evolution - Is there any complex organism that is both autotroph and heterotroph?

Just look up kleptoplasty
http://en.wikipedia.org/wiki/Kleptoplasty
The slugs who most frequently employ it would fit your more restrictive definition. Now, if we're getting technical, they aren't born that way. They steal the chloroplasts, but you didn't say, so I guess you need to revise your expectations again. ;)

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