.  He was looking for middle Eocene age fossils. The rocks there are about 47 million years old and the faunal variety was incredible.  We found fossil primates, early carnivores that preceded dogs and cats, rodents, birds, turtles, crocodiles, rhinos, tapirs, and large herbivores like titanitheres.  This was a very interesting time in earth's history because there were archaic animals living side by side with the ancestors of the animals we have now.  There were ecosystems dominated by browsing herbivores which isn't the case now since most modern mammalian ecosystems now are dominated by grazing herbivores.  There was a myriad of condylarths, hoofed mammals whose connection to modern mammals is still unknown.  That part of North America (Wyoming) was also home to at least three kinds of primates.  The biggest one was about the size of a house cat, the medium-sized one was about the size of a squirrel, and the smallest was the size of a mouse.  The environment had to be rich enough and have a forest canopy expansive enough to support primates, which is totally unlike anything in the United States today.  

For geology my favorite experience was hiking the Grand Canyon top to bottom to top in one day.  That was just stunning. 

Question 8: Do you have a favorite destination when it comes to fossils?  Why?

DW: Southwestern Wyoming for reasons stated above.

Question 9: You work out of Philadelphia, a major city.  Most people imagine open wild places when they think of fossils and geological formations.  What do you think people should know about the deep time history behind Philly?

DW: The bedrock in Philadelphia is hard metamorphic rock thats around 500 million years old, and devoid of fossils.  On top of that bedrock is two kinds of sediments. One is about 3 million years old and the other is only about 17 thousand years old.  These may be devoid of fossils also.  So there is a huge span of time missing from Philadelphia's observable geologic history. 

Question 10: A popular image of paleontologists is that they are constantly out in the field digging up fossils, which is true sometimes.  What people don’t realize is that a lot of paleontology work is conducted in a lab as well.  In your experience how much time have you spend in the lab and in the field?  What do you prefer?

DW: I prefer fieldwork.  I like discovering new things and being the first to see them.  I have done lab work, like cleaning and reassembling specimens.  I've also cataloged and organized specimens.  That's all fun, but I ultimately prefer being out finding and excavating fossils.  The fever for discovery is real.  

Question 11: You also run a website aimed to educate young people about paleontology.  Can you tell us more about that?

DW: I started the website to make paleontology more accessible to young people.  Some videos are on there as well as many photos that show viewers different aspects of paleontology.  One of my main goals here is to show that paleontology more than just dinosaurs. The website also features girls and boys of all colors in an inclusive environment working in the field, so all viewers can see themselves in this context.  

Question 12: Are there any fossils you’d like to work with that you haven’t yet?

DW: YES.  Shovel-tusked elephant!  I think an elephant with four tusks, like the gompotheres or Platybellodon is so cool.  I'd also like to work with pterosaurs and giant snake, like Titanoboa.  There were probably snake fossils around when I was working in Wyoming, but their bones are so delicate, they are hardly ever found.  Given how many small and medium sized mammals were out there that could serve as prey, paired with the hot, humid climate, there HAD to be large snakes around back in the Eocene.  It's just a matter of finding one.

Question 13: Do you ever get criticized on any of your work?  How do you handle it?

DW: Talk it out. Most disagreements I've experienced have been about whether or not to take a fossil out of the ground.  Collecting fossils early in the field schedule can sometimes be favorable because it seems like a good specimen and we have the means to collect it.  However, sometimes when it's early in the field season we decide to leave it there in favor of possibly finding an even better specimen int he field.  Sometimes we ultimately decide not to collect a particular fossil because doing so will be too much work/effort, or they're just too close to a major road to safely do so.  

Question 14: A common idea is that paleontology is just a “for fun” science, with no real impact or noticeable effect that helps the world.  Do you think paleontology has a bigger part to play to than this?  How?

DW: Yes, paleontology absolutely plays a bigger part.  First of all, the world needs more paleontologists because we need to understand how life on this planet developed over geologic time.  Second, and maybe even more importantly, is that paleontology is a gateway science for really young people to get interested in other sciences.  The world needs more doctors, energy engineers, and waste management engineers.  Toddlers don't roll out of bed interested in, let alone understanding, these things, but they are interested in paleontology.  If you want more people in these important science fields, medical, and engineering fields, paleontology is the way to get it.  Paleontology teaches kids how to think scientifically, how to collect and interpret data, how to form a hypothesis and so on.  Most kids interested in paleontology don't stick with paleontology.  They usually go on to other sciences as they get older and progress in school.

Question 15: Who was the first paleontologist you met?  How was that interaction?

DW: I first met a paleontologist when I was volunteering at a museum when I was eighteen years old.  Later on as I kept my interest, however, I did meet some really incredible people in the field.  John Alexander, from the Burke Museum in Seattle, Jim Kirkland, of the Utah Geologic Survey, and Richard Zakrzewski at Fort Hayes State University in Kansas (now retired) are probably the top three when it comes to people who have inspired me.  Also Christian Sidor.  I med John Alexander and Don Prothero at the AMNH when I was measuring Miocene rhino specimens for my graduate research.  

Question 16: What is your favorite prehistoric animal?  Was it different when you were younger? 

DW: When I was a really little kid my favorite was Brontosaurus. Now my favorite dinosaur might be Kentrosaurus. (which I chose for the logo on my website). This is probably because when I was younger my dad got me a book about dinosaurs and when I opened the book and noticed on the inside cover was a world map with dinosaurs illustrated over each continent.  I remember seeing what I now know was Kentrosaurus (which wasn't labeled in this book) placed over central Africa.  I remember immediately looking through the rest of the book for this awesome spiky dinosaur, but couldn't find it!  They mentioned Stegosaurus, of course, but it didn't match the image on the inside cover.  I felt ripped off.  When it comes to prehistoric mammals, I love rhinos, saber-toothed cats, and four-tusked elephants, like Stegotetrabelodon.  

Kentrosaurus by Christopher DiPiazza

Question 17: If you could use a time machine to go back and pick only one prehistoric animal to bring back from history and observe alive and in person, which would it be and why?

DW: Quetzalcoatlus.  I want to see an animal with a 45-foot wingspan take off.  I would love to see how it does that.  If you ever watched a large heron or eagle takeoff it is not easy.  I'm so curious to see how these gigantic pterosaurs achieved the same thing.  I'd also love to see a sauropod migration.  I try to imagine a herd of 30-40 ton animals all together in a group going back to their ancestral lands.  It must have been a sight to see.  

Question 18: Back to the time machine.  This time you can go back to any place and time period and have a look at what the environment was really like.  Which one would you pick and why?

DW: I'd have to go back and look at Antarctica when it was tropical.  I'd also want to see Antarctica when it was in transition from temperate to boreal.  There must have been a whole community of miocene mammals there that dealt with snow seasonally.  We know very little of this part in earth's history.  It would have had about 20 million years worth of evolution there we have never seen any trace of.  Marsupials with thick fur?  Cold-adapted monotremes?  Who knows?  

Question 19: Which is your favorite museum?  Why?

DW: The American Museum of Natural History in New York.  It has almost everything.  If you're looking for the biggest prehistoric science buffet (literally and figuratively) this is the place to go.  I could go there every week and always learn new things.  

Question 20: What hobbies do you have?  (Don’t have to be paleo-related.)

DW: I like to do pen and pencil illustration and woodworking.  The logo of my website of Kentrosaurus I illustrated.  I like to bake and am a foodie as well.

Gritty...

Question 21: What prehistoric beast do you think shares the most in common with Gritty?

DW: Back in the pliocene or late miocene there were probably species of primates that had long hair.  I refuse to believe that the longest haired primates alive today are the record holders.  So if there was a prehistoric monkey with extra long orange hair, that would be a reminder of Gritty.