The plesioturtle or long necked sea turtle theory has been doing the rounds for a while. I covered the idea in 2013 in this article, being inspired by a Nessie documentary from 2009 which looked at it. I wrote a more recent article in 2021 where giant turtles had been proposed in 1933 as an explanation for the Loch Ness Monster, albeit without the long neck. The theory is rational enough and has been applied to other forms of aquatic cryptids.
Now I don't know when this theory came into being, but it looks like someone was thinking about it back in about 1895 as the above four inch Chocolat Suchard "trading" card shows. However, what the artist was trying to say is not so apparent. We have the traditional plesiosaurus, but with a shell on its back, like the turtles of today. We then have a picture in the top right corner of Chelonia Midas or the Green Sea Turtle.
What are we to deduce from these juxtaposed illustrations? The plesiosaur had a shell and the modern sea turtle is its descendant? Or is he re-imagining a plesiosaur based on the sea turtle? A couple of other monster cards from the company show similar themes for an Elasmosaurus and Iguanodon, a comparison of the large of yesterday with the little of today.
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