Yangtze giant soft-shell turtle
In 2007, scientists found a female Yangtze giant soft-shell turtle in a zoo in Changsha.  The turtle had been there for more than fifty years, before Yangtze giant soft-shell turtles became rare.  The people in the zoo knew she was a large, female turtle but not that she had become one of the rarest on Earth.  The deputy director of the zoo was attending a conference about tigers and went to the speech about turtles for fun.  He saw they were talking about the same kind of turtle as the one in his zoo.