I Know Dino Podcast: Brachiosaurus


Episode 39 is all about Brachiosaurus, a sauropod with longer forelimbs than hindlimbs.

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On this episode, we talk about:

  • The dinosaur of the day: Brachiosaurus, whose title means “arm lizard”
  • Brachiosaurus is a sauropod that lived within the Jurassic in North America
  • Described by Elmer S. Riggs in 1903, primarily based on fossils discovered within the Colorado River
  • Kind species is Brachiosaurus altithorax, and Riggs mentioned it was “the biggest identified dinosaur
  • Brachiosaurus means “arm lizard”, named so as a result of the size of its arms was uncommon for a sauropod
  • Title “altithorax” means “deep breastplate” as a result of it had a deep, huge chest cavity
  • Holotype is correct humerus, proper femur, proper ilium, proper coracoid, sacrum, trunk, two caudal (tail) vertebrae, and a few ribs
  • Kind species primarily based on a partial postcranial skeleton (fossils collected in 1900)
  • Riggs and his staff (from the Discipline Columbian Museum, now the Discipline Museum of Pure Historical past of Chicago), went to the realm after Riggs despatched inquiries about fossil finds in 1899 to rural areas. S.M. Bradbury, a dentist and newbie fossil collector, responded
  • Kind species weren’t the primary Brachiosaurus bones discovered, but it surely was the primary attributed. A cranium was present in 1883 in Colorado, despatched to Charles Marsh, who used it in his restoration of Brontosaurus/Apatosaurus. Within the Nineteen Seventies Jack McIntosh and David Berman determined the cranium was extra like a Camarasaurus, however in 1998 Kenneth Carpenter and Virginia Tidwell analyzed it and located it to be considerably in between a Camarasaurus and Giraffatitan bracai (thought of Brachiosaurus brancai on the time). It’s not assigned to a species but it surely’s labeled as Brachiosaurus
  • Cranium was loosely hooked up to its skeleton (like different sauropods), so after it died, simple to detach, both through predators or erosion (explains combine up in cranium for Brachiosaurus v. Camarasaurus)
  • Kind species bones went on show on the Discipline Museum in 1908, however there was solely 20% of the skeleton, so it wasn’t mounted. In 1993, “holotype bones had been molded and forged” and lacking components primarily based on Giraffatitan fossils. It was mounted in 1994 within the Discipline Museum, till 1999 when it was moved to United Airways Terminal One in O’Hare Worldwide Airport so the museum may show the T-rex Sue. The identical yr, the museum mounted a second forged of Brachiosaurus outdoors the museum. Solely the humerus and two dorals are actual and on show within the museum
  • Kind specimen is probably the most full one discovered thus far (which isn’t very full)
  • The household, and the genus, has had some reclassificiations
  • Till 2009, Giraffititan was thought of to be a Brachiosaurus
  • Giraffaititan is totally different from Brachiosaurus as a result of it had totally different trunk vertebrae. Olshevsky made Giraffaititan its personal genus and in 2009 Michael Taylor printed a examine on the variations and located 26 “distinct osteological (bone-based) characters), which is greater than Diplodocus v. Barosaurus; Brachiosaurus had a 23% longer trunk vertebrae collection and 20-25% longer physique and a taller tail
  • Additionally a shoulder blade assigned to Brachiosaurus that was once thought of a part of the species Ultrasauros (episode 20)
  • Kingham reassigned Brachiosaurus to the genus Astrodon in 1969, however not many accepted it
  • Brachiosaurus fossils present in Colorado, Oklahoma, Utah, and Wyoming
  • Uncommon sauropod of the Morrison Formation
  • Morrison Formation was semiarid, with dry and moist seasons and flat floodplains. It had river lining forests (in any other case no different bushes) of conifers, tree ferns and extra. Different sauropods within the space included Apaotsaurus, Barosaurus, Camarasaurus, Diplodocus
  • Brachiosaurus was uncommon within the space. John Foster discovered 12 specimens of Brachiosaurus versus 112 Apatosaurus and 179 Camarasaurus and 98 Diplodocus
  • 2012, a juvenile sauropod postcranial skeleton present in Morrison Formation in Wyoming, most likely a Brachiosaurus
  • As a result of solely incomplete specimens of Brachiosaurus have been discovered, a whole lot of estimates of the way it seemed are primarily based on Giraffititan
  • Michael Taylor analyzed Giraffitian and Brachiosaurus in 2009 and estimated Brachisaurus was about 82 ft (25 m) lengthy
  • Might have weighed as a lot as 35 metric tons and 56 metric tons, although a number of dimension estimates are primarily based on Giraffatitan (previously Brachiocsaurus brancai) as a result of it’s extra full specimen
  • A 2014 examine in PLOS Biology estimated Brachiosaurus weighed 62 tons (56 metric tons)
  • Had massive air sacs within the neck and trunk (hold it lighter)
  • Very lengthy neck, small cranium, and enormous physique (like most sauropods), however forelimbs had been longer than hindlimbs and tail was shorter in comparison with its neck
  • Brachiosaurus cranium was only one/two hundredth of its physique quantity
  • As much as 4-50 ft (12-16 m) tall
  • Very giraffe-shaped
  • Couldn’t truly rear on its hindlimbs (like in Jurassic Park)
  • Couldn’t rear up on hindlegs. Heinrich Mallison discovered that although different sauropods may try this, Brachiosaurus had too lengthy of entrance limbs and wouldn’t have been steady, and likewise it didn’t matter because it may already attain vegetation at such a tall top, in comparison with different sauropods
  • Neck was most likely not very cell however would have pointed upwards naturally
  • Thought-about to be a “excessive browser”, consuming vegetation that was 30 ft (9m) off the bottom
  • Might have additionally eaten decrease vegetation (10-16 ft or 3-5 m above floor)
  • Based on Wilkinson and Graeme Ruxton in 2011, Brachiosaurus, with its 30ft lengthy (9m) neck, could have saved time and power by low shopping for meals (‘reduces the general price of foraging by 80 %, in contrast with dinosaurs with shorter necks’)
  • In all probability ate ginkos, conifers, tree ferns, massive cycads
  • Ate in up and down movement of jaws, with tooth shearing plant matter after they closed
  • 2008 examine within the Royal Society mentioned Brachiosaurus could have swallowed its meals entire (tooth may strip vegetation however not break up massive chunks)
  • Would take soft-tissue evaluation to know for certain in the event that they had been excessive browsers or low browsers
  • Nonetheless, being a excessive browser would imply it didn’t need to compete for meals with different herbivores
  • Spoon-shaped tooth
  • Had 52 tooth, 26 on high and 26 on backside
  • Ate 440 to 880 (200-400 kilograms) of meals on daily basis, although newer estimates put it at 260 kilos or 120 kilograms per day
  • In all probability traveled in herds and migrated for meals
  • In all probability appreciated flat land, an excessive amount of power to climb hills and fewer prone to fall
  • Brachiosaurus most likely walked on its toes (digitigrade stance, like canine and cats), in comparison with “plantigrade” like people, the place heels and toes contact the bottom when strolling
  • Had a claw on the primary toe of every entrance foot and claws on the primary three toes of its rear toes (every foot had 5 toes)
  • Was most likely warm-blooded, like different sauropods, and the big nasal arch could have helped cool its mind (earlier than the air sacs had been identified about and Brachiosaurus was thought to weigh much more, scientists thought it couldn’t have been warm-blooded)
  • Scientists used to suppose as a result of it was so massive it had excessive physique temperatures, however in 2011 they had been in a position to calcualte its temperature to be 100.8 levels F (38.2 C), primarily based on ratios of some isotopes in Brachiosaurus tooth, so it most likely stored cool with a decrease metabolism as an grownup
  • Decreasing its physique temperature and slowing metabolism would imply it could not have needed to spend as a lot time consuming
  • Had massive hearts and hypertension to pump blood up its neck to its mind (heads had been held up excessive), so its blood stress was presumably 400 mm Mercury, 3-4 instances increased than a people’
  • Scientists used to suppose Brachiosaurus lived within the water, as a result of its nostrils are on the high of its head, however Brachiosaurus had air-filled pockets in its our bodies, so would have been too buoyant in water, in line with a 2004 examine in journal Biology Letters
  • Arch of bone over the snout and in entrance of the eyes
  • Nostrils had been regarded as on an “enlarged bump in entrance of its eyes”, however in 2001 Lawrence Witmer analyzed muscle attachment scars on dinosaurs and current day animal skulls and located that Brachiosaurus nostrils had been close to the tip of its snout
  • The crest that scientists used to suppose was the nostril on high of its head now could also be a resonating chamber to amplify sounds it made
  • Might have had an excellent sense of odor
  • Adults had no predators (largest predators had been Allosaurus, Ceratosaurus and Torvosaurus, which had been half its dimension)
  • Lengthy tail may whip at predators
  • Might have lived so long as 100 years
  • Had leathery pores and skin
  • Eggs present in linear sample, so most likely laid eggs when strolling (and doubtless didn’t maintain eggs)
  • Brachiosaurus has appeared in Jurassic Park and Strolling with Dinosaurs, and a mannequin from Jurassic Park was used within the 1997 particular version of Star Wars Episode IV: A New Hope
  • The “rontos” from Taooine had been primarily based on Brachiosaurus from Jurassic Park (in Star Wars)
  • 1991 GX7, a principal belt asteroid, was named 9954 Brachiosaurus
  • Household is Brachiosauridae (present in North America and Africa and Asia)
  • Brachiosaurids had been quadrupedal, with longer forelimbs than hindlimbs
  • They most likely went extinct within the early Cretaceous, although there’s some proof some could have lived within the late Cretaceous
  • Numerous debate over which animals are on this household
  • Former Brachiosaurus embrace Lusotitan, Giraffatitan
  • Different Brachiosaurids embrace Astrodon, Bothriospondylus, Dinodocus, Pelorosaurus, Pleurocoelus, and Ultrasaurus (however many are thought of doubtful)
  • One other Brachiosaurid is Europsaurus holgeri, a dwarf sauropod (solely 20 ft lengthy) that lived on an island off the coast of Germany
  • One other Brachiosaurid could also be an Asian dinosaur, Qiaowanlong


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