Dubois never returned to the Dutch East Indies, but his field workers continued to excavate at Trinil until 1900.
Dubois never returned to the Dutch East Indies, but his field workers continued to excavate at Trinil until 1900. Two additional isolated teeth, Trinil 4, a left M2, and Trinil 5, a left P3, were found in 1897, and much later in time Dubois' attention was drawn to four other femoral fossils—a substantial part of the shaft and the much-abraded proximal end, designated Trinil 6, and three femoral shaft fragments, Trinil 7–9, that were “found in a collection of fossil bones acquired from excavations executed at Trinil in 1900”—that were also assigned to P. erectus.12 A fifth femoral shaft fragment was also allocated to P. erectus, but while Dubois noted that it “is certainly not from Trinil,” he suggested there is “some probability” that it comes from Kedung Brubus.13 Prompted by the discovery of OH 28,14 Michael Day and Theya Molleson15 examined all of the Trinil femora (i.e., Trinil 3, 7–9, and the fifth femoral shaft fragment) using radiography and microscopy. They concluded that the fifth femoral shaft fragment “is not hominine, hominid or even primate”,15 p. 151, and expressed doubts about whether the femoral remains from Trinil are the same age as the calotte and the teeth.15 A decade later, Gail Kennedy16 addressed the traditional morphometric affinities of the Trinil femora, with a focus on Trinil 3, in a multivariate analysis. Her conclusion was that “although the Trinil femora demonstrate a few characters, particularly in the lower shaft, similar to those in Homo erectus, their overall pattern unequivocally allies them with the sapient comparative group.” A more sophisticated recent analysis by Chris Ruff and colleagues17 came to the same conclusion, suggesting that Trinil 3 “derives from a much more recent period than the calotte”,17 p. 147. But, Ruff and colleagues also conceded that the Trinil 7–9 femora “may represent H. erectus”,17 p. 147.