World Science

More “little people” fossils found

March 11, 2008
Courtesy Public Library of Science
and World Science staff

Re­search­ers say they have dis­cov­ered more fos­sils of min­ia­ture, is­land-dwelling peo­ple, adding a new twist to the sa­ga of so-called “hob­bit” fos­sils re­ported found in In­do­ne­sia in 2004.

A sci­en­tif­ic de­bate has raged over wheth­er those came from a spe­cies of min­ia­ture hu­ma­n­s—as their disco­verers ar­gued—or just from dis­eased, or­di­nary peo­ple.

A map indicates the relative locations of Flores, Indonesia (lower-left red arrow) and Palau (upper-right red arrow.)

If the form­er were true, this would fit in with the fact that ma­ny spe­cies of an­i­mals al­so evolve in­to small forms on is­lands. But sev­er­al stud­ies have chal­lenged the view that the In­do­ne­sian spec­i­mens rep­re­sent a new spe­cies; for ex­am­ple, a pa­per in the March 5 is­sue of the jour­nal Pro­ceed­ings of the Roy­al So­ci­e­ty B sug­gests the “hob­bits” were in real­ity mal­nour­ished cretins.

The disco­very of ad­di­tion­al, some­what si­m­i­lar fos­sils on oth­er is­lands may both re­new and com­pli­cate the de­bate.

In this week’s is­sue of the re­search jour­nal PLoS One, Lee Berger and col­leagues of the Uni­ver­s­ity of the Wit­wa­ters­rand, South Af­ri­ca, Rut­gers Uni­ver­s­ity and Duke Uni­ver­s­ity in North Car­o­li­na de­scribe new­found fos­sils of lit­tle hu­ma­ns from other is­lands.

They lived 1,400 to 3,000 years ago, ac­cord­ing to the re­search­ers, and share some fea­tures with the ear­li­er spec­i­mens, dubbed Ho­mo flo­re­sien­sis by their disco­verers. The name came from the loca­t­ion of disco­very, In­do­ne­sia’s Flo­res Is­land.

The new find­ings comes in­stead from Palau, an is­land chain in the west­ern cen­tral Pa­cif­ic. Palau con­sists of a main is­land of Ba­bel­daob, with hun­dreds of smaller rock is­lands to the south­west. These con­tain ca­ves and rock shel­ters, ma­ny of which have yielded pre­his­tor­ic hu­man re­mains.

The new spec­i­mens from two such ca­ves, Uche­li­ungs and Ome­dokel, which seem to have been used as bur­i­al sites, re­search­ers said.

Both ca­ves, they added, yielded skele­tons of in­di­vid­u­als who would have been small even rel­a­tive to oth­er such popula­t­ions and are ap­prox­i­mately the size of H. flo­re­sien­sis or small mem­bers of the ge­nus Aus­tra­lo­pith­e­cus. These fos­sils were dat­ed to be­tween 1410 and 2890 years ago. The Ome­dokel cave en­trance al­so con­tained re­mains of larg­er peo­ple dat­ed to around a mil­len­ni­um ago, the re­search­ers said.

These ca­ves have pro­vid­ed and will con­tin­ue to pro­vide a wealth of spec­i­mens, which will need deeper stu­dy, the in­ves­ti­ga­tors added. But pre­lim­i­nar­y anal­y­sis of more than a doz­en in­di­vid­u­als in­clud­ing a male who would have weighed around 43 kg (95 lb) and a female of 29 kg (64 lb) show that these peo­ple “had ma­ny cran­io­fa­cial fea­tures con­sid­ered un­ique to H. sapi­ens,” our spe­cies, re­search­ers said.

“These in­di­vid­u­als are likely to be from a hu­man popula­t­ion who ac­quired re­duced stat­ure, for some rea­son,” the re­search­ers said in an­nounc­ing the find­ing March 10.

“It is well es­tab­lished that popula­t­ions liv­ing on iso­lat­ed is­lands of­ten con­sist of in­di­vid­u­als of smaller stat­ure than their main­land cousin­s—a phe­nom­e­non known as is­land dwarf­ism. This is true not just for hu­ma­ns but for ma­ny an­i­mals in­clud­ing ex­tinct mam­moths and ele­phants from is­lands off Si­be­ria, Cal­i­for­nia and even in the Med­i­ter­ra­nean. Al­ter­na­tively, the is­land may have been col­o­nized by a few small in­di­vid­u­als, be­tween 3,000 and 4,000 years ago who, through ex­ten­sive in­breed­ing, and oth­er en­vi­ron­men­tal drivers, pro­duced a small-bodied popula­t­ion, which con­tin­ued to in­hab­it Palau un­til at least 1,400 years ago.”

As well as hav­ing char­ac­ter­is­tics of H. sapi­ens, the Palau fos­sils al­so have fea­tures seen in H. flo­re­sien­sis, the re­search­ers said.

Berger and col­leagues said they don’t in­fer from these fea­tures any di­rect rela­t­ion­ship be­tween the peo­ples of Palau and Flo­res. How­ev­er, they added, the ob­serva­t­ions do sug­gest that at least some of the fea­tures which have been tak­en as ev­i­dence that the Flo­res in­di­vid­u­als are mem­bers of a sep­a­rate spe­cies, may be a com­mon adapta­t­ion in hu­ma­ns of re­duced stat­ure.

Anal­y­sis of the Palau spec­i­mens probably won’t set­tle ar­gu­ments over the sta­tus of H. flo­re­sien­sis as there are fea­tures of Flo­res ma­n, such as small brain size, not found in the peo­ple of Palau, Berger and col­leagues added. Nev­er­the­less, they said, the find­ings sug­gest that at least some of the un­usu­al fea­tures seen in Flo­res are due to en­vi­ronment rath­er than an­ces­tral her­it­age.

“Above all, the skele­tons from Palau should greatly in­crease our un­der­stand­ing of the pro­cess of is­land dwarf­ism in hu­man popula­t­ions and of the an­cient co­lon­iz­a­tions of Ocea­nia,” the re­search­ers said in their an­nounce­ment. The study was funded by the Na­tional Ge­o­graph­ic So­ci­e­ty Mis­sion Pro­grams. A doc­u­men­ta­ry on the find­ings, “Mys­tery Skulls of Palau,” pre­mieres Mon­day, March 17 at 10 PM on the Na­tional Ge­o­graph­ic Chan­nel in the U.S.