First direct evidence of ammonoid ovoviviparity

Discussion in 'Cephalopod Fossils' started by DWhatley, Sep 7, 2015.

  1. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    First direct evidence of ammonoid ovoviviparity
    Aleksandr A. Mironenko, Mikhail A. Rogov 2015 (subscription)

     
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  2. tonmo

    tonmo Titanites Staff Member Webmaster Moderator

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    Cool! Had to Google it, of course :rolleyes:

    Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos that develop inside eggs remain in the mother's body until they are ready to hatch.
     
  3. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I wonder if this was translated to English since this statement, "These facts confirm earlier speculations that at least some ammonoids could have been ovoviviparous and that, like many modern cephalopods, they could have reproduced in mass spawning events. " does not make a lot of sense. Extant cephalopods do not keep fertilized eggs internally.
     
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  4. tonmo

    tonmo Titanites Staff Member Webmaster Moderator

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    [looks up 'extant'...]
    Yeah! :smile:
    Like every modern cephalopod...
     
  5. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Would be nice to see this fossil, and see if there is a way of telling whether the eggs were laid inside the egg layer's shell or just an empty, convenient shell. Anyone have a spare copy of this paper ;)
     
  6. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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    Hmmm... may have to spring for the $6 for access to this... blurry pictures in preview look interesting. But I too would question whether deposited in an empty shell.
     
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  7. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    I'm curious to know if they are really ammonite eggs laid by the original occupant or eggs laid in an empty shell. Current species behavior makes me think the later is most likely.
     
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  8. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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    In reading the preview, it appears that the evidence of ovoviviparity is that all the eggs are of the same developmental stage (if they had been laid in an empty shell, by multiple ammonites then the eggs would have different developmental stages) AND there were no other artifacts in the shell (like fish scales, other shells or plant remains).
     
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  9. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    @cuttlegirl but would that look any different if a single live ammonite laid the eggs in the shell of a dead one?
     
  10. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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    Well, then it would have to be freshly dead, no algae growth, no other debris from the ocean floor - at least that is their stance on this. When I have an extra 48 hours, I am going to spring for the $6 and I will share a synopsis.
     
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  11. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    After reading and thinking about their 5 hypotheses... seems plausible, at least for one genus.
     
  12. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    After reading the paper, I think the statement that I found odd was intended to imply these ammonites produced a quantity of offspring at one time vs the onesie twosies of the modern day nautilus BUT it was interesting to learn that there actually ARE living octopuses that are ovoviviparous (Vitreledonella and Ocythoe).
     
  13. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Getting to know the great diversity of extinct and extant cephalopods ;)
     
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