November 22, 2008 | David F. Coppedge

Turtle Vaults Over 65 Million Year Evolutionary Hurdle

The Scots are bragging about their latest missing link – a swimming turtle.  The BBC News could hardly contain the excitement over this claim to evolutionary fame: “The new species forms a missing link between ancient terrestrial turtles and their modern, aquatic descendants,” the article said.  But along with celebration, there were admissions of ignorance:

“Why did turtles enter the water?  We have no idea.  It’s a mystery – like asking why cetaceans went back into the sea,” said Jérémy Anquetin, of the department of palaeontology at the Natural History Museum.
    “Little by little, we are filling the gaps.
    “Now, we know for sure that there were aquatic turtles around 164 million years ago.
    “Eileanchelys may represent the earliest known aquatic turtle.
    “It is part of a new revision we are having about turtle evolution”….
   “This new turtle is very exciting”, said Dr Walter Joyce, an expert in turtle evolution, formerly of the Peabody Museum of Natural History, Yale University.
    “Keep in mind that a 65 million year gap used to exist in the fossil record between the oldest known turtles from the Late Triassic and basically modern turtles in the Late Jurassic.”

Additional revelations about the gap came up: the differences between the fossil and modern freshwater turtles are minor – “small differences” in cranial anatomy.  The fossil was found in a state of “exceptional preservation” in alternating series of mudstone, shale and limestone, with sharks, salamanders and rare lizards and dinosaurs in the same strata.  Joyce made another admission of doubt about the evolution story: “Finally, although it is really difficult to assess the ecological habitat preferences of turtles, the authors make a compelling case that by this stage in evolution turtles had started moving into aquatic habitats.”  As to why they did so, Anquetin had just said, “We have no idea.”

The BBC got one thing right: the gap was in the evolutionary story, not in the real world.  A turtle found exceptionally preserved in sediments along with other creatures – a turtle so similar to modern freshwater turtles it looks “like the ones you can buy in the pet shop” with only minor differences in the internal cranial structure; a few samples stuffed into a 65 million year gap in the evolutionary fable that is undergoing revision anyway – why are we supposed to believe the spin that this helps explain turtle evolution?  This proposed “missing link” does not help fill the Credibility Gap.  About the only thing you can believe in the story is Anquetin’s confession, “We have no idea.”

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