| Homo naledi | |
|---|---|
 | |
| The 737 known elements ofH. naledi | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorhini |
| Family: | Hominidae |
| Genus: | Homo |
| Species: | †H. naledi |
| Binomial name | |
| †Homo naledi Berger et al., 2015 | |
  Rising Star Cave Rising Star Cave (South Africa) Show map of South Africa Rising Star Cave Rising Star Cave (Greater Johannesburg) Show map of Greater Johannesburg | |
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| Location ofRising Star Cave inCradle of Humankind,South Africa. | |
Homo naledi is anextinctspecies ofarchaic human discovered in 2013 in theRising Star Cave system,Gauteng province, South Africa, part of theCradle of Humankind, dating back to theMiddle Pleistocene 335,000–236,000 years ago. The initial discovery comprises 1,550 specimens of bone, representing 737 different skeletal elements, and at least 15 different individuals. Despite this exceptionally high number of specimens, their classification with otherHomo species remains unclear.
Along with similarities to contemporaryHomo, they share several characteristics with the ancestralAustralopithecus as well as earlyHomo (mosaic evolution), most notably a small cranial capacity of 465–610 cm3 (28.4–37.2 cu in), compared with 1,270–1,330 cm3 (78–81 cu in) in modern humans. They are estimated to have averaged 143.6 cm (4 ft 9 in) in height and 39.7 kg (88 lb) in weight, yielding a small relative brain size,encephalization quotient, of 4.5.H. naledi brain anatomy seems to have been similar to contemporaryHomo, which could indicate comparable cognitive complexity. The persistence of small-brained humans for so long in the midst of bigger-brained contemporaries revises the previous conception that a larger brain would necessarily lead to an evolutionary advantage, and their mosaic anatomy greatly expands the known range of variation for the genus.
H. naledi anatomy indicates that, although they were capable of long-distance travel with a humanlike stride and gait, they were morearboreal than otherHomo, better adapted to climbing andsuspensory behaviour in trees thanendurance running. Tooth anatomy suggests consumption of gritty foods covered in particulates such as dust or dirt, suggesting a diet of nuts and tubers.[2]
Although they have not been associated with stone tools or any indication of material culture, they appear to have been dexterous enough to produce and handle tools, and therefore may have manufacturedEarly orMiddle Stone Ageindustries found in excavations near their fossils, since no other human species in the vicinity at that time has been discovered. It has also been controversially postulated that these individuals were buried deliberately by being carried into and placed in the chamber. Some researchers suggest thatH. naledi also may have carved crosshatched rock signs in a passage to what could be a burial chamber, but many paleontologists question this hypothesis.
On 13 September 2013 while exploring theRising Star Cave system in theCradle of Humankind, South Africa, cavers Rick Hunter and Steven Tucker foundhominin fossils at the bottom of theDinaledi Chamber.[3] On 24 September, they returned to the chamber and took photographs that they showed to South Africanpalaeoanthropologists Pedro Boshoff andLee Rogers Berger on 1 October.[3] Berger assembled an excavation team that included Hunter and Tucker, the so-called "Underground Astronauts".[4]
The chamber had been entered at least once before, by cavers in the early 1990s. They rearranged some bones and may have caused further damage, although much of the floor in the chamber had not been walked on prior to 2013.[5] The site lies about 80 m (260 ft) from the main entrance, at the bottom of a 12 m (39 ft) vertical drop, and the 10 m (33 ft) long main passage is only 25–50 cm (10 in – 1 ft 8 in) at its narrowest.[5] In total, more than 1,550 pieces of bone belonging to at least fifteen individuals (9 immature and 6 adults)[6] have been recovered from theclay-rich sediments. Berger and colleagues published the findings in 2015.[7]
The fossils represent 737 anatomical elements – including portions of the skull, jaw, ribs, teeth, limbs, and inner ear bones – from old, adult, young, and infantile individuals. There are also somearticulated or near-articulated elements, including the skull with the jaw bone, and nearly complete hands and feet.[7][5] With the number of individuals of both genders across several age demographics, it then became the richest assemblage of associated fossil hominins discovered in Africa. Aside from theSima de los Huesos collection and laterNeanderthal and modern human samples, the excavation site has the most comprehensive representation of skeletal elements across the lifespan, and from multiple individuals, in the hominin fossil record by that time.[7]
Theholotype specimen, DH1, comprises a male partialcalvaria (top of the skull), partialmaxilla, and nearly completejawbone. Theparatypes, DH2 through DH5, all comprise partial calvaria. Because the remains came from Rising Star Cave, in 2015, Berger and colleagues named the speciesHomo naledi with the specific name meaning "star" in theSotho language.[7]
The remains of at least three additional individuals (two adults and a child) were reported in the Lesedi Chamber of the cave byJohn Hawks and colleagues in 2017.[8]
In 2017, the Dinaledi remains were dated to 335,000–236,000 years ago in theMiddle Pleistocene, usingelectron spin resonance (ESR) anduranium–thorium (U-Th) dating on three teeth, and U-Th andpaleomagnetic dating of the sediments they were deposited in.[1] Previously, the fossils were thought to have dated to 1–2 million years ago,[7][9][10][4] because no similarly small-brained hominins had been known from such a recent date in Africa.[11] The smaller-brainedHomo floresiensis of Indonesia lived on an isolated island and, apparently, became extinct shortly after the arrival of modern humans.[12]
The ability of such a small-brained hominin to have survived for so long in the midst of bigger-brainedHomo has greatly revised previous conceptions ofhuman evolution and the notion that a larger brain would necessarily lead to an evolutionary advantage.[11] Their mosaic anatomy also greatly expands the range of variation for the genus.[13]
H. naledi is hypothesised to have branched off very early from contemporaneousHomo. It is unclear whether they branched off at approximately the time ofH. habilis,H. rudolfensis, andA. sediba, are asister taxon toH. erectus and the contemporaneous large-brainedHomo, or are a sister taxon to the descendants ofH. heidelbergensis (modern humans and Neanderthals). This places the branching from contemporaryHomo in a range of time from as early as thePliocene to 900,000 years ago at the latest. It is also possible that their ancestors speciated after an interbreeding event betweenHomo and late australopithecines.[11] Comparison of skull features reveals thatH. naledi has the closestaffinities toH. erectus.[13]
It is unclear whether theseH. naledi were an isolated population in the Cradle of Humankind, or were ranged across Africa. If the latter, then severalgracile hominin fossils from African sites that traditionally have been classified as lateH. erectus might instead representH. naledi specimens.[14]
Although earlier study placedH. naledi as a late offshoot fromH. erectus in the phylogenetic tree,[15] the recent study placesH. naledi as an early offshoot fromH. erectus in the phylogenetic tree.[16]
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Two maleH. naledi skulls from the Dinaledi chamber had cranial volumes of approximately 560 cm3 (34 cu in), and two female skulls 465 cm3 (28.4 cu in). A maleH. naledi skull from the Lesedi chamber had a cranial volume of 610 cm3 (37 cu in). The Dinaledi specimens are more similar to the cranial capacity of australopithecines. For comparison,H. erectus averaged approximately 900 cm3 (55 cu in),[8] and modern humans 1,270 and 1,130 cm3 (78 and 69 cu in) for males and females respectively.[17] The Lesedi specimen is more within the range ofH. habilis andH. e. georgicus. Theencephalization quotient ofH. naledi was estimated at 3.75, which is the same as the pygmyH. floresiensis, but notably smaller than all otherHomo. ContemporaryHomo were all above 6,H. e. georgicus at 3.55, andA. africanus at 3.81.[18] It is unclear whetherH. naledi inherited small brain size from the last commonHomo ancestor, or whether it was evolved secondarily and more recently.[19]
The skull morphology is more similar toHomo, with a slenderer shape, theasymmetry in both thetemporal andoccipital lobes of the brain, and reducedpost-orbital constriction, with the skull not becoming narrower behind the eye-sockets.[7][19] Thefrontal lobe morphology is more or less the same in allHomo brains despite size, and differs fromAustralopithecus, a characteristic that has been implicated in the production of tools, the development of language, and sociality.[19]
Similarly to modern humans (but not to fossil hominins, including South African australopithecines,H. erectus, and Neanderthals) the permanent second molar ofH. naledi erupted comparatively late in life, emerging alongside the premolars instead of before, a characteristic that indicates a slower maturation unusually comparable to modern humans.[20] The tooth formation rate of the front teeth is also most similar to modern humans.[21] The overall size and shape of the molars most closely resemble those of three unidentifiedHomo specimens from the localSwartkrans and East AfricanKoobi Fora Caves, and are similar in size (but not shape) to PleistoceneH. sapiens. The necks of the molars are proportionally similar to those ofA. afarensis andParanthropus.[22]
Unlike modern humans and contemporaryHomo,H. naledi lacks several accessory dental features, and has a high frequency of individuals who present maincusps, namely themetacone (midline on the tongue-side) andhypocone (to the right on the lip-side) on the second and third molars, and a Y-shaped hypoconulid (a ridge on the lip-side toward the cheek) on all three molars.[23] The premolars ofH. naledi are characterised by a well-developed P3 and P4 metaconid, strongly developed P3 mesial marginal ridge, a larger P3 than P4, and tall crowns, distinguishing them from the premolars of otherHomo species.[24] Nonetheless,H. naledi also has many dental similarities with contemporaryHomo.[23]
Theanvil (amiddle ear bone) more resembles those of chimps, gorillas, andParanthropus thanHomo.[25] LikeH. habilis andH. erectus,H. naledi has a well-developed brow-ridge with a fissure stretching across just above the ridge and, likeH. erectus, a pronouncedoccipital bun.H. naledi has some facial similarities withH. rudolfensis.[23]
TheH. naledi specimens are estimated to have, on average, stood approximately 143.6 cm (4 ft 9 in) and weighed 39.7 kg (88 lb). This body mass is intermediate between what is typically seen inAustralopithecus andHomo species. Like otherHomo, female and maleH. naledi were likely about the same size, males on average about 20% larger than females.[18] A juvenile specimen, DH7, is skeletally consistent with a growth rate similar to the faster ape-like trajectories of MH1 (A. sediba) andTurkana boy (H. ergaster). Because dental development is so similar to that of modern humans, a slower maturation rate is not completely out of the question. Using the faster growth rate, DH7 would have died at 8–11 years old, but using the slower growth, DH7 would have died at 11–15 years old.[26]
Concerning thespine, only the tenth and elevenththoracic vertebrae (in the chest region) are preserved from presumably a single individual, which are proportionally similar to those of contemporaryHomo, although being the smallest recorded of any hominin. The two transverse processes of the vertebra, which jut out diagonally, are most similar to those of Neanderthals. Theneural canals within are proportionally large, similar to modern humans, Neanderthals, andH. e. georgicus. The eleventh rib is straight like that ofA. afarensis, and the twelfth rib is robust in cross-section like that of Neanderthals. Like Neanderthals, the twelfth rib appears to have supported strongintercostal muscles above, and a strongquadratus lumborum muscle below. Unlike Neanderthals, there was weak attachment to thediaphragm. Overall, thisH. naledi specimen appears to have been small-bodied compared with otherHomo species, although it is unclear whether this single specimen is representative of the species.[27]
The shoulders are more similar to those of australopithecines, with theshoulder blade situated higher on the back and farther from the midline, shortclavicles, and little or no humeral torsion.[7] Elevated shoulder and clavicle bones indicate a narrow chest.[27] Thepelvis and legs have features reminiscent ofAustralopithecus, including anterposteriorly compressed (from front to back)femoral necks, mediolaterally compressed (from left to right)tibiae, and a somewhat circularfibular neck;[28][29] which indicate a wide abdomen. This combination would preclude efficientendurance running inH. naledi, unlikeH. erectus and descendants. Instead,H. naledi appears to have been morearboreal.[27]
Themetacarpal bone of the thumb, which is used in holding and manipulating large objects, was well-developed and had strong crests to support itsopponens pollicis muscle used in precision-pinch gripping, and itsthenar muscles. This is more similar to otherHomo thanAustralopithecus.H. naledi appears to have had strongflexor pollicis longus muscles like modern humans, with humanlike palm and finger pads, which are important for forceful gripping between the thumb and fingers. UnlikeHomo, theH. naledi thumb metacarpal joint is comparably small, relative to the thumb's length, and the thumbphalangeal joint is flattened. The distal thumb phalanx bone is robust, and proportionally more similar to those ofH. habilis andP. robustus.[30]
The metacarpals of the other fingers share adaptations with modern humans and Neanderthals to be able to cup and manipulate objects, and thewrist joint is broadly similar to that of modern humans and Neanderthals. Conversely, the proximal phalanges are curved and are almost identical to those ofA. afarensis andH. habilis, which is interpreted as an adaptation for climbing andsuspensory behaviour. Such curvature is more pronounced in adults than juveniles, suggesting that adults climbed just as much or more so than juveniles, and this behaviour was common. The fingers are proportionally longer than those of any other fossil hominin, other than the arborealArdipithecus ramidus and a modern human specimen fromQafzeh cave, Israel, which is consistent with climbing behaviour.[30]
H. naledi was abiped and stood upright.[7] Like otherHomo, they had stronginsertion for thegluteus muscles, well-definedlinea aspera (a ridge running down the back of the femur), thickpatellae, long tibiae, and gracile fibulae. These indicate that they were capable of long-distance travel.[29] TheH. naledi foot was similar to that of modern humans and otherHomo, with adaptations forbipedalism and a humanlike gait. Theheel bone has a low orientation, comparable to those of non-human great apes, and theankle bone has a low declination, which possibly indicate the foot would have been subtly stiffer during the stance phase of walking before the foot pushed off the ground.[31]
The adult rightmandible U.W. 101-1142 has a bony lesion, suggestive of abenign tumour. The individual would have experienced some swelling and localised discomfort, but the tumour's position near themedial pterygoid muscle (likely causing discomfort on the jaw hinge) may have impeded function of the muscle, and changed elevation of the right side of the jaw.[32]
Dental defects inH. naledi specimens during 1.6–2.8 and 4.3–7.6 months of development were most likely caused by seasonal stressors. This may have been due to extreme summer and winter temperatures causing food scarcity. Minimum winter temperatures of the area average about 3 °C (37 °F), and can drop below freezing. Staying warm for an infant of the small-bodiedH. naledi would have been difficult, and winters likely increased susceptibility to respiratory diseases. Environmental stressors are consistent with present-dayflu seasons in South Africa peaking during winter, and paediatricdiarrhoea hospitalisation being most frequent at the height of the rainy season in summer.[33]
Local hominins were likely preyed upon by large carnivores, such as lions, leopards, and hyaenas. There seems to be a distinct paucity of large carnivore remains from the northern end of the Cradle of Humankind, where Rising Star Cave is located, possibly because carnivores preferred the Blaaubank River to the south that may have offered better hunting grounds with a greater abundance of large prey items. Alternatively, because many more sites are known in the south than the north, carnivore spatial patterns may not be well-represented by the fossil record (preservation bias).[34]
Dental chipping and wearing indicates the habitual consumption of small hard objects, such as dirt and dust, and cup-shaped wearing on the back teeth may have stemmed from gritty particles. These could have originated from unwashed roots and tubers. Alternatively, aridity could have stirred up particulates onto food items, coating food in dust. It is possible that they commonly ate larger hard items, such as seeds and nuts, but these were processed into smaller pieces before consumption.[35][36]
H. naledi occupied a seemingly uniqueecological niche from previous South African hominins, includingAustralopithecus andParanthropus. The teeth of all three species indicate that they needed to exert high shearing force to chew through perhaps plant or muscle fibres. The teeth of otherHomo cannot produce such high forces perhaps due to the use of some food processing techniques, such as cooking.[35]
H. naledi could have producedEarly Stone Age (Acheulean and possibly the earlierOldowan) orMiddle Stone Ageindustries because they have the same adaptations to the hand as other human species that are implicated in tool production.[11][18]H. naledi is the only identified human species to have existed during the early Middle Stone Age of theHighveld region, South Africa, possibly indicating that this species manufactured and maintained this tradition at least during this time period. In this scenario, such industries and stone cutting techniques would have evolved independently several times among differentHomo species and populations, or were transported over long distances by the inventors or apprentices and taught.[11]
Since the first publication of results from the Dinaledi Chamber, there has been scholarly debate on whether the fossils excavated from the cave provide evidence ofH. naledi engaging in intentional burial activity. If proven true, Dinaledi Chamber would be the oldest known hominin burial, beating out the c. 78,000 year oldH. sapiens burial fromPanga ya Saidi cave in Kenya by some 160,000 years.[37][38][39] However, a lack of proof regarding thetaphonomic,stratigraphic, andmineralogical claims made by the excavators has caused significant academic backlash.
In 2015, excavating archaeologists Paul Dirks, Lee Berger, and their colleagues concluded that the bodies had to have been deliberately carried and placed into the chamber by people because they appear to have been intact when they were first deposited in the chamber. They found no evidence of trauma from being dropped into the chamber nor evidence of predation. Furthermore, the chamber is inaccessible to large predators, appears to be an isolated system, and has never been flooded. There is no hidden shaft through which people could have accidentally fallen in, and there is no evidence of some catastrophe that killed all the individuals inside the chamber. The excavating team stated that it is possible that the bodies were dropped down a chute and fell slowly due to the narrowness and irregularity of the path down. Thus, they concluded that, since natural forces were apparently not at play, the bodies must have been deliberately buried. Since the cave is unlit, those burying them would have required artificial light to navigate the cave. The archaeologists have reported finding evidence for fire which may support this claim, yet they have not published it as of July 2024.[40] The excavators claim that the site was used repeatedly for burials since the bodies were not all deposited at the same time.[41]
In 2016, paleoanthropologist Aurore Val countered that discounting natural forces for depositing the bodies is unjustified. She identified evidence of damage done by beetles, beetle larvae, and snails, which facilitate decomposition. Since the chamber does not present ideal conditions for snails and does not contain snail shells, she argued that decomposition began before deposition in the chamber, potentially discounting the excavators' claims of intentional burial.[42] Invertebrate damage to the fossils was later confirmed by a 2021 analysis of a fragmentary skull, although this analysis also concludes that it is likely that "some" hominin agency was involved in the deposition of the bone fragments.[43]
In 2017, Dirks, Berger, and colleagues reaffirmed that there is no evidence of water flow into the cave and that it is more likely that the bodies were deliberately deposited into the chamber. They theorized that as it is possible that theH. naledi bones were deposited by contemporaryHomo, such as the ancestors of modern humans, rather than otherH. naledi, but that the cultural behavior of burial practices is not impossible forH. naledi. They proposed that placement in the chamber may have been done to remove decaying bodies from a settlement, prevent scavengers, or as a consequence of social bonding and grief.[44]
In 2018, anthropologist Charles Egeland and colleagues echoed Val's arguments and stated that there is insufficient evidence to conclude that such an early hominid species had developed a concept ofafterlife as often associated with burials. They said that the preservation of the Dinaledi individuals is similar to those of baboon carcasses that accumulate in larger caves, either by natural death of cave-dwelling baboons or by a leopard dragging carcasses into caves.[45]
Between July and September 2025, Berger and colleagues officially published three peer-reviewed papers presenting possible evidence supporting thatH. naledi buried their dead near carvings on the cave walls, which include geometrical shapes and a symbol composed of two cross-hatching equal signs.[46][47][48] Back in 2023, when Berger and colleagues published the three papers without peer review aspreprints,[49][50][51] critics argued that Berger et al. exploitedeLife's new preprint publication model to garner attention and initial reviewer statements were highly critical.[52][53][54] Other paleoanthropologists such as Michael Petraglia criticized the causative link between theH. naledi fossils and the incisions, pointing out that, without dating,correlation is not causation.[55][56][57]
In 2025, the paleoanthropologists Kimberly K. Foecke, Alain Queffelec and Robyn Pickering found the data analysis of "Evidence for deliberate burial of the dead byHomo naledi" to be "heavily influenced by a presupposed narrative" and published a paper to criticize the preprint's faulty statistical methods. A primary concern is that Berger's original geochemical soil analyses purported to show a difference between the soil directly surrounding the fossils and further away as evidence that the ground had been dug up, presumably to bury the bodies. Foecke, Queffelec & Pickering (2025) reanalyzed the data in the pre-prints regarding the soil and were unable to replicate Berger's findings, thus undermining a key piece of evidence in the burial hypothesis.[58][59]
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