The recently discovered Late Pleistocene dwarf hominid remains (designated Homo floresiensis) from Liang Bua Cave, Flores Island, Indonesia (Brown et al. 2004) is associated with Palaeolithic artifacts and a vertebrate faunal assemblage (Morwood et al. 2004). They follow previous discoveries of Palaeolithic artefacts and early Mid-Pleistocene fauna from the Soa Basin (Morwood et al. 1999, Sondaar et al. 1994).
Liang Bua Cave contains remains of small to medium-sized species such as birds, fish, reptiles, frogs, rodents and bats. Large vertebrates include tortoise, Komodo dragons and other large varanids, and Stegodon (a primitive elephant). Pleistocene stegodonts are commonly found in Island Southeast Asia (Allen 1991: Table 3), but conclusive indications of their associations and possible exploitation by Palaeolithic humans are scarce (Allen 1991: 256-257). No evidence of anthropogenic butchering marks has turned up so far from the Soa Basin (van den Bergh et al. 2001: 626). In contrast, the Mid-Pleistocene deposits from Dadong Cave, Guizhou Province, Southwest China, comes from an occupation context which indicates human exploitation of these elephantoids (Bekken et al. 2004).
Liang Bua Cave stands out for two remarkable findings: the first scientifically reported discovery of Pleistocene dwarf humans and a reported association of dwarf Stegodon remains, which establishes co-existence with humans (Morwood et al. 2004). The dwarf Stegodon remains (no species designated) are described, without fanfare, as an assemblage dominated by juvenile individuals. However, a Late Pleistocene dwarf Stegodon species from Flores is news indeed and calls for further clarification.
The present understanding of the succession of Stegodon species on Flores is that endemic dwarfs, represented by the Early Pleistocene species Stegodon sondaarii (from the Ola Bula Formation and Kopo Watu), became extinct by around 840 kyr (van den Bergh et al. 2001). These dwarf forms were then replaced by the medium to large-sized S. florensis, a species closely related to the S. trigonocephalus group found in Java and Wallacea islands. Thus, dwarf stegodonts became extinct before the proposed early Mid-Pleistocene peopling of Flores (Morwood 1998) and the species to co-exist with any human population on Flores should have been the normal sized Stegodon florensis. Therefore, the report that a dwarf species of Stegodon co-existed with Mid-Pleistocene hominids on Flores well after the extinction of S. sondarii is either low-key reporting at its most extreme or an error.
Dwarf endemism on Flores and other Lesser Sunda Islands may have been a recurrent phenomenon throughout the Pleistocene. Consequently, the discovery of a new dwarf Stegodon species from Liang Bua, if confirmed, deserves more than passing mention. In view of its potential biogeographic importance, the significance of finding yet another dwarf species on Flores should have been made apparent in the Morwood et al. (2004) report. Ideally, it should be reported in full as a separate paper.
However, the fact that so little is made of this recent discovery leaves us wondering if the Stegodon remains associated with the hominid remains were really of dwarf form. Perhaps dwarf Stegodons were found in the deposit from earlier horizons but the juvenile remains found in the upper sectors came from a normal sized population. Vagueness regarding species designation of the Stegodon remains simply reinforce this uncertainty. Dwarf Homo hunting dwarf Stegodon sounds plausible and even a little romantic, but is it correct?
The contradiction between the existing Pleistocene record of Stegodon on Flores and the report on the archaeological discoveries at Liang Bua made by Morwood et al. (2004) calls for clarification. Although understandably overshadowed by the astonishing finds of dwarf hominids persisting into the Late Pleistocene, correct and clear reporting of associated fauna should not be sacrificed. While other questions may remain regarding the dating and association of artefacts at this site, and with the taxonomy of the hominin material reported, the ambiguous nature of the information provided on the Stegodon remains is certainly troubling.
