This week we'll be checking out a gigantic swamp beast. Make way for Mastodonsaurus!
Mastodonsaurus was a member of the ancient order of vertebrates, called the temnospondyls, which were related to today's amphibians. (some studies suggest modern amphibians are also a branch of the temnospondyl order) Mastodonsaurus includes a few species, which lived in what is now Eurasia, fossils found in Germany, England, and Russia, during the Triassic period, 230 million years ago. Mastodonsaurus was a meat-eater when alive and the largest species, Mastodonsaurus giganteus, could exceed 20 feet (6m) in length from snout to tail. The genus name translates to "breast tooth lizard" which is a bit misleading since it wasn't a lizard nor do any of its teeth particularly resemble breasts of any kind. (But the broken one that was first examined by scientists who named it apparently did.)
Life reconstruction in watercolors of a territorial dispute between two Mastodonsaurus giganteus by Christopher DiPiazza.
Mastodonsaurus had a proportionally huge, flattened, skull, with large eye sockets on the top. This is an adaptation to be able to raise its eyes above the water and still stay relatively hidden while stalking prey. Modern crocodilians and certain frogs have the same feature for the same purpose. The inside of Mastodonsaurus' mouth was lined with sharp, cone-shaped teeth, ideal for making sure whatever animal it bit couldn't escape. The most astonishing feature, however, was the pair of extra long, tusk-like teeth growing up from the tip of its bottom jaw. These two teeth would fit through actual holes present in the top of the animal's mouth when closed. The rest of Mastodonsaurus' body reinforced the idea that it was primarily an aquatic animal. It's legs were proportionally small and weak, but it had a long, strong tail that it could have used to propel itself through the water of its swampy home.
Mastodonsaurus skull on display at the Muschelkalk Museum. Photo credit: Ghedoghedo
Mastodonsaurus would have been the top predator of its environment. At its adult size it would have been able to devour a variety of other animals that it shared its habitat with. It was likely an ambush predator, relying on stealth to snap up fish that swam to close to its mouth, or even grabbing land animals as they came to the water to drink. It is unlikely Mastodonsaurus would have left the water much when alive. Its anatomy just wasn't equipped to spend extended time on land. There are also fossil beds of many Mastodonsaurus that all died practically on top of each other. This implies they were trapped in a body of water that was drying up as they were forced closer and closer to the center until their deaths.
References
Damiani, Ross J. (2001). "A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli)". Zoological Journal of the Linnean Society. 133 (4): 379–482.
Moser, Markus& Schoch, Rainer 2007 "Revision of the type material and nomenclature of Mastodonsaurus giganteus (Jaeger) (Temnospondyli) from the middle Triassic of Germany" Palaeontology505:1245-1266:
Schoch, R.R. (1999). "Comparative osteology of Mastodonsaurus giganteus (Jaeger, 1828) from the Middle Triassic (Lettenkeuper: Longobardian) of Germany (Baden-Württemberg, Bayern, Thüringen)". Stuttgarter Beiträge zur Naturkunde Serie B. 278: 1–175.
This week we'll be checking out a giant carnivore that has been continuing to gain popularity since its discovery. Make way for Giganotosaurus carolinii!
Giganotosaurus was a meat-eating dinosaur that lived in what is now Argentina during the late Cretaceous period, between 99 and 97 million years ago. The genus name translates to "Giant Southern Lizard". Giganotosaurus is famous for being one of the largest carnivorous dinosaurs known, the largest specimens estimated at about 41feet(12.5meters) long from snout to tail, based on known fossil material.
Gigianotosaurus life reconstruction in watercolors by Christopher DiPiazza
Gignotosaurus was a member of the carcharodontosaurid family, a branch of carnivorous dinosaurs that flourished during most of the Cretaceous period as the dominant land predators until they were eventually replaced by tyrannosaurids in the northern hemisphere and abelisaurids in the southern hemisphere. Carcharodontosaurids are characterized by having relatively long skulls that slightly taper towards the tip of the snout. Their jaws were lined with blade-like ,serrated teeth, which is how this group earned its name, the "shark-toothed lizards". Acrocanthosaurus and Concavenator are two other members of this family that have been featured on Prehistoric Beast of the Week.
Giganotosaurus had a huge skull that measures between five and six feet long. The surface above its snout and eyes was rough in texture, implying there was some sort of horn-like keratin material growing there in life. This dinosaur probably had some kind of low crest on its head in life either for display within the species, or possibly for some sort of combat. The teeth were blade-like and serrated, like those of a shark, and the jaws were long and laterally narrow. The tip of the lower jaw jutted down a bit, forming a "chin". It is thought that this "chin" could have added extra momentum if Giganotosaurus was making contact with the front of its jaws as it bit.
Giganotosaurus skeletal mount on display at the Fernbank Museum of Natural History in Georgia. (image credit: Johnathan Chen)
All these jaw features imply Giganotosaurus wasn't adapted for crushing bone with its jaws, but rather making fast slices through soft tissue. This reflects a hunting strategy aimed at making the prey animal bleed to death with deep cuts, rather than paralyzing it with a crushing blow, like a Tyrannosaurus might. This makes sense since Giganotosaurus would have shared its environment with several large species of sauropod dinosaurs, some of which were larger than Giganotosaurus, and all of them would have been slower, so the strategy of slicing hunks of flesh off over a longer period of time, causing severe bleeding, makes sense for hunting a prey item that was too large to be taken down in one powerful bite.
That is all for this week! Feel free to comment below!
References
Calvo, J. O.; Coria, R. A. (1998). "New specimen of Giganotosaurus carolinii (Coria & Salgado, 1995), supports it as the largest theropod ever found". Gaia. 15: 117–122.
Coria, R. A.; Salgado, L. (1995). "A new giant carnivorous dinosaur from the Cretaceous of Patagonia". Nature. 377 (6546): 224–226.
Coria, R. A.; Currie, P. J. (2002). "The braincase of Giganotosaurus carolinii (Dinosauria: Theropoda) from the Upper Cretaceous of Argentina". Journal of Vertebrate Paleontology. 22(4): 802–811.
Leanza, H. A; Apesteguía, S.; Novas, F. E; de la Fuente, M. S (2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25 (1): 61–87.
Novas, F. E.; Agnolín, F. L.; Ezcurra, M. D.; Porfiri, J.; Canale, J. I. (2013). "Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia". Cretaceous Research. 45: 174–215.
Therrien, F.; Henderson, D. M.; Ruff, C. B., 2005, "Bite Me: Biomechanical models of theropod mandibles and implications for feeding". In: Carpenter, K., The Carnivorous Dinosaurs. Life of the Past. Indiana University Press. pp. 179–237
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. Hypacrosaurusstebingeri 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.
This week let's celebrate a newly described dinosaur. Check out Tlatolophus galorum!
Watercolor life reconstruction of Tlatolophus by Christopher DiPiazza.
Tlatolophus was a hadrosaurid ("duck-billed") dinosaur that lived in what is now Coahuila, Mexico, during the Late Cretaceous, about 73 million years ago. It was a massive animal, measuring about 39 feet (12 meters) from beak to tail and would have eaten plants when alive. The genus name translates to "word crest" because this dinosaur's bony head crest resembles the Aztec glyph meant to represent speech.
Aztec word glyph which coincidentally resembles Tlatolophus' crest, just rotated. Originally from Codex Barbonicus. Image taken from Mexicolore.co.uk.
Like many large dinosaur fossils, Tlatolophus is known from incomplete remains. That being said, the parts that were unearthed give important information about this dinosaur. Most amazing is the fact that almost the whole skull was intact, including the elaborate crest. (It's frustrating when a new hadrosaurid, family of dinosaurs known for having diverse crests, is discovered with no head, leaving us completely in the dark as to what it would have really looked like.) Tlatolophus' crest was shaped like a sideways teardrop, sweeping back, behind the animals head and flaring out at the end. The crest was hollow and connected to the animal's nasal cavity, suggesting it may have aided in producing some sort of sound in life.
Photograph of Tlatolophus' beautifully complete skull, featured in the recent paper cited below.
Like all hadrosaurids, Tlatolophus had a beak in the front of its snout which would have had a keratin sheath growing over it in life. This beak would have evolved for clipping off mouthfuls of vegetation which would then be shredded by the many tiny, tightly packed, teeth in the back of the mouth. Tlatolophus also likely would have been able to walk on all fours, or on its hind legs depending on what suited it best. It is thought that hadrosaurids most comfortably walked on all fours, but would rear up to reach higher plants while feeding, or to run faster as bipeds to escape predators.
Tlatolophus also had a long tail, proportionally longer than what is typically seen in other hadrosaurids, which made up about half the animal's total body length. It is a total mystery why this specific hadrosaurid evolved such a long tail. Maybe it had something to do with courtship display? Maybe it was evolved to hit rival adults for dominance? Long tails are also effective weapons against predators that may try to attack from behind. A strong impact from a tail like that would surely knock a similarly-sized tyrannosaurid over, giving Tlatolophus time to escape. We may never know for sure, however.
It is interesting to note that paleontologists deducted, based on features of the skull, that Tlatolophus was closely related to another, more famous, hadrosaurid that also sported a striking crest, Parasaurolophus. What's interesting is that Tlatolophus is even more closely related to Parasaurolophus, which is found in Canada and the United States, more than the hadrosaurid that it coexisted with in Mexico, called Velafrons. It just goes to show how much different populations of closely related dinosaurs were moving around and settling in different areas over the millions of years they reigned.
That is all for this week! As always feel free to comment below!
References
Ramírez-Velasco, Á. A.; Aguilar, F. J.; Hernández-Rivera, R.; Gudiño Maussán, J. L.; Rodriguez, M. L.; Alvarado-Ortega, J. (2021). "Tlatolophus galorum, gen. et sp. nov., a parasaurolophini dinosaur from the upper Campanian of the Cerro del Pueblo Formation, Coahuila, northern Mexico". Cretaceous Research. in press: Article 104884.
Today we will be checking out a dinosaur with historical significance, Astrodon johnstoni!
Astrodon was a plant-eating sauropod dinosaur that roamed what is now the eastern part of the United States, during the early Cretaceous period, about 112 million years ago. Adults would have measured between 50 to 60 feet (15 to 18 meters) long from snout to tail. The genus name translates to "star tooth" and the species name honors Christopher Johnson, the dentist and professor who studied the first known fossils of this dinosaur back in the 1800s.
Watercolor life reconstruction of Astrodon johnstoni by Christopher DiPiazza
Astrodon was one of the first fossil dinosaurs to be discovered and named in North America. It was initially known from a few teeth discovered and studied in Maryland, where Professor Christopher Johnson, at the Baltimore Dental College, noticed they had a star-shaped pattern in the cross section, and thus Astrodon earned its genus name. Over the years more fossils from Astrodon would be discovered in the eastern half of the United States, including many bones from juvenile individuals.
Original Astrodon tooth currently at the Yale Peabody Museum. Photo courtesy of Kenneth Carpenter.
By comparing its bones to other sauropods, it is currently thought Astrodon was a kind of macronarian, which is a clade of sauropod dinosaurs that had boxy skulls with large nasal cavities. In fact, the term, macronarian, translates to "big nose" based on this common feature. Another example of a macronarian sauropod is the larger and very famous, Brachiosaurus.
Juvenile Astrodon bones on display at the Maryland Science Center.
Astrodon had somewhat shorter vertebra in its neck when compared to some of its relatives, like Brachiosaurus. Based on the fact that most sauropod dinosaurs had about the same number of neck vertebrae, it could be assumed that Astrodon's neck would have been proportionally shorter.
Astrodon's teeth were spoon-shaped and therefore ideal for scraping leaves off of branches and clipping softer foliage. Like all sauropods, Astrodon wouldn't have had any teeth in the back of its mouth for chewing. Rather it would have swallowed plant material whole and possibly ingested small rocks, called gastroliths, to aid in mechanical digestion within the stomach.
When alive, Astrodon would have shared its environment with a number of other dinosaurs, like the meat-eating Deinonychus, which may have hunted young Astrodon, and Acrocanthosaurus, which likely could have been able to hunt adults. It also shared its environment with the tiny ceratopsian, Aquilops and the enormous ankylosaur, Priconodon.
References
Carpenter, Kenneth; Tidwell, Virginia (2005). "Reassessment of the Early Cretaceous sauropod Astrodon johnstoni Leidy 1865 (Titanosauriformes)". In Kenneth Carpenter; Virginia Tidswell (eds.). Thunder Lizards: The Sauropodomorph Dinosaurs Indiana University Press.
d'Emic, Michael D. (2013). "Revision of the sauropod dinosaurs of the Lower Cretaceous Trinity Group, southern USA, with the description of a new genus". Journal of Systematic Palaeontology. 11 (6): 707–726.
P. Larkin. 1910. The occurrence of a sauropod dinosaur in the Trinity Cretaceous of Oklahoma. Journal of Geology 17:93–98
Today we will be looking at a well-loved, and extremely important dinosaur. Check out Deinonychus antirrhopus! Deinonychus was a meat-eating dinosaur that lived in what is now the United States, including Wyoming, Montana, Oklahoma, and even parts of the East coast, including Maryland, during the Early Cretaceous Period, between 115 and 108 million years ago. It was relatively small, measuring about eleven feet long from snout to tail. (about half of that length consisting of tail) The name, Deinonychus, translates to "Terrible Claw" in reference to the second digit on each of its feet, which possessed an enlarged, crescent-shaped talon, which was retractable, like a switchblade.
Prey's eye view of Deinonychus antirrhopus life reconstruction by Christopher DiPiazza.
Starting in the 1800s, when the first dinosaur was seriously recognized by science, the image of dinosaurs was that of hulking, oafish lizard-like creatures. That all changed when the bones of Deinonychus were unearthed in the 1960s, however. It was the first dinosaur that really made paleontologists stop and reassess their views on the way dinosaurs lived by showing signs of being a fast-moving, light-weight creatures that shared more characteristics with birds than with other reptiles. Since then, many more bird-like dinosaurs have been discovered, of course. Most people now, especially younger dinosaur lovers, would see small, bird-like dinosaurs as a commodity in their books and toy collections, but one shouldn't forget that Deinonychus was society's first taste of this concept.
Deinonychus skeletal mount on display at the American Museum of Natural History in New York.
When alive, despite its size, Deinonychus possessed weapons which would have made it a formidable predator. The most obvious were the feet, each possessing a second digit with an almost five inch long "killer claw" which could be held above the ground when not in use to prevent wear, and swung forward for stabbing, when attacking. Each of the hands was equipped with three long fingers, each tipped with a hook-shaped claw, as well. Inside the mouth, Deinonychus had many small, blade like teeth, which were serrated. The jaws of this dinosaur were designed for slicing off bite-sized pieces of meat. Deinonychus' tail was long (took up about half of its total body length) and had small bony rods running down its length. We call these structures ossified tendons, which are present in a lot of different kinds of dinosaurs. They would have made the tail stiff, like a fishing pole, and would have helped the dinosaur make sharper turns while running. Although only bones have ever been found, it is likely Deinonychus was covered in feathers just like a bird, based on more well-preserved remains of other dinosaurs which were extremely closely related to it and predated it, like Velociraptor and Microraptor.
Deinonychus food diagram
There are a few ideas as to exactly how Deinonychus hunted. The first, and most well-known is that Deinonychus hunted in groups to kill larger prey. The idea is that these predators could have used their powerful hind legs to jump onto larger dinosaurs and clung on using their front claws and used tails for balance. Then they would have used their deadly claws on their feet to bicycle kick into their prey's body, essentially disemboweling it until it collapsed. This pack-hunting idea is supported by an amazing discovery of the larger plant-eating dinosaur, Tenontosaurus, with Deinonychus teeth marks on its bones. One could argue that there is a strong chance the Tenontosaurus was already dead and that the Deinonychus were merely scavenging it, but bones from Deinonychus were found nearby as well, which many suggest supports the narrative that smaller meat-eaters attacked it, and in self defense the larger plant-eater managed to kill some in self-defense before it died. It's a cool idea, and has been recreated in art countless times, (Seriously, poor Tenontosaurus' whole identity has been reduced to "Deinonychus food" in most books and other media.) but still really can't be totally proven. Some who oppose this idea argue that perhaps the Deinonychus were not pack hunters, were all drawn to the plant-eater's dead body, and killed a few of each other as they fought over the meat, which is equally plausible.
The second idea of Deinonychus' hunting behavior delves into its killer claw more deeply. Believe it or not, many modern birds also actually have an enlarged second digit talon on their feet. The ones that do, like most hawks and eagles, use this claw to pin down smaller prey (alive or dead) to stabilize it as they tear bite-size chunks of meat off with their sharp beaks. It is very possible that dinosaurs like Deinonychus could have hunted mostly smaller prey as well, like smaller dinosaurs, baby dinosaurs, and mammals, and used their talons for the same purpose. The video below I took at my job of our Eurasian Hawk demonstrating this technique on a dead mouse.
Eggs that are believed to have belonged to Deinonychus have also been discovered. It all started when the rocks from which a Deinonychus skeleton was extracted were examined more closely. It was discovered that they contained dinosaur eggshells. The next question was whether or not the Deinonychus was eating the eggs, which could have belonged to another dinosaur, or if it the eggs were its own and it was protecting them. Soon after, tiny bones, called gastralia, were discovered with the eggshells. Gastralia, or belly ribs, as they are sometimes called, are found on the underside of a dinosaur's torso. This suggested that the Deinonychus' chest and belly were in contact with the eggs, and it very well may have been incubating them, much like parent birds do today. Not only does this support the idea that Deinonychus was guarding its own eggs, it also suggests that Deinonychus was endothermic! ("warm-blooded") Think about it. Only an animal that produces its own body heat would brood eggs to keep them warm. Ectothermic ("cold-blooded") animals, like lizards and crocodiles, rely on the sun, decomposing nesting material, or other outside sources of warmth to incubate their eggs. (There are exceptions, like some pythons who incubate their eggs, creating warmth with muscle friction, but this is an exception, not a norm.) What a great find!
That is all for this week! As always feel free to comment below or on our facebook page!
References
Fowler, D. W.; Freedman, E. A.; Scannella, J. B.; Kambic, R. E. (2011). Farke, Andrew Allen, ed. "The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds". PLoS ONE6 (12): e28964. Makovicky, P.J.; Grellet-Tinner, G. (2000). "Association between a specimen of Deinonychus antirrhopus and theropod eggshell". In Bravo, A.M. and T. Reyes. First international symposium on dinosaur eggs and babies,Isona i Conca Dellà Catalonia, Spain, 23–26 September 1999. pp. 123–128.
Maxwell, W. D.; Ostrom, J.H. (1995). "Taphonomy and paleobiological implications of Tenontosaurus–Deinonychus associations". Journal of Vertebrate Paleontology15 (4): 707–712. Ostrom, John
Harold (1970). "Stratigraphy and paleontology of the Cloverly Formation
(Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana". Bulletin of the Peabody Museum of Natural History35: 1–234.
Ostrom, J. H. (1969). "Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana". Peabody Museum of Natural History Bulletin30: 1–165.
Ostrom, J.H. (1976). "On a new specimen of the Lower Cretaceous theropod dinosaur Deinonychus antirrhopus". Breviora439: 1–21.
Turner, Alan H.; Makovicky, Peter J.; Norell, Mark A. (2007). "Feather quill knobs in the dinosaur Velociraptor". Science317 (5845): 1721.
Xu, X.; Zhou, Z.; Wang, X.; Kuang, X.; Zhang, F. & Du, X. (2003). "Four-winged dinosaurs from China". Nature421 (6921): 335–340.
This week we're revisiting a VERY popular prehistoric beast that despite its mainstream presence, probably isn't as well understood as lots of people think. Let's make way for *dunDUn...dunDUN...dundundundundundun...* everyone's favorite giant shark, Otodus megalodon!
Life reconstruction in watercolors of Otodus megalodon by Christopher DiPiazza.
Otodus megalodon (commonly just referred to as its species name, megalodon) was a gigantic shark that measured over 16 meters (52 feet) long from snout to tail, living from 23 million to as recent as 3.6 million years ago in the Miocene and the Pliocene epochs. So while this beast never actually was alive at the same time as non-avian dinosaurs, it was around at the same time as primates that were ancestors of modern humans! (Unless those primates frequently went swimming in the open ocean they would have had nothing to worry about from megalodon, however.) The genus name, Otodus, translates to "ear tooth" because of the shape of the teeth in some members of this genus. The species name, megalodon, translates to "big tooth" because...look at it.
As far back as the 1600s, people were finding gigantic triangular fossils and thought they were fossilized tongues from dragons. Danish scientist, Nicolas Stenos, finally found out they were actually teeth from a gigantic prehistoric shark (just as impressive as a dragon if you ask me). Since then, megalodon teeth have been discovered on every continent except Antarctica. Where I currently live in Maryland, there's a site only a bit over an hour's drive from me, in fact, where the public can find their very own megalodon teeth to take home with them.
Nicolas Steno's illustration of megalodon from the 1600s.
Like all sharks, most of megalodon's skeleton was made of cartilage (same material that is in our noses and ears) instead of bone. That being said only fossils of its teeth, jaws, and some vertebra have ever been discovered. Judging by the size of these fossils, however, which includes individual teeth that are almost 18cm (over 7 inches) long, the largest specimens of this shark were estimated to have been almost 16 meters (52 feet) long from nose to tail. To put it into perspective that's the same size as a modern Humpback Whale. Even though not much of this shark's actual anatomy is truly known, the teeth themselves are are actually quite common (since sharks tend to shed and replace them a lot). However, since the teeth and other known elements of this shark are similar in appearance to that of modern Great White Sharks (Carcharodon carcarias) it is possible megalodon could have looked similar to them in life...just a lot bigger. This being said, megalodon wasn't as closely related to Great Whites as most people think. In fact, megalodon used to be considered the same genus as Great Whites, Carcharodon, but has since been placed into the genus of extinct sharks, Otodus, instead. Paleontologists found out that the similarities between megalodon and Great White teeth are likely a result of convergent evolution, not an actual close relationship, and that Great Whites are more closely related to the seemingly different Mako Shark than they are to megalodon. Great Whites and megalodon appear to have shared a common ancestor much farther back during the Cretaceous period.
Reconstructed mount of megalodon jaws on display at the Baltimore Aquarium in Maryland, USA.
So what was a shark as large as megalodon eating? Fossil evidence in the form of numerous fossilized whale bones with chew and bite marks on them suggest it was a whale-eater. It was also likely going after pinnepeds(seals), large fish, and turtles. Basically megalodon was an opportunistic predator, going after any animal it could overpower, and for an almost 16 meter long shark... that's basically everybody. This is in part thanks to this shark's incredible biting ability. It is estimated that an adult megalodon had a bite force between 108,5000 and 182,200 newtons! (24,400 and 41,000lbf) On top of that power, megalodon's teeth were serrated on the edges, like steak knives, so if it shook its head from side to side after biting, it would have been able to completely slice through fat, muscle, and even bones of large whales. It is possible megalodon wasn't completely care-free, however, even as an adult. The similarly sized, and equally monstrous toothed whale, Livyatan lived at the same time and place as megalodon. These two marine heavyweights were likely competitors and may have also hunted each other depending on which individual was larger than the other in each interaction.
So why did such a powerful predator go extinct? We may never know for sure but lots of experts feel it may have been a drastic change in environmental temperature that led to its demise. During megalodon's time on earth, geological activity led to a decrease in global temperature which diminished tropical waters a large shark would thrive in. A shark like megalodon likely didn't have the adaptations to deal with cooler temperatures, especially at such a large size. Many modern sharks give birth in shallower, warmer waters, called nurseries. If megalodon did the same but on a larger scale, there is a chance this climate change event could have eliminated whatever specific places it was using to reproduce, thus also leading to its extinction.
Lastly I feel it is important to note that despite what you may hear on certain television shows, megalodon is most certainly gone forever. It's definitely not still out there in the deepest parts of the ocean hiding somewhere. We know this prehistoric predator was hunting whales in life. Whales often hang out near the ocean's surface. We'd see a megalodon by this point if any were still alive. I'm not sure where the idea of this beast as a cryptid came from, but it's most definitely not based on anything credible.
Works Cited
Augilera, Orangel A.; García, Luis; Cozzuol, Mario A. (2008). "Giant-toothed white sharks and cetacean trophic interaction from the Pliocene Caribbean Paraguaná Formation". Paläontologische Zeitschrift. 82 (2): 204–208.
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