Original: He first described the species as Pithecanthropus erectus ( '' upright ape-man '' ) , based on a calotte ( skullcap ) and a modern-looking femur found from the bank of the Solo River at Trinil , in East Java .
Simplified: Dutch anatomist Eugene Dubois ( 1890s ) first described it as Pithecanthropus erectus , based on a skullcap and a modern-looking thighbone found from the bank of the Solo River at Trinil , in Java .