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PLoS One completely surprised me today by releasing this paper, “Small-Bodied Humans from Palau, Micronesia.” The research comes from South African and American researchers, and the paper was edited by John Hawks, who apparently can really keep a secret it seems. I had no idea about this study and find it a really remarkable find since fossils of another small bodied human, Homo floresiensis, were found about 1,000 miles south of these new findings.

If I read this correctly, a minimum of 25 individuals have been found. Lots more will be found according the authors, which is always welcoming to me. The Palau fossils are of small peopleOR-15:18-001 and B:OR-14:8-005, similar in size to the Flores hominins. Preliminary analysis of more than a dozen individuals, including a male weighing about 43 kg and a female weighing about 29 kg, document that these were tiny. Analyzing some of the cranial and dental features like the distinct presence of a maxillary canine fossa, a clearly delimited mandibular mental trigone, moderate bossing of the frontal and parietal squama, a lateral prominence on the temporal mastoid process, reduced temporal juxtamastoid eminences and an en maison cranial vault profile with the greatest interparietal breadth high on the vault indicates that these individuals were simply small H. sapiens adapted for life on a small island.

So how were these bones found? Lead author, Lee Berger, writes to National Geographic News that he was kayaking around rocky islands about 370 miles east of the Philippines, when he found the bones in a pair of caves in 2006. Crazy story! I wish I would find something like that while vacationing. He reports that the,

“the [Ucheliungs and Omedokel] caves were littered with bones that had been dislodged by waves and piled like driftwood. Others had remained buried deep in the sandy floor, and more, including several skulls, were cemented to the cave walls.”

Radiocarbon dating was applied to pinpoint an age for the bones. The antiquity of the bones is between 1,410 and 2,890 years ago, which is remarkably much more recent than 18,000 year old antiquity of the Flores hominins. Along with the small size, the Palau fossils have similar features to H. floresiensis, such as their pronounced supraorbital tori, non-projecting chins, relative megadontia, expansion of the occlusal surface of the premolars, rotation of teeth within the maxilla and mandible, and dental agenesis.

But again, Berger and colleagues do not infer from these features any direct relationship between the peoples of Palau and Flores; however, they conservatively write that these similarities may be a common adaptation in humans of reduced stature. In their own words,

“Based on the evidence from Palau, we hypothesize that reduction in the size of the face and chin, large dental size and other features noted here may in some cases be correlates of extreme body size reduction in H. sapiens. These features when seen in Flores may be best explained as correlates of small body size in an island adaptation, regardless of taxonomic affinity. Under any circumstances the Palauan sample supports at least the possibility that the Flores hominins are simply an island adapted population of H. sapiens, perhaps with some individuals expressing congenital abnormalities.”

Again the paper is published in PLoS One, which is an open access journal. That means you can download the original report and read it for yourself for free. I really recommend you do, this seems like one of the more significant paleoanthropological finds for 2008. Here’s the citation:

    Berger, L.R., Churchill, S.E., De Klerk, B., Quinn, R.L., Hawks, J. (2008). Small-Bodied Humans from Palau, Micronesia. PLoS ONE, 3(3), e1780. DOI: 10.1371/journal.pone.0001780