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Marine monsters question

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  • #2
    Galvasean
    Registered Users Posts: 30,746 ✭✭✭✭Galvasean


    Liopleurodon was a pliosaur that lived during the mid-late Jurassic period (the middle stage of the era of the dinosaurs). While depicted in the popular TV series Walking With Dinosaurs as a gigantic 25 meter long monster, in reality Liopleurodon seems to be only about 9 meters (30 feet) long at most. However close relatives of Liopleurodon exceeded 15 meters (50 feet) in lenght, some perhaps as much as 19 meters (64 feet).
    An idea of size:
    paddle_urib.jpg

    The giant mosasaurs lived in the late Cretaceous period (the end of the dinosaur era), taking the niche left over when the pliosaurs seemingly died out. They are not closely related to the pliosaurs. The similarities are a result of convergent evolution. In fact mosasaurs' closest relatives are monitor lizards and snakes. Among the largest types were Hainosaurus, Tylosaurus and Mosasaurus (I think Mosasaurus hoffmannii was the largest species of Mosasaurus. Incidently Mosasaurus maximus was a medium-large member of the group, about 30 feet long.). They reached lenghts between 40 and 50 feet, possibly more in some cases. As to which is the largest of all is up for debate. Their maximum sizes may have overlapped, with certain individuals groing much larger than the average mature size, therefore making it difficult to state for certain which was the biggest for sure.


  • #3
    Galvasean
    Registered Users Posts: 30,746 ✭✭✭✭Galvasean


    Galvasean wrote: »
    The giant mosasaurs lived in the late Cretaceous period (the end of the dinosaur era), taking the niche left over when the pliosaurs seemingly died out.

    Correction: A type of very large pliosaur called Brachauchenius lived in the late Cretaceous. It was 11 meters (36 feet) long. It may have been the decendant of Liopleurodon.

    brachauchenius1.jpg
    Among the largest types were Hainosaurus, Tylosaurus and Mosasaurus (I think Mosasaurus hoffmannii was the largest species of Mosasaurus. Incidently Mosasaurus maximus was a medium-large member of the group, about 30 feet long.). They reached lenghts between 40 and 50 feet, possibly more in some cases. As to which is the largest of all is up for debate. Their maximum sizes may have overlapped, with certain individuals groing much larger than the average mature size, therefore making it difficult to state for certain which was the biggest for sure.

    There was also Oronosaurus, a mosasaur specialised for eating hard shelled prey, which was 12 meters (40 feet) long.

    prognathodon_curii_col.jpg


  • #4
    Rubecula
    Registered Users Posts: 8,551 ✭✭✭Rubecula


    Fantastic answer, just the sort of thing I was looking for. And now that I know all that, a more weird question.

    On a TV documentary there was some sort of sea creature with a "double" bite. A bit like Alien in the sci fi films. It had a sort of extendable second jaw.

    I found this a bit hard to believe to be honest, but can you either confirm it or poor salt on the whole story?

    I have no idea what it was called.


  • #5
    Galvasean
    Registered Users Posts: 30,746 ✭✭✭✭Galvasean


    I suppose the prehistoric predatory fish Xiphactinus (which incidentally shared the sea with the mosasaurs) had jaws with jutted out and pulled back in quickly to make a suction, like many modern fish. It only had the one jaw though. Xiphactinus could hod it's own. It was a good 20 feet long.
    xiphactinus.jpg

    I'm not sure about a second mouth, but many species of mosasaur has extra teeth located in the upper palette inside their mouth. They can bee seen in this skeleton:
    15.jpg

    However, I think this may be what you are looking for. Modern moray eels actually have a secondary set of jaws inside their mouth:
    http://notexactlyrocketscience.wordpress.com/2007/09/05/moray-eels-attack-alien-style-with-second-pair-of-jaws/

    moray-bite.jpg?w=468


  • #6
    Rubecula
    Registered Users Posts: 8,551 ✭✭✭Rubecula


    Modern Moray eels? Well that settles it, I am now officially terrified of the sea. I am not going paddling again.:D


    Actually after looking at that I assume I remembering something else about Mosasaurs.

    I seem to be developing a fixation on them.

    Change of tack,

    Pliosaurs, Plesiosaurs. Any connection between the two?

    (I am only asking because you are pretty good with the info.)

    Oh and I believe there was also a Giant Ichthyosaur. How big did these things get? I assumed they only got to about dolphin size.


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  • #7
    Kess73
    Registered Users Posts: 25,560 ✭✭✭✭Kess73


    Rubecula wrote: »
    Modern Moray eels? Well that settles it, I am now officially terrified of the sea. I am not going paddling again.:D


    Actually after looking at that I assume I remembering something else about Mosasaurs.

    I seem to be developing a fixation on them.

    Change of tack,

    Pliosaurs, Plesiosaurs. Any connection between the two?

    (I am only asking because you are pretty good with the info.)

    Oh and I believe there was also a Giant Ichthyosaur. How big did these things get? I assumed they only got to about dolphin size.


    Shonisaurus was a huge Ichtyosaur, which could grow to anything up to 70ft in length depending on species. The popularis was long considered the largest Ichtyosaur for a long time at 50ft, until the Sikanniensis was found to grow to 70ft.


    800px-Shonisaurus_compared_to_a_human.svg.png



    shonisaurus.jpg


    http://en.wikipedia.org/wiki/Shonisaurus




    Another large Ichtyosaur was the Cymbospondylus which grew to about 30ft

    cymbospondylus_closeup.jpg

    http://en.wikipedia.org/wiki/Cymbospondylus


  • #8
    Galvasean
    Registered Users Posts: 30,746 ✭✭✭✭Galvasean


    Rubecula wrote: »
    Pliosaurs, Plesiosaurs. Any connection between the two?

    Well yeah, a pliosaur is a type of plesiosaur. The plesiosauria family is made up of two main lines; the plesiosauroidea (the ones with the long necks, sometimes referred to as elasmosaurs) and the pliosauroidae (short necks, big heads).

    The biggest of the long necked variety were Thalassomedon (40 feet long) and Elasmosaurus (46 feet).

    wallpaper_sm.4.2.jpg


  • #9
    Rubecula
    Registered Users Posts: 8,551 ✭✭✭Rubecula


    I never realised that Ichthyosaurs grew to that kind of size. the could rival even the great whales of modern times with a size like that.

    I am not sure that it would be easy to prove but I suspect it may be possible that the Shonisaurus was the prehistoric version of a Sperm whale? (Yep one is a reptile and one is a mammal.) I don't suppose there is any evidence for them feeding on giant molluscs. (Not saying squid as I don't think they had evolved back then)


  • #10
    marco_polo
    Moderators, Science, Health & Environment Moderators Posts: 10,076 Mod ✭✭✭✭marco_polo


    I think you could certainly make a reasonable argument that Ichtosaurs were filling similar ecological roles to modern toothed whale in Jurassic ecosystems.

    Where palaentologists are lucky enough to find evidence from stomach contents it suggestd that many varies of cephalopods such as the extinct belemnites and ammonites were a preferred food source for many species of Ichthyosaurs

    There would almost certainly have been large squid available as a food source for Shonisaurus (from what I know a few meteres long though not quite in the same league as modern squid giants) and it would certainly not be unreasonable to speculate (suppose even) that these were likely to have been a prominent food source for Shonisaurus based on what is known about other Ichthyosaur diets.

    AFAIK The real giant ancient squids such as tusoteuthis do not appear in the fossil record until the late cretaceous period about 80 million years ago, roughly 10 million years after the last of the Ichtosaurs had become extinct.


  • #11
    Galvasean
    Registered Users Posts: 30,746 ✭✭✭✭Galvasean


    marco_polo wrote: »
    AFAIK The real giant ancient squids such as tusoteuthis do not appear in the fossil record until the late cretaceous period about 80 million years ago, roughly 10 million years after the last of the Ichtosaurs had become extinct.

    Poor Tusoteuthis, fell prey to a giant salmon (seems everything was big in them days!). Check out this fun piece I found on Wikipedis:
    A fossil of the predatory salmonid, Cimolichthys nepaholica, was found with the gladius of T. longa in its gullet. The back portion of the gladius was in the stomach region, while the mouth of C. nepaholica had remained opened, suggesting that the fish had died in the middle of swallowing the squid, tail first. Researchers strongly suspect that as the fish was swallowing Tusoteuthis, the head and or tentacles remained outside the mouth, thus blocking the gills of the fish, and suffocating it as it swallowed its prey

    It's quite possible that large cephalopods (squid, octopus etc.) lived during the Triassic alongside Shonisaurus. Their soft bodies do not fossilise easily so you'd never know what kinds we haven't found yet. The earliest squid realtive known is 500 million years old.


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  • #12
    marco_polo
    Moderators, Science, Health & Environment Moderators Posts: 10,076 Mod ✭✭✭✭marco_polo


    Galvasean wrote: »
    Poor Tusoteuthis, fell prey to a giant salmon (seems everything was big in them days!). Check out this fun piece I found on Wikipedis:


    It's quite possible that large cephalopods (squid, octopus etc.) lived during the Triassic alongside Shonisaurus. Their soft bodies do not fossilise easily so you'd never know what kinds we haven't found yet. The earliest squid realtive known is 500 million years old.

    Mmm.. giant Salmon.

    Hehe Suffication by giant squid, probabl not the way I would choose to go myself if I had the choice. :)


  • #13
    Rubecula
    Registered Users Posts: 8,551 ✭✭✭Rubecula


    Ahhh yes, the old Calimari Choke Hold. Very effective in two falls or a submission I believe.:D


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