The_skull_of_Homo_naledi.pdf

The skull of Homo naledi
Myra F. Laird a, b, *
, Lauren Schroeder b, c, d, e
, Heather M. Garvin b, f, g
, Jill E. Scott b, h, i
,
Mana Dembo b, j, k
, Davorka Radov
ci
c b, l
, Charles M. Musiba b, m
, Rebecca R. Ackermann d, e
,
Peter Schmid b, n
, John Hawks b, o
, Lee R. Berger b
, Darryl J. de Ruiter b, p, **
a
Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
b
Evolutionary Studies Institute and Centre for Excellence in PaleoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
c
Department of Anthropology, University at Buffalo, SUNY, NY 14261, USA
d
Department of Archaeology, University of Cape Town, Rondebosch 7701, South Africa
e
Human Evolution Research Institute, University of Cape Town, Rondebosch 7701, South Africa
f
Department of Applied Forensic Sciences, Mercyhurst University, Erie, PA 16546, USA
g
Department of Anthropology/Archaeology, Mercyhurst University, Erie, PA 16546, USA
h
Department of Anthropology, The University of Iowa, Iowa City, IA 52242, USA
i
Department of Sociology and Anthropology, Metropolitan State University of Denver, CO 80217, USA
j
Department of Archaeology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
k
Human Evolutionary Studies Program, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
l
Department of Geology and Paleontology, Croatian Natural History Museum, Demetrova 1, 10000 Zagreb, Croatia
m
Department of Anthropology, University of Colorado Denver, CO 80217, USA
n
Anthropological Institute and Museum, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
o
Department of Anthropology, University of Wisconsin e Madison, Madison, WI 53593, USA
p
Department of Anthropology, Texas AM University, College Station, TX 77843, USA
a r t i c l e i n f o
Article history:
Received 9 September 2015
Accepted 15 September 2016
Available online xxx
Keywords:
Cranial and mandibular variation
Dinaledi
South Africa
Homo
Rising Star cave system
a b s t r a c t
The species Homo naledi was recently named from specimens recovered from the Dinaledi Chamber of
the Rising Star cave system in South Africa. This large skeletal sample lacks associated faunal material
and currently does not have a known chronological context. In this paper, we present comprehensive
descriptions and metric comparisons of the recovered cranial and mandibular material. We describe 41
elements attributed to Dinaledi Hominin (DH1eDH5) individuals and paratype U.W. 101-377, and 32
additional cranial fragments. The H. naledi material was compared to Plio-Pleistocene fossil hominins
using qualitative and quantitative analyses including over 100 linear measurements and ratios. We ﬁnd
that the Dinaledi cranial sample represents an anatomically homogeneous population that expands the
range of morphological variation attributable to the genus Homo. Despite a relatively small cranial ca-
pacity that is within the range of australopiths and a few specimens of early Homo, H. naledi shares
cranial characters with species across the genus Homo, including Homo habilis, Homo rudolfensis, Homo
erectus, and Middle Pleistocene Homo. These include aspects of cranial form, facial morphology, and
mandibular anatomy. However, the skull of H. naledi is readily distinguishable from existing species of
Homo in both qualitative and quantitative assessments. Since H. naledi is currently undated, we discuss
the evolutionary implications of its cranial morphology in a range of chronological frameworks. Finally,
we designate a sixth Dinaledi Hominin (DH6) individual based on a juvenile mandible.
© 2016 Elsevier Ltd. All rights reserved.
1. Introduction
The evolution of Homo has been challenging to interpret, both in
eastern Africa, where the majority of early Homo fossils have been
discovered, and in southern Africa (e.g., Broom and Robinson, 1949;
Leakey et al., 1964; Hughes and Tobias, 1977; Tobias, 1991; Wood,
1991; Asfaw et al., 1999; Spoor et al., 2007; Ant
on, 2012).
Recently, several crania and mandibles in varying states of
completeness were recovered from the Dinaledi Chamber in the
Rising Star cave system of South Africa and attributed to the novel
species Homo naledi (Berger et al., 2015). Individuals from the
sample range in age from neonate to older adult and most areas of
* Corresponding author.
** Corresponding author.
E-mail addresses: lairdm@uchicago.edu (M.F. Laird), deruiter@tamu.edu
(D.J. de Ruiter).
Contents lists available at ScienceDirect
Journal of Human Evolution
journal homepage: www.elsevier.com/locate/jhevol
http://dx.doi.org/10.1016/j.jhevol.2016.09.009
0047-2484/© 2016 Elsevier Ltd. All rights reserved.
Journal of Human Evolution xxx (2016) 1e24
Please cite this article in press as: Laird, M.F., et al., The skull of Homo naledi, Journal of Human Evolution (2016), http://dx.doi.org/10.1016/
j.jhevol.2016.09.009

the cranium are represented, with the exception of the mid-facial
region and basicranium.
The Dinaledi assemblage was found in a dolomitic cavern within
the Rising Star cave system located near the sites of Swartkrans and
Sterkfontein (Berger et al., 2015). The geological age of the Dinaledi
assemblage is presently unknown, and there are no associated
faunal remains or archaeological traces (Dirks et al., 2015).
Although the majority of fossils were disarticulated and com-
mingled, some elements were discovered in anatomical articula-
tion, indicating that initial deposition occured prior to or during
early stages of decomposition (Dirks et al., 2015). The Dinaledi
cranial remains, similar to the overall assemblage, experienced
limited post-depositional taphonomic alteration. Minimal abrasion
on the ectocranial surfaces of the cranial elements suggests low
energy depositional environments. There is considerable frag-
mentation that was likely caused by sediment loading processes,
consistent with bone breakage patterns observed on the associated
flat and long bones (Dirks et al., 2015). A concerted effort to refit
these fragmented crania has met with considerable success.
Although their geologic age is unknown, these specimens
inform the morphological diversity of the genus Homo. They
expand the range of individuals with cranial capacities on the lower
end of the Homo range. Here, we provide detailed descriptions and
metric comparisons of all available H. naledi cranial and mandibular
fossils that preserve diagnostic morphology. These descriptions and
metrics expand on those provided in the initial announcement of
the species (Berger et al., 2015) and include the description of a new
Dinaledi Hominin individual (DH6). We exclude teeth from
consideration, since the large dental sample from Dinaledi is the
subject of work in progress.
2. Materials and methods
Cranial and mandibular specimens of H. naledi were compared to
fossils attributed to Australopithecus afarensis, Australopithecus afri-
canus, Australopithecus sediba, Homo habilis sensu stricto, Homo
rudolfensis, Homo erectus sensu lato, Middle Pleistocene Homo, and
Homo sapiens (Table S1). Anatomical descriptions cover the
morphology of the cranial vault, cranial base, preserved portions of
the face, and mandible. Descriptions of holotype and paratype
specimens are presented as anatomical units, and fragmentary re-
mains are organized by element. In the anatomical descriptions, we
describe discrete features following the conventions of Weidenreich
(1943), Rightmire (1990), Tobias (1991), Wood (1991), and Strait and
Grine (2004). Full trait characterizations and phylogenetic analyses
are presented in Dembo et al. (2016). Metric comparisons were
based on 20 cranial vault,12 cranial base,13 face,13 maxilloalveolar,
and 25 mandibular linear measurements, in original specimens of
H. naledi and from the comparative samples (taxonomic affiliations
for the hominin samples in Table 1; measurements in SOM
Tables S1eS5). Most of the measurements follow Wood (1991)
and other measures are described. Ratios were also calculated for
key measurements to examine differences in shape in the absence
of size: five cranial vault, five cranial base, three face, five max-
illoalveolar, and five mandibular. Full multivariate analyses of cra-
nial shape were undertaken elsewhere (Schroeder et al., in review).
Surface models of H. naledi fossils are available for download at
Morphosource.org in the Rising Star Project, and we encourage
readers to access these materials to accompany this paper.
3. Dinaledi holotype and paratype specimens
In the initial announcement, five partial crania were attributed
to unique individuals, referred to as Dinaledi Hominins (DH) 1e5,
and were designated as either holotype or paratype specimens of
H. naledi (Berger et al., 2015). Specimen U.W. 101-377 was also
designated as a paratype since it preserved a relatively complete
and unworn dentition, and we recognize that this mandible may
belong to one of the numbered DH individuals. To this we now add
another cranial individual, DH6 (U.W. 101-1400), recognized in this
paper and represented by a subadult individual with deciduous
dentition in place. The smaller number of cranial individuals (six)
relative to the larger number of dental individuals (15) reflects the
fragmented nature of the assemblage (Dirks et al., 2015). It is likely
that some of the cranial and mandibular fragments described in the
section below could be refit or reattached to a current DH
numbered individual if intervening fragments are excavated. The
current list of skull fragments associated with DH numbered in-
dividuals, updated from Berger et al. (2015), is presented in Table 2.
3.1. Dinaledi Hominin 1
The holotype specimen DH1 consists of a partial calvarium,
partial maxilla, and a complete mandibular corpus with partial
mandibular rami (Table 2; Figs. 1e4). The calvarium is in two main
portions: the first portion comprises a large part of the occipital,
including the nuchal planum and the mastoid and supramastoid
regions of the left and right temporals; the second portion consists
of large parts of the left and right parietals and a segment of the
frontal bone. The maxilla consists of two well-fitting skeletal
fragments preserving the left I1
to P4
, two molars that refit to the
maxilla (M1
and M2
), and one associated molar (M3
) that refits via
the mesial interproximal contact facet. The mandible is recon-
structed from five well-fitting fragments that form the corpus
preserving the complete dentition and much of the rami. A right
condyle refits to the mandibular ramus and a left condyle is
tentatively associated. The maxilla and mandible are associated
with the rest of the DH1 cranium based on spatial proximity during
excavation (Berger et al., 2015). The cranial sutures preserved in
DH1 include the coronal, sagittal, squamosal, lambdoidal, and
occipitomastoid. The coronal, lambdoidal, and occipitomastoid
sutures are fused. DH1 is considered an adult individual due to the
fused sutures, full eruption and occlusion of the maxillary and
mandibular third molars, and a higher degree of occlusal wear.
3.1.1. Cranium In superior view, the cranial vault is widest at the
slightly laterally inflated mastoid processes, tapering anteriorly to
be narrowest at the postorbital region (Fig. 1). In posterior view, the
gently rounded cranial vault is widest above the marked mastoid
crests and tapers slightly to its bi-parietal breadth. There is a
slight parasagittal keel between bregma and lambda along the
sagittal suture.
3.1.2. Frontal A fragmentof the left frontalis preserved that includes
approximatelythelateralone-third ofthesuperiororbital marginand
the supraorbital torus (Fig.1). It refits to the posterior-most portion of
the frontal bone that is preserved along the fused coronal suture on
the main vault fragment. This fragment preserves a low, sloping
appearance of the frontal. The anteriorly projecting supraorbital
torus is ~6.0 mm thick mid-orbit, vermiculate in appearance, and is
clearly delineated by a moderately deep supratoral sulcus. The
strong superior and inferior temporal lines are separated by a
1.0 mm channel for about 13.0 mm. The temporal lines are widely
spaced on the vault. A small, lateral portion of the frontal sinus is
exposed on the medial side of the fragment. The preserved portion
of the frontal squama is 5.0 mm thick.
3.1.3. Parietals Parts of both parietals are preserved, the left side
being the better represented. The left parietal is present from
bregma inferiorly to the largely complete sphenoidal angle and
posteriorly about halfway to the occipital angle (Fig. 1C). A portion
of the inferior left parietal reveals parietal striae. The less well
preserved right parietal includes the frontal angle at bregma and
M.F. Laird et al. / Journal of Human Evolution xxx (2016) 1e24
2
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extends almost to the point of the occipital angle. The inferior half
of the right parietal is not preserved. Neither side preserves the
mastoid angle. Both the left and right parietals show moderate
bossing, and there is slight prelambdoidal flattening along the
midsagittal plane. Parietal foramina are preserved superior to the
occipital angle on both sides. Weak superior and inferior
temporal lines are visible along the extent of the parietals,
curving inferiorly to become distinct as well-marked angular tori.
The angular tori continue onto the temporal bones superior to
the external auditory meatus (EAM). Endocranially, a distinct
sagittal sulcus and meningeal grooves are preserved. The
parietals are 4.5 mm thick at bregma, 4.0 mm thick at the left
sphenoidal angle, 5.0 mm thick at the left parietal boss, and
5.0 mm thick on the fragment closest to the right occipital angle.
3.1.4. Temporals The temporal bones preserve the majority of the
left mandibular fossa, most of the superior half of the left EAM, the
left superior portion of the mastoid process, and a small portion of
the posterior right mastoid process. The left mandibular fossa shows
a shallow articular surface that is medially bounded by a moderate
entoglenoid process. The sphenosquamosal suture is lateral to the
mass of the entoglenoid process, thus the sphenoid does not
contribute to the mandibular fossa articular surface. The mandibular
fossa projects slightly laterally beyond the lateral wall of the cranium
and has a moderately projecting articular eminence that is princi-
pally posteriorly oriented. The left root of the zygoma of the tem-
poral bone is preserved and is oriented approximately 30.0
anteroinferiorly relative to the estimated Frankfort horizontal (FH)
plane. While the anterior half of the EAM is mostly absent, there is a
small triangular postglenoid process that lacks its inferior tip. The
posterior half of a small ovoid EAM is present on the left temporal
bone with a thick tympanic plate. Part of a small but distinct
suprameatal spine is present. On the left temporal, the marked
supramastoid crest runs superoposteriorly from the laterally inflated
mastoid region. There is a wide and shallow depression between the
supramastoid crest and mastoid crest, with the two crests diverging
anteriorly. The superior portion of the left mastoid process is pre-
served. Its anterior face is convex and rugose for attachments of mm.
sternocleidomastoid and splenius capitis. As the tip of the mastoid is
not preserved, the inferior and endocranial surface reveals a highly
pneumatized mastoid region. Meningeal grooves are present on the
endocranial surface. Posterior to the origin of the petrous portion of
the temporal, a weak sigmoid sinus is present. The left temporal
squama is 5.0 mm thick superior to the EAM.
3.1.5. Occipital The occipital is preserved as a strip of bone from
left to right asterion, extending superiorly and inferiorly just above
and below the nuchal lines (Fig. 2). The occipital squama is convexly
curved with a well-developed occipital torus. The supreme nuchal
lines meet to form an external occipital protuberance. A projecting
tuburculum lineara is formed by the superior nuchal lines 5.0 mm
below the external occipital protuberance. The strongly expressed
superior nuchal lines demarcate the superior extension of the
attachments of m. semispinalis capitis. A sharply marked external
occipital crest divides these attachment sites. A foramen is visible
on the left side of the aforementioned crest. The superior nuchal
lines extend bilaterally toward the asterionic region, where the
occipital bone thickens noticeably (to become 8.5 mm thick).
Endocranially, the left cerebral fossa is almost complete and a
small segment of the left cerebellar fossa is present. On the right,
the inferior half of the cerebral fossa is present, along with a
small segment of the cerebellar fossa. The four fossae are
demarcated by a prominent cruciform eminence. The internal
occipital protuberance is more inferiorly positioned than the
external occipital protuberance. The sagittal sulcus divides into
transverse sulci that are right dominant into the sigmoid sinuses.
The right and left cerebral fossae of the occipital are 4.5 mm thick.
3.1.6. Maxilla The left maxilla is relatively complete anteriorly and
includes LI1
eLM2
(Fig. 3). The palate is missing posteriorly from
about the level of the M1
, as is most of the body superior to the
alveolar process. Buccally, the alveolar process is preserved from I1
to the mesial portion of M1
. Lingually, the left palatine process is
preserved from I1
to mesial M2
. The median palatine suture is
partially visible and is preserved from I1
to the level of M1
. A large
maxillary sinus is exposed superiorly, with parts of the anterior,
inferior, lateral, and medial walls preserved. The left lateral edge of
the incisive foramen and incisive canal is preserved. The palate is
shallow anteriorly and becomes deeper posteriorly. Mirror imaging
of the left maxilla shows a wide palate. The dental arcade is
parabolic with slight medial displacement of M2
, while the incisors
Table 1
Affinities of comparative cranial and mandibular materials.
Many of the specimens listed below are controversially assigned to individual species. Rather than debate taxonomic attributions, we follow conventional hypodigms as
outlined below. Where possible original specimens were examined, and if not possible, comparisons were made with casts and published reports.
Australopithecus afarensis: Attributed materials from Hadar, Laetoli, and the Middle Awash. Australopithecus afarensis specimens include: A.L. 129-23, A.L. 145-35, A.L. 162-
28, A.L. 188-1, A.L. 198-1, A.L. 199-1, A.L. 200-1, A.L. 207-13, A.L. 266-1, A.L. 277-1, A.L. 288-1, A.L. 311-1, A.L. 33-125, A.L. 333-1, A.L. 333-105, A.L. 333-2, A.L. 333-45, A.L.
333w-12, A.L. 333w-60, A.L. 400-1a, A.L. 417-1, A.L. 444-2, A.L. 58-22, Garusi 1, LH 4, MAK-VP 1/12.
Australopithecus africanus: Specimens attributed to A. africanus include materials from Taung, Sterkfontein, and Makapansgat. This taxon includes: MLD 1, MLD 2, MLD 6,
MLD 9, MLD 12, MLD 22, MLD 29, MLD 34, MLD 37/38, MLD 40, MLD 45, Sts 5, Sts 7, Sts 17, Sts 19, Sts 20, Sts 26, Sts 36, Sts 52a, Sts 52b, Sts 67, Sts 71, Stw 13, Stw 73, Stw
252, Stw 384, Stw 404, Stw 498, Stw 505, Stw 513, Taung 1, TM 1511, TM 1512.
Australopithecus sediba: Specimens attributed to A. sediba include materials from Malapa. This taxon includes specimens MH1 and MH2.
Homo habilis sensu stricto: Samples from East Lake Turkana, Hadar, Olduvai Gorge, Swartkrans, and Sterkfontein were included in this taxon. This taxon includes the
following specimens: KNM-ER 1813, KNM-ER1805, KNM-ER 42703, A.L. 666-1a
, OH 7, OH 13, OH 16, OH 24, OH 62a
, SK 27, Stw 53.a
Homo rudolfensis: Specimens attributed to H. rudolfensis include materials from East Lake Turkana, Uraha, and Olduvai Gorge. This taxon includes the following specimens:
UR-501, KNM-ER 1470, KNM-ER 1590, KNM-ER 3732, KNM-ER 3891, KNM-ER 819, KNM-ER 1482, KNM-ER 1483, KNM-ER 1801, KNM-ER 1802, KNM-ER 60000, KNM-
ER 62000, KNM-ER 62003, OH 65.
Homo erectus sensu lato: This taxon includes specimens from Bouri, Choukoutien, Daka, Dmanisi, Gonwagling, Hexian, Konso, East and West Lake Turkana, Nanjing,
Ngandong, Olduvai Gorge, Sambungmacan, Sangiran, Swartkrans, Ternifine, and Trinil. This taxon includes the following specimens: BOU-VP-2/66, Choukoutien A2,
Choukoutien F1, Choukoutien G1, Choukoutien H1, Choukoutien K1, Choukoutien Pa86, Choukoutien E1, Choukoutien H3, Choukoutien L1, Choukoutien L2,
Choukoutien L3, Daka, D2280, D2282, D2700, D3444, D4500, Gonwagling, Hexian, KA 10-1, KNM-ER 730, KNM-ER 820, KNM-ER 992, KNM-ER 1808, KNM-ER 3733,
KNM-ER 3883, KNM-ER 42700, KNM-ER 15000, Nanjing 1, Nanjing 2, Ngandong 1, Ngandong 3, Ngandong 5, Ngandong 6, Ngandong 7, Ngandong 11, Ngandong 12,
Ngandong 13, Ngandong 14, OH 9, OH 12, Sambungmacan 1, Sambungmacan 3, Sambungmacan 4, Sangiran 1b, Sangiran 2, Sangiran 4, Sangiran 5, Sangiran 6, Sangiran
8, Sangiran 9, Sangiran 10, Sangiran 17, Sangiran 22, Sangiran 27, Sangiran 31, Sangiran Bk7805, Sangiran Ng8503, SK 15, SK 45, SK 847, Stw 80, Ternifine I, Ternifine II,
Ternifine III, Trinil II.
Middle Pleistocene (MP) Homo: Specimens attributed to MP Homo include materials from Eliye Springs, Arago, Atapuerca SH, Bodo, Broken Hill, Cave of Hearths, Ceprano,
Dali, Elandsfontein, Hexian, Jinniushan, Kapthurin, Mauer, Narmada, Ndutu, Petralona, Reilingen-Schwetzingen, Solo, Steinheim, Swanscombe. This taxon includes the
following specimens: KNM-ES 11693, Arago 2, Arago 13, Arago 21, Atapuerca 1, Atapuerca 2, Atapuerca 4, Atapuerca 5, Atapuerca 6, Cave of Hearths, Hexian PA830,
SAM-PQ-EH1, Kabwe, Mauer, Ndutu, Sale, Petralona, Reilingen-Schwetzingen, Steinheim
a
Some authors of this paper prefer assigning A.L. 666-1, OH 62, and Stw 53 outside of the genus Homo. However, here we follow conventional taxonomic attribution.
M.F. Laird et al. / Journal of Human Evolution xxx (2016) 1e24 3
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project anteriorly beyond the bi-canine line. The nasoalveolar clivus
is flattened and squared at the prominent canine jugum. The inferior
root of the zygomatic process of the maxilla is anteriorly positioned
and originates at the level of P4
/M1
. There is a midline fragment
preserving the anterior nasal spine, superior opening of the
incisive canal, and small parts of the right and left nasal floor. The
anterior nasal spine is anteriorly projecting, and the nasal floor
slopes into the nasoalveolar clivus and is not internally depressed.
The incisor and canine juga are well-developed, along with what
appear to be distinct juga above the tips of the roots of the P3
.
These latter juga delineate a shallow canine fossa.
3.1.7. Mandible The mandible consists of a nearly complete corpus
and portions of both rami, including the condyles and complete
dentition (Fig. 4). The right mandibular condyle refits to the ramus,
but the left condyle is tentatively associated based on a small
portion of refit and close spatial proximity in situ. There are
several small fragments missing from the corpus where pieces
were refit, and most of the rami anterior to the condyles are not
preserved. The dental arcade is parabolic with slight medial
displacement of M2 and M3 (Fig. 4A). The symphysis is vertically
oriented. A small but prominent mental protuberance is present,
which combined with faint lateral tubercles defines a weak
mental trigone (Fig. 4D). Weak mandibular incurvations delineate
the mental trigone, resulting in a weak indication of a mentum
osseum. A well-developed interdigastric spine projects
posteroinferiorly at the midline of the symphysis, separating two
shallow and narrow digastric fossae. Mental spines are present on
the internal surface of the symphysis. The area of the lingual
alveolar plane (i.e., post-incisive planum) is steeply inclined and
not shelf-like, thus a lingual alveolar plane proper is not present
(see Tobias, 1991: 325). There is no indication of a superior
transverse torus, and a weak inferior transverse torus is
positioned slightly above the basal margin extending posteriorly
to about the level of the P3/P4. The mental foramina open
posteriorly and are positioned inferior and distal to P3, slightly
above the level of the mid-corpus. An accessory mental foramen
is present superior to the right mental foramen. A supreme
lateral torus (Dart, 1925) is present, separating the plane of the
extramolar sulcus from that of the lateral corpus. The superior
lateral torus is weakly defined, traversing to the mental foramen
before curving upward to contact the P3 jugum. The marginal
torus is weakly developed and defines a shallow intertoral sulcus.
The anterior marginal tubercle is represented by a slight swelling
and roughening of bone below the C/P3. There is no clear
indication of a posterior marginal tubercle. The corpus is short
superoinferiorly and thick buccolingually. The lateral prominence
Table 2
Holotype and paratype specimens and referred materials.
Side Element
Holotype specimen
DH1
U.W. 101-1248a
L Mandibular condyle
U.W. 101-1261 L Mandibular corpus with P3eM3
U.W. 101-1269 L M3
U.W. 101-1275 L, R Frontal fragment
U.W. 101-1277 L Maxilla fragment with I1
eM2
U.W. 101-1281 R Mandibular condyle
U.W. 101-1283 L, R Mandibular corpus with LCeRM1
U.W. 101-1289 L Mandibular ramus fragment
U.W. 101-1290 R Parietal fragment
U.W. 101-1330 L, R Parietal fragment
U.W. 101-1349 L Parietal fragment
U.W. 101-1350 L, R Parietal fragment
U.W. 101-1371 R Mandibular corpus with M2eM3
U.W. 101-1387 L Temporal fragment
U.W. 101-1398 L Frontal fragment
U.W. 101-1410 R Mandibular ramus fragment
U.W. 101-1421 R Occipital fragment
U.W. 101-1463 R M1
U.W. 101-1473 L, R Occipital fragment
Paratype specimens
DH2
U.W. 101-218 R Occipitoparietal fragment
U.W. 101-221 L, R Temporo-parieto-occipital fragment
DH3
U.W. 101-196a
L Mandibular condyle
U.W. 101-361a
L Mandibular corpus with M2eM3
U.W. 101-396 L Parieto-temporal fragment
U.W. 101-521 L Occipital fragment (new refit on suture)
DH4
U.W. 101-1372 R Temporal fragment
U.W. 101-1528 R Temporal (tympanic) fragment
U.W. 101-1584 R Temporal fragment of the EAM
DH5
U.W. 101-004 L Temporal (mastoid) fragment
DH6
U.W. 101-1400 L Juvenile mandible with dcedm2 and M1
Paratype
U.W. 101-377 R Mandibular corpus with CeM2
Referred material
Cranial remains
U.W. 101-008 R Zygomatic
U.W. 101-200 L, R Occipital fragment (moved from DH3)
U.W. 101-265 L Zygomatic fragment
U.W. 101-346 L Petrous temporal fragment
U.W. 101-409 R Zygomatic fragment
U.W. 101-599 R Temporal fragment refit 981
U.W. 101-874 R Frontal fragment (moved from DH3)
U.W. 101-906 L Frontoparietal fragment
U.W. 101-950 R Temporal fragment at EAM
U.W. 101-1227 L Temporal at postglenoid
U.W. 101-1234 L Occipital fragment
Table 2 (continued )
Side Element
U.W. 101-1278 L Zygomatic
U.W. 101-1332 R Zygomatic-Temporal fragment of
zygomatic arch
U.W. 101-1354 R Zygomatic
U.W. 101-1425 R Frontal-parietal fragment
U.W. 101-1530 L Frontal fragment at orbit
Mandibular remains
U.W. 101-001 R Mandible with P3eM3
U.W. 101-010 R Mandible with CeP3
U.W. 101-325 L Mandibular condyle fragment
U.W. 101-733 R Coronoid process
U.W. 101-795 R Coronoid process
U.W. 101-1001 L Mandibular ramus fragment
U.W. 101-1142 R Mandible with M2eM3
a
Fragments that are tentatively associated with numbered Dinaledi hominins.
4
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is large and extends across the entire lateral post-canine dental
row, with its point of greatest lateral extension at the mesial M2.
The alveolar prominence is well-developed and overhangs the
continuous anterior and posterior subalveolar fossae, which are
weakly delineated by a slight swelling of bone below the M2. The
basal corpus is thick and evenly rounded along its entire length
until the pregonial incisure. The mandibular recess is deep and
the extramolar sulcus is broad. The anterior aspect of the right
masseteric tuberosity is large and laterally projecting. The gonial
region is everted inferiorly near the masseter attachment, but
inverted superiorly on the ascending ramus (Fig. 4B). A deeply
excavated masseteric fossa is bordered superoposteriorly by a
well-developed lateral eminence of the ramus. The pharyngeal
crest is well-defined and sharp. A deep and well-defined
mylohyoid groove is evident on the left side, but the structure is
shallow and diffusely defined on the right. The mylohyoid line is
faint and indistinct. The right mandibular foramen is positioned
anterosuperiorly and the left is damaged. The pterygoid fossa is
small but deeply excavated. The condyles are mediolaterally
elongated with axes oriented close to the coronal plane. Both
condyles have some cortical erosion damage. Medially, the
endocondyloid buttress is weakly developed inferior to the
condyle, rapidly fanning out of existence without contacting the
triangular torus. Laterally the ectocondyloid buttress is low,
rounded, and weakly developed.
The paratype specimen DH2 is a partial calvarium reconstructed
from well-fitting fragments (Table 2, Fig. 5). It consists of sections of
frontal, left and right parietals, right temporal, and occipital. The
coronal suture is fused. The sagittal suture is present and partially
Figure 1. Anterior fragment of H. naledi DH1 calvarium in (A) superior, (B) inferior, (C) left lateral, and (D) right lateral views. Scale bar ¼ 2 cm.
Figure 2. Posterior fragment of H. naledi DH1 calvarium in (A) posterior, (B) anterior, (C) left lateral, (D) right lateral, (E) inferior, and (F) superior views. Scale bar ¼ 2 cm. The frontal
fragment is unglued and not pictured in D.
j.jhevol.2016.09.009

fused. The right squamosal suture and right leg of the lambdoidal
suture are partially fused. Based on the degree of fusion in these
sutures, DH2 is an adult. Berger et al. (2015) included frontal frag-
ments U.W. 101-906 and U.W. 101-1111 in DH2; however, we ﬁnd
that these elements would introduce a large degree of asymmetry
between the left and right temporal lines and exclude these spec-
imens from DH2 here.
3.2.1. Cranium In lateral view, the cranial vault displays a gentle
curvature with post-bregmatic and prelambdoidal ﬂattening of the
parietals and slight occipital bossing (Fig. 5E and F). In superior
view, the vault is narrowest anteriorly, with the greatest width at
the mastoid crest and tapering slightly towards the posterior
occipital (Fig. 5D). In posterior view, the calvarium displays parietal
bossing and a slight keeling along the sagittal suture (Fig. 5B).
3.2.2. Frontal A small portion of the right frontal is preserved
anterior to the fused coronal suture. This fragment extends from
bregma to the point where the temporal line crosses the coronal
suture.
3.2.3. Parietals The right parietal is preserved at the frontal angle,
along the sagittal suture, at the occipital angle, and for most of the
mastoid angle. The sphenoid angle of the right parietal is not pre-
served. Of the left parietal, the superior half is preserved, including
most of the frontal angle and the occipital angle. The right parietal
bossing and the superior part of the left bossing are present, and a
parietal foramen is present on the right side. Parietal striae are
Figure 3. The maxilla of H. naledi DH1 in (A) inferior, (B) superior, (C) left lateral, (D) medial, (E) posterior, and (F) anterior views. Scale bar ¼ 2 cm.
Figure 4. The mandible of H. naledi DH1 in (A) superior, (B) inferior, (C) posterior, (D) anterior, (E) right lateral, and (F) left lateral views. The superior most fragments composing the
ascending ramus and condyle pictured in E and F are unglued and not pictured in AeD. Scale bar ¼ 2 cm.
6
j.jhevol.2016.09.009

present along the posterior aspect of the right squamosal suture. A
weak temporal line arches across the right parietal but is not pre-
sent on what is preserved of the left parietal, indicating widely set
temporal lines. The temporal line on the right side joins a marked
supramastoid crest, forming a weak angular torus on the mastoid
angle of the parietal bone. Deep meningeal grooves, arachnoid
foveae, and the sagittal sulcus are preserved on the endocranial
surface. The parietal bones are thin (5.5 mm at the anterior portion
of the left parietal) and are slightly thicker posteriorly and medially
along the sagittal suture (6.0 mm at the posterior portion of the left
parietal).
3.2.4. Temporal The posterior aspect of the right temporal pre-
serves part of the squama, the superior-most aspect of the mastoid,
the posterosuperior edge of the mandibular fossa, the root of the
zygoma above the mandibular fossa, and the posterior margin of
the EAM (Fig. 5E). The posterior mandibular fossa has a triangular
postglenoid process that extends 7.0 mm inferiorly before being
truncated by damage. The root of the zygoma is angled
approximately 30 downward from the estimated FH. The small
EAM is ovoid in shape and positioned slightly medial to the
lateral wall of the calvarium. A small fragment of the tympanic is
preserved on the superior margin of the EAM, and a strong
suprameatal spine is present on the posterosuperior margin. The
posterior aspect of the temporal is broken at the parietal notch.
Mastoid pneumatization is present on the posteroinferior aspect
of the temporal. The middle meningeal groove is visible on the
posterior endocranial surface of the temporal. The thickness of
the bone in the asterionic region is 11.5 mm.
3.2.5. Occipital A small portion of the left occipital is preserved
just to the right of lambda and part of the right occipital is pre-
served inferior to lambda along the right lambdoidal suture. The
thickness at lambda is 6.0 mm.
The paratype specimen DH3 consists of a partial calvarium and
mandible (Table 2, Figs. 6 and 7). This mandible is tentatively
associated with this specimen based on the ﬁt of the mandibular
condyle to the mandibular fossa and its close spatial proximity to
the calvarium in situ. The calvarium is reconstructed from 11 well-
ﬁtting fragments, consisting of sections of the frontal, left parietal,
left temporal, and sphenoid. Berger et al. (2015) include occipital
fragment U.W. 101-200 and frontal fragment U.W. 101-874. In our
analyses, we exclude these fragments from DH3 as they are
inconsistent with the preserved morphology. Specimen U.W. 101-
200 overlaps with preserved morphology of the lambdoidal suture
in DH3, and the temporal line, supraorbital torus, and orbital
shape on specimen U.W. 101-874 are unlike that of DH3. The cor-
onal suture is fused and visible endocranially. A small (3.0 mm)
section of the sagittal suture is preserved posterior to bregma. The
sphenofrontal and sphenotemporal sutures are fused and visible
in parts. The sphenoparietal suture is not visible due to fragmen-
tation of the cranium in the region of pterion. The left squamosal
suture, including the parietomastoid aspect, is visible and open,
displaying a large degree of overlap between the temporal and
parietal bones. The left portion of the lambdoidal and the left
occipitomastoid sutures are completely open and present on the
parietal and temporal bones, respectively. The preserved
mandibular corpus extends from the mandibular condyle to the
symphysis, including M2 and M3. The superior portion of the
mandibular corpus is missing along an oblique line from the M2
down to the basal symphysis. DH3 is an older adult based on the
degree of suture closure and on the degree of occlusal wear of the
associated teeth.
3.3.1. Cranium In lateral view, there is a projecting supraorbital
torus, a deep supratoral sulcus, and a gently sloping frontal, all of
which combine with the curved appearance of the parietals to
produce a rounded cranial contour (Fig. 6A and B). In superior view
from mirrored images, the vault is narrowest anteriorly, displaying
moderate postorbital constriction, with the greatest width at the
supramastoid crest (Fig. 6C). In posterior view from mirrored
images, the temporal and parietal bones form the vertically
oriented walls of the vault, and the greatest breadth of the vault
is seen along the mastoid region (Fig. 6F).
Figure 5. Views of H. naledi DH2 in (A) anterior, (B) posterior, (C) inferior, (D) superior, (E) right lateral, and (F) left lateral views. Scale bar ¼ 2 cm.
j.jhevol.2016.09.009

3.3.2. Frontal The left frontal squama, supraorbital torus, and su-
perior orbit are preserved (Fig. 6E). Laterally, the frontal is well
preserved to the frontozygomatic suture. Posteriorly, it articulates
with the sphenoid, with some damage in the region of pterion.
The frontal is broken just lateral to glabella exposing a large,
multi-chambered frontal sinus. The anteriorly projecting
supraorbital torus is well-developed and weakly arched with
rounded lateral corners and is clearly delineated by a well-
deﬁned supratoral sulcus. The supraorbital torus is thickest in the
glabella region (10.0 mm), thinner near mid-orbit (6.0 mm), and
thicker again laterally (7.0 mm). There is a slight midline
depression at glabella, but mirror imaging of this specimen
indicates that DH3 had a continuous supraorbital torus. The
superior wall, part of the posterior wall, and the rounded
superior margin combine to reveal a relatively small orbit. A
moderately well-deﬁned temporal crest is positioned on the
posterior aspect of the lateral supraorbital torus. A prominent
inferior temporal line and a faint superior temporal line are
positioned medial to the lateral wall of the cranium in the area of
the temporal fossa. There is a 5.5 mm diameter taphonomic divot
located just anteromedial to the temporal line in the supratoral
sulcus. Moderate postorbital constriction (79.0%) was evaluated
as an index of the postorbital breadth (68.0 mm in DH3) divided
by the superior facial breadth (86.0 mm in DH3; SOM Table S1).
The frontal squama is low and sloping from the supratoral sulcus
to the coronal suture with slight frontal bossing.
Figure 6. Homo naledi DH3 specimen in (A) left lateral, (B) medial, (C) superior, (D) inferior, (E) anterior, and (F) posterior views. Scale bar ¼ 2 cm.
Figure 7. Mandible U.W. 101-361 is potentially associated with DH3. Shown in (A) left lateral, (B) superior, (C) medial, and (D) inferior views. Scale bar ¼ 2 cm.
8
j.jhevol.2016.09.009

3.3.3. Parietal Anterior and inferior portions of the left parietal are
preserved, including the sphenoidal angle and approaching the
frontal angle, but not the occipital or mastoid angles. The temporal
lines continue from the frontal onto the parietal and join the
marked supramastoid crest to form a moderate angular torus. Pa-
rietal striae are present along the squamosal border. Deep menin-
geal grooves, arachnoid foveae, and the sagittal sulcus are
preserved on the endocranial surface. The thickness of the left
parietal is moderate (6.5 mm near bregma) and increases posteri-
orly (9.0 mm at the mastoid angle).
3.3.4. Sphenoid The superior aspect of the greater wing of the left
sphenoid is preserved. A branch of the middle meningeal groove is
present on the endocranial surface.
3.3.5. Temporal The majority of the left temporal is preserved,
revealing a weakly curved superior margin of the temporal squama.
The petrous portion of the temporal, including the petrous pyra-
mid, internal auditory meatus, and jugular foramen, is preserved
(Fig. 6D). Lateral flaring of the root of the zygoma begins superior to
the mandibular fossa rather than the EAM and is anteroinferiorly
angled about 30.0 relative to the estimated FH. The mandibular
fossa is shallow with a posteriorly oriented anterior wall. It is
positioned mostly medial to the wall of the temporal squama.
The articular eminence is flat anteroposteriorly, not convex, and
is posteriorly oriented. The small postglenoid process is triangular
in shape and contacts the tympanic plate, and the tympanic plate
forms a flattened, steeply inclined posterior wall of the
mandibular fossa. The elongated and inferiorly projecting
entoglenoid process is principally oriented posterolaterally. The
sphenosquamosal suture is present anterior to the mandibular
fossa and the sphenoid does not contribute to the medial wall of
the entoglenoid process. The preglenoid plane is small and
parallel to the estimated FH. The tympanomedian angle,
measured from the sagittal plane, is 79.0. Measured from the
sagittal plane, the petromedian angle is 46.0. The small EAM is
thick, especially inferiorly, and is medially positioned, ovoid in
shape, and obliquely oriented. There is a suprameatal spine
present on the superoposterior margin of the EAM. The
supramastoid crest is well-developed, with a wide and shallow
depression between the supramastoid and mastoid crests, with
the two crests diverging anteriorly. The superior and posterior
aspects of a small mastoid process are preserved and
considerable pneumatization is visible anteroinferiorly. There is a
deep groove along the long axis of the mastoid process for the
attachment of the sternocleidomastoid muscle. Inferiorly, there is
a weak crista petrosa and vaginal process, alongside a strong
Eustachian process. Deep and narrow digastric and occipital
grooves, separated by a pronounced juxtamastoid crest, are
present medial to the mastoid process. On the endocranial
surface, deep middle meningeal grooves and a well-excavated
sigmoid sulcus are present.
3.3.6. Occipital A small portion of the left occipital bone is pre-
served along the lambdoidal suture, revealing a shallowly
impressed continuation of the sigmoid/transverse sulcus. The
maximum thickness of this fragment is 13.0 mm.
3.3.7. Mandible The mandible that we tentatively associate with
DH3 comprises a left mandibular condyle, ascending ramus, and
corpus fragment (Fig. 7). The corpus fragment preserves a complete
but heavily worn M2 and M3. The corpus is robust, with a
pronounced lateral prominence across the entire buccal surface,
and its greatest lateral extension is at the level of the M2/M3. The
alveolar prominence is well-developed and overhangs the
continuous anterior and posterior subalveolar fossae. The basal
corpus is thick and evenly rounded along its entire length until
the pregonial incisure. The supreme lateral torus (Dart, 1954) is
well-developed, delimiting the plane of the extramolar sulcus
from the plane of the lateral corpus. The superior lateral torus is
mostly missing, although the weak marginal torus delineates a
shallow intertoral sulcus. The mandibular recess is deep and
grades into a wide extramolar sulcus, continuing with an oblique
line that terminates around M2. The gonial angle has been
fractured and is slightly displaced lingually, but preserves strong
masseteric and medial pterygoid tuberosities. The lateral
eminence of the ramus is low and rounded. The mandibular
foramen is preserved and opens posterosuperiorly. Inferior to the
mandibular foramen is a shallow mylohyoid groove and a faint
mylohyoid line. The mandibular condyle preserves part of the
articular surface and a distal portion of the mandibular notch.
The condyle has a moderate pterygoid fovea and short condylar
neck, alongside a weak endocondyloid buttress that likely did not
reach the triangular torus.
The paratype specimen DH4 consists of portions of the right
parietal, right temporal, and occipital bones (Table 2, Fig. 8). The
right squamosal, right side of the lambdoidal, and right occipito-
mastoid sutures are preserved. All of the sutures are open ectoc-
ranially and partially closed endocranially, which indicates that this
individual was likely a young adult.
3.4.1. Parietal The posteroinferior quadrant of the right parietal
bone is preserved at the mastoid angle (Fig. 8A and B). The posterior
extent of the temporal line is evident, continuing as a moderate
angular torus. Parietal striae are preserved along the squamosal
suture. Endocranially, branching grooves for the meningeal
arteries are visible (Fig. 8A). The bone thickens at the most
superior portion (6.0 mm) and thins at the squamosal suture
(3.0 mm).
3.4.2. Temporal The temporal bone preserves a low curved
portion of the squama for articulation at the squamosal suture, the
superior portion of the mastoid region, the EAM, tympanic plate,
and the root of the zygomatic process. The zygomatic root tilts
downward at approximately 30.0 to the estimated FH, and infe-
riorly, a small portion of the postglenoid process is preserved
(Fig. 8C). The EAM is ovoid in shape and thicker posteroinferiorly,
with the longitudinal axis set at an oblique angle to the FH. A
suprameatal spine is present above the superoposterior portion.
The tympanic plate is preserved to the lateral margin of the
carotid canal and includes the anterior half of the stylomastoid
foramen. The mastoid process is small with convex lateral
inflation and the face is rugose for muscle originations. The tip of
the mastoid is not preserved. Orientation of the mastoid process
is nearly vertical in the superoinferior plane, but has a slight
posterior tilt. Posterior to the mastoid process is a deep and
narrow digastric groove. An occipitomastoid crest is preserved
along the occipitomastoid suture. The supramastoid crest is
angled superoposteriorly and connects to the prominent angular
torus and temporal line on the parietal. Endocranially, a portion
of the sigmoid sulcus is visible. The pneumatization of the
temporal bone is visible endocranially. The thickness of the
temporal squama is 3.5 mm.
3.4.3. Occipital The occipital is preserved on the right side along
the lambdoidal suture from the inferior-most portion of the
cerebral fossa to the superior cerebellar fossa, and medially, it is
preserved until just lateral to the cruciate eminence. The right
superior nuchal line is prominent, terminating laterally near the
asterionic region, while forming a tuberculum lineara medially.
Endocranially, the right cerebral and cerebellar fossae are divided
by the transverse sulcus. The most inferior meningeal groove
terminates above the transverse sulcus. Thickness of the occipital
in the cerebral fossa is 5.5 mm, and 4.0 mm in the cerebellar fossa.
j.jhevol.2016.09.009

DH3 and DH4 do not have overlapping preserved morphology
and are similar in size. However, we classify these fragments as
separate individuals because they differ in the inﬂation of the
mastoid region, depth of the digastric groove, robusticity and po-
sition of the temporal lines, and difference in closure of the occi-
pitomastoid and lambdoidal sutures. Specimen preservation also
supports differentiating these fragments, as DH3 has manganese
staining that is not present on DH4.
The paratype specimen DH5 is a partial left temporal and oc-
cipital fragment (Fig. 9). The occipitomastoid suture is present and
fused. DH5 was an adult based on the degree of suture closure.
3.5.1. Temporal The temporal preserves the posteroinferior corner
of the squama, posterosuperior mandibular fossa, root of the
zygoma, EAM, mastoid process, and the lateral-most aspect of the
petrous portion of the temporal (Fig. 9A). The root of the zygoma
is angled approximately 30 downward relative to FH. The
mandibular fossa is shallow and projecting 6.5 mm inferiorly is a
small triangular-shaped postglenoid process. A thick tympanic
plate is preserved. The EAM is ovoid, superoinferiorly elongated,
and laterally oriented with an anterosuperior tilt to the long axis.
A projecting suprameatal spine is present on the posterosuperior
margin of the EAM, and a suprameatal crest is present. The
mastoid process is relatively short and triangular in cross-section
along a parasagittal plane. The face of the mastoid is laterally
convex, and there is marked rugosity on the lateral surface for
origination of mm. sternocleidomastoid and splenius capitis. The
mastoid tip is rounded, and when oriented in a vertical plane, the
mastoid process projects 28.5 mm inferiorly from the horizontal
plane of porion. A deep and wide digastric groove and moderate
occipital groove, separated by a pronounced juxtamastoid
eminence, are present medial to the mastoid process. There is a
large mastoid foramen posterior to a marked mastoid crest, and a
stylomastoid foramen is present on the posteromedial edge of the
tympanic plate. Mastoid pneumatization, deep middle meningeal
grooves, and a well-excavated sigmoid sulcus are visible on the
endocranial surface. The temporal squama is 5.5 mm thick.
3.5.2. Occipital The left inferolateral aspect of the occipital is
preserved. The lambdoidal suture is visible crossing the sigmoid
sinus at its inferior third, and it continues in a posteromedial di-
rection relative to the sigmoid sinus. Parts of the lambdoidal suture
are fused. The lateral portion of the left cerebral fossa is present and
is 5.0 mm in thickness.
DH4 and DH5 preserve opposing sides and do not have over-
lapping preserved morphology. However, we classify these frag-
ments as separate individuals due to the difference in sutural fusion
and mastoid morphology. DH4 has an open ectocranial occipito-
mastoid suture, whereas this suture is completely fused in DH5.
Additionally, the face of the mastoid process is more rugose and the
mastoid notch is smaller in DH5.
DH6 currently comprises a single mandibular specimen, U.W.
101-1400, a juvenile left mandibular fragment with the dceM1
dentition (Fig. 10). The corpus is preserved distal to dm2, with the
crypt for M1. The area of the lingual alveolar plane is steeply in-
clined and not shelf-like. A moderate supreme lateral torus (Dart,
1954) is evident, delineating the extramolar plane from the
lateral plane. The mental foramen is positioned above mid-corpus
height, at the level of the dc/dm1 (Fig. 10B). There is a deeply
excavated anterior subalveolar fossa, which itself is occupied by a
small foramen at its anterior extent. A small mandibular recess is
preserved distal to dm2. The basal corpus is thick and evenly
rounded along its extent.
3.7. U.W. 101-377
The paratype specimen U.W. 101-377 is a relatively complete
right hemi-mandible preserving the corpus and dentition from the
C to the M2 (Fig. 11). As M2 is not fully erupted to the occlusal row
and there are low levels of attrition, this is a juvenile individual. Part
Figure 8. Homo naledi DH4 specimen in (A) endocranial/medial, (B) ectocranial/lateral, (C) inferior, and (D) superior views. Scale bar ¼ 2 cm.
10
j.jhevol.2016.09.009

of the oblique line is preserved and terminates at the medial edge of
M2. The superior lateral torus is weakly developed and courses to
the mental foramen where it terminates. The marginal torus is
weakly developed and delineates a shallow intertoral sulcus. The
lateral prominence is well-developed, encompassing the entire
lateral face with its greatest lateral extent at the M1/M2. The post-
erosuperiorly directed mental foramen is positioned above mid-
corpus height and is located between P3 and P4 (Fig. 11B). Medi-
ally, the continuous anterior and posterior subalveolar fossae are
moderately excavated below the subalveolar fossa. The basal
corpus is thick and evenly rounded for its entire extent.
4. Other notable H. naledi cranial and mandibular materials
Although the likelihood exists that some of the specimens
described below belong to the above mentioned numbered DH
crania, we discuss them separately at present as we cannot defin-
itively refit them to more complete specimens. Likewise, the
mandibles described below may derive from the same individuals
as the DH2, DH4, or DH5 crania.
4.1. Frontal fragments (Fig. 12)
U.W.101-009 is a partial left frontal preserving the superolateral
aspect of the orbit, the anterior portion of a moderate inferior
temporal line, a relatively broad supratoral sulcus, and the lateral
and posterior walls of an exposed frontal sinus. Internally, moder-
ately impressed sulci are visible. Frontal vault thickness at the most
medial portion is 5.5 mm.
U.W. 101-874 is the right portion of a frontal bone that preserves
the superior aspect of the orbit, a ~10.0 mm section of the supra-
orbital torus, part of the supratoral sulcus, and part of the lateral and
posterior walls of an exposed frontal sinus. The anterior portion of
the inferior and superior temporal line is preserved posterior to the
supratoral sulcus. A portion of the supraorbital notch is present on
the medial portion of the fragment. The anteriorly projecting
supraorbital sulcus is 8.0 mm in thickness and is delineated poste-
riorly by a distinct supratoral sulcus.
U.W. 101-906 is a fragment of a left frontal that includes
approximately the lateral half of the superior orbital margin and
the supraorbital torus, as well as a small portion of the parietal. The
coronal suture is fully fused. The anteriorly projecting supraorbital
torus is ~6.0 mm thick, sharpens slightly anteriorly, is vermiculate
in appearance, and is clearly delineated posteriorly by a moderately
deep supratoral sulcus. The strong, sharply defined temporal lines
are indistinct from each other, and they are positioned medial to
the lateral wall of the cranium in the area of the temporal fossa. The
preserved portion of the frontal squama is 5.5 mm thick.
U.W. 101-1252 is a left frontal fragment that preserves a small
portion of the supraorbital torus. The 6.0 mm thick supraorbital
torus is vermiculate in appearance and is rounded at the lateral
corner. There is a shallow but distinct supratoral sulcus. The tem-
poral line is faint and angles superoposteriorly.
U.W. 101-1425 is a right frontoparietal fragment. The coronal
suture is visible with some sutural fusion. There is a faint temporal
line on the inferior frontal and parietal. Internally, moderately
impressed sulci are visible. Thickness at the coronal suture is about
5.0 mm.
U.W. 101-1530 is a left frontal fragment at orbit preserving a
small portion of the supraorbital torus. This specimen potentially
reflects pathological conditions from infection and possible orbital
fracture, but requires additional study.
4.2. Zygomatic fragments (Fig. 13)
U.W. 101-008 is an adult right zygomatic preserving the frontal,
zygomatic, and maxillary processes. A small portion of maxilla
adheres to the zygomatic, exposing a portion of the maxillary sinus.
The frontozygomatic and zygomaticomaxillary sutures are pre-
served. Externally, the lateral surface is slightly flattened with a
very gentle curvature, retaining a moderate malar prominence and
a single zygomaticofacial foramen perforating the central portion of
Figure 9. DH5 specimen U.W. 101-004 in (A) ectocranial/lateral, (B) endocranial/medial, (C) inferior, and (D) superior views. Scale bar ¼ 2 cm.
j.jhevol.2016.09.009

the zygomatic body. The masseteric attachment origin is visible as a
rugose ridge on the inferior face of the temporal process. On the
temporal face of the frontal process, two zygomaticotemporal
foramina are preserved just below a faint orbital eminence (emi-
nentia orbitalis). At the superior extent of the frontal process, the
origin of m. temporalis results in a weak temporal crest. Medially,
the orbital plate is well-preserved with a single large zygomati-
coorbital foramen on the inferolateral corner of the orbital cavity.
Superior to the latter, a faint marginal tubercle (tuberculum mar-
ginale) can be observed. The anteroposterior breadth of the most
inferior portion of the frontal process is 12.0 mm, frontomalare-
jugale is 26.0 mm, and frontomalare-orbitale is 31.0 mm.
U.W. 101-265 is a portion of an adult left zygomatic with the
frontal process and the most superior portion of the zygomatic
body preserved. The body is perforated by a single zygomaticofacial
foramen, located inferior to the frontal process of the bone. The
internal orbital cavity contains a single large zygomaticoorbital
foramen. The posterior margin of the frontal process shows a
marked orbital eminence. The anteroposterior breadth of the most
inferior portion of the frontal process is 14.0 mm. The orbital rim is
thick and rounded.
U.W. 101-409 is a fragment of adult right zygomatic bone with a
partial frontal process, the inferolateral portion of the orbital rim,
and a small portion of the superior zygomatic body. The frontozy-
gomatic suture is visible in the orbital cavity surface of the frontal
process. The anteroposterior breadth of the most inferior portion of
the frontal process is 9.5 mm. The internal inferolateral corner of
the orbit is perforated by a single, large zygomaticoorbital foramen.
Figure 10. Homo naledi specimen DH6 (U.W. 101-1400) in (A) superior, (B) lateral, (C)
inferior, and (D) medial views. Scale bar ¼ 2 cm.
Figure 11. Homo naledi paratype specimen U.W. 101-377 in (A) superior, (B) lateral, (C)
inferior, and (D) medial views. Scale bar ¼ 2 cm.
12
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U.W. 101-1278 is an adult, left, almost complete zygomatic with
the frontal, temporal, and maxillary processes exposing a portion of
the maxillary sinus. Portions of frontozygomatic and zygomatico-
maxillary sutures are visible. The body is perforated by a single
zygomaticofacial foramen, located below the anterior edge of the
frontal process near the inferior margin of the bone. The posterior
edge of the frontal process shows an orbital eminence. There is a
masseteric tubercle on the inferior edge of the zygomatic. The
anteroposterior breadth of the most inferior portion of the frontal
process is 11.5 mm. The orbital rim is thick and rounded. Medially, a
single large zygomaticoorbital foramen is present in the infero-
lateral corner of the orbital cavity.
U.W. 101-1354 is a portion of an adult right zygomatic that is
missing the inferior portion at the masseteric origin but preserves
the frontal, temporal, and part of the maxillary processes. A portion
of the frontozygomatic suture is preserved on the frontal process
that includes small pieces of the frontal bone. A single zygomati-
cofacial foramen perforates the central portion of the body, located
halfway between the anterior and posterior margins of the frontal
process. The posterior margin of the frontal process exhibits an
orbital eminence, as well as a rounded rugosity marking the origin of
the temporalis muscle. The posterior surface of the frontal process is
perforated by two zygomaticotemporal foramina. The internal
orbital cavity is perforated by a single large zygomaticoorbital fo-
ramen. The anteroposterior breadth of the most inferior portion of
the frontal process is 11.5 mm.
4.3. Temporal fragments (Figs. 14 and 15)
U.W. 101-231 is a right temporal fragment of the most medial
portion of the petrous. This fragment preserves the internal audi-
tory meatus and a relatively pronounced arcuate eminence that is
positioned above the remnant of the subarcuate fossa. On the in-
ternal aspect of the fragment, the oval window is visible.
U.W. 101-346 is a robust partial left temporal preserving the
petrous pyramid, the EAM, and a portion of the mastoid region. A
large section of the small, triangular-shaped postglenoid process
contacts the tympanic, which forms the posterior wall of the
mandibular fossa as a ﬂattened and steeply inclined face. There is a
weak but somewhat sharpened crista petrosa. The stylomastoid fo-
ramen and carotid canal are preserved on the inferior surface, and the
anterior auditory meatus is present on the endocranial surface. There
is a relatively pronounced arcuate eminence that is positioned above
the subarcuate fossa. There is a thick tympanic plate surrounding the
EAM, which is medially positioned, ovoid in shape, and obliquely
oriented. Aweak suprameatal spine is presenton the posterosuperior
margin of the EAM. The suprameatal crest is well-developed and
angles superoposteriorly at the midpoint of the EAM. Only the most
superomedial portion of the mastoid is present and considerable
mastoid pneumatization is visible posteroinferiorly.
U.W. 101-546 is a right temporal fragment with an EAM, thick
tympanic plate, weak crista petrosa, superolateral portion of the
mandibular fossa, and root of the zygoma. The suprameatal crest is
weak. A weak suprameatal spine is present on the posterosuperior
margin of the EAM. There is a small triangular postglenoid process
present that extends 8.5 mm inferiorly. The tympanic forms the
posterior wall of the mandibular fossa as a ﬂattened and steeply
inclined face. The root of the zygoma is angled downward at about
30.0 to the estimated FH. A small portion of the superior-most
mastoid process is preserved revealing mastoid pneumatization.
U.W. 101-950 is a right temporal fragment at the superior
portion of the EAM. The posterior portion preserves part of the
mastoid process showing pneumatization. There is a slight supra-
meatal spine at the posterosuperior rim of the EAM.
U.W. 101-1044 is a left temporal fragment of the most medial
portion of the petrous. The fragment preserves the internal audi-
tory meatus. A large arcuate eminence is present on the superior
aspect, underlain by the subarcuate fossa. The specimen is damaged
so as to reveal the oval window, as well as the prominence of the
lateral semicircular canal.
U.W. 101-1227 is a left sphenoid-temporal fragment preserving
the anterior half of the mandibular fossa and the lateral wall of the
foramen spinosumdthe enclosure for the foramen spinosum is not
preserved. The sphenosquamosal suture bisects the entoglenoid
process, and the sphenoid does not contribute to the medial wall of
the mandibular fossa. The articular eminence is oriented posteriorly
Figure 12. Homo naledi frontal fragments in (A) anterior and (B) posterior views. Specimen U.W. 101-1425 also preserved parietal bone. Scale bar ¼ 2 cm.
j.jhevol.2016.09.009

in the mandibular fossa. The preglenoid plane is small and parallel to
the estimated FH. A small segment of the fragment preserves a
groove for the middle meningeal artery. Although much of the fossa
is missing, the preserved portion of the mandibular fossa appears to
be shallow.
U.W. 101-1243 is a left temporal fragment at the root of the
zygomatic process. The inferior aspect of the anteromedial portion
preserves the ﬂare of the zygomatic arch, and the posterior portion
preserves the lateral part of the articular eminence.
U.W. 101-1332 is a right zygomatic process of the temporal.
Given its overall small size and porous surface, this is likely from a
juvenile individual. The fragment preserves a small segment of the
anterolateral-most articular eminence. Anterior to this is a protu-
berance of bone indicating a well-developed origin for the masseter
muscle.
U.W. 101-1388 is a right temporal fragment preserved superior
to the EAM. Pneumatization is marked. The anteroinferior extent of
a moderate angular torus is present above a slight suprameatal
spine that itself is positioned on the posterosuperior aspect of the
EAM. Around the suprameatal spine, the bone is highly porous.
U.W. 101-1415 is a right temporal fragment of the tympanic part
of the petrous. Laterally, the fragment preserves a small part of the
inferior rim of the EAM, and the superior surface preserves part of
the auditory canal. The medial aspect terminates with the inferior
half of the carotid canal. The posterior surface preserves the sty-
lomastoid foramen.
4.4. Parietal fragment (Fig. 16)
U.W. 101-599 is a parietal fragment with distinctly impressed
parietal striae. There are meningeal impressions on the endocranial
surface. The fragment is 6.0 mm thick.
4.5. Occipital fragments (Fig. 17)
U.W. 101-054 is a left occipital fragment preserving the lamb-
doidal suture and a portion of the cerebral fossa. The superior
nuchal line is present on the ectocranial surface and the endo-
cranial surface is impressed by meningeal grooves.
U.W. 101-200 is an adult occipital fragment that preserves much
of the left cerebral fossa and a small portion of the right cerebral
fossa. The occipital planum is preserved superiorly, including a
portion of the lambdoidal suture and lambda. The well-developed
right and left superior nuchal lines meet in the midline, although
the area of the tuberculum linearum and external occipital protu-
berance is broken away. Superior to the nuchal lines is a well-
developed occipital torus traversing across the specimen below
the horizontally disposed lambdoidal suture. The height of the
Figure 13. Homo naledi zygomatic fragments in (A) anterior, (B) posterior, and (C) medial views. U.W. 101-409 (C) is in superior view. Scale bar ¼ 2 cm.
14
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occipital planum from lambda to the estimated position of the
occipital protuberance is at least 45.0 mm. The sagittal sulcus is
preserved endocranially, reaching to the superior part of the
cruciform eminence.
U.W. 101-770 is a right portion of an adult occipital bone pre-
serving segments of the lambdoidal and occipitomastoid sutures.
Ectocranially, the specimen is marked by a pronounced superior
nuchal line, and the bone thickens as it approaches the asterionic
region. Above the nuchal line a segment of the occipital plane is
preserved, while below the nuchal line the preserved nuchal plane
is flat but steeply angled. Endocranially, a small portion of the right
cerebral fossa, a deeply impressed transverse sulcus, and a superior
portion of the right cerebellar fossa are present. The fragment is
13.5 mm thick at the asterionic region.
U.W. 101-1234 is a left portion of an adult occipital bone, pre-
serving a segment of the lambdoidal suture and a portion of the left
occipitomastoid suture. The left portion of the inferior occipital
plane and the superior portion of the left flat nuchal plane are
present. On the ectocranial surface, the lateral extent of the supe-
rior nuchal line thickens markedly as it approaches the asterionic
region, and the nuchal plane is mostly flat and steeply inclined.
Endocranially, portions of the cerebral and cerebellar fossae are
preserved, separated by a deeply impressed transverse sulcus. The
fragment is 9.0 mm thick at the asterionic region.
Figure 14. Homo naledi temporal fragments in (A) posterior view for U.W. 101-231 and U.W. 101-1044, lateral view for U.W. 101-346, U.W. 101-546, and U.W. 101-1415, and (B)
inferior view. Scale bar ¼ 2 cm.
Figure 15. Homo naledi temporal fragments in (A) ectocranial/lateral and (B) endocranial/medial views. Scale bar ¼ 2 cm.
j.jhevol.2016.09.009

4.6. Mandibular fragments (Fig. 18)
U.W. 101-001 is an adult right mandibular fragment that pre-
serves the mandibular corpus and dentition from RP3 to RM3. The
oblique line is marked and terminates at the distal M2. The supreme
lateral torus (Dart,1954) is moderately developed and separates the
plane of the extramolar sulcus from the plane of the lateral corpus.
The superior lateral torus is weakly developed, traversing to the
mental foramen, where it is truncated by damage. The marginal
torus is mostly encased in matrix, but an intertoral sulcus is
palpable. The distal portion of the posteriorly opening mental fo-
ramen is preserved above mid-corpus at the mesial edge of P4. The
alveolar prominence weakly overhangs the continuous anterior
and posterior subalveolar fossae. A striation-type of mandibular
torus is indicated from M2 anteriorly. The basal corpus is thick and
evenly rounded along its extent until the pregonial incisure. The
mandibular recess is moderately deep and the extramolar sulcus is
wide. The masseteric fossa is deeply excavated, and there are
moderate masseter insertion lines on the preserved medial portion
of the gonial angle. The pharyngeal crest is well-developed and
sharp. The mylohyoid line is faint and the mylohyoid groove is deep,
with a small foramen present about midway.
U.W. 101-010 is a fragment of an adult right mandibular corpus
preserving the C and P3. At the anterior extent of the fragment a
thickening of bone indicating the mental protuberance is present,
but the cortical surface is not preserved. A moderately developed
interdigastric spine projects posteroinferiorly at the midline of the
symphysis, with a shallow, rounded digastric fossa immediately
adjacent. A moderately deep genioglossal pit is present, occupied
by several mental spines. Although damaged, it is apparent that the
area of the lingual alveolar plane is steeply inclined and not shelf-
like. There does not appear to be a superior transverse torus, but a
weak, basally disposed inferior transverse torus is present. The
mental foramen is located above mid-corpus at the distal extent of
P3. The anterior marginal tubercle is indicated by a slight thickening
and roughening of bone below P3. The anterior subalveolar fossa at
P3 is deeply excavated. The preserved basal corpus is thick and
evenly rounded.
U.W. 101-325 is a left mandibular condyle fragment. The artic-
ular surface has been eroded away leaving little visible morphology.
U.W. 101-733 is a right coronoid process of the mandible. The
anterior border has a sharp edge, and the superior aspect preserves
a marked m. temporalis attachment. There is a slight ectocoronoid
buttress and a more distinctly marked endocoronoid buttress that
likely terminated on a well-developed triangular torus (although
the triangular torus itself is not preserved).
U.W. 101-795 is an adult right coronoid process that preserves
much of the anterior edge and a small part of the posterior edge.
The anterior edge of the coronoid ﬂares slightly medially and is
marked by an especially pronounced insertion for the temporalis
muscle. The ectocoronoid and endocoronoid buttresses are
moderately developed.
U.W. 101-1001 is a left mandibular ramus fragment that pre-
serves a segment of the mandibular notch. The lateral eminence of
the ramus is low and rounded. A segment of the triangular torus is
preserved, as well as a small portion of the rounded anterior border.
U.W. 101-1142 is an adult right mandibular fragment preserving
the M2 and M3. The marked lateral prominence encompasses the
Figure 16. Homo naledi parietal fragments in (A) ectocranial/lateral and (B) endocranial/medial views. Fragment U.W. 101-599 is inferior and fragment U.W. 101-981 is superior.
Scale bar ¼ 2 cm.
16
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entire lateral face of the mandible, with its greatest lateral extent at
M2. The mandibular recess is deep, with awide extramolar sulcus and
oblique line that terminates at the distal end of M2. Only the mesial
portion of the gonial angle is preserved, and it shows a pronounced
buccal ﬂange for the insertion of the masseter. The masseteric fossa is
deeply excavated. Lingually, the mylohyoid line and groove are faint.
The continuous anterior and posterior subalveolar fossae are
moderately deep. Within the posterior subalveolar fossa is a small,
Figure 17. Homo naledi occipital fragments in (A) ectocranial/posterior, (B) lateral, and (C) endocranial/anterior views. Scale bar ¼ 2 cm.
Figure 18. Homo naledi mandible fragments in (A) superior, (B) lateral, (C) inferior, and (D) medial views. U.W. 101-325 (C) is in posterior view. Image (A) is in anterior view and (C)
is in posterior view for specimens U.W. 101-733 and U.W. 101-795. Scale bar ¼ 2 cm.
j.jhevol.2016.09.009

bony extrusion that might indicate an osteoma. The basal corpus is
thick and evenly rounded along its extent until the pregonial incisure.
The pharyngeal crest is well-developed and sharp, and there is a
small post molar trigone (of Klaatsch). A large, oval mandibular fo-
ramen is present, with no indication of a lingula.
5. General descriptions
5.1. Cranium
A minimum of six individuals represented by crania and/or
mandibular material have been recovered from the Dinaledi
Chamber: the holotype (DH1) calvarium with associated maxilla
and mandible, four partial calvaria (DH2, DH3, DH4, and DH5), and
a juvenile mandible (DH6). DH1eDH6 are in various states of
completeness, although the remains are generally well-preserved
and relatively undistorted. These skulls, supplemented by a
collection of fragments (Table 2), form the basis of the taxonomic
descriptions below. Measurements are derived from the original
specimens or from mirror-imaged reconstructions described in
Berger et al (2015; full list of measurements in SOM Tables S1eS5).
Most regions of the skull are represented by material from the
collection, with the exception of the midface and basicranium.
In lateral view, the cranial vault is anteroposteriorly short with
frontal bossing and prelambdoidal flattening. The sagittal length of
the vault measured from bregma to lambda is 79.0 mm in DH1 and
66.0 mm in DH2 (SOM Table S1). The morphology of the nuchal
region appears to be sexually dimorphic, with variable degrees of
nuchal muscle markings observed across specimens and a promi-
nent external occipital protuberance and tuberculum linearae
evident on DH1. Vault shape in posterior view is pentagonal with
slight double parasagittal keeling (Lordkipanidze et al., 2006)
observed between bregma and lambda on either side of the sagittal
suture. Parietal bossing is evident, but vault breadth is greatest in
the supramastoid region. Supramastoid breadth varies from
115.0 mm in DH1 to 102.0 mm in DH3 (SOM Table S1). In superior
view, vault shape is widest posteriorly and narrows anteriorly with
slight postorbital constriction (the narrowest cranial width is 79.0%
of the superior facial breadth, measured from reconstructed DH3).
The cranial vault is generally thin, becoming thicker in the temporal
and occipital regions. Adult cranial capacities were virtually
reconstructed in Berger et al. (2015) and estimated to range be-
tween 465 cm3
(DH3) and 560 cm3
(DH1). Size differences in cra-
nial capacity likely reflect sexual dimorphism (Berger et al., 2015).
There is a well-defined, continuous, supraorbital torus with a
distinct supratoral sulcus. The superolateral corners of the orbits are
rounded and the superior margins are thin laterally. In DH3, thick-
ness of the occipital torus is 9.0 mm medially, 7.0 mm at the midline
of the orbit, and 7.0 mm laterally (SOM Table S3). There is no
zygomatic prominence, no flaring of the zygomatics, and the inferior
root of the zygomatic process of the maxilla originates anteriorly
between P3
and P4
. The shape of the palate is parabolic, the palate is
relatively broad, and depth of the palate is shallow anteriorly
(3.0 mm at the canines) but deepens posteriorly (10.0 mm at M2
;
SOM Table S4). A mediolaterally flat nasoalveolar clivus combines
with the weak canine juga to create a squared maxillary profile. The
temporal lines are widely spaced. The minimum distance, in the
transverse plane, between the right and left temporal lines ranges
from 56.0 mm in DH1 and DH3 to 45.0 mm in DH2 (SOM Table S1).
These lines extend toward the mastoid angle on the parietal where a
distinct angular torus is present. The root of the zygomatic process of
the temporal is oriented approximately 30.0 anteroinferiorly rela-
tive to the estimated FH. Lateral flaring of the root of the zygomatic
process begins superior to the mandibular fossa rather than the
EAM. The squamosal suture is curved and low in height. The height
of the squamosal suture from FH is 40.0 mm in DH3 (SOM Table S1).
The mandibular fossa is positioned almost entirely medial to the
temporal squama, is moderate in depth (5.0 mm in DH3), and is
bordered by a small triangular-shaped postglenoid process that
together with the flat and steeply inclined anterior face of the
petrous temporal forms the posterior wall of the fossa. An elongated,
inferiorly projecting entoglenoid process forms the medial bound-
ary of the mandibular fossa. Both the tympanic and petrous portions
of the temporal are coronally-oriented (tympanomedian angle is
79.0; petromedian angle is 46.0). The tympanic region has a small,
obliquely oriented, oval EAM (varying between 8.0 and 10.0 mm in
superoinferior length and 5.0e6.0 mm in anteroposterior breadth),
a projecting Eustachian process, a small vaginal process, and a weak
crista petrosa. A small suprameatal spine is present. The mastoid
process is triangular in cross-section in a parasagittal plane, has a
rounded apex, a slight lateral inflation, and displays a deep and
narrow digastric groove. Length of the mastoid process is 25.0 mm in
DH3 (SOM Table S2). Expression of the occipital torus, external oc-
cipital protuberance, and tuberculum lineara varies from slight in
the smaller individual (DH4) to a pronounced protrusion in the
largest specimen (DH1). As these features are more pronounced in
specimens with larger cranial capacities (e.g., DH1), these differ-
ences are likely sexually dimorphic.
5.2. Mandible
A minimum of five adult and two juvenile mandibles are known
from Dinaledi, two of which have been associated with crania: U.W.
101-1261 with DH1, and U.W. 101-361 tentatively with DH3. The
relatively gracile mandibular corpus is parabolic in shape, accentu-
ated by the well-developed lateral prominence at M2. Width of the
mandibular corpus at M2 varies from 21.0 mm in DH1 to 19.0 mm in
U.W. 101-001 and U. W. 101-1142 (SOM Table S5). The mandibular
symphysis is vertical with a slight mandibular incurvation delin-
eating a faint mental trigone, indicating the presence of a weak
mentum osseum. Lingually, the area of the post-incisive planum is
not shelf-like, but instead slopes steeply to the genial tubercles that
are positioned inferiorly on the corpus. The basally positioned
inferior transverse torus is weak and a superior transverse torus is
absent. The anterior and posterior subalveolar fossae are continuous
and deeply excavated. Mental foramina are positioned above mid-
corpus height between P3 and P4 and open posteriorly. Distance of
the mental foramen from the basal margin varies from 15.0 to
16.0 mm and the distance from the alveolar margin to the mental
foramen varies from 8.0 mm in U.W.101-377 to 15.0 mm in U.W.101-
010 (SOM Table S5). The mandibular fossa and extramolar sulcus are
moderately wide. The root of the ramus originates high on the lateral
corpus at the mesial border of M2. The inverted gonial angle reveals
relatively well-defined ectoangular tuberosities and a moderately
deep masseteric fossa. Attachment sites for mm. masseter, medial
pterygoid, and temporalis are markedly rugose.
6. Comparative analysis: results
What follows are qualitative and quantitative comparisons of
H. naledi relative to other hominin taxa. Individual and mean
measurements and ratios for each species are presented in SOM
Tables S1eS5.
6.1. Homo naledi versus A. africanus
Australopithecus africanus differs from H. naledi in having a bell-
shaped cranial vault, closely spaced temporal lines (closest
approach of the temporal lines is 21.0 mm in A. africanus, 52.0 mm
in H. naledi), a moderate to marked postorbital constriction (index
18
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of postorbital breadth to superior facial breadth is 69.0 mm in
A. africanus, 79.0 mm in H. naledi), a lack of a well-defined supra-
orbital torus and supratoral sulcus, a mandibular fossa positioned
largely lateral to the temporal squamae, a large EAM (area of the
EAM averages 103.0 mm2
in A. africanus, 38.0 mm2
in H. naledi), a
marked canine jugum/anterior pillar, a pronounced zygomatic
prominence with flared zygomatic arches, a less vertically oriented
mandibular symphysis, a lingual alveolar plane that is weakly in-
clined and shelf-like ending in a distinct superior transverse torus,
and an inflated medial mandibular corpus with minimal excavation
of subalveolar fossae (Dart, 1925; Broom, 1947; Broom et al., 1950;
Lockwood and Tobias, 1999, 2002; Clarke, 2013). Quantitatively,
H. naledi has an absolutely and relatively taller cranium, with longer
parietal-temporal, parietal-lambdoid, and posterior cranial lengths
and a greater ratio of cranial height to porionic breadth than A.
africanus (SOM Table S1). At the same time, the frontal squama
angle is greater in H. naledi (50.0, compared to 43.0 in
A. africanus), indicating a slightly more elevated forehead. Although
there is overlap in the absolute degree of postorbital constriction,
H. naledi has relatively less constriction than A. africanus (Fig. 19A).
The squamous suture is slightly taller and slightly shorter than is
seen in A. africanus. The mandibular fossa of H. naledi is absolutely
longer anteroposteriorly than that of A. africanus, while fossa length
is about the same as breadth in H. naledi, unlike the relatively
mediolaterally broad fossa of A. africanus (Fig. 19B, Table 3, SOM
Table S2). The mandibular fossa also appears shallower in depth
in H. naledi (Fig. 19E, Table 3). Although there is overlap in terms of
cranial vault breadth between the two species, bi-mastoid breadth
in H. naledi is considerably smaller than in A. africanus, reflecting
the fact that the mastoids are tucked under the cranium to a much
greater extent in H. naledi. The EAM of H. naledi is both relatively
and absolutely smaller than that of A. africanus. For example, the
mean area of the EAM (the product of the superorinferior and
anteroposterior distances) is 103.0 mm2
in A. africanus and
38.0 mm2
in H. naledi (Fig.19F, SOM Table S2). The face of H. naledi is
mediolaterally narrower than A. africanus, with H. naledi having
absolutely smaller measures of superior facial breadth, biorbital
breadth, and supraorbital torus breadth (SOM Table S3). Anterior
interorbital breadth is absolutely and relatively (versus orbit
breadth) narrow in H. naledi, even though absolute orbit breadth
overlaps with A. africanus. Malar height is not as great in H. naledi,
while at the same time the nasoalveolar clivus is taller than is seen
in A. africanus. Maxilloalveolar length in H. naledi is shorter than in
A. africanus, and although there is overlap between the groups in
terms of maxilloalveolar breadth, in H. naledi the maxilloalveolar
process is relatively broader than in A. africanus (Fig. 19C, SOM
Table S4). Although there is overlap between H. naledi and A. afri-
canus in maxillary incisor and premolar tooth row lengths and
canine alveolus length, the molar row of H. naledi on average is
slightly shorter than that of A. africanus, while the inter-canine
distance is considerably narrower than that of A. africanus. The
mandibular corpus measurements and ratios of H. naledi are
considerably smaller than those of A. africanus (SOM Table S5).
Likewise, the mandibular premolar and molar tooth rows, along
with the canine alveolus, are absolutely smaller in H. naledi (mean
P3eP4 alveolar length is 15.0 mm and M1eM2 alveolar length is
37.0 mm) compared to A. africanus (mean P3eP4 alveolar length is
18.0 mm and M1eM2 alveolar length is 42.0 mm), although this
distinction becomes less apparent when scaled against corpus
breadth at M1 (SOM Table S5).
6.2. Homo naledi versus A. sediba
Homo naledi crania have a more pronounced and continuous
supraorbital torus bounded by a more distinct supratoral sulcus, a
longer and more vertically oriented frontal, a distinct angular torus,
a well-defined supramastoid crest, a zygomatic root angled ante-
roinferiorly relative to the estimated FH, and a flattened nasoal-
veolar clivus, all of which differentiate them from A. sediba (Berger
et al., 2010). Quantitative measures also distinguish H. naledi from
A. sediba. Homo naledi has an absolutely superoinferiorly taller
cranial vault, a longer parietalecoronal breadth, and a squamosal
suture that is shorter in anteroposterior length, but taller in
superoinferior height than in A. sediba (SOM Table S1). The
mandibular fossa of H. naledi is absolutely anteroposteriorly longer,
and H. naledi has a mediolaterally narrower articular eminence
compared to A. sediba (SOM Table S2). Greater alveolar height, a
slightly wider orbit, and a narrower interorbital region distinguish
the facial measures of H. naledi from A. sediba (SOM Table S3). The
maxilloalveolar process of H. naledi is slightly narrower medi-
olaterally (SOM Table S4). Palate depth of H. naledi is shallower than
that of A. sediba anteriorly, but becomes notably broader and
deeper and is similar in depth with A. sediba at M1
(SOM Table S4).
Maxillary incisor and maxillary and mandibular premolar alveolar
rows are shorter in H. naledi, highlighting in particular the uniquely
elongated premolar row of A. sediba (SOM Tables S4 and S5).
Although H. naledi has a mandibular symphysis that is slightly
larger in area compared to A. sediba, H. naledi has a smaller corpus
area (SOM Table S5). The mental foramen is positioned relatively
higher on the mandibular corpus in H. naledi, and the extramolar
sulcus is broader than in A. sediba (SOM Table S5).
6.3. Homo naledi versus H. habilis sensu stricto
Homo naledi crania can be distinguished from H. habilis sensu
stricto in possessing a less arched supraorbital contour, a supra-
meatal spine, an occipital torus, and parasagittal keeling, although
they share some elements of supraorbital and temporal
morphology (for example, the presence of a supraorbital sulcus,
intermediate thickness of the supraorbital torus, a projecting
entoglenoid process, a relatively deep and shallow mandibular
fossa, and a coronally-oriented petrous; Leakey et al., 1964, 2012;
Leakey, 1973; Tobias, 1991; Wood, 1991). The zygomatics are more
robust in H. naledi, with pronounced rugosity marking the origin of
masseter. The nasoalveolar clivus in H. naledi is notably transversely
flattened, unlike the more convexly curved region in H. habilis
(typified by KNM-ER 1813). Homo naledi possesses a well-
developed and distinctly anteriorly projecting anterior nasal
spine, unlike the more subdued anterior nasal tubercle of H. habilis.
The lingual alveolar plane of the mandible of H. naledi is steeply
inclined and not shelf-like and there is no indication of a superior
transverse torus, unlike H. habilis. Quantitative measurements also
distinguish H. naledi from H. habilis. Although there is overlap in
cranial vault height and length between H. naledi and H. habilis,
cranial height relative to bi-porionic breadth is slightly greater in
H. naledi, reflecting its somewhat taller and narrower cranium
(Fig.19D, SOM Table S1). Parietal-coronal breadth is smaller and the
squamosal suture is longer and lower in H. naledi than in H. habilis
(SOM Table S1). The mandibular fossa of H. naledi is shallower in
depth and longer anteroposteriorly, but shorter mediolaterally than
that of H. habilis, resulting in a distinctly different shape of the fossa
(Fig. 19B and E, Table 3, SOM Table S2). At the same time, the
articular eminence of H. naledi is absolutely and relatively narrower
mediolaterally than that of H. habilis, although there is overlap in
articular eminence depth (SOM Table S2). Although the length of
the mastoid process is roughly equivalent, the mastoid tips are
notably medially inflected in H. naledi, thus reducing the bi-mastoid
breadth relative to H. habilis (SOM Table S2). The EAM of H. naledi is
smaller than that of H. habilis, in particular in anteroposterior
breadth and EAM area (Fig. 19F, SOM Table S2). The face of H. naledi
j.jhevol.2016.09.009

is narrower than that of H. habilis and the supraorbital torus chord/
arc index is less arched in H. naledi (SOM Table S3). Anterior
interorbital breadth is absolutely less in H. naledi, but when scaled
by orbital breadth, overlaps with OH 24 (SOM Table S3). The tall
alveolar height of H. naledi overlaps with AL 666-1 alone within H.
habilis; however, the ﬂat nasoalveolar clivus of H. naledi is unlike
that of AL 666-1 (SOM Table S4). The maxilloalveolar process of
H. naledi is shorter and narrower than H. habilis; however, the two
Figure 19. Ratios of (A) postorbital breadth/superior facial breadth, (B) mandibular fossa length/breadth, (C) maxillo-alveolar length/breadth, (D) cranial height/bi-porionic breadth,
(E) mandibular fossa depth/length, and (F) area of the EAM. Most groups include a low number of individuals, but for visualization boxplots are shown covering the ﬁrst to third
quartiles, the whiskers extend 1.5 times the interquartile range, and the middle bar is the mean. Specimens that are outliers or that plot on the whiskers are labeled. A full list of
specimens and values can be found in SOM Tables S1eS5.
20
j.jhevol.2016.09.009

taxa do not overlap in the ratio of maxilloalveolar length to breadth
(Fig. 19C, SOM Table S4). The maxillary and mandibular premolar
and molar alveolar rows are absolutely shorter in H. naledi (SOM
Tables S4 and S5). Similar to comparisons with A. sediba, the
anterior palate is absolutely narrower mediolaterally and shallower
in depth in H. naledi than in H. habilis, but there is overlap in the
posterior palate for both measures with H. habilis specimens (SOM
Table S4). Mandibular symphysis area is larger in H. naledi but
mandibular corpus area is more gracile. But there is overlap in H.
habilis and H. naledi absolute mandibular dimensions (SOM
Table S5). Other distinguishing mandibular measures include a
mental foramen that is positioned more superiorly on the corpus
and a broader extramolar sulcus in H. naledi (SOM Table S5).
6.4. Homo naledi versus H. rudolfensis
Despite sharing a flat and squared nasoalveolar clivus with
H. rudolfensis, H. naledi is distinguished relative to this taxon in its
smaller cranial capacity (maximum of 560 cc in H. naledi compared
to 770 cc in H. rudolfensis), parasagittal keeling, occipital torus,
marked supraorbital torus and supratoral sulcus, more anteriorly
placed zygomatic root, weak crista petrosa, and steeply inclined
mandibular lingual alveolar plane that lacks a superior transverse
torus. Quantitative measures of the cranial vault of H. rudolfensis are
larger in both absolute length and height (SOM Table S1). However,
relative cranial vault dimensions are not as distinct between the
taxa (SOM Table S1). Absolute mandibular fossa depth in H. naledi is
similar to H. rudolfensis, but H. naledi has a shallower relative fossa
depth (when scaled to fossa length) and an absolutely longer fossa
(Fig. 19E, Table 3, SOM Table S2). The ratio of articular eminence
breadth to mandibular fossa breadth is smaller in H. naledi (80.0% in
H. naledi, 100.0% in H. rudolfensis; SOM Table S2). Facial breadths of
H. naledi are relatively smaller than that of H. rudolfensis KNM-ER
1470 (SOM Table S3). The supraorbital torus is narrower and
thinner than in H. rudolfensis, but not as arched as seen in the
chord/arc index (SOM Table S3). Anterior interorbital breadth, both
absolute and relative to orbit breadth, is narrower in H. naledi. The
face of H. naledi has shorter zygomatics and a taller nasoaleveolar
clivus than H. rudolfensis, with the exception of KNM-ER 1470 (SOM
Table S3). The palate of H. rudolfensis is considerably larger and
deeper than H. naledi, although the shape of the maxilloalveolar
process is similar to that of KNM-ER 1470 (SOM Table S3). Both the
mandibular symphysis and corpus are notably smaller and more
gracile in H. naledi, and the mental foramen is positioned higher on
the corpus in H. naledi (SOM Table S5).
6.5. Homo naledi versus H. erectus sensu lato
Homo naledi crania can be distinguished from H. erectus crania in
possessing a more anteriorly positioned root of the zygomaxillary
process at P3
/P4
(unlike the P4
/M1
position typically found in
H. erectus, although this does tend to be variable), a laterally posi-
tioned horizontal EAM that is almost coplanar with the wall of the
cranium, a weak crista petrosa, a small vaginal process (moderate to
large in H. erectus), a laterally inflated mastoid process (not inflated
in H. erectus), and a sloping mandibular lingual alveolar plane that
lacks a superior transverse torus. H. erectus encompasses a wide
range of morphological variation, particularly with the inclusion of
specimens from Dmanisi. Despite the morphological variation
across H. erectus, quantitative measures of H. naledi fall outside of
the H. erectus range of variation. Absolute measures of vault size
including cranial vault breadth and postorbital breadth are nar-
rower in H. naledi than in H. erectus, although they overlap in
relative comparisons (e.g., supramastoid breadth/temporal
breadth; SOM Table S1). The squamous suture of H. naledi is rela-
tively taller in height from FH and shorter in anteroposterior length
than H. erectus (SOM Table S1). The mandibular fossa in H. naledi is
relatively similar in width and length, but most H. erectus speci-
mens have a wider fossa relative to length (Fig. 19B, Table 3, SOM
Table S2). Similarly, the mandibular fossa in H. naledi is shallower
in depth relative to its length relative to all measured H. erectus
(Fig. 19E, Table 3). The articular eminence of H. naledi is both
absolutely and relatively narrower than H. erectus, although there is
overlap between the groups in articular eminence depth. The
strongly medially inflected mastoid processes result in a bi-mastoid
breadth that is narrower in H. naledi compared to H. erectus. The
narrow bi-entoglenoid breadth of H. naledi only overlaps with
KNM-ER 42700; however, when bi-entoglenoid breadth is scaled to
temporal breadth the two taxa appear more similar (Table 3). The
area of the EAM is notably smaller in H. naledi (Fig. 19F). The face of
H. naledi is generally narrower than that of H. erectus, only over-
lapping in superior facial breadth with the smaller Dmanisi speci-
mens (SOM Table S3). The supraorbital torus is absolutely smaller in
H. naledi, while the chord/arc index overlaps only with D2700
among H. erectus (Table 3). Similarly, the supraorbital torus is
thicker in H. erectus medially and at the orbital midline, with the
exception of the thin torus in KNM-ER 42700 that overlaps with
H. naledi. The anterior interorbital breadth of H. naledi is narrower
than H. erectus, and when scaled to orbital breadth, only one
specimen of H. erectus, KNM-WT 15000, exceeds the value
encountered in H. naledi. The maxilloalveolar process in H. naledi is
Table 3
Select ratios of bivariate measurements (100).a
H. naledi A. africanus A. sediba H. habilis H. rudolfensis H. erectus MP Homo
Mean DH1 DH2 DH3 UW
101-001
UW
101-377
Mean MH1 Mean Mean Mean Mean
Cranial height/porionic breadth 79 77 76 85 72 67 72 74 74 82
Supra-mastoid breadth/temporal breadth 103 105 105 99 111 109 108 104 105
Postorbital breadth/superior facial breadth 79 69 81 73 74 80 81
Temporal lines/parietal breadth 51 52 45 55 27 56 32 43 57 90
Squamous suture height/breadth 67 52 42 42 58 52
Mandibular fossa length/breadth 96 60 52 58 79 75
Mandibular fossa depth/length 21 48 50 52 32 51
Articular eminence breadth/mandibular
fossa breadth
80 106 104 111 100 117
Bi-ento-glenoid breadth/temporal breadth 58 62 57 55 58 54
Supra-orbital torus breadth chord/arc 75 84 86 88 87 85
Anterior interorbital breadth/bi-orbital breadth 27 22 26 23 24 25 24
Anterior interorbital breadth/orbit breadth 72 53 65 58 61 62 59
Maxillo-alveolar length/breadth 93 107 100 95 96 98 90
Mental foramen height/corpus height at P4 40 42 41 38 53 50 46 49 48
a
Full measures are available in the SOM Tables.
j.jhevol.2016.09.009

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