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The Ornithopod Thread- Hadrosaurs, iguanodonts and kin



  • Adam Khor wrote: »
    I think it has been suggested that Iguanodon's thumb spike had venom too, like the platypus', although I think there's no evidence of it found thus far. But wouldn´t it be cool? :D

    was iguanodon bigger than megalania ?

  • was iguanodon bigger than megalania ?

    Yes, by far.

    Nowadays it is believed that a 7 meter long megalania would weigh a bit less than two tons, and not everyone thinks it got that large, whereas Iguanodon was 3-5 tons, and perhaps even more since there's evidence of T-Rex sized individuals (and they were very robust animals).

  • Also turns out that megalania is more of a monitor lizard than a Komodo dragon.

    So perhaps the denizens of Oz weren't fighting the largest venomous creature that ever lived 40,000 years ago.

    It can't have been fun with two ton salties waiting in / near water and two ton lizards wandering around elsewhere

    When you consider the animals humans faced when they got to Oz you'd wonder why they stayed

  • Also turns out that megalania is more of a monitor lizard than a Komodo dragon.

    Well, Komodo dragons ARE monitor lizards. And monitor lizards are probably all venomous, so megalania would still be if not the largest, then one of the largest venomous animals of all time.

    When you consider the animals humans faced when they got to Oz you'd wonder why they stayed

    Well all evidence seems to indicate that big crocs and giant monitor lizards were not rarities that evolved in islands, but rather common thing all over Asia and Oceania (and I think they found giant monitor lizard remains in Africa as well) and that Komodos are just the last remnants of said linneages. Plus in other continents the marsupial lions would be replaced by actual lions and tigers, bears, hyenas... I think the situation was just as bad everywhere. :cool:

  • Adam Khor wrote: »
    Well all evidence seems to indicate that big crocs and giant monitor lizards were not rarities
    salties are ocean going and komodo dragons have no problem swimming between islands.

    our ancestors have faced/wiped out some nasty critters all right

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  • let's not forget ye olde platypus

    it's so much that it's poison is very toxic but that the pain it causes is not eased by morphine because it behaves in a different way to things like snake venom.

    not sure if you could call platypus venom convergent because it is so different
    The platypus is my favourite mammal

  • Adam Khor wrote: »
    Maybe Iguanodon and similar dinosaurs such as Ouranosaurus and Lurdusaurus used their spikes in similar ways- meaning, not only as defensive weapons but to fight same species rivals and perhaps even targeting the most vulnerable spots of their opponents. Going for the eyes and stuff. Scary.

    Interesting. I'd never thought of the Iguanadon thumb spike as being a sexually selected trait. I had a quick look at the literature (well, wikipedia) and there doesn't seem to be much evidence for sexual dimorphism in this species.

  • I think this guy is condemned to be forever mixed up with Altirhinus, even though it is a true duckbilled dino, not an iguanodont.

    Not a lot of free access info to this moment, and no images. It was long known as the "Sabinas saurolophine", it had a very broad and arched snout, and that's about it.

    This is the skull of a "Sabinosaurus" which I'm not sure if its the same as Latirhinus, or just a regular Kritosaurus. Seems this sort of dino was very common in southern North America back then.


  • It seems to be some sort of iguanodont but the name has not been revealed yet.


    Article is in Spanish. Here's the important stuff:
    ... at least six specimens of an eight-meter long herbivore whose main trait is the beak, very sharp and divergent (?), very different from the flat beak of other dinosaurs.
    The remains of the new dinosaur, an ornithopod, were revealed yesterday before the press by the director of the Fundación Dinópolis, Luis Alcalá, who explained that during the last two years and a half, 348 bones from six specimens of different sizes and probably both genders have been identified. Worth mentioning are three skulls, two of them fairly complete, teeth, bones from the scapula and pelvis, and limbs, vertebrae and ribs.
    Alcalá didn´t want to reveal the name of the new species for the time being, for its analysis has yet to be published in scientific journals. He did say that its age is estimated to be about 113 and 110 million years and is a relative to Iguanodon, another common dinosaur in the area.
    Alcalá also noted the importance of the fossil site, for it dates back to the Albian, the last stage of the Early Cretaceous, an age of which there are very few fossil remains in Europe.
    Besides the dinosaurs, the site has yielded numerous remains of crocodiles, turtles, fish and other known species of dinosaurs, as well as diverse plants and invertebrates- a total of about 5.000 bones

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  • Iguanodon approves.


  • Galvasean wrote: »
    Iguanodon approves.


    Then again, he tends to approve of everything...

  • Adam Khor wrote: »
    Then again, he tends to approve of everything...

    I have a friend who broke her thumb recently. We all call her 'Iggy' now :D

  • It's a small ornithopod, similar to Gasparinisaura and Talenkauen.

    It was about 1.5 meters long and was found in Antarctica:

    Chances are high it was fuzzy even tho it appears naked here:

  • Oh boy oh boy oh boy!!!!!!
    How long do we have to wait?

  • Galvasean wrote: »
    Oh boy oh boy oh boy!!!!!!
    How long do we have to wait?

    I don´t know but if its tomorrow it will still be too long! :eek::pac:

  • Good find Adam.

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  • In Alberta, Canada.

    The dino was said to be 30 meters long at first! However, other articles say its 12-15 meters long which is a lot more likely.


  • Fantastic fossil photo would love to be helping on that dig and find out some more information. well done on the photo has made my evening.

  • Cute lil' bugger according to the restorations.

  • Some hadrosaurs crested (Lambeosaurinae). Others (Hadrosaurinae) not. Crests had nasal passages. Underwater snorkel? Air reservoir? Adaptive advantage? Hide underwater? Crested also webbed feet? Not crested with camel feet? Crested more aquatic than not crested? Missing link? Evolved from crested water to not crested land?

  • Some hadrosaurs crested (Lambeosaurinae). Others (Hadrosaurinae) not.

    Except some hadrosaurines (if not most) may have had soft-tissue crests that didn´t preserve well as fossils. At least one Edmontosaurus specimen has what appears to be traces of a chicken-like comb. It has also been suggested for as long as I can remember that many hadrosaurines had inflatable air sacs around their nostrils (explaining the unusually large, arched noses). These sacs would not only be brightly colored to catch the eye of potential mates, but also amplify their calls.
    Crests had nasal passages. Underwater snorkel? Air reservoir?

    The snorkel/air tank was suggested for Parasaurolophus at one point, but the amount of air they could have stored in there would be insignificant compared to what could be kept in their lungs, for example. Most importantly, there's no opening in the tip of the crest, which renders it useless as a snorkel.
    Not that it matters, since now it appears hadrosaurs were land animals only; their toenails had even evolved into a sort of hooves to better support their weight, and the so-called webbing found in some of them was actually distorted soft tissue that would have enveloped the three main digits of the forefeet for better support (meaning a hadrosaur could not move its "fingers" independently, as they were bound together by this "mitten" into a single unit). The tail was also pretty rigid; no good for swimming.
    Crested more aquatic than not crested? Missing link? Evolved from crested water to not crested land?

    There's really no evidence that hadrosaurs were aquatic at any point of their evolution. Also, crested and "non-crested" hadrosaurs coexisted for a very long time.

    The consensus now is that the crests of lambeosaurines served two purposes; one of them visual, as an aid to recognize the age and gender of other hadrosaurs (males apparently had bigger and more elaborate crests), and the other acoustic, to produce and amplify sounds by means of the air passages inside the crests.
    The call of Parasaurolophus was even recreated in the 90s, based on a well preserved skull from a male, and with the aid of a computer. The resulting sound is fascinating, if somewhat eerie:

    The video also states that the area of the brain dedicated to hearing is most developed in Parasaurolophus. That the males had bigger crests also makes sense if they were the ones calling potential mates over large distances. Interestingly, the modern cassowary communicates via infrasounds over long distances (the lowest call of any known bird), and has a crest very reminiscent of a hadrosaur's (Corythosaurus casuarius was named after it). There's good evidence that the crest or "casque" of the cassowary has a lot to do with these low frequency calls, either as an amplifier, a reception device, or both.

  • Adam Khor thanks. Useful. Informative.

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  • Dear Adam,

    This is very useful info about Hadrosaurs. Recently I read an interesting article about the fossil remains of a juvenile crested Hadrosaur (about one year old at the time of death) which had only a tiny, budding bump on his head. This seems to indicate that baby Hadrosaurs of the crested variety probably hatched without the typical protuberance, which would later develop and grow as these dinosaurs matured. A similar case would be that of modern deer; the fawns' horns begin to sprout months after birth.