Simplify the following text for a Grade 9 native English-speaking person.
Original: Paranthropus boisei was discovered by Mary Leakey on July 17 , 1959 , at the FLK Bed I site of Olduvai Gorge in Tanzania ( specimen OH 5 ) .
Simplified: Paranthropus boisei was discovered by Mary Leakey in July 1959 at the site of Olduvai Gorge in Tanzania .