Parts of the skin are completely black in the 1.8 pre release.
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duplicates
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[media][media][media]

Duplicate of MC-68726

Not an issue/bug according to me. It seems that you don't use the new 1.8 skin layout. This new skin method permits to personalise all the parts of your body instead of duplicate some parts.
If you don't create some parts, it will replace it by black areas.