Sartono (1980) summarizes his taxonomic reassessment of the Indonesian hominin fossils by stating “Recently, a reappraisal has been carried out on the taxonomic status of the Javanese Pleistocene hominids which suggests the existence of one genus of Homo only consisting of two species, these are Homo erectus (the former Pithecanthropus ) and Homo palaeojavanicus (the former Meganthropus palaeojavanicus ) (Sartono 1975b, 1976). Each of these species again consists of two subspecies. They are Homo erectus ngandongensis and Homo erectus trinilensis, while the second species comprises Homo palaeojavanicus sangiranensis and Homo palaeojavanicus modjokertensis (fig. 6a). If the various subspecies of the Pleistocene man are put in their respective stratigraphic positions, then the following scheme will be obtained, i.e. the progressive Homo erectus ngandongensis with the larger brain and fragile mandible was the late one evolving from the earlier primitive Homo erectus trinilensis having a smaller brain volume but a more robust mandible. This latter in turn may evolve from the earlier Homo palaeojavanicus modjokertensis with the more fragile mandibles than the more robust mandible of the earliest Homo palaeojavanicus sangiranensis (Sartono 1976 fig. 12, 1979a fig. 2)” (p. 125-126).
These taxonomic remarks are then qualified in the very next paragraph where Sartono (1980) states, “Author admits that the above taxonomic scheme is not a final one. Future discoveries on the Javanese Pleistocene hominids will surely add more to our knowledge of these early men.” (p. 126)
This last sentence appears to indicate a conditional taxonomic proposal, and thus the subspecies name “trinilensis” is unavailable.