In our 87th episode, we got to speak with Cameron White, Head of Gallery Experience at the Royal Tyrrell Museum. To learn more about the museum, check out our video in part 2 of our #EpicDinosaurRoadTrip.
Episode 87 is all about Iguanodon the second dinosaur ever named.
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In this episode, we discuss:
- The dinosaur of the day: Iguanodon
- Name means “iguana tooth”
- Ornithopod that lived in the early Cretaceous, in what is now Belgium and maybe other parts of Europe
- Other dinosaurs in the area include predators Aristosuchus, Eotyrannos, Baryonyx, and Neovenator, and other herbivores like Hypsilophodon, Mantellisaurus, the armored herbivore Polacanthus, and Pelorosaurus, a sauropod
- Named in 1825 by Gideon Mantell, an English geologist
- Second dinosaur named after Megalosaurus (discussed in episode 47); one of the three dinosaurs to define Dinosauria
- The other genera used to define Dinosauria was Hylaeosaurus
- There was tension between Mantell and Richard Owen (a scientist and man who named Dinosaursia who was also a creationist and opposed the “transmutationism” idea of evolution. When he described Dinosauria, he said they were advanced and mammal-like, with characteristics that God gave them, and could not have transmuted from reptiles to mammal-like animals
- Transmutation was the theory before Darwin’s theory of evolution
- Mantell and Owen had a rivalry, and some historians think Owen took a lot of credit for Mantell’s work
- The story of how Iguanodon was discovered was that Mary Ann, Gideon Mantell’s wife, found the teeth in 1822 in Sussex, England, while her husband was visiting a patient. But Mantell didn’t take his wife with him when visiting patients, and in 1851 he admitted he had found the teeth
- Mantell first found large fossils at a quarry in Whitemans Green in 1820, but he thought they belonged to a giant crocodile. In his notebooks he mentioned in 1821 that he found herbivorous teeth and thought it might belong to a large reptile. He presented the teeth to the Royal Society of London in 1822 but they thought it was just fish teeth or rhinoceros teeth (happened again in 1823 when Charles Lyell showed the teeth to Georges Cuvier, a French naturalist).
- William Buckland was one of the members of the Geological Society of London to say the teeth belonged to a fish or rhino
- Cuvier was known for correctly identifying Pterodactylus as a flying reptile
- He thought the teeth were of a rhino, but the next day had his doubts, but Lyell only told Mantell about Cuvier’s first thoughts of the teeth, so Mantell put them to the side for a while
- Then Buckland described Megalosaurus in 1824 and was invitied to see Mantell’s collection. He thought it was a dinosaur, though not an herbivore. So Mantell sent some teeth to Cuvier, who said in June 1824 that they were reptilian, possibly of a giant herbivore’s (admitting to his mistake in 1823).
- Cuvier wrote a public retraction that he now thought the teeth were reptilian, not mammalian
- Mantell’s discovery was now widely accepted
- In September of 1824 Mantell went to the Royal College of Surgeons but couldn’t find any similar teeth. Then Samuel Stutchbury, an assistant curator, saw that they looked like a larger version of iguana teeth he had recently worked on
- Because of this, Mantell named the animal Iguanodon (he was going to call it Iguana-saurus, but his friend William Daniel Conybeare said that name was more applicable to an iguana, so a better name would be Iguanoides (meaning Iguana-like) or Iguanodon
- Conybeare said Iguanasaurus might cause confusion between the dinosaur and iguanas
- Mantell wrote a letter about Iguanodon to the Portsmouth Philosophical Society in December 1824, and the Hampshire Telegraph published about it, but misspelled the name (Iguanadon instead of Iguanodon)
- Mantell published his findings formally in February 1825 (presented the paper to the Royal Society of London)
- Mantell didn’t give it a species name, but in 1829 Friedrich Holl named it Iguanodon anglicum, which later became anglicus
- The name anglicum was changed to anglicus for correct grammar
- After Stutchbury recognized the tooth looked like a giant iguana tooth, Mantell estimated the size of the body of Iguanodon by multiplying how many times bigger it’s tooth was compared to an iguana’s tooth. He guessed it was 59 ft (18 m) long, bigger than Megalosaurus, though it’s not true
- Weighed around 3.4 tons, about 33 ft (10 m) long as an adult (some may have been as long as 43 ft (13 m))
- Only two valid species of Iguanodon currently: bernissartensis (described by George Albert Boulenger in 1881) and galvensis, described in 2015 and based on fossils found in Spain
- The original type species was Iguanodon anglicus, but that was only based on a single tooth, and only partial remains have been found. In 2000, the International Commission on Zoological Nomenclature changed the neotype to Iguanodon bernissartensis (the original Iguanodon tooth is at the national museum of New Zealand in Wellington, but it’s not on display)
- They got it after Walter Mantell, Gideon Mantell’s soon, moved there after his father died (he got the fossil collection)
- Iguanodon bernissartensis is the neotype, which replaces Iguanodon anglicus as the type species that newly found Iguanodon fossils are compared to
- Clade Iguanodontia has been a wastebasket taxon for ornithopods that are neither hypsilophodontids or hadrosaurids
- Well known Iguanodontia include Dryosaurus, Camptosaurus, Ouranosaurus, and hadrosaurs
- What we know about Iguanodon has changed significantly since 1825, based on new finds
- Because there were only fragments of dinosaurs found in the beginning, a lot of assumptions were based on current living creatures
- Mantell thought Iguanodon had a horn on its nose (instead of a thumb spike) based on it being similar to a horn of a South American iguana with a Kangaroo-like stance
- Iggy, a famous Iguanodon replica, is in the kangaroo pose, which was thought to be accurate when they mounted the Iguanodon
- World Wars and the Great Depression meant Iguanodon wasn’t really studied in the early 1900s
- A dinosaur renaissance started in 1969 with Deinonychus, and soon after David B. Norman analyzed how it ate and other aspects of Iguanodon, and it became a well known dinosaur
- In 1834 in an excavation of a quarry in Maidstone, a more complete Iguanodon specimen was found (other than the tooth Mantell found) However it was still only a partial skeleton. Mantell identified it as Iguanodon based on its teeth. This skeleton was used in the first Iguanodon reconstructions, but it was not complete, and Mantell thought the horn went on the nose
- The skeleton, known as the Maidstone skeleton, is preserved in a slab and on display at the Natural History Museum in London (also nicknamed Gideon Mantell’s “Mantel-piece”); replica is nicknamed Iggy
- Bensted concluded it was an Iguanodon, and wrote in his notebook, along with sketches: “The remains of the Iguanodon were discovered by one of the workmen blasting the layer with gunpowder, the bore being placed in the middle of a rise, or mound in the stone”
- There was quarry blasting. Bensted also wrote, “The separation of the mass was so complete, that some parts were thrown by the force of the powder to a considerable distance, and a month had elapsed before I had fitted the fragments together in their relative places.”
- The Maidstone skeleton helped Gideon Mantell identify his dinosaur, Iguanodon
- The borough of Maidstone added Iguanodon to their coat of arms in 1949 . And that specimen is linked to Iguanodon mantelli, a species Christian Erich Hermann von Meye named in 1832 to replace Iguanodon anglicus, but it was found in a different formation from Iguanodon anglicus. Because it’s from a different formation, it was eventually reclassified as Mantellisaurus in 2012
- In May 2014, the Maidstone Museum got back the original case of Iggy the Iguanodon and are on display in the Kent Earth Heritage Gallery
- In 1878 in Bernissart Belgium, the largest Iguanodon to date was found. Two mineworkers, Jules Créteur and Alphonse Blanchard, accidentally hit a skeleton that they thought was petrified wood
- They excavated the skeletons and in 1882 Louis Dollo reconstructed them. They found 38 Iguanodon individuals, most of them adults (new species, Iguanodon bernissartensis, though one specimen called Iguanodon mantelli, now known as Dollodon bampingi)
- Louis Dollo was a Belgian paleontologist
- Iguanodon bernissartensis was named for Bernissart, where the coal mine were the 38+ Iguanodon specimens were found
- Not clear why there were so many Iguanodons in the Bernissart coal mines
- A complete Bernissart specimen showed Dollo that the spikes were not on Iguanodon’s nose, but on its thumbs
- The holotype was one of the first dinosaur skeletons put on display. They used adjustable ropes attached to scaffolding to help give it a lifelike pose. They were put on display in 1883, and then moved in 1891 to the Royal Museum of Natural History (19 are in the basement, but 9 are on display still). Can also see a replica at the Oxford University Museum of Natural History and the Sedgwick Museum in Cambridge
- The Iguanodon replica at Cambridge’s Sedgwick Museum is nicknamed Iggy
- At the time there were no standardized ways to preserve fossils, and they often had “pyrite disease” which is when crystalline pyrite in the bones are oxidized to iron sulphate. To help preserve the Iguandon finds, they covered the fossils in wet clay, sealed them with paper and plaster, and then when they were transported, preserved them with boiling gelatine and an oil of cloves, then removed the visible pyrite and hardened them with hide glue, and repaired damages with papier-mache. But this accidentally caused more damage. The museum in Brussels worked to restore the fossils in 1935-36, using alcohol, arsenic, and shellac. The fossils were worked on again in 2003-2007, using polyvinyl acetate and cyanoacrylate and epoxy glues
- Dollo showed that Owen’s interpretation of Iguanodon was incorrect, and he modelled the skeletal mounts after cassowaries and wallabies, and moved the spikes to the thumbs. It wasn’t completely correct, but these were some of the first complete dinosaur specimens (he gave it a tripod tail, which in real life would have had to be broken to bend that way)
- The coal mine were Iguanodon was found has been abandoned (from scientific study) since 1921
- One Iguanodon found had a fractured hip bone, two others had osteoarthritis
- Probably not a herding animal
- May have traveled in small groups, though Iguanodon findings don’t have many hatchlings or juveniles (which is why it may not have been a herding animal)
- Because Iguanodon was an early named dinosaur, a lot of species have been assigned to it over the years (though it was not wastebasket taxon like Megalosaurus)
- Still lots of debate over what is Iguanodon and what species of Iguanodon
- Other “Iguanodons” were from four other continents
- Reassigned species include Iguanodon hoggi, now Owenodon, Iguanodon albinus, now Albisaurus albinus, Iguanodon atherfieldensis, now Mantellisaurus, Iguanodon exogyrarum, now Ponerosteus, Iguanodon prestwichii, now Camptosaurus or Cumnoria, Iguanodon dawsoni, now Barilium, Iguanodon fittoni, now Hypselospinus
- Also Iguanodon hollingtoniensis, now Darwinsaurus, Iguanodon seelyi, now considered by some to be a synonym of Iguanodon bernissartensis, Iguanodon phillipsi, now Priodontognathus, Iguanodon praecursor, now considered a sauropod and possibly Neosodon, Iguanodon mongolensis, now Altirhinus
- Also dubious species, Iguanodon anglicus, Iguanodon ottingeri
- Large and tall, but narrow skulls, with toothless beaks (probably covered in keratin), and teeth similar to an iguanas
- Teeth were similar to an iguanas, but bigger (only had one replacement tooth at a time for each tooth, unlike hadrosaurids)
- Upper jaw had 29 teeth on each side, no teeth in the front, and 25 teet in the lower jaw (teeth in lower jaw were wider)
- Could shear vegetation, which meant it could bite tough plant matter
- Could eat tough vegetation
- Probably had some sort of cheek structure to keep food in its mouth
- Had a horny, toothless beak
- Probably had a cropping beak, to bite off twigs
- Not sure what exactly it ate. Its size meant it could eat low-lying plants and plants up to 16.5 ft (5 m) high. Still, Iguanodon is considered to be medium to large herbivore for its habitat
- Because Iguanodon could find food in both low and high places, it had an advantage and could spread out in wider areas (also, when bipedal, easier to spot predators)
- Dollo thought Iguanodon had a tongue similar to a giraffes (prehensile, to gather food), but that’s since been rejected
- Dollo may have thought it had a giraffe like tongue because of a broken lower jaw
- More fossils show it had a muscular, non-prehensile tongue (moved food within its mouth)
- Thumbs had spikes (early restorations thought the spikes were on Iguanodon’s nose)
- Still not clear what exactly the thumb spikes were used for
- Had large thumb spikes, which may have been used for defense or foraging for food
- One person thought the thumb spike had a venom gland, but the spike was not hollow, so this theory hasn’t been accepted
- Thumb spike may have helped break open seeds and fruits, or as a weapon
- Thumb spikes were between 2-6 inches long
- The fifth digit was flexible, nearly prehensile (ex: the way a chameleon’s tail can curve around a branch), so probably could reach hard to get to parts of plants
- Had a long, dextrous little finger, maybe for moving objects (gathering food)
- The three middle fingers were close together, almost like one (inflexible, but made it easier to be on all fours)
- Herbivore that could shift from bipedal to quadrupedal
- Had strong legs, but was not a good runner. Had three toes
- Most likely quadrupedal most of the time and then bipedal for high browsing
- Juveniles have shorter arms than adults (60% of hindlimb length v 70% for adults), so as it aged, became more quadrupedal
- Had long arms (75% length of legs), with inflexible hands with three central fingers (to bear weight when it’s quadrupedal)
- Iguanodon’s forelimbs were 75% the length of the hindlimbs, which would make it easy to fully extend and walk on all fours, and then they could bend their elbows to get closer to vegetation on the ground
- In 1849, Mantell realized that Iguanodon had slender forelimbs and were not heavy, but he died in 1852 and could not weigh in on Richard Owen’s Crystal Palace dinosaur sculptures
- Had thick back legs
- Could not gallop, max speed is estimated to be 14.9 mph (24 kph)
- Could run for short distances, away from predators
- Footprints have been found on the Isle of Wight in England. It wasn’t clear they were Iguanodon footprints at first (Samuel Beckles said in 1854 they looked like bird tracks), then an Iguanodon hing leg was found nearby in 1857 and it had three-toed feet, which showed the three-toed footprints could be Iguanodon (so no direct evidence, but these tracks are thought to be Iguanodon)
- Had a stiff tail
- A stiff tail would help with balance
- Originally depicted as bipedal with its tail dragging on the ground, like a tripod (third leg)
- David Norman reexamined Iguanodon and concluded that it was not like a tripod because its tail was stiff with ossified tendons
- Ossified tendons are tendons that have turned to bone during an animal’s lifetime
- Iguanodon’s tail is now always depicted as straight and high off the ground
- Tendons can bend, so as an embryo Iguanodon had tendons supporting their tails so the tail could curl around the body and it could fit in a smaller sized egg
- Because of this, when it first hatched it probably had limp, droopy tails, but maybe only for a few days or weeks
- In December 2011, a bone thought to belong to the tail vertebrae of an Iguanodon was found in a garden in Sunderland, UK. However, the rocks in that area it was found are older than dinosaurs, so curators at the Sunderland Museum think the bone was lost or dropped by someone there at some point or it got there by glacial transport
- Because of Richard Owen dinosaurs were seen as large animals with scales and lots of teeth, which Owen had translated into the Crysal Palace dinosaur sculptures
- Benjamin Waterhouse Hawkins, who sculpted the dinosaurs, had a dinner party inside the standing Iguanodon sculpture before it was finished (or so the story goes, he actually had the party in the mould used to cast the sculpture)
- It was a publicity stunt to celebrate the dinosaur sculptures
- Dinner was on December 31, 1853
- The dinner lasted until after midnight
- They built a stage in order to deliver the courses, including mock turtle soup, cod in oyster sauce, pheasant, woodcock and snipe, and “Nougat à la Chantilly”
- There were 21 guests at Hawkins’ dinner party, including Richard Own. They ate ham, drank wine, and started singing, “The Jolly Old Beast is Not Deceased, There’s Life in Him Again!”
- Other guests at the Hawkins dinner party included Edward Forbes, John Gould, and Joseph Prestwich
- They also ate raised pigeon pie, roast turkey, ham, boiled chicken and celery sauce, Cotolettes de Moutonaux Tomates, Currie de Lapereaux au riz, Salmi de Perdrix and Mayonnaise de filets de Sole
- The newspapers the next day reported on the event. Hawkins apparently said, “The roaring chorus was so fierce and enthusiastic as almost to lead to the belief that the herd of iguanodons were bellowing.”
- Richard Owen sat at the head of the table, inside the Iguanodon’s head and gave a speech about how accurate the sculpture was
- In 1855 funding was cut to create more dinosaur sculptures, and the Iguanodon was one of 3 at Crystal Palace
- Iguanodon appears in Sir Arthur Conan Doyle’s 1912 story, The Lost World (they roam in herds in South America)
- There’s also an extra large Iguanodon that walks around Paris in Nicolas Flammarion’s The World Before Man, published in 1886
- And there’s an Iguanodon stampede in Robert Bakker’s Raptor Red
- 1989 CB3 main belt asteroid has been named 9941 Iguanodon
- The 9941 Iguanodon asteroid was found on February 4, 1989, inside a rocky belt between Mars and Jupiter
- Can see Iguanodon in the Disney movie Dinosaur (Aladar)
- Also inspired Godzilla, along with Tyrannosaurus and Stegosaurus
- And has been in many Land Before Time movies
- Also in the 1999 Walking with Dinosaurs documentary
- Fun Fact: Despite some other dinosaur groups not doing so well; Ornithopods (mostly hadrosauroids) got super successful in the late cretaceous, 40% of known ornithopod species are from just the last 30MY of the Mesozoic. Or to put it another way 40% of ornithopods are from less than the last 20% (30/165) of the reign of dinosaurs.
For those who may prefer reading, see below for the full transcript of our interview with Cameron White:Continue Reading …
