LYCOS RETRIEVER 
Turtle: Shells
built 279 days ago
One unique feature of the turtle is its shell. This protective skeletal structure is an armored enclosure for the soft vital internal organs. The upper part of the shell, called the carapace, is covered with large scale-like structures known as scutes. The carapace is connected to the underside, called the plastron, by hard-shelled plates known as lateral bridges.
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Edible species include several marine turtles, the green turtle (traditional ingredient of turtle soup), the diamondback terrapin, and the soft-shelled turtles. Catching females when they lay eggs on land has contributed to a serious decline in many species, since it can take 10 to 30 years for some turtles to reach sexual maturity.
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The painted turtle, or otherwise known as the Chrysemys Picta, is one of the wetland's most diverse reptiles. This animal can be very shy and hard to spot in the wild, but can be located by it's colorful shell.
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The earliest known turtle is proganochelys, though this species already had many advanced turtle traits, and ... probably had many millions of years of preceding "turtle" evolution and species in its ancestry. It did lack the ability to pull its head into its shell (and it had a long neck), and had a long, spiked tail ending in a club, implying an ancestry occupying a similar niche to the ankylosaurs (though, presumably, only parallel evolution).
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The sea turtle's reptilian body is wonderfully adapted to life in the ocean. Their shells are lighter and more streamlined than those of their terrestrial counterparts, and their front and rear limbs have evolved into flippers making them efficient and graceful swimmers, capable of swimming long distances in a relatively short period of time.
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