Researchers May Have Found Origin of Turtle's Mysterious Shell

The Ottawa Citizen ^ | January 19, 2009 | Tom Spears

[nickcarraway]

Xiao-chun Wu has spent years studying fossils, and he finally has enough evidence to write his own Just So Story: How the Turtle Got His Shell.

Publishing today in a science journal, his Chinese, Canadian and American team has some stunning evidence: two well-preserved fossils of ancestral turtles that swam in the shallow ocean of present-day China more than 220 million years ago.

These are the oldest turtles ever found, even older than most dinosaurs.

Turtles have lived a long time without changing much.

They've had a broad top shell and smaller bottom one for something like 216 million years, as they evolved into sea-living giants and little turtles in ponds.

But the shell has always been a puzzle. How does an animal evolve a shell?

What does it come from?

One theory has been that it began with plates of bones in an animal's skin, like a crocodile today, and like some species of dinosaur.

These "dermal" bones may have grown big enough to fuse together into an armour plate, eventually fusing with the spine and ribs as well.

But the two turtles from southern China support a competing view.

They had full lower armour (useful if an attacker swam up from below) but only the beginnings of an upper shell.

And there are no bony plates in the skin.

Instead, the upper ribs are spreading out at this period into broad defensive shields.

But they haven't formed a plate.

"There's space between the ribs, like a frame" with the spaces waiting to be filled in later, said Mr. Wu, a research scientist who specializes in dinosaurs and ancient reptiles. Since there were open spaces, the whole frame had to be covered with skin.

[JoeProBono]

[ClearCase_guy]

Turtles have lived a long time without changing much.

There are a lot of animals that have lived a long time without changing much. On the other hand, many of the animals that are seen as evidence that species change are actually extinct. They tell me that the change is to help them survive, but I'm not sure how well that works. Turtles, cockroaches, sponges, coelecanths, horseshoe crabs, these things seem to have started out so well that they didn't need to change in order to adapt to changing environments.

Weird, huh?

[pabianice]

There is some imprecision in this article. The turtle's top shell is, in fact, its spine and rib cage. This means the turtle's shoulders and hips are inside its rib cage, with the bottom shell (plastron) completing the coverage with the top shell (caripace). Way cool.

Recommend books by Archie Carr.

[blackpacific]

How does an animal evolve a shell?

How does a creature that has no computer programming ability whatsoever develop a program which generates a new appendage, inserts it into the master program (DNA), and does so without any specification, or formal validation, and without any knowledge that the proposed “evolved” structure will actually be beneficial? Wow, it’s pretty cool that animals can do this, I suppose there is no need for an Agent cause.

[Robert A Cook PE]

So, this guy has worked for years just to find out where turtles come from. Cool.

But, I generally suspect that almost all turtles come out from the inside of their shell. (Those that don't come out from the inside of their shell, are usually found quite quietly dead, which is not a good thing for future evolutions.)

Then again, most (male) turtles that don't come outside their shell don't reproduce very well either - which we are also taught is not a good evolutionary doctrine.

So, we are back to the question:

Which comes out first? The turtle outside of the shell, or the turtle inside the shell?

[martin_fierro]

[RichInOC]

You’ve got a turtle head pokin’ out!

[Quix]

Pending turtle soup, I see.

LOL.

Just avoid the last piece. I learned too late . . . it’s an insult.

[JoeProBono]

Hah!

[Quix]

Would you be willing to try and find a pic of the ET in the

Varginha

case

that we could hotlink to?

[SunkenCiv]

-sidebar-

Tropical Turtle Fossil Found in Arctic
LiveScience.com on Yahoo | 2/1/09 | LiveScience Staff
Posted on 02/01/2009 1:11:58 PM PST by NormsRevenge
http://www.freerepublic.com/focus/f-news/2176350/posts

[SunkenCiv]

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[Ken H]

Turtles have lived a long time without changing much.

Or as Xiao-chun Wu would likely put it, "Turtle live long time. No much change."

[ApplegateRanch]

How does a creature that has no computer programming ability whatsoever develop a program which generates a new appendage, inserts it into the master program...

He gets a job at Microsoft as a software developer?

[zeugma]

"Turtle live long time. No much change."

The turtle Darwin brought back from the Galapagos Island is apparently alive and well in a museum in New York.

So yes, they live long time.

[Fred Nerks]

EARLIEST TURTLE FOSSIL SHELL

The fossil turtle Odontochelys semitestacea has a fully formed shell shielding its belly, but an incomplete upper shell, extending from its ribs and backbone. Photograph: Institute of Vertebrate Palaeontology and Palaeanthropology, Beijing