I Know Dino Podcast Present Notes: Majungasaurus (Episode 124)


In our 124th episode, we acquired an opportunity to speak to Ariel Marcy, a biologist, PhD scholar, tutor, and creator of the tutorial recreation “Go Extinct!” by her startup STEAM Galaxy. Get “Go Extinct!” at steamgalaxy.com and observe Ariel’s progress on her new video games at aemarcy.com

Episode 124 can also be about Majungasaurus, a big Abelisaurid that lived within the Cretaceous in what’s now Madagascar.

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On this episode, we focus on:

Information:

  • New tyrannosaur from Montana named Daspletosaurus horneri printed with an outline of crocodile-like delicate lips.
  • A brand new early Jurasic crested theropod was present in China referred to as Shuangbaisaurus anlongbaoensis however it could already be synonymized.
  • A juvenile titanosaur was discovered north of Sao Paulo, Brazil and reveals younger titanosaurs additionally had some hole bones.
  • New CT scans of the latest Murusraptor braincase discovery reveals their probably intelligence and sense of odor.
  • Tristan the T. rex on the Museum für Naturkunde had some enamel sampled which can assist researchers study extra about its food regimen.
  • California is one step nearer to having a state dinosaur because of Assemblyman Richard Bloom
  • The Waterloo Area Museum in Ontario, Canada is internet hosting an exhibit referred to as Tyrannosaurs: Meet the Household for the primary time in North America
  • Scott Hartman celebrated #UtahraptorWeek by creating a brand new stockier skeletal of Utahraptor.
  • A new video reveals the historical past of Dinosaurs in India.
  • In keeping with a brand new Nature article, though Individuals don’t agree on a lot, apparently all of us love dinosaurs!
  • A brand new dinosaur documentary can be popping out quickly (probably) referred to as The Day the Dinosaurs Died
  • Hearthstone has formally launched its “Journey to Un’Goro” growth full with tons of dinosaurs.
  • A brewery in Denver, Colorado acquired its dinosaur planter again after some “Very mild web stalking”

The dinosaur of the day: Majungasaurus

  • Identify means Majunga dome
  • Kind species (solely species): Majungasaurus crenatissimus
  • Species title means “most notched” and refers to all of the serrations on its tooth
  • For some time it was referred to as Majungatholus, and now that’s thought-about to be a junior synonym
  • Charles Depéret, a French paleontologist, described the primary theropod fossils from Madagascar in 1896 (two tooth, a claw, and a few vertebrae {that a} French military officer had discovered). These fossils have been labeled as Megalosaurus (wastebasket taxon), and named a brand new species: Megalosaurus crenatissimus. Later Depéret reassigned these fossils to Dryptosaurus, one other taxon not well-known
  • The fossils have been present in 1895 by French scientists who have been with the French army on a expedition to safe the island from the British
  • Over the subsequent 100 years French collectors discovered extra fragments within the Mahajana Province in Madagascar. René Lavocat described theropod tooth in 1955, and people tooth matched the tooth that Depéret had described earlier, however he additionally described a strongly curved jaw bone that was completely different from Megalosaurus and Dryptosaurus. Primarily based on this dentary, Lavocat made a brand new genus Majungasaurus
  • Majungasaurus is an older spelling of Mahajanga
  • In 1979, Hans-Dieter Sues and Philippe Taquet described a dome-shaped cranium fragment as Majungatholus atopus, a pachycephalosaur (the primary one described within the southern hemisphere)
  • In 1993, a workforce from the State College of New York at Stony Brook and the College of Antananarivo began the Mahajanga Basin Challenge, which have been plenty of expeditions to the Mahajanga Province. On the primary expedition they discovered lots of of theropod tooth that seemed like Majungasaurus. Over the course of seven expeditions they discovered tens of 1000’s of fossils, many which have been new species
  • In 1996 scientists discovered an entire theropod cranium, which had a dome-shaped horn on the highest (just like the dome that Sues and Taquet described as Majungatholus atopus). In 1998, Majungatholus was redescribed as an abelisaurid (as a substitute of a pachycephalosaur). Majungasaurus crenatissimus was named earlier than Majungatholus atopus, however scientists thought that what was desscribed as Majungasaurus was too fragmentary to assign to the identical species as this cranium. Over the subsequent 10 years extra skulls (much less full) have been discovered, in addition to partial juvenile and grownup skeletons, and remoted bones and 1000’s of shed tooth. All these collectively type a virtually full skeleton, although a lot of the forelimbs, pelvis, and tip of the tail usually are not identified.
  • In 2007, all these bones have been a part of a monograph, made up of seven scientific papers on all features of Majungasaurus (from materials discovered between 1993 and 2001). The dentary that Lavocat was reevaluated and located to be attribute for the species. The title Majungasaurus changed Majungatholus.
  • David Krause, from Stony Brook College and who was a part of the Mahajanga Basin Challenge, determined to offer again to the local people in Madagascar who helped him all through the years on his expeditions. They instructed him they needed training for his or her youngsters, and wish to rent a train, which price $500 per 12 months. He and his workforce raised the cash for the trainer’s wage, and in 1998 Krause based the Madagascar Ankizy Fund (named after the Malagasy phrase for kids). They’ve constructed faculties and offered well being care.
  • Krause helped discover the Majungasaurus cranium in 1996
  • Among the best studied theropods from the southern hemisphere
  • Appears to be extra carefully associated to abelisaurids from India than abelisaurids from South America or Africa
  • Bipedal, with a brief snout
  • About 20-23 ft (6-7 m) lengthy, although there are estimates, based mostly on fragments, of some being so long as 26 ft (8 m)
  • Weighed about 2,400 lb (1,100 kg), although bigger ones might have weighed as much as 3,300 lb (1,500 kg)
  • Had a protracted tail to assist stability
  • Had brief forelimbs, with stocky hind limbs
  • Had 4 digits on every hand, although it was thought to solely have two digits and no claws. The specimen studied had no pits and grooves the place claws would usually be hooked up, and its finger bones have been fused collectively, so the hand was motionless
  • A 2012 examine of one other specimen discovered the 4 digits have been very brief and rigid, and had small claws on the second and third digits
  • Toes had three digits, and the primary digit was smaller and didn’t contact the bottom
  • Had a robust, muscular neck
  • Had a large, brief cranium, and had a rounded, dome-like horn on the roof of the cranium, which was initially considered a pachycephalosaur dome
  • Cranium had a tough texture
  • Had nasal bones that have been thick and fused collectively
  • Horn on the highest of the cranium was most likely coated with keratin
  • CT scans discovered that the nasal construction and horn on the highest of the top had hole sinus cavities, probably to scale back weight
  • Majungasaurus most likely competed with one another, utilizing the fused nasals and the horn on prime of its head, although how is unclear (the horn’s hole cavity means it was not robust sufficient to make use of for combating, and doubtless was extra for show). Majungasaurus had some variation within the horns, however no proof of sexual dimorphism
  • As Majungasaurus grew and have become older, its cranium acquired taller and extra sturdy, and the cranium bones have been extra fused and eye sockets turned smaller. This reveals juveniles and adults most likely had completely different diets
  • Michael D’Emic’s analysis reveals it was one of many slowest rising theropods, based mostly on traces of arrested development on the bones. Took Majungasaurus 20 years to mature
  • A CT scan of an entire cranium allowed scientists to reconstruct the mind and interior ear construction. The mind was small relative to its physique measurement, however was just like different non-coelurosaurian theropods. One distinction is in comparison with different theropods, Majungasaurus had a smaller floccus (which controls stability coordination). Due to this, it most likely didn’t transfer its head rapidly to search for and go after prey. Additionally its interior hear reveals it held its head straight and horizontal to the bottom. In all probability went after slower prey, like massive sauropods
  • Apex predator, that preyed on Rapetosaurus (sauropod)
  • Had extra tooth in higher and decrease jaws, in comparison with different abelisaurids
  • Could have bitten prey and held on till its prey stopped combating (chunk and maintain strategy)
  • Had a versatile decrease jaw, might have helped forestall fractures when holding onto its prey
  • Tooth curved on the entrance edge however have been straighter within the again, probably to carry tooth in place when biting (as a substitute of slicing prey)
  • In all probability specialised in looking sauropods (stocky legs would have helped it chunk and maintain), and didn’t should be as quick to go after slower sauropods
  • Majungasaurus tooth marks have been discovered on Rapetosaurus (so it ate them, although not clear if it killed them)
  • One of many few dinosaurs with direct proof of cannibalism
  • In 2007 scientists printed about some finds that confirmed Majungasaurus practiced cannibalism. Majungsaurus bones have been discovered with tooth marks that seemed the identical as tooth marks discovered on sauropods within the space.
  • Lots of the chunk marks on Majungasaurus have been on limb bones that have been solely accessible throughout deadly fight, in keeping with Scott Sampson in Dinosaur Odyssey
  • Majungasaurus is the one massive identified theropod within the space, in order that most likely means they ate up one another. Majungsaurus is the one non-avian theropod confirmed to be cannibalistic (although there may be proof of cannibalism in different species)
  • Not clear if Majungasaurus hunted one another or simply scavenged carcasses (although Komodo dragons generally kill one another in feeding frenzies of carcasses)
  • Scientists have been capable of reconstruct Majunasaurus’ respiratory system. Had air sacs like trendy birds that allowed for a “movement by air flow”, that means the air flows by the lungs a technique (air inhaled isn’t combined with air exhaled, which is environment friendly)
  • This reveals that the break up between ceratosaurs (which led to Majungsaurus) and the tetanurans (which led to birds) occurred early on with theropods. This frequent avian respiratory system would have developed earlier than the break up, and helps present that birds are dinosaurs
  • In 2007 a report described 4 Majungasaurus pathologies, based mostly on the stays of 21 people. No wounds discovered on the cranium, however one had a damaged and healed toe bone. One other had a bony development on the underside of a again vertebra, most likely from cartilage conversion throughout improvement. One other had irregular development on its tail vertebra, most likely from ossification of a ligament. One other had abnormalities on 5 massive tail verebrae. Three have been fused collectively at a number of factors, making a stable bony mass. No signal of different vertebrae after the fifth one, so the tail was shorter than most (about 10 vertebrae brief). Could possibly be from extreme trauma that resulted in shedding the tip of the tail after which an infection, or the an infection got here first and a part of the tail fell off. First instance of tail truncation present in a non-avian theropod
  • Majungasaurus lived in a semi-arid local weather on a coastal flood plain. Sea ranges have been rising. Madagascar was an island even when Majungasaurus.
  • Had moist and dry seasons. Annually, animals that died from lack of water have been then swept away by water through the moist season and buried (led to numerous preserved fossils)
  • Different animals that lived on the similar time and place embrace fish, frogs, lizards, snakes, crocodylomorphs, and a few mammals and birds, in addition to the noasaurid Masiakasaurus, two titanosaurs, together with Rapetosaurus. Additionally probably the dromaeosaurid Rahonavis
  • A part of Indominus rex’s DNA in Jurassic World is Majungasaurus
  • Can see Majungasaurus within the fifth episode of the miniseries When Dinosaurs Dominated, hosted by Jeff Goldblum
  • May also see Majungasaurus within the first episode of Jurassic Struggle Membership (speaking about its cannibalism)
  • Each reveals referred to as it Majungatholus
  • Can see Majungasaurus in BBC’s Planet Dinosaur (and it’s referred to as Majungasaurus)

Enjoyable truth: Coprolite can protect fragile specimens (type of like amber) permitting paleontologists to check organism that the couldn’t discover in a typical geological formation.

For many who might choose studying, see under for the total transcript of our interview with Ariel Marcy:

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