There's NO missing link in Human evolution
In September 1890, Eugene Dubois's workers found a human, or human-like, fossil at Koedoeng Broeboes. This consisted of the right side of the chin of a lower jaw and three attached teeth. In August 1891 he found a primate molar tooth. Two months later and one meter away was found an intact skullcap, the fossil which would be known as Java Man. In August 1892, a third primate fossil, an almost complete left thigh bone, was found between 10 and 15 meters away from the skullcap.
In 1894 Dubois published a description of his fossils, naming them Pithecanthropus erectus, describing it as neither ape nor human, but something intermediate.
Java Man, especially if reconstructed with gibbon-like body proportions, had an index of 1/2, which placed it nicely in the gap between apes and humans, thus providing the missing link. (Gould 1993)