"Long before it's in the papers"
September 10, 2015

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Remote cave chamber yields huge trove of human fossils

Sept. 10, 2015
Courtesy University of the Witwatersrand
and World Science staff

More than 1,550 pieces of fos­sil­ized bone have turned up in a re­mote cave cham­ber in South Af­ri­ca, rep­re­sent­ing what some sci­en­tists say is a pre­vi­ously un­known spe­cies of hu­man.

The spe­cies, dubbed Ho­mo na­le­di, seems to have in­ten­tion­ally put bod­ies of its dead in a re­mote cave cham­ber, mak­ing it per­haps the old­est known case of such a be­hav­ior among hu­mans or their close ev­o­lu­tion­ary rel­a­tives, re­search­ers said.

Fossils attributed to the new species H. naledi. The broad thumb suggests it was an expert climber, scientists say. (Photo courtesy John Hawks/University of Wisconsin-Madison)


The cave cham­ber was so hard to reach that it re­quired re­cruit­ing a team of six very thin sci­en­tists, all wom­en, to get in­side.

Sci­en­tists at the Un­ivers­ity of the Wit­wa­ters­rand in South Af­ri­ca, the Na­t­ional Ge­o­graph­ic So­ci­e­ty and oth­er in­sti­tu­tions an­nounced the find­ings Sept. 10. They are de­scribed in two pa­pers in the re­search jour­nal eLife.

The discovery is the larg­est trove of fos­sil­ized hu­man bones known in Af­ri­ca, re­search­ers said.

But some dis­put­ed wheth­er the bones are def­i­nitely a new spe­cies. “The few ‘u­nique’ fea­tures that po­ten­tially de­fine the new spe­cies need fur­ther scruti­ny,” Chris­toph Zol­likofer, an an­thro­po­l­o­gist at the Un­ivers­ity of Zu­rich, told Britain’s The Guard­i­an news­pa­per. Some sug­gest­ed the fossils look like they come from the al­ready known spe­cies Ho­mo erec­tus.

Ac­cord­ing to the sci­en­tists be­hind the re­port, they first dis­cov­ered the fos­sils in 2013 while work­ing with vol­un­teer ca­vers in a cave known as Ris­ing Star in the Cra­dle of Hu­man­kind World Her­it­age Site, some 50 kilo­me­ters (30 miles) north­west of Jo­han­nes­burg.

The fos­sils, still un­dat­ed, lay in a cham­ber about 90 me­ters (some 100 yards) from the cave en­trance. So far, the team has re­cov­ered parts of at least 15 in­di­vid­u­als of the same spe­cies, a small frac­tion of the fos­sils be­lieved to re­main in the cham­ber.

“With al­most every bone in the body rep­re­sented mul­ti­ple times, Ho­mo naledi is al­ready prac­tic­ally the best-known fos­sil mem­ber of our lin­eage,” said Lee Berger of the Ev­o­lu­tion­ary Stud­ies In­sti­tute at Wits Un­ivers­ity and a Na­t­ional Ge­o­graph­ic Explorer-in-Residence, who led two ex­pe­di­tions that found and re­cov­ered the fos­sils.

H. naledi was named af­ter the Ris­ing Star ca­ve—”naledi” means “s­tar” in Se­so­tho, a South Af­ri­can lan­guage. 

“Over­all, Ho­mo naledi looks like one of the most prim­i­tive mem­bers of our ge­nus,” or evolu­tion­ary branch, said John Hawks of the Un­ivers­ity of Wisconsin-Madison, a sen­ior au­thor on the pa­per de­scrib­ing the new spe­cies. “But it al­so has some sur­pris­ingly hu­man-like fea­tures.” 

H. naledi had a ti­ny brain,” about the size of an or­ange, and a very slen­der body, he added. The re­search found that on av­er­age H. naledi stood about 1.5 me­ters (a­bout 5 feet) tall and weighed about 45 kg (al­most 100 pounds).

H. naledi’s teeth are de­scribed as si­m­i­lar to those of the earliest-known mem­bers of our ge­nus, such as Ho­mo ha­bilis, as are most fea­tures of the skull. The shoul­ders, how­ev­er, are more like those of apes. “The hands sug­gest tool-using ca­pa­bil­i­ties,” said re­search team mem­ber Tra­cy Kiv­ell of the Un­ivers­ity of Kent, U.K. “Sur­pris­ingly, H. naledi has ex­tremely curved fin­gers, more curved than al­most any oth­er spe­cies of early ho­minin, which clearly demon­strates climb­ing ca­pa­bil­i­ties.” Hom­inins are an evo­lution­ary group consist­ing of hu­mans and their close re­la­tives.

This con­trasts with the feet, which are “vir­tually in­dis­tin­guish­able from those of mod­ern hu­mans,” said Wil­liam Harcourt-Smith of Leh­man Col­lege at the City Un­ivers­ity of New York, and the Amer­i­can Mu­se­um of Nat­u­ral His­to­ry, who led the study of the feet. Its feet, com­bined with its long legs, sug­gest that the spe­cies was well suit­ed for long-dis­tance walk­ing. “The com­bina­t­ion of ana tom­i­cal fea­tures in H. naledi dis­tin­guishes it from any pre­vi­ously known spe­cies,” added Berger.

That cave cham­ber has “al­ways been iso­lat­ed from oth­er cham­bers and nev­er been open di­rectly to the sur­face,” said Paul Dirks of James Cook Un­ivers­ity in Queens­land, Aus­tral­ia, lead au­thor of an eLife pa­per on the con­text of the find. “The re­mains were found prac­tic­ally alone in this re­mote cham­ber in the ab­sence of any oth­er ma­jor fos­sil an­i­mals,” one of sev­er­al fea­tures taken as clues that the site served as a bur­i­al place.


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More than 1,550 pieces of fossilized bone have turned up in a remote cave chamber in South Africa, representing what some scientists say is a previously unknown species of human. The species, dubbed Homo naledi, seems to have intentionally put bodies of its dead in a remote cave chamber, making it the oldest known case of such a behavior among humans or their close evolutionary relatives, researchers said. The cave chamber was so hard to reach that it required recruiting a team of six very thin scientists, all women, to get inside. Scientists at the University of the Witwatersrand in South Africa, the National Geographic Society and other institutions announced the findings Sept. 10. They are described in two papers in the research journal eLife. The discovery is the largest trove of fossilized human bones known in Africa, researchers said. But some disputed whether the bones are definitely a new species, suggesting they instead look like they come from the already known species Homo erectus. “The few ‘unique’ features that potentially define the new species need further scrutiny,” Christoph Zollikofer, an anthropologist at the University of Zurich, told Britain’s The Guardian newspaper. According to the scientists behind the report, they first discovered the fossils in 2013 while working with volunteer cavers in a cave known as Rising Star in the Cradle of Humankind World Heritage Site, some 50 kilometers (30 miles) northwest of Johannesburg. The fossils, still undated, lay in a chamber about 90 meters (some 100 yards) from the cave entrance. So far, the team has recovered parts of at least 15 individuals of the same species, a small fraction of the fossils believed to remain in the chamber. “With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” said Lee Berger of the Evolutionary Studies Institute at Wits University and a National Geographic Explorer-in-Residence, who led two expeditions that found and recovered the fossils. H. naledi was named after the Rising Star cave—”naledi” means “star” in Sesotho, a South African language. “Overall, Homo naledi looks like one of the most primitive members of our genus, but it also has some surprisingly human-like features, enough to warrant placing it in the genus Homo,” said John Hawks of the University of Wisconsin-Madison, a senior author on the paper describing the new species. “H. naledi had a tiny brain, about the size of an average orange (about 500 cubic centimeters), perched atop a very slender body.” The research shows that on average H. naledi stood approximately 1.5 meters (about 5 feet) tall and weighed about 45 kilograms (almost 100 pounds). H. naledi’s teeth are described as similar to those of the earliest-known members of our genus, such as Homo habilis, as are most features of the skull. The shoulders, however, are more like those of apes. “The hands suggest tool-using capabilities,” said research team member Tracy Kivell of the University of Kent, U.K.. “Surprisingly, H. naledi has extremely curved fingers, more curved than almost any other species of early hominin, which clearly demonstrates climbing capabilities.” This contrasts with the feet, which are “virtually indistinguishable from those of modern humans,” said William Harcourt-Smith of Lehman College, City University of New York, and the American Museum of Natural History, who led the study of H. naledi’s feet. Its feet, combined with its long legs, suggest that the species was well suited for long-distance walking. “The combination of anatomical features in H. naledi distinguishes it from any previously known species,” added Berger. That cave chamber has “always been isolated from other chambers and never been open directly to the surface,” said Paul Dirks of James Cook University in Queensland, Australia, lead author of the eLife paper on the context of the find. “The remains were found practically alone in this remote chamber in the absence of any other major fossil animals,” one of several clues that the site served as a burial place.