# Reappraisal of the Morphological Affinities of the Maba
1 Cranium: New Evidence From Internal Cranial
Anatomy

Jiaming Hui, Xiujie Wu, Antoine Balzeau

► To cite this version:

Jiaming Hui, Xiujie Wu, Antoine Balzeau. Reappraisal of the Morphological Affinities of the Maba 1 Cranium: New Evidence From Internal Cranial Anatomy. American Journal of Biological Anthropology, 2025, 187 (1), pp.e70064. 10.1002/ajpa.70064. hal-05346960

HAL Id: hal-05346960

https://hal.science/hal-05346960v1

Submitted on 26 Nov 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Reappraisal of the morphological affinities of the Maba 1 cranium:
new evidence from internal cranial anatomy

Jiaming Hui¹,²,³, Xiujie Wu¹, Antoine Balzeau²,⁴

1. Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China

2. PaleoFED team, UMR 7194 Histoire Naturelle de l'Homme Préhistorique, MNHN-CNRS-UPVD, Paris, France

3. Sorbonne Université, Paris, France

4. Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium

## Correspondence

Xiujie Wu, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044, China
Email: wuxiujie@ivpp.ac.cn

Jiaming Hui, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044, China
Email: huijiaming@ivpp.ac.cn

## Abstract

**Objectives:** Maba 1 is a critical fossil from the late Middle Pleistocene Asia. It is well-
known for the Neandertal-like face, while its neurocranium shows affinities with many
hominin taxa, which makes the taxonomic status of Maba 1 controversial. Beyond the
limited information from the external surface, we investigate in details its internal
structures, which are largely unexplored.

**Materials and Methods:** We reconstructed and described its frontal sinuses, diploic vessels, endocast, and bone thickness, using micro-CT data. Linear measurements were applied for the frontal sinuses and endocast, and the latter was also analysed through geometric morphometrics. A comparison is made after considering the preservation of Maba 1 and the availability of comparative specimens.

**Results:** The linear discriminant analyses for the frontal sinus cluster Maba 1 with *H. neanderthalensis*. The Maba 1 diploic vessels anastomosed with the parietal foramen, a rare trait among *H. neanderthalensis*. The Maba 1 endocast differs from *H. erectus* in the frontal lobe, but it was generally closer to *H. erectus* than to *H. neanderthalensis* and *H. sapiens*. Generally, Maba 1 shares higher resemblances with other debated specimens, including LH18, Djebel Irhoud, and Broken Hill 1. The bregmatic thickness of Maba 1 differed from most *H. erectus*, while patterns in other areas share similarities with *H. neanderthalensis* and some *H. erectus*.

**Discussion:** The internal structures of Maba 1 shows a combination of morphological features found in various species. These further evidences the high morphological variability among Asian hominins in the late Middle Pleistocene. Maba 1 currently cannot be definitely classified in any known hominin taxon.

**Keywords:** Middle Pleistocene hominins, human evolution, internal cranial anatomy, China, micro-computed tomography
**Research Highlight:**

Micro-CT reveals the undiscovered vascular structures in Maba 1 cranium.

Admixture of morphological affinities manifests in the internal anatomy.

Maba 1 cannot be certainly classified in any known hominin taxon and it can be
temporarily considered as an Asian 'Non-erectus'.

**1. Introduction**

The Maba 1 cranium was excavated from the Lion Rock, Guangdong province, southern China (Woo & Pen, 1959). This partial cranium retains the upper half of the neurocranium and a few fragments of the facial bones (Figure S1). Chronological studies have given this fossil an age of 300-130 ka (Shen et al., 2014; Yuan et al., 1986), which corresponds to the late Middle Pleistocene. This time period is key to understanding the human evolutionary history of Eurasia, as it is a turning point witnessing dramatic climate changes in East Asia as well as an increased morphological variability among local hominin paleodemes (Li et al., 2017; Liu et al., 2022; Wu et al., 2023). Chinese fossils from this period show a combination of archaic *H. erectus* morphological traits and derived traits resembling *H. sapiens*. Especially, many have been reported to possess affinities with *Homo heidelbergensis*, *Homo neanderthalensis*, or Denisovans (Chen et al., 2019; Liu et al., 2022; Wu et al., 2014; Wu & Athreya, 2013), which indicates a possible co-existence of hominin paleodemes, or a dispersal of European or African hominin gene flows. Moreover, this period also corresponds to a unique human diversity all over the Old World with several different species spread all over the different areas, whereas the question of their distribution in Asia is also
fully opened. In this context, contributing to the clarification of the human diversity in Asia is important to understand the global evolution of hominins.

Maba 1 is among those fossils with noticeable morphological features resembling Middle & Late Pleistocene hominins from Europe and Africa. The supraorbital torus, orbit, and nasal bones of Maba 1 have been found to be Neandertal-like (Woo & Pen, 1959; Wu, 1988; Wu & Bruner, 2016). Considering the age of Maba 1 is much earlier than those of 'classic Neanderthals', this fossil may not show clear evidence of the dispersal of *H. neanderthalensis* in East Asia. Instead, as mentioned by Wu (2017), Maba 1 may indicate that the gene flow from the ancestor of *H. neanderthalensis* reached East Asia. Still, it remains questionable whether those Neandertal-like traits in Maba 1 signify a phylogenetic relationship or a result of convergent evolution.

Meanwhile, different aspects of Maba 1 endocranial surfaces, as assessed through linear morphometrics (Wu & Bruner, 2016), seem to be similar to those of different species. For instance, the narrow width of the frontal lobe is similar to that of *H. erectus* and *H. heidelbergensis*, while the curve of frontal squama is close to that of *H. neanderthalensis* and *H. sapiens* (Figure 4). This complex pattern makes the taxonomic status of Maba 1 controversial. However, the existence of cranial features of both *H. erectus* and *H. sapiens* within Maba 1, creates an important case in validating the 'Continuity with Hybridization hypothesis' which postulates that the local *H. erectus* in East Asia continually evolves into *H. sapiens* while concurrently receiving gene flow from Western Eurasia (Wu, 1988, 2006; Wu & Athreya, 2013). A recent phylogenetic study based on a large number of cranial morphological characters further suggests that Maba 1 should cluster with Xuchang (Ni et al., 2021). The population represented by
Xuchang is proposed to be either *H. juluensis* or perhaps Denisovans (Gokhman, 2019; Wu & Bae, 2024). This renders the position of Maba 1 even more elusive because Denisovans are not yet defined anatomically.

In addition, the recent taxonomic discussion has led to the naming of a number of *Homo*
species, including *H. floresiensis*, *H. luzonensis*, *H. naledi*, *H. longi*, and *H. juluensis*
(Bae & Wu, 2024; Détroit et al., 2019; Hautavoine et al., 2024; Hurst et al., 2024; Kaifu
et al., 2024; Ni et al., 2021; Roksandic et al., 2022), several of which appear to be
employed to replace the designation “archaic” *H. sapiens*. While *H. naledi*, *H. floresiensis* and *H. luzonensis* are widely recognized due to their distinct anatomical
traits, they remain somewhat peripheral to the debates on *H. sapiens* origins. Instead,
debates largely focused on species denomination and nomenclature, particularly
regarding taxa such as *H. heidelbergensis*, *H. rhodesiensis*, *H. bodoensis*, *H. juluensis*,
and *H. longi*. Further research is needed to refine our understanding of cranial variation
within these groups and to provide more comprehensive anatomical descriptions of the
specimens classified within them. Similarly, a Denisovan fossil with well-preserved
morphological information and genetic/proteomic information is necessary within the
published literature. This type of fossil would allow for a detailed comparison with
specimens that are well-established to belong to certain species and those that are not,
to clarify the anatomical characteristics of a potentially new species. Without such a
fossil, the debate can hardly be closed and thus, in the current state of knowledge, we
aim to document Maba 1 thoroughly and analyze it within the largest comparison record
ever used for this type of specimen.

Constrained by the incompleteness of Maba 1 cranium, the limited morphological
information from the external surface could hardly provide enough empirical data for a comprehensive taxonomic or phylogenetic interpretation. In this context, it is necessary to turn to the internal structural anatomy for new clues. The frontal sinus, cranial vault thickness (CVT), and diploic venous channels (DCs) are generally well preserved in Maba 1 fossil. As suggested by many studies (Balzeau, 2013; Balzeau et al., 2022; Copes & Kimbel, 2016; Hui & Balzeau, 2023), their morphology may function as taxonomic signals distinguishing hominin species. For instance, the frontal sinus shows low variation and specific shapes in *H. neanderthalensis*, while it shows very high variation in *H. sapiens* and strong asymmetry in *H. erectus*. The CVT pattern in *H. erectus* shows evident thickening in the bregmatic area, while *H. neanderthalensis* and *H. sapiens* are characterized with an evident thinning in the anterosuperior part of the parietal bone. As for the DCs, *H. neanderthalensis* exhibits an absence of the DC anastomosis with parietal foramina, as well as the isolation between parietal DCs and transverse sinus. *H. sapiens* presents with the inconsistent anastomosis between the DC and the frontal sinus (the mucous membrane).

However, these internal structures in Maba 1 have not been described in detail nor used in taxonomical discussion. In this current study, by applying high-definition micro-CT, we aim to detect the micro-and macroscopic details of these structures. And for the endocast, which has been analyzed previously using linear morphometrics by Wu & Bruner (2016), we aim to collect new data by reassessing it through 3D geometric morphometrics and describing the morphology. We provide detailed descriptions, images, and complete morphometric data (Figures 1-5, Tables S2) to allow for future independent studies to be completed by other researchers. All of this will provide evidence for discussing the taxonomic and phylogenetic meaning of Maba 1. It will
also help us understand the specificities of this fossil, especially its implication in the
human evolutionary history in East Asia. Moreover, through this study, we aim to test
the usefulness of internal cranial structures in identifying affinities of Pleistocene Asian
fossils, looking for an effective and reliable approach for wide application.

## 2. Materials and methods

### 2.1 Materials

The Maba 1 specimen is curated in the Institute of Vertebrate Paleontology and
Paleoanthropology (IVPP), Chinese Academy of Sciences. The specimen was in
fragments when discovered, and only the upper half of the cranium has been found and
reassembled. In detail, the specimen is composed of the nasal bones, right zygomatic
bone, frontal bone, parietal bones, and small portions of the sphenoid, temporal, and
maxilla bones (Figure S1). Additionally, the center of the frontal squama and left
parietal bone are missing and replaced with artificial materials.

The internal structures of the Maba 1 specimen are generally well-preserved. Although taphonomic damages in the supraorbital ridge make the anterior surface of the frontal sinus slightly exposed, it does not impact the following measurements. Some sediments fill in the diploe, rendering the boundary of some diploic cavities unclear, but most emissary and diploic venous channels are identifiable. Finally, the ectocranial and endocranial surfaces are slightly eroded (most erosion is smaller than 1.0 mm in thickness), which does not considerably impact the accuracy of cranial vault thickness (CVT) measurements and the morphometric analysis of endocast.

The selection of comparative samples depends on the analyses that are performed
(Table S1). For the frontal sinuses, Maba 1 is compared to the database offered in our published paper on the frontal sinuses of hominins (Balzeau et al., 2022), which includes 12 early hominins (*Sahelanthropus*, *Australopithecus*, and *Paranthropus*), 15 *H. erectus* s.l. (from Africa, Georgia and Asia), 17 Middle Pleistocene fossils with unclear taxonomic positions, 13 *H. neanderthalensis*, eight fossil *H. sapiens*, one *H. naledi*, and one *H. antecessor*. Also, 345 extant *H. sapiens* (sex information unknown, 103 from Europe, 78 from Alaska, 71 from the Pacific area, 48 from Greenland, 13 from Middle and South America, 12 from Africa, 11 from India, 9 from China) are included in the frontal sinus comparison. Moreover, a linear discriminant analysis (LDA, see below the methodological explanations) of frontal sinuses dimensions was calculated on a subsample of this material to include only well-preserved specimens. Those data were from Balzeau et al. (2022). In this context, the samples for this particular analysis focused on the Maba specimen comprise 12 early hominins included as a single group, 14 *H. erectus*, 21 *H. neanderthalensis* and 105 *H. sapiens*. This discriminant analysis was used to clarify the affinities of characteristics of the sinuses of Maba 1 compared to large fossil hominin groups.

In the analyses of the DC network, Maba 1 is compared to the published data of five *H. neanderthalensis* and four fossil *H. sapiens* (Hui & Balzeau, 2023). For the analysis of the CVT, Maba 1 is compared to the CVT colormaps of eight Asian *H. erectus*, seven *H. neanderthalensis*, seven fossil *H. sapiens*, and Broken Hill 1. The colormaps of these comparative specimens were either collected from our previously published paper (Balzeau, 2013), or generated in this current study from high-definition micro-CT images (including Trinil 2, Hexian, Broken Hill 1, La Ferrassie 1, La Quina H5, La Chapelle-aux-Saints 1, Spy 1, Spy 10, Cro Magnon 1, Cro Magnon 2, Cro Magnon 3,
and Abri Pataud 1).

Finally, for the endocast, the comparative sample comprises seven early hominins, 13 *H. erectus* s.l., 9 *H. neanderthalensis*, 9 fossil *H. sapiens*, 35 extant *H. sapiens*, and three specimens without a clear taxonomic status (Ngaloba LH 18, Djebel Irhoud 1, and Broken Hill 1). 3D models were obtained from original CT images or from volumetric numerisation of the physical casts. The detailed list of specimens used in each analysis is included in the supplementary information (Table S1) and data is from previously published work (Balzeau et al., 2017; Hurst et al., 2024).

## 2.2 Methods

The micro-CT scanning of the Maba 1 specimen was conducted in the IVPP, with the platform GE v|tome|x m300&180. The resolution was set as 0.053 mm, allowing us to inspect morphological details of the frontal sinus, diploe, and the endocranial surface.

Based on the micro-CT image stacks, the 3D model of the frontal sinus was segmented manually in the software 3D Slicer (version 4.13). The measurements on the virtual frontal sinus model were conducted following the protocol published by Balzeau et al. (2021 and 2022). In details, we measured the heights, lengths, and maximal extensions as 2D projections in lateral, superior, and anterior views (Figure 1 and Table 1), as well as the volume of the entire model. This includes the maximal lateral extension (W), maximal height (H), maximal length of left sinus (ALl), maximal length of right sinus (ALr), maximal medio-lateral extension of the left sinus (SLl), maximal medio-lateral extension of the right sinus (SLr), anterio-posterior length along the horizontal direction (AP), and the length from the most anterior point to the most supero-posterior point
(AP2). In order to discuss the affinities of the Maba 1 frontal sinus, a linear discriminant analysis (LDA) was performed through the software PAST (version 5.02) to make a comparison between Maba 1 and a large comparative database detailed in our previous works (Balzeau et al., 2022). The measurements used in this analysis were W, H, 2AL (2AL=All+ALr, the combined anterior length of the sinus), 2SL (2SL=SLl+SLr, the combined superior length), and 2AP (2AP=AP+AP2, the combined anterior dimension). The data classification was done by assigning each point to the group that gives minimal Mahalanobis distance to the group mean. This distance is calculated from the pooled within-group covariance matrix, giving a linear discriminant classifier. The given and estimated group assignments are listed for each point and are detailed in Table S2 and S3. Moreover, group assignment is cross-validated by a leave-one-out cross-validation (jackknifing) procedure (Hammer et al., 2001).

The DC network of Maba 1 was segmented following the protocol published by Hui & Balzeau (2023). By inspecting the CT images and transparent cranial model in 3D Slicer, we located the vascular channels in the diploic layer and then segment them with the FloodFilling and Paint functions in the software. The 3D model of the vascular channels was not complete due to taphonomic damages, but it was still informative in terms of drainage pathway and distribution pattern. The DC analysis was partly based on the data from the author's PhD thesis (Hui, 2024).

The CVT was estimated using the software Avizo (version 2019.1). After inputting in Avizo the 3D models of the ectocranial and endocranial surfaces, the distance between them were automatically calculated by the SurfaceDistance function, which was equal to the bone thickness. The distance was then presented as a colormap on the ectocranial
surface. For the sake of comparison, the color scale of the colormap was set as same as
those in published literatures, with the color scale ranging from light blue (thinner) to
red (thicker) (Balzeau, 2013; Balzeau & Charlier, 2016; Hui & Balzeau, 2024).
Additionally, the areas thinner than 2.0 mm were entirely colored in white, and those
thicker than 22.0 mm were entirely colored in yellow. The range between 2 and 22 mm
was used for all specimens, it allows for a direct comparison of the global range of
thickness variation and its distribution in the different parts of the vault. In the CVT
color maps, we could identify the relative thick and thin areas. Additionally, with the
Measurement function in Avizo, we could measure the thickness value of any point on
the cranium.

In 3D slicer, we collected the coordinate data of the 3D landmarks on the endocasts of
Maba 1 and comparative sample. Landmarks were selected to represent the maximal
extension of the different parts that are preserved on the endocast of Maba (Table 2),
which means the main extension of a lobe in a particular orientation, limit between
lobes, and internal anatomical structures. Those points were used in our previous
studies of endocranial anatomy (Balzeau et al., 2017; Hurst et al., 2024; Balzeau et al.,
in revision). In total, 12 landmarks were selected to describe as much as possible aspects
related to brain anatomy. 3D coordinate data for the landmarks were transformed to
Procrustes coordinates with software PAST (version 5.02) for all the specimens for
which the complete set of landmarks was preserved (n=75). During this step, specimens
are first translated so that the mean of all the centroid are at the origin, then the scale
component is removed as it the rotational component. When all specimens are
superimposed, shape comparison between specimens can be performed. The result of
3D landmark configuration was visualized through a principal component analysis
(PCA) and a linear regression of the size (obtained during Procrustes transformation) and Procrustes-fitted landmark positions were computed.

Moreover, linear measurements of the length, height and width of different areas of the endocast were extracted from these 3D coordinates in 3D slicer (Table 3). Morphometric data for the Maba 1 and comparative sample were scaled relative to each individual's endocranial volume. In this context, the cube-root of the endocranial volume (EV) for each individual was used to scale each linear variable ((xi/(3√EVi)*100)). Univariate analyses were carried out using adjusted z-score (Azs) following the protocol published by Scolan et al. (2012), in which 95% of the variation of the reference population is included between -1 and +1. An Azs lower than -1 or higher than +1 is, therefore, outside 95% of the variation of the reference population. Considering the statistical approaches, we used several different procedures that were conducted with the software PAST (version 5.02). We explored the whole information expressed by our results, including "non-significant" or "negative" results as suggested by Amrhein et al. (2019).

# 3. Results

## 3.1 The frontal sinuses

The frontal sinuses of Maba 1 were well preserved. Only a small proportion of the anterior extension of the left frontal sinus is exposed due to incomplete preservation of the frontal torus. But it does not influence the shape and extension of the sinuses there. No reconstruction was necessary to obtain the full volume of the sinuses. Moreover, the maximal extensions of the pneumatisation were visible in all directions as they are fully
preserved (Figure 1). As a result, measurements were quantifiable in all directions
without problems following our protocol.

The left sinus was larger the right one. On both sides, the sinuses were globular,
particularly for their medial extension. Their uppermost extension exhibited some
digitations. However, a large cell propagated from the postero-medial origin of the
sinuses on both sides and formed an elongated volume that continued vertically and
laterally along the endocranial wall of the frontal bone. These cells represented the most
lateral extension of the sinuses on both sides.

For the entire frontal sinuses, the volume was estimated as 10222 mm³, maximal lateral extension (W) was 75.0 mm, maximal height (H) was 40.9 mm, anterio-posterior length along the horizontal direction (AP) was 23.6 mm, and the length from the most anterior point to the most supero-posterior point (AP2) was 27.8 mm. For the left sinus, the maximal length (AL1) was 40.3 mm, maximal medio-lateral extension (SL1) was 43.4 mm. For the right sinus, the maximal length (ALr) was 36.6 mm, the maximal medio-lateral extension (SLr) was 36.9 mm. Compared to the result of comparative sample, the dimensions of Maba 1 were relatively large and fell within the range of *H. erectus* and *H. neanderthalensis* both in terms of absolute and relative dimensions (Table S4, and Balzeau et al., 2022). In contrast, the dimensions quantified for Maba 1 are outside the range of variation observed in Bodo, Broken Hill and Petralona (Table S4). When projected in the LDA computed on the data compiled in our previous study, Maba 1 was classified in the *H. neanderthalensis* sample for the absolute and relative dimensions. The groups used in those analyses were early hominins, *H. erectus*, *H. neanderthalensis*, and *H. sapiens*. We obtained percentages of correct classification of respectively 79.6% and 64.5% for the LDA with the absolute and relative dimensions
among those different groups (See Table S2 and Table S3 for the details of the classification among groups). Those values are relatively high despite the large variation in the shape and size of the frontal sinuses, and are likely related to the fact that we have used large comparative samples (even though *H. heidelbergensis* group is not included in the LDA for insufficient sample size). In the LDA computed on the absolute dimensions and on the relative dimensions, Maba 1 was also found plotted within the distribution of *H. sapiens*, *H. erectus*, and *H. neanderthalensis* on the projection corresponding to the two first axes. This is related to the great variation observed for sinus expansion between and among species. Some particularities are visible, but with a superposition of the ranges of variation of the different species. Maba 1 has quite large sinuses with a good expansion in 3D that makes this specimen plot at the junction of the variation of the different analysed species. Still, the size of Maba 1 frontal sinuses are much smaller than Broken Hill 1, Bodo, and Petralona. The last three specimens have debated taxonomic statuses, but they are frequently assigned to *H. heidelbergensis* / *H. rhodesiensis*.

## 3.2 The cranial vault thickness

Maba 1 cranium is globally thinner than Hexian, Broken Hill 1, and Cro Magnon 1, and it was comparable to Trinil 2, La Chapelle-aux-Saints 1, La Ferrassie 1, Spy 1, and Spy 10. The frontal crest on the endocranial surface of the frontal bone led to a narrow thickening (9.0-14.0 mm) extending in the anteroposterior direction (Figure 2a, 2b, 2e).

Generally, the preserved part of the Maba 1 frontal squama was not obviously thicker than its parietal bones. This was different from what we observed in fossil *H. sapiens* specimens and from the record of extant *H. sapiens* (Balzeau, 2013), where the frontal squama tended to be thicker than the parietal bone.
In detail, there is a thinning of the bone in the area corresponding to the medio-lateral extension of the third frontal convolution (Figure 2c, 2d, 2e). At the juncture between the frontal and parietal bones, the bregmatic area (around 7.0 mm) of Maba 1 had neither pronounced relief on the ectocranial surface nor obvious thickening. This pattern was similar with *H. neanderthalensis* and *H. sapiens*, while Hexian, Trinil 2, Broken Hill 1, and Petralona all manifested thickened bregmatic areas. In addition, in many Asian *H. erectus* crania (e.g., Sambungmacan, Ngawi, and Ngandong), the bregmatic area possesses a considerably thickening radiating along the sagittal and coronal plans and forming a 'cross' pattern (Balzeau, 2013), which was not found in Maba 1 (Figure 2). Posterior to the bregma, the midsagittal area of Maba 1 was slightly thickened (6.5-10.0 mm), though it does not express a well-developed keel on the ectocranial surface. Instead, the thickening was caused by the relief on the endocranial surface. There were elongated regions of thinning (4.0-6.0 mm) lateral and adjacent to the sagittal suture on both parietal bones (Figure 2 and S2), which corresponded to the parasagittal development of the upper and medial extension of the frontal and parietal lobes on the endocranial surface. Such thinning pattern was also found in Trinil 2, La Chapelle-aux-Saints 1, and La Ferrassie 1. Lateral to the parasagittal thinning, was an area of increasing thickness (peaked at 10.0 mm) located at the central and posterior part of each parietal bone. This was also caused by the reliefs on the endocranial surface, in the relatively flattened area of the medial part of the frontal and parietal lobes. There is a limited thickening at the posterior borders of the parietal bone in these medial areas compared to the thickness in the anterior part.

### 3.3 The diploic and emissary vascular system
The diploic and emissary vascular networks of Maba 1 were incomplete due to taphonomic damages. Nevertheless, rich DCs and emissary venous channels (ECs) were distributed in the preserved neurocranium and facial area. Also, visual inspections of the micro-CT images and 3D models found a large number of foramina on the ectocranial and endocranial surfaces. These foramina were the inlets or outlets of the DCs, bridging them with other vascular systems.

In detail, the DCs in the frontal bone anastomosed with the periorbital vessels, frontal sinus (the mucous membrane), superior sagittal sinus, superficial temporal vessels, and middle meningeal vessels. These DCs in the frontal bone also extended inferoanteriorly into the right zygomatic bone and inferoposteriorly into the right sphenoid bone (Figure 3a, 3b, 3c), anastomosing with ophthalmic vessels and the stem of middle meningeal vessels respectively. The frontal DCs were connected with those in the parietal, where the DCs were scattered all over the bones (Figure 3c, 3d, 3e, 3f). These parietal DCs anastomose with superficial temporal vessels, superior sagittal sinus, and middle meningeal vessels.

Many ECs were located in the frontal crest. They bridged the superficial temporal vessels and superior sagittal sinus. Similarly, a large parietal foramen is located in the left parietal bone, close to the sagittal suture. The parietal foramen houses an EC, which also bridged the superficial temporal vessels and superior sagittal sinus. Additionally, this parietal foramen was connected with the DCs (Figure S3).

From this, the drainage pathway preserved in Maba 1 cranium was not obviously different from those of *H. neanderthalensis*, fossil *H. sapiens*, or extant humans. The
drainage pathway in the asterional area could show taxonomical signal (Hui & Balzeau,
2023), but this area was missing in Maba 1. The only feature preserved in Maba 1 with
potential taxonomic significance was the presence of parietal foramen, which was a
rather rare trait in *H. neanderthalensis* but common in all other *Homo* species (De
Stefano & Hauser, 1992; Hui & Balzeau, 2023; Manzi et al., 2000).

3.4 The endocast

The surface of the endocast is well preserved (Figure 4). The middle meningeal system
is well visible on the right hemisphere and is represented by several branches that
diverge from the anterior branch (Figure 4b, 4c, 4e). Imprints propagate anteriorly on
the relief of the second and third frontal convolutions. A branch is anterior to the central
sulcus, a second one is located posteriorly to this sulcus and covers the parietal lobe.
The pattern seems to be similar on the left hemisphere for which we only see the parietal
lobe and a limited postero-superior portion of the frontal lobe (Figure 4a). The sagittal
sinus forms a large relief visible nearly on the whole preserved extension of the
interhemispheric junction between the frontal and parietal lobes (Figure 4e). The
inferior extension of the third frontal convolution is clear, the separation from the upper
part of the temporal lobe is reduced, the sylvian valley is therefore a deep and narrow
depression (Figure 4b, 4e, 4d).

Sulcal imprints were partly visible. Those imprints include small branches of the
inferior and medial frontal sulci. We are able to estimate the course of the central sulci
as well as the position of the midsagittal transition between the parietal and occipital
lobes. Those aspects are important as they allowed us to locate crucial landmarks related
to the brain structure for morphometric analyses (Figure S4).
The linear regression of size vs. Procrustes-fitted landmark positions showed an overall
significant relationship with size (r=0.4572, p < 0.001). PC1 and PC2 expressed 21%
and 15.4% of the variance. Some of the different groups were distinguished along a
combination of PC1 and PC2 (Figure 5 see also Figure S4 for the illustration of the
deformation along PC1 and PC2). Early hominins showed low PC1 and PC2 values,
and almost share a large overlap with the *H. erectus* range. The sample of *H. neanderthalensis* was out of the distribution range of these two earlier groups, with
relatively higher values on PC1 and low values on PC2. The recent and fossil *H. sapiens*
samples were well distinguished from the other groups with higher values on both PCs.
Maba 1 fell within the distribution of *H. erectus* in this analysis. However, scores for
Maba 1 on both PCs entered the variation range for the other samples, except for the
PC2 values of the *H. neanderthalensis* sample. Interestingly, Maba 1 was very close to
three other specimens (Broken Hill 1, Ngaloba LH 18, Djebel Irhoud 1) that were not
assigned a priori to any group (Figure 5).

As for the linear dimensions of the endocast (Table S5 and S6), both absolute and
relative data were compared. The Azs scores allowed for a direct comparison between
Maba 1 and the analysed hominin samples. When considering absolute data, Maba 1
was significantly larger than the early hominin and *H. erectus* groups. Maba 1 was
globally smaller than the mean levels of *H. neanderthalensis* and *H. sapiens*, but it fell
within the variation range of these samples. Azs scores were quite high for the
dimensions that concern the endocast width (WBE, MFWE, MPWE) when Maba 1 was
compared to *H. erectus*, which means Maba 1 is larger than the *H. erectus* specimens.
Maba 1 had a rather low value for the frontal chord compared to *H. sapiens* (Azs=-0.9,
Table S5, S6). When Maba 1 was compared to *H. neanderthalensis*, all Azs scores were negative except for the parietal cord.

When relative dimensions are considered, the Azs scores did not show any significant
differences between Maba 1 and the comparative samples. Maba 1 had relative
dimensions that were more different with *H. neanderthalensis* than with the other
samples, with in particular Azs scores of -0.9 for the maximal width of the parietal lobes
and 0.8 for the parietal cord. These two values highlighted a difference in their brain
structures, showing Maba 1 had relatively narrower parietal lobes but a larger antero-
posterior extension of those lobes in their medial part. In agreement with the geometric
morphometric analysis, all absolute and relative dimensions of Maba 1 were very
similar to those of Broken Hill 1, Djebel Irhoud 1 and Ngaloba LH 18.

**4. Discussion**

4.1 The morphological pattern of Maba 1

Since the discovery of Maba 1 fossil, studies on the external morphology and linear
measurements have noticed its admixture of *H. erectus* features and more derived
features resembling Late Pleistocene hominins (Liu et al., 2022; Pope, 1992; Woo &
Pen, 1959; Wu & Bruner, 2016). The derived features were considered mainly
concentrated in the facial area, while the rest of the neurocranium was considered more
archaic and resembling *H. erectus* and *H. heidelbergensis* (Wu & Bruner, 2016).
Nevertheless, this combination is also visible in other Asian fossils. As mentioned
above, Maba 1 is considered related to Neandertals or Denisovans, while the
relationships between Neandertals and Denisovans is still a great matter of debate. The
difference between Neandertals and Denisovans have not been thoroughly described from an anatomical perspective. Furthermore, it remains necessary to detail the relationships between *H. neanderthalensis*, *H. sapiens*, and Denisovans to better clarify the distinctions between these groups and the evolutionary polarity of many anatomical traits they share. A major limitation is the lack of a comprehensive description of Denisovan cranial anatomy to date. But this does not prevent us from exploring in further detail the information available in the fossil hominin record.

Reaching the level of internal anatomy, we are faced with the same difficulties. Maba 1 shows a complex combination of internal anatomical features that are found in various well-identified hominin species. What is new is that the CVT analysis found a few interesting features in the neurocranium. As shown in this study and previous findings (Balzeau, 2013), a thickened bregmatic area with a cross-like thickening radiating from the bregma is a common feature among Middle Pleistocene hominins. Also, it is particularly visible among Asian *H. erectus*. However, this feature is not present in Maba 1. The parasagittal thinning pattern in Maba 1 is similar to some *H. neanderthalensis* specimens, but it is also found in *H. erectus* in relation to the medial increase in bone thickness. Additionally, the relatively thin cranium of Maba 1 is in contrast with the more robust and thicker crania in many *H. erectus*. However, although traditional views consider a globally thick cranium as a feature of *H. erectus*, this study together with previous findings suggest that the thickness is not unique to *H. erectus* (Balzeau, 2013; Copes & Kimbel, 2016). In fact, within *H. erectus* the thickness is also variable. Finally, the Maba 1 fossil displays a homogeneous distribution of bone thickness on the frontal and parietal bones. This pattern is comparable to that in *H. neanderthalensis*.
Our re-analysis of the Maba 1 endocast with both linear and geometric morphometrics presents a similar picture as the previous study (Wu & Bruner, 2016). The incomplete preservation of the endocasts prevents a complete analysis of the brain shape. Its general morphology is closer to *H. erectus* than to later encephalized species, *H. neanderthalensis* and *H. sapiens*. This is related in particular to a shorter frontal lobe in the antero-posterior direction compared to *H. neanderthalensis* and *H. sapiens* (Table S5 and Figure S4). Nevertheless, Maba 1 shows a relatively large third frontal convolution, absolutely larger width dimensions and a relatively shorter frontal lobe compared to *H. erectus* (Table S5). In fact, Maba 1 shares the higher resemblances in the preserved anatomical area with other debated specimens: Ngaloba LH 18, Djebel Irhoud 1 or Broken Hill 1. This is clear from the multivariate analysis (Figure 5) where Maba is projected very close to these three specimens. Additionally, it is also clear from comparing the dimensions of Maba with the variation observed among the three most documented species—*H. erectus*, *H. neanderthalensis* and *H. sapiens* (Table S5).

Another noticeable feature of Maba 1 is the large frontal sinus, which has been mentioned frequently but had never been estimated quantitatively (Pope, 1992; Wu & Bruner, 2016). The measurements in this current study confirm the relatively large size of Maba 1 frontal sinus, which is within the range of *H. neanderthalensis* and *H. erectus*. Still, the comparative data also show that the large frontal sinus may also be present in *H. sapiens*. A feature of the *H. sapiens* frontal sinus is its high variability in size. The linear discriminant analysis based on absolute and relative dimensions cluster Maba 1 with *H. neanderthalensis*. This is related to a large expansion of the frontal sinuses but also with a relatively constrained antero-posterior expansion. The sinuses have a
relative expansion in the vertical direction that slightly resemble the pattern seen in *H. sapiens*. Among the materials studied, the *H. sapiens* sample showed relatively restricted anteroposterior sinus expansion compared to the other samples, therefore it is thinner in this orientation and more elongated vertically. In Maba 1, the sinuses are relatively high compared to their antero-posterior extent (Table S4). However, Maba 1 also has large sinuses compared to *H. sapiens* both for absolute and relative dimensions. Other species exhibit large sinuses with more globular cells in terms of relative dimensions. In terms of absolute dimensions (Table S4), Maba 1 is closer to *H. neanderthalensis*. Interestingly, the sinuses of Maba 1 differ clearly from the particular morphology observed in Broken Hill 1, Petralona and Bodo. The frontal sinuses of the last three are rather asymmetric, extremely huge, possessing complex globular cells, and occupying more than one-third of the frontal bone (Balzeau et al., 2022). This special shape and size make Broken Hill 1, Petralona, and Bodo distinct from most hominin fossils. It would also be interesting to know the expression of these features in several fossils from the continental Asia for which no information is yet available, such as Dali, Harbin, Xuchang among many others.

Finally, the DC system of Maba 1 is highly developed. The system communicates with the extracranial and intracranial venous network, as well as the frontal sinus. In terms of morphology and physiology, the DC system in the preserved cranium exhibits similarities to those of Late Pleistocene hominins and extant humans.

## 4.2 Taxonomical considerations

Maba 1 was considered a 'Chinese Neandertal' for their resemblance manifested in the facial area (Pope, 1992). However, this study did not find characteristics uniquely
belonging to *H. neanderthalensis* in Maba 1 internal structures. The CVT thinning pattern and frontal sinus dimensions in Maba 1 are similar to *H. neanderthalensis*, but its features could also be found in *H. sapiens* and other debated hominins from this period. On the other hand, some traits may distinguish Maba 1 from 'Classic Neanderthals'. The endocranial morphology of Maba 1 is more reminiscent of Asian *H. erectus* and African Middle Pleistocene hominins than of *H. neanderthalensis*, as discussed above. Some particularities of the preserved anatomical areas nevertheless distinguish Maba 1 from *H. erectus*. This concerns a relatively short antero-posterior extension of the frontal lobes, a well developed third frontal convolution, and a larger endocranial size in Maba 1.

What is more, this study has noticed the anastomosis between the DC system and the previously undiscovered parietal foramen. The parietal foramen is a rather rare structure among *H. neanderthalensis* and is common in almost all other hominids (De Stefano & Hauser, 1992; Hui & Balzeau, 2023; Manzi et al., 2000). The parietal foramen is also found in Xujiayao 11 (Wu et al., 2013), from another Neandertal-like Chinese paleodeme, but this is possibly due to a paleopathological condition and may not be homologous to the one found in Maba 1.

From the linear dimensions of the endocast, the previous study revealed that Maba 1 clustered with Broken Hill 1 (Wu & Bruner, 2016), a hominin with unclear taxonomic status but sometimes classified as *H. rhodesiensis/ H. heidelbergensis*. This current study confirms this finding in the linear measurements, but following a Procrustes analysis minimizing the influence from size, we found the endocranial shape of Maba 1 is close to Broken Hill 1 and even closer to Djebel Irhoud 1, Ngaloba LH 18, and
Asian *H. erectus*. Additionally, the general cranial thickness and frontal sinus size of Maba 1 are much smaller than those of Broken Hill 1.

A recent phylogenetic study makes the classification of Maba 1 even more interesting, as it suggests Maba 1 clusters with Xuchang (Ni et al., 2021), a possible member of the Denisovan group (Gokhman, 2019). The gracile cranium of Maba 1 is indeed similar to Xuchang, and they both share some similarities with *H. neanderthalensis*. However, these two also show evident differences in the neurocranial morphology. Xuchang is well-known for its large endocranial capacity peaking at 1800 cc (Li et al., 2017), while the estimated capacity of Maba 1 is only around 1300 cc (Wu & Bruner, 2016). Xuchang neurocranium expands laterally, with an extremely large cranial breadth over those of all Late Pleistocene hominins (Li et al., 2017). This is in accordance with the reconstruction of Denisovan cranial anatomy based on DNA methylation maps (Gokhman, 2019). On the contrary, Maba 1 shows a relatively narrow width of the parietal lobes on the endocast. Additionally, another perspective suggests that Xuchang and Denisovans belong to a newly established species: *H. juluensis* (Wu & Bae, 2024). Besides Xuchang, this species includes another cranial specimen from Xujiayao, which likewise exhibits an extremely large cranial capacity (1700 cc). Clearly, Maba 1 does not possess an exceptionally large brain, which is considered as a feature of *H. juluensis*. This might prevent the classification of the Maba 1 as *H. juluensis*. However, we currently cannot rule out the possibility that the brain size variation range of this species is actually enormous. Therefore, future research should also explore the variation range of cranial capacity within this species.

Considering all these comparisons, Maba 1 currently cannot be classified in any known
hominin group. Previous studies highlighted the derived features in Maba 1 facial area, such as the gracile tori and the circular profile of the orbit, which contrast with those robust tori from most Asian *H. erectus* (Liu et al., 2022; Wu & Bruner, 2016). Our work shows that the difference between Maba 1 and *H. erectus* group also emerges in the internal structures, particularly in CVT patterns and frontal lobe. For these reasons, it is likely that Maba 1 is not within this archaic group (*H. erectus*). Moreover, the CVT pattern of Maba 1 also differs from those of Broken Hill 1 and Petralona, and its frontal sinuses exhibit distinctions from Broken Hill 1, Petralona, and Bodo—three specimens frequently regarded as representatives of *H. rhodesiensis / H. heidelbergensis*. It should be noted, however, that high variability in CVT and frontal sinus dimensions may exist within *H. rhodesiensis / H. heidelbergensis*. Further studies are required to add more endocast and DC specimens from this species to compare with Maba 1. Also, Maba 1 differs from most *H. neanderthalensis* and *H. sapiens* specimens for its endocranial morphology. The taxonomic questions concerning Maba 1 is common among the late Middle Pleistocene hominins in China. Many Chinese fossils from this period are difficult to classify for their admixture of morphological affinities. For this reason, many fossils are referred as ‘Non-erectus’ Asian Middle Pleistocene hominins (Wu et al., 2023; Xing et al., 2019), which seems to be a temporary and appropriate group to allocate Maba 1.

Two limits to our work are the incomplete preservation of the specimen and the
availability of detailed comparative information for all the analysed traits, especially
the information for other Asian fossils from the same chronological period.
Nevertheless, our study shows the potential of such a detailed approach that includes
as much anatomical information as possible. Indeed, different information and
interpretations may arise from observing the particularities of each anatomical area or
structure. It is promising to combine information on bone thickness, internal
composition, diploic system, frontal sinuses, endocranial anatomy, together with the
more classic cranial anatomy. It remains necessary to include in future studies more
anatomical information with potentials in taxonomy, like the proportion of three layers
of cranial bones. Furthermore, to interpret specimens like Maba 1 that show a
combination of features observed classically in different hominins, a crucial step will
be to associate a skull with the genetic sequence attributed to the Denisovans.

## Acknowledgements

This study was funded by the National Key Research and Development program of China (2023YFF0804502), National Natural Science Foundation of China (42372001, 42472006), the French National Research Agency (ANR-20-CE27-0009), and China Scholarship Council. We would like to thank Wu Liu and Letian He for their support. We also thank the editors and reviewers for their comments.

## Data Availability statement

Maba 1 fossil is curated by the Institute of Vertebrate Paleontology and
Paleoanthropology (IVPP), Chinese Academy of Sciences. Requests for access to the
imaging dataset of IVPP should be sent to the collection department of IVPP. The
measurement data have been provided in this article. The other data (e.g., 3D models
and CVT colormaps) generated in this study are available upon formal request through
email to the corresponding author.

## Conflicts of Interest
The authors declare no conflicts of interest.

## References

Amrhein, V., Trafimow, D., & Greenland, S. (2019). Inferential statistics as descriptive statistics: There is no replication crisis if we don't expect replication. *The American Statistician*, 73(s1), 262–270. https://doi.org/10.1080/00031305.2018.1543137

Bae, C. J., & Wu, X. (2024). Making sense of eastern Asian Late Quaternary hominin variability. *Nature Communications*, 15(1), 9479. https://doi.org/10.1038/s41467-024-53918-7

Balzeau, A. (2013). Thickened cranial vault and parasagittal keeling: Correlated traits and autapomorphies of *Homo erectus?* *Journal of Human Evolution*, 64(6), 631–644. https://doi.org/10.1016/j.jhevol.2013.02.005

Balzeau, A., Albessard-Ball, L., Kubicka, A. M., Filippo, A., Beaudet, A., Santos, E., Bienvenu, T., Arsuaga, J.-L., Bartsiokas, A., Berger, L., Bermúdez de Castro, J. M., Brunet, M., Carlson, K. J., Daura, J., Gorgoulis, V. G., Grine, F. E., Harvati, K., Hawks, J., Herries, A., Buck, L. T. (2022). Frontal sinuses and human evolution. *Science Advances*, 8(42), eabp9767. https://doi.org/10.1126/sciadv.abp9767

Balzeau, A., Albessard-Ball, L., Kubicka, A. M., Noûs, C., & T. Buck, L. (2021). Frontal sinus variation in extant species of the genera *Pan*, *Gorilla* and *Homo*. *Bulletins et Mémoires de La Société d'anthropologie de Paris*, 33(2). https://doi.org/10.4000/bmsap.7840

Balzeau, A., & Charlier, P. (2016). What do cranial bones of LB1 tell us about *Homo floresiensis*? *Journal of Human Evolution*, 93, 12–24. https://doi.org/10.1016/j.jhevol.2015.12.008

Chen, F., Welker, F., Shen, C.-C., Bailey, S. E., Bergmann, I., Davis, S., Xia, H., Wang, H., Fischer, R., Freidline, S. E., Yu, T.-L., Skinner, M. M., Stelzer, S., Dong, G., Fu, Q., Dong, G., Wang, J.,
Zhang, D., & Hublin, J.-J. (2019). A late Middle Pleistocene Denisovan mandible from the
Tibetan Plateau. *Nature*, **569**(7756), 409–412. https://doi.org/10.1038/s41586-019-1139-x

Copes, L. E., & Kimbel, W. H. (2016). Cranial vault thickness in primates: *Homo erectus* does not have uniquely thick vault bones. *Journal of Human Evolution*, **90**, 120–134.
https://doi.org/10.1016/j.jhevol.2015.08.008

De Stefano, G. F., & Hauser, G. (1992). Epigenetic traits of the Circeo I skull. In *The Circeo I Neandertal Skull, Studies and Documentation* (pp. 273–300). Instituto Poligrafico e Zecca Dello Stato.

Détroit, F., Mijares, A. S., Corny, J., Daver, G., Zanolli, C., Dizon, E., Robles, E., Grün, R., & Piper, P. J. (2019). A new species of *Homo* from the Late Pleistocene of the Philippines. *Nature*, **568**(7751), 181–186. https://doi.org/10.1038/s41586-019-1067-9

Gokhman, D. (2019). Reconstructing Denisovan anatomy using DNA methylation maps. *Cell*, **179**, 180–192. https://doi.org/10.1016/j.cell.2019.08.035

Hammer, O., Harper, D. A. T., & Ryan, P. D. (2001). PAST: Paleontological statistics software package for education and data analysis. *Palaeontologia Electronica*, **4**(1), 9.

Hautavoine, H., Arnaud, J., Balzeau, A., & Mounier, A. (2024). Quantifying hominin morphological diversity at the end of the middle P leistocene: Implications for the origin of *Homo sapiens*. *American Journal of Biological Anthropology*, **184**(2), e24915.
https://doi.org/10.1002/ajpa.24915

Hui, J. (2024). *Comparative anatomy of the diploic vessels in hominids: Implications for the evolutionary history of human cranial blood circulation* [PhD, Sorbonne University].
https://theses.hal.science/tel-04743615
Hui, J., & Balzeau, A. (2023). The diploic venous system in *Homo neanderthalensis* and fossil *Homo sapiens*. A study using high-resolution computed tomography. *American Journal of Biological Anthropology*, 182(3), 412-427. https://doi.org/10.1002/ajpa.24843

Hui, J., & Balzeau, A. (2024). Investigating the relationship between cranial bone thickness and diploic channels: A first comparison between fossil *Homo sapiens* and *Homo neanderthalensis*. *The Anatomical Record*, 307(6), 2036-2046. https://doi.org/10.1002/ar.25360

Hurst, S. D., Holloway, R. L., Balzeau, A., Garvin, H. M., Vanti, W. B., Berger, L. R., & Hawks, J. (2024). The endocast morphology of LES1, *Homo naledi*. *American Journal of Biological Anthropology*, 184(4), e24983. https://doi.org/10.1002/ajpa.24983

Kaifu, Y., Kurniawan, I., Mizushima, S., Sawada, J., Lague, M., Setiawan, R., Sutisna, I., Wibowo, U. P., Suwa, G., Kono, R. T., Sasaki, T., Brumm, A., & Van Den Bergh, G. D. (2024). Early evolution of small body size in *Homo floresiensis*. *Nature Communications*, 15(1), 6381. https://doi.org/10.1038/s41467-024-50649-7

Li, Z.-Y., Wu, X., Zhou, L.-P., Liu, W., Gao, X., Nian, X.-M., & Trinkaus, E. (2017). Late Pleistocene archaic human crania from Xuchang, China. *Science*, 355(6328), 969-972. https://doi.org/10.1126/science.aal2482

Liu, W., Athreya, S., Xing, S., & Wu, X. (2022). Hominin evolution and diversity: A comparison of earlier-Middle and later-Middle Pleistocene hominin fossil variation in China. *Philosophical Transactions of the Royal Society B: Biological Sciences*, 377(1847), 20210040. https://doi.org/10.1098/rstb.2021.0040

Manzi, G., Gracia, A., & Arsuaga, J.-L. (2000). Cranial discrete traits in the Middle Pleistocene humans from Sima de los Huesos (Sierra de Atapuerca, Spain). Does hypostosis represent any
increase in "ontogenetic stress" along the Neanderthal lineage? *Journal of Human Evolution*, 38(3), 425-446. https://doi.org/10.1006/jhev.1999.0362

Ni, X., Ji, Q., Wu, W., Shao, Q., Ji, Y., Zhang, C., Liang, L., & Ge, J. (2021). Massive cranium from Harbin in northeastern China establishes a new Middle Pleistocene human lineage. *The Innovation*, 2(3), 100130. https://doi.org/10.1016/j.xinn.2021.100130

Pope, G. G. (1992). Craniofacial evidence for the origin of modern humans in China. *American Journal of Physical Anthropology*, 35(S15), 243-298.

https://doi.org/10.1002/ajpa.1330350610

Roksandic, M., Radović, P., Wu, X., & Bae, C. J. (2022). Resolving the “muddle in the middle”: The case for *Homo bodoensis* sp. nov. *Evolutionary Anthropology: Issues, News, and Reviews*, 31(1), 20–29. https://doi.org/10.1002/evan.21929

Scolan, H., Santos, F., Tillier, A.-M., Maureille, B., & Quintard, A. (2012). Des nouveaux vestiges néanderthaliens à Las Pélénos (Monsempron-Libos, Lot-et-Garonne, France). *Bulletins et mémoires de la Société d'anthropologie de Paris*, 24(1-2), 69-95.

https://doi.org/10.1007/s13219-011-0047-x

Shen, G., Tu, H., Xiao, D., Qiu, L., Feng, Y., & Zhao, J. (2014). Age of Maba hominin site in southern China: Evidence from U-series dating of Southern Branch Cave. *Quaternary Geochronology*, 23, 56–62. https://doi.org/10.1016/j.quageo.2014.06.004

Woo, J., & Pen, R. (1959). Fossil human skull of early paleoanthropic stage found at Mapa, Shao-quan, Kwangtung Province. *Vertebrata Palasiatica*, 3(4), 176-182.

Wu, X. (1988). Comparative study of early *Homo Sapiens* from China and Europe. *Acta Anthropologica Sinica*, 7(4), 287-293.
Wu, X. (2006). Evidence of multiregional human evolution hypothesis from China. *Quaternary Sciences, 26*(5), 702–709.

Wu, X. (2017). Application of computed tomography in the internal anatomy of the Maba cranium. *Quaternary Sciences, 37*(4), 679–685. https://doi.org/10.11928/j.issn.1001-7410.2017.04.01

Wu, X., & Athreya, S. (2013). A description of the geological context, discrete traits, and linear morphometrics of the Middle Pleistocene hominin from Dali, Shaanxi Province, China. *American Journal of Physical Anthropology, 150*(1), 141–157.

https://doi.org/10.1002/ajpa.22188

Wu, X., & Bae, C. J. (2024). Xujiayao *Homo*: A new form of large brained hominin in Eastern Asia. *PaleoAnthropology*, In press.

Wu, X., & Bruner, E. (2016). The endocranial anatomy of Maba 1. *American Journal of Physical Anthropology, 160*(4), 633–643. https://doi.org/10.1002/ajpa.22974

Wu, X., Crevecoeur, I., Liu, W., Xing, S., & Trinkaus, E. (2014). Temporal labyrinths of eastern Eurasian Pleistocene humans. *Proceedings of the National Academy of Sciences, 111*(29), 10509–10513. https://doi.org/10.1073/pnas.1410735111

Wu, X., Pei, S., Cai, Y., Tong, H., Zhang, Z., Yan, Y., Xing, S., Martinón-Torres, M., Bermúdez De Castro, J. M., & Liu, W. (2023). Morphological and morphometric analyses of a late Middle Pleistocene hominin mandible from Hualongdong, China. *Journal of Human Evolution, 182*, 103411. https://doi.org/10.1016/j.jhevol.2023.103411

Wu, X., Xing, S., & Trinkaus, E. (2013). An enlarged parietal foramen in the late archaic Xujiayao 11 neurocranium from Northern China, and rare anomalies among Pleistocene *Homo*. *PLOS*
ONE, 8(3), 10.

Xing, S., Martinón-Torres, M., & Bermúdez De Castro, J. M. (2019). Late Middle Pleistocene hominin teeth from Tongzi, southern China. *Journal of Human Evolution, 130*, 96–108.

https://doi.org/10.1016/j.jhevol.2019.03.001

Yuan, S., Chen, T., & Gao, S. (1986). Uranium series chronological sequence of some palaeolithic sites in South China. *Acta Anthropologica Sinica, 5*(2), 179–190.

<figure><img src="image_2.png" /><figcaption>**Figure 1** The frontal sinuses of Maba 1. Maximal lateral extension (W), maximal height (H), and maximal length of the left and right sinuses (anterior length: AL1 and ALr) measured from the most medial and inferior point of the sinus to the more distant point of the extension of the sinus vertically and laterally measured in anterior view; maximal mediolateral extension of the left and right sinus (superior length: SL1 and SLr) measured in superior view; length from the most anteriorly protruding point of the sinus to the most posterior point in an horizontal direction (AP) and length from the most anterior point to the maximal superoposterior</figcaption></figure>
extension of the sinuses (AP2) measured in left lateral view).

<figure><img src="image_3.png" /><figcaption>**Figure 2** The cranial vault thickness colormap of Maba 1 cranium (a, anterior; b, anterolateral; c, lateral; d, superior; e, posterior). The color scale ranges from 2 to 22 mm. The damaged area is colored in gray.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>**Figure 3** The diploic venous channels (blue) of the Maba 1 cranium (a, anterior; b, anterolateral; c, lateral; d, lateral; e, posterior; f, superior). The figure is from the author's PhD thesis (Hui 2024).</figcaption></figure>
<figure><img src="image_5.png" /><figcaption>**Figure 4** The endocast of the Maba 1 cranium (a, anterior; b, lateral; c, superior; d, posterior). The endocranial vascular imprints (pink lines) and sulci (dash lines) are marked in (e). To distinguish the sulci, they are colored differently. The frontal ones are in blue, and the central sulcus are red.</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>**Figure 5** Two first components of the 3D landmark PCA of the Procrustes-fitted landmark positions obtained on 75 endocasts with the complete landmark configuration. Maba 1 is marked in purple. Brown: Early hominins, red: *Homo erectus*, blue: *Homo neanderthalensis*,</figcaption></figure>
gray: fossil Homo sapiens, green: fossils with controversial status, black: extant Homo sapiens. Labels for fossils: Sts 5, S5; Sts 60, S60; KNM-ER 13750, 13750; KNM-ER 23000, 23,000; KNM-ER 1805, 1805; KNM-ER 1813, 1813; OH16, OH16; KNM-ER 3883, 3883; KNM-ER 3733, 3733; Sambungmacan 3, Sm3; Sangiran 2, Sa2; Sangiran 17, Sa17; Ngandong 5, N5; Ngandong 7, N7; Ngandong 12, N12; Zhoujoudian I, Z1; Zhoujoudian II, Z2; Zhoujoudian X, Z10; Zhoujoudian XII, Z12; La Ferrassie 1, LF; La Quina H5, LQ5; La Chapelle aux Saints, LCP; Monte Circeo, MC; Saccopastore, Sac; Spy 1, Sp1; Spy 10, Sp10; Feldhofer, F; Tabun C1, TC1; Broken Hill 1, BH; Djebel Irhoud 1, DI1; Ngaloba LH 18, LH18; Brno 3, B3; Cro-Magnon 1, CM1; Dolni Vestonice 1, DV1; Pataud, P; Predmost 3, P3; Predmost 3, P3; Predmost 4, P4; Predmost 9, P9; Predmost 10, P10; Skhul 5, Sk5.

<table><caption>Table 1. Definitions of the measurements recorded for the frontal sinus</caption><thead><tr><td>Measurement</td><td>Abbr.</td><td>Definition</td><td>View</td></tr></thead><tbody><tr><td>Width</td><td>W</td><td>Maximum lateral extension of pneumatization</td><td>Anterior</td></tr><tr><td>Height</td><td>H</td><td>Maximum superoinferior height of pneumatization</td><td>Anterior</td></tr><tr><td>Anterior length (left)</td><td>ALl</td><td>Maximum inferomedial to superolateral length of left sinus</td><td>Anterior</td></tr><tr><td>Anterior length (right)</td><td>ALr</td><td>Maximum inferomedial to superolateral length of left sinus</td><td>Anterior</td></tr><tr><td>Anterior length</td><td>2AL</td><td>ALl + Alr</td><td>-</td></tr><tr><td>Superior length (left)</td><td>SLl</td><td>Maximum mediolateral extension of left sinus</td><td>Superior</td></tr><tr><td>Superior length (right)</td><td>SLr</td><td>Maximum mediolateral extension of right sinus</td><td>Superior</td></tr><tr><td>Superior length</td><td>2SL</td><td>SLl + SLr</td><td>-</td></tr><tr><td>Antero-posterior length</td><td>AP</td><td>Anteroposterior length</td><td>Lateral</td></tr><tr><td>Antero-posterior length 2</td><td>AP2</td><td>Most anterior point to most superoposterior point</td><td>Lateral</td></tr><tr><td>Combined AP length</td><td>2AP</td><td>AP + AP2</td><td>-</td></tr><tr><td>Cube root of the volume</td><td>RCV</td><td>Cube root of the volume</td><td>-</td></tr></tbody></table>
<table><caption>Table 2. List and definition of the endocranial landmarks</caption><thead><tr><td>Name of the point</td><td>Anatomical description</td></tr></thead><tbody><tr><td>Endocranial bec (Eb)</td><td>The antero-inferior point between the first frontal convolutions</td></tr><tr><td>Left frontal pole (IFP) and Right frontal pole (rFP)</td><td>The frontal pole as defined in upper and lateral view as the more protruding point of each frontal lobe in those views in the anterior direction.</td></tr><tr><td>Left Broca (IB) and right Broca (rB)</td><td>The point on the "broca's cap", in the middle of the circular relief (antero-posteriorly) and roughly centered vertically, which is not too high on the 3rd frontal convolution and not too low as an inferior point of the relief. *</td></tr><tr><td>Endobregma (EB)</td><td>The intersection of the coronal and sagittal sutures.</td></tr><tr><td>Perpendicular (P)</td><td>At the level of the depression that is just above the lambda. It is an approximation of the uppermost extension of the occipital lobes, i.e. the position of the perpendicular fissure.</td></tr><tr><td>Left maximal width frontal (lmwF) and right maximal width frontal (rmwF)</td><td>The bilateral points located along the course of the coronal suture where the frontal profile is the larger in anterior view. It is also visible in superior view.</td></tr><tr><td>Left max width parietal (lmwP) and right max width parietal (rmwP)</td><td>The bilateral points where the width is maximal on the lateral walls of the parietal lobes. It might corresponds to the area of the supramarginal gyrus.</td></tr><tr><td>Central sulci intersection (S)</td><td>The projection of the posterior extension of the central sulci, it is their midsagittal junction. This point is often interpreted from the visible evidence for the inferior extension of the central sulci.</td></tr></tbody></table>

<table><caption>Table 3. List and definition of the dimensions measured on endocasts</caption><thead><tr><td>Dimension</td><td>Definition</td></tr></thead><tbody><tr><td>FalCE</td><td>Frontal cord, measured between the endocranial bec and the medial junction between the frontal and parietal lobes.</td></tr><tr><td>WBE</td><td>Maximal width between the Broca's cap.</td></tr><tr><td>MFWE</td><td>Maximal width measured on the frontal lobes.</td></tr><tr><td>MPWE</td><td>Maximal width measured on the parietal lobes.</td></tr><tr><td>Eb-P</td><td>Length between the endocranial bec and the perpendicular fissure.</td></tr><tr><td>PalCE</td><td>Parietal cord, measured between the medial junction between the frontal and parietal lobes and the medial junction between the parietal and occipital lobes.</td></tr></tbody></table>

<footnote>* Bilateral points are in a similar position and located at the same antero-posterior and infero-superior position on the left and right sides to calculate endocranial widths. See Balzeau et al., 2017; Hurst et al., 2024; Balzeau et al., in revision for previous applications.</footnote>
Supplementary information

<table><caption>Table S1: The inventory of fossil specimens included in comparative analyses. Data for comparative specimens are from our previously published papers (Balzeau, 2013; Balzeau et al., 2022; Hui & Balzeau, 2023)</caption><thead><tr><td>Specimen</td><td>Taxon</td><td>Comparative analyses</td></tr></thead><tbody><tr><td>TM 266-01-060-1</td><td>Sahelanthropus tchadensis</td><td>FS</td></tr><tr><td>Sts 5</td><td>Australopithecus africanus</td><td>FS; Endo</td></tr><tr><td>Sts 60</td><td>A. africanus</td><td>Endo</td></tr><tr><td>Sts 71</td><td>A. africanus</td><td>FS</td></tr><tr><td>StW 505</td><td>A. africanus</td><td>FS</td></tr><tr><td>StW 573</td><td>A. prometheus?</td><td>FS</td></tr><tr><td>BOU-VP-12/130</td><td>A. garhi</td><td>FS</td></tr><tr><td>U.W. 88-50</td><td>A. sediba</td><td>FS</td></tr><tr><td>KNM-WT 17000</td><td>Paranthropus aethiopicus</td><td>FS</td></tr><tr><td>SK 48</td><td>P. robustus</td><td>FS</td></tr><tr><td>DNH 155</td><td>P. robustus</td><td>FS</td></tr><tr><td>OH 5</td><td>P. boisei</td><td>FS</td></tr><tr><td>KNM-ER 13750</td><td>P. boisei</td><td>Endo</td></tr><tr><td>ER23000</td><td>P. boisei</td><td>Endo</td></tr><tr><td>STW 53</td><td>Australopithecus?</td><td>FS</td></tr><tr><td>KNM-ER 1805</td><td>H. habilis</td><td>Endo</td></tr><tr><td>KNM-ER 1813</td><td>H. habilis</td><td>Endo</td></tr><tr><td>OH 16</td><td>H. habilis</td><td>Endo</td></tr><tr><td>KNM-ER 3733</td><td>H. erectus</td><td>Endo</td></tr><tr><td>KNM-ER 3883</td><td>H. ergaster / H. erectus</td><td>FS; Endo</td></tr><tr><td>OH 9</td><td>H. erectus</td><td>FS</td></tr><tr><td>D2280</td><td>H. erectus / H. georgicus</td><td>FS</td></tr><tr><td>D2282</td><td>H. erectus / H. georgicus</td><td>FS</td></tr><tr><td>D2700</td><td>H. erectus / H. georgicus</td><td>FS</td></tr><tr><td>D3444</td><td>H. erectus / H. georgicus</td><td>FS</td></tr><tr><td>D4500</td><td>H. erectus / H. georgicus</td><td>FS</td></tr><tr><td>Trinil 2</td><td>H. erectus</td><td>FS; CVT</td></tr><tr><td>Hexian</td><td>H. erectus</td><td>CVT</td></tr><tr><td>Zhoukoudian 1</td><td>H. erectus</td><td>Endo</td></tr><tr><td>Zhoukoudian 2</td><td>H. erectus</td><td>Endo</td></tr><tr><td>Zhoukoudian 3</td><td>H. erectus</td><td>Endo</td></tr><tr><td>Zhoukoudian 10</td><td>H. erectus</td><td>Endo</td></tr><tr><td>Zhoukoudian 12</td><td>H. erectus</td><td>Endo</td></tr><tr><td>Sangiran 2</td><td>H. erectus</td><td>Endo</td></tr></tbody></table>
<table>
  <tr>
    <td>Sangiran 17</td>
    <td>H. erectus</td>
    <td>FS; Endo</td>
  </tr>
  <tr>
    <td>Skull IX</td>
    <td>H. erectus</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Sambungmacan 3</td>
    <td>H. erectus</td>
    <td>Endo</td>
  </tr>
  <tr>
    <td>Sambungmacan 4</td>
    <td>H. erectus</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Ngandong 1</td>
    <td>H. erectus</td>
    <td>FS; CVT</td>
  </tr>
  <tr>
    <td>Ngandong 5</td>
    <td>H. erectus</td>
    <td>Endo</td>
  </tr>
  <tr>
    <td>Ngandong 7</td>
    <td>H. erectus</td>
    <td>FS; CVT; Endo</td>
  </tr>
  <tr>
    <td>Ngandong 12</td>
    <td>H. erectus</td>
    <td>FS; CVT; Endo</td>
  </tr>
  <tr>
    <td>Ngawi 1</td>
    <td>H. erectus</td>
    <td>FS; CVT</td>
  </tr>
  <tr>
    <td>Lesedi 1</td>
    <td>H. naledi</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Broken Hill 1</td>
    <td>H. heidelbergensis/ Homo rhodesiensis?</td>
    <td>FS; CVT; Endo</td>
  </tr>
  <tr>
    <td>TD6-15</td>
    <td>H. antecessor</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>HK 87</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Bodo</td>
    <td>H. heidelbergensis/ Homo rhodesiensis?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Ehringsdorf H1024</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Ehringsdorf H1025</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Petralona</td>
    <td>H. heidelbergensis/ Homo rhodesiensis?</td>
    <td>FS; CVT</td>
  </tr>
  <tr>
    <td>Ceprano</td>
    <td>H. heidelbergensis?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Aroeira</td>
    <td>H. heidelbergensis?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>SHS 5</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>SHS 12</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>SHS 13</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>SHS 15</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>SHS 17</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Steinheim</td>
    <td>H. heidelbergensis?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Zuttiyeh</td>
    <td>?</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Feldhofer</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Neandertal</td>
    <td>H. neanderthalensis</td>
    <td>Endo</td>
  </tr>
  <tr>
    <td>Saccopastore</td>
    <td>H. neanderthalensis</td>
    <td>Endo</td>
  </tr>
  <tr>
    <td>La Ferrassie 1</td>
    <td>H. neanderthalensis</td>
    <td>FS; CVT; DV; Endo</td>
  </tr>
  <tr>
    <td>La Quina H5</td>
    <td>H. neanderthalensis</td>
    <td>FS; CVT; DV; Endo</td>
  </tr>
  <tr>
    <td>Guattari</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Forbes' Quarry 1</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Krapina 3</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Krapina 6</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>La Chapelle-aux-Saints 1</td>
    <td>H. neanderthalensis</td>
    <td>FS; CVT; DV; Endo</td>
  </tr>
  <tr>
    <td>Spy 1</td>
    <td>H. neanderthalensis</td>
    <td>FS; CVT; DV; Endo</td>
  </tr>
  <tr>
    <td>Spy 10</td>
    <td>H. neanderthalensis</td>
    <td>FS; CVT; DV; Endo</td>
  </tr>
  <tr>
    <td>Amud</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
  <tr>
    <td>Apidima 2</td>
    <td>H. neanderthalensis</td>
    <td>FS</td>
  </tr>
</table>
<table><tr><td>Monte Circe</td><td>H. neanderthalensis</td><td>Endo</td></tr><tr><td>Tabun C1</td><td>H. neanderthalensis</td><td>FS; Endo</td></tr><tr><td>LH 18</td><td>?</td><td>FS; Endo</td></tr><tr><td>Jebel Irhoud 1</td><td>?</td><td>FS; Endo</td></tr><tr><td>Qafzeh 9</td><td>H. sapiens</td><td>FS</td></tr><tr><td>Hofmeyr</td><td>H. sapiens</td><td>FS</td></tr><tr><td>Cro Magnon 1</td><td>H. sapiens</td><td>FS; CVT; DV; Endo</td></tr><tr><td>Cro Magnon 2</td><td>H. sapiens</td><td>FS; CVT; DV</td></tr><tr><td>Cro Magnon 3</td><td>H. sapiens</td><td>FS; CVT; DV</td></tr><tr><td>Abri Pataud 1</td><td>H. sapiens</td><td>FS; CVT; DV; Endo</td></tr><tr><td>Afalou 2, 30, 34</td><td>H. sapiens</td><td>FS; CVT</td></tr><tr><td>Taforalt XI C1, XV C4, XV C5</td><td>H. sapiens</td><td>FS</td></tr><tr><td>Rochereil</td><td>H. sapiens</td><td>CVT</td></tr><tr><td>Skhul 5</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Predmost 3</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Predmost 4</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Predmost 9</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Predmost 10</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Dolní Věstonice 1</td><td>H. sapiens</td><td>Endo</td></tr><tr><td>Brno 3</td><td>H. sapiens</td><td>Endo</td></tr></table>

Note: FS, frontal sinus; CVT, cranial vault thickness; DV, diploic venous system; Endo, endocast.
<table><caption>Table S2: Confusion matrix of the specimen numbers in each given group (rows) assigned to the different groups (columns) by the classifier after the discriminant analysis based on the absolute dimensions of the frontal sinuses (see Balzeau et al., 2022 for the whole database).</caption><thead><tr><th></th><th>Early hominins</th><th><i>H. erectus</i></th><th><i>H. neanderthalensis</i></th><th><i>H. sapiens</i></th><th>Total</th></tr></thead><tbody><tr><th>Early hominins</th><td>10</td><td>2</td><td>0</td><td>0</td><td>12</td></tr><tr><th><i>H. erectus</i></th><td>2</td><td>9</td><td>2</td><td>1</td><td>14</td></tr><tr><th><i>H. neanderthalensis</i></th><td>1</td><td>2</td><td>14</td><td>4</td><td>21</td></tr><tr><th><i>H. sapiens</i></th><td>1</td><td>3</td><td>13</td><td>88</td><td>105</td></tr><tr><th>Total</th><td>14</td><td>16</td><td>29</td><td>93</td><td>152</td></tr></tbody></table>

<table><caption>Table S3: Confusion matrix of the specimen numbers in each given group (rows) assigned to the different groups (columns) by the classifier after the discriminant analysis based on the relative dimensions of the frontal sinuses (see Balzeau et al., 2022 for the whole database).</caption><thead><tr><th></th><th>Early hominins</th><th><i>H. erectus</i></th><th><i>H. neanderthalensis</i></th><th><i>H. sapiens</i></th><th>Total</th></tr></thead><tbody><tr><th>Early hominins</th><td>7</td><td>3</td><td>1</td><td>1</td><td>12</td></tr><tr><th><i>H. erectus</i></th><td>4</td><td>6</td><td>2</td><td>2</td><td>14</td></tr><tr><th><i>H. neanderthalensis</i></th><td>1</td><td>5</td><td>11</td><td>4</td><td>21</td></tr><tr><th><i>H. sapiens</i></th><td>4</td><td>8</td><td>19</td><td>74</td><td>105</td></tr><tr><th>Total</th><td>16</td><td>22</td><td>33</td><td>81</td><td>152</td></tr></tbody></table>
<table><caption>Table S4. Morphometric data (mm) for the pneumatisation of the frontal bone for Maba 1 and among extant samples of *Pan*, *Gorilla* and *Homo sapiens* and for fossils hominin groups.</caption><thead><tr><th></th><th>W</th><th>H</th><th>2AL</th><th>2SL</th><th>2AP</th><th>RCV</th><th>Wr</th><th>Hr</th><th>2ALr</th><th>2SLr</th><th>2APr</th></tr></thead><tbody><tr><td><strong>Maba</strong></td><td><strong>75.0</strong></td><td><strong>40.9</strong></td><td><strong>76.9</strong></td><td><strong>80.4</strong></td><td><strong>51.4</strong></td><td><strong>21.7</strong></td><td><strong>345.6</strong></td><td><strong>188.5</strong></td><td><strong>354.3</strong></td><td><strong>370.0</strong></td><td><strong>236.8</strong></td></tr><tr><td colspan="12">Pan paniscus (n = 32)</td></tr><tr><td><strong>Mean</strong></td><td><strong>30.7</strong></td><td><strong>15.7</strong></td><td><strong>32.7</strong></td><td><strong>35.4</strong></td><td><strong>28.3</strong></td><td><strong>12.2</strong></td><td><strong>244.8</strong></td><td><strong>129.6</strong></td><td><strong>263.7</strong></td><td><strong>281.5</strong></td><td><strong>226.1</strong></td></tr><tr><td><strong>V*</strong></td><td>41.3</td><td>33.1</td><td>39.4</td><td>41.6</td><td>40.1</td><td>28.2</td><td>21.7</td><td>23.9</td><td>21.1</td><td>20.9</td><td>22.8</td></tr><tr><td colspan="12">Pan troglodytes (n = 33)</td></tr><tr><td><strong>Mean</strong></td><td><strong>40.8</strong></td><td><strong>18.4</strong></td><td><strong>43.1</strong></td><td><strong>51.7</strong></td><td><strong>41.3</strong></td><td><strong>16.8</strong></td><td><strong>241.3</strong></td><td><strong>110.3</strong></td><td><strong>258.0</strong></td><td><strong>303.5</strong></td><td><strong>243.8</strong></td></tr><tr><td><strong>V*</strong></td><td>27.4</td><td>24.3</td><td>22.7</td><td>30.2</td><td>30.1</td><td>19.8</td><td>12.8</td><td>18.1</td><td>13.5</td><td>15.2</td><td>15.3</td></tr><tr><td colspan="12">Gorilla (n = 33)</td></tr><tr><td><strong>Mean</strong></td><td><strong>64.9</strong></td><td><strong>24.1</strong></td><td><strong>61.1</strong></td><td><strong>81.5</strong></td><td><strong>73.2</strong></td><td><strong>23.7</strong></td><td><strong>275.8</strong></td><td><strong>101.7</strong></td><td><strong>259.2</strong></td><td><strong>344.2</strong></td><td><strong>307.7</strong></td></tr><tr><td><strong>V*</strong></td><td>20.8</td><td>26.0</td><td>21.5</td><td>23.8</td><td>26.1</td><td>21.8</td><td>9.6</td><td>13.6</td><td>11.2</td><td>14.4</td><td>11.8</td></tr><tr><td colspan="12">Homo sapiens (n = 345)</td></tr><tr><td><strong>Mean</strong></td><td><strong>32.9</strong></td><td><strong>18.4</strong></td><td><strong>34.1</strong></td><td><strong>32.3</strong></td><td><strong>19.9</strong></td><td><strong>11.6</strong></td><td><strong>247.3</strong></td><td><strong>138.1</strong></td><td><strong>248.4</strong></td><td><strong>229.2</strong></td><td><strong>145.7</strong></td></tr><tr><td><strong>V*</strong></td><td>59.8</td><td>59.8</td><td>63.3</td><td>68.9</td><td>68.6</td><td>56.9</td><td>47.2</td><td>42.3</td><td>43.9</td><td>46.0</td><td>44.7</td></tr><tr><td colspan="12">Australopiths (n = 6)</td></tr><tr><td><strong>Mean</strong></td><td><strong>42.3</strong></td><td><strong>27.3</strong></td><td><strong>52.7</strong></td><td><strong>49.8</strong></td><td><strong>49.6</strong></td><td><strong>19.4</strong></td><td><strong>212.4</strong></td><td><strong>144.3</strong></td><td><strong>272.0</strong></td><td><strong>248.4</strong></td><td><strong>255.2</strong></td></tr><tr><td><strong>V*</strong></td><td>40.9</td><td>15.1</td><td>30.7</td><td>45.2</td><td>31.9</td><td>22.2</td><td>24.9</td><td>17.7</td><td>26.8</td><td>30.7</td><td>23.9</td></tr><tr><td colspan="12">Homo erectus (n = 14)</td></tr><tr><td><strong>Mean</strong></td><td><strong>49.3</strong></td><td><strong>25.2</strong></td><td><strong>54.6</strong></td><td><strong>53.9</strong></td><td><strong>43.1</strong></td><td><strong>18.1</strong></td><td><strong>256.2</strong></td><td><strong>131.9</strong></td><td><strong>281</strong></td><td><strong>276.2</strong></td><td><strong>223.3</strong></td></tr><tr><td><strong>min</strong></td><td>29.0</td><td>15.6</td><td>31.5</td><td>27.6</td><td>28.1</td><td>-</td><td>150.0</td><td>101.6</td><td>232.1</td><td>203.4</td><td>179.5</td></tr><tr><td><strong>max</strong></td><td>80.2</td><td>34.2</td><td>76.0</td><td>83.8</td><td>56.9</td><td>-</td><td>382.5</td><td>190.1</td><td>394.2</td><td>382.5</td><td>319.3</td></tr><tr><td><strong>V*</strong></td><td>46.9</td><td>43.6</td><td>47.7</td><td>50.5</td><td>44.5</td><td>41.1</td><td>39.4</td><td>38.0</td><td>38.9</td><td>40.7</td><td>37.5</td></tr><tr><td colspan="12">Homo heidelbergensis (n = 8)</td></tr><tr><td><strong>Mean</strong></td><td><strong>47.6</strong></td><td><strong>29.0</strong></td><td><strong>55.4</strong></td><td><strong>47.8</strong></td><td><strong>37.0</strong></td><td><strong>17.1</strong></td><td><strong>217.5</strong></td><td><strong>134.4</strong></td><td><strong>246.3</strong></td><td><strong>205.8</strong></td><td><strong>167.8</strong></td></tr><tr><td><strong>min</strong></td><td>19.7</td><td>16.9</td><td>20.5</td><td>24.1</td><td>21.2</td><td>-</td><td>110.4</td><td>70.8</td><td>146.9</td><td>114.8</td><td>93.2</td></tr><tr><td><strong>max</strong></td><td>72.5</td><td>40.1</td><td>84.6</td><td>81.9</td><td>52.8</td><td>-</td><td>323.3</td><td>196.1</td><td>377.6</td><td>302.7</td><td>240.7</td></tr><tr><td><strong>V*</strong></td><td>30.2</td><td>26.2</td><td>35.3</td><td>43.1</td><td>30.2</td><td>24.3</td><td>21.7</td><td>15.7</td><td>24.1</td><td>19.2</td><td>15.0</td></tr><tr><td colspan="12">Homo neanderthalensis (n = 13)</td></tr></tbody></table>
<table><thead><tr><th>Mean</th><th>63.5</th><th>31.5</th><th>66.4</th><th>67.6</th><th>44.4</th><th>22.6</th><th>276.2</th><th>138.8</th><th>290.6</th><th>292.1</th><th>193.6</th></tr></thead><tbody><tr><td>min</td><td>45.1</td><td>27.2</td><td>57.8</td><td>51.6</td><td>34.7</td><td>-</td><td>136.3</td><td>56.8</td><td>134.2</td><td>153.6</td><td>91.6</td></tr><tr><td>max</td><td>84.4</td><td>38.6</td><td>86.0</td><td>88.7</td><td>57.1</td><td>-</td><td>327.4</td><td>174.5</td><td>353.3</td><td>342.0</td><td>221.7</td></tr><tr><td>V*</td><td>13.8</td><td>11.8</td><td>12.5</td><td>14.5</td><td>13.4</td><td>11.3</td><td>5.5</td><td>9.5</td><td>7.2</td><td>6.2</td><td>8.0</td></tr><tr><td colspan="12" style="text-align: center;">Homo rhodesiensis (n = 3)</td></tr><tr><td>Mean</td><td>103.3</td><td>56.7</td><td>109.3</td><td>121.7</td><td>104.4</td><td>38.9</td><td>266.6</td><td>146.8</td><td>281.7</td><td>312.6</td><td>268.7</td></tr><tr><td>min</td><td>91.6</td><td>51.3</td><td>95.7</td><td>103.7</td><td>87.1</td><td>-</td><td>257.4</td><td>138.2</td><td>265.9</td><td>284.1</td><td>259.2</td></tr><tr><td>max</td><td>115.0</td><td>60.6</td><td>125.6</td><td>147.5</td><td>113.7</td><td>-</td><td>280.3</td><td>157.0</td><td>292.8</td><td>336.3</td><td>280.3</td></tr><tr><td>V*</td><td>12.3</td><td>9.1</td><td>14.9</td><td>19.7</td><td>15.4</td><td>15.9</td><td>5.2</td><td>7.2</td><td>4.6</td><td>6.0</td><td>3.7</td></tr></tbody></table>

Note: Morphometric data (except Maba 1) are from Balzeau et al.(2022). Mean, minimal, and maximal values (only for fossil *Homo* samples) as well as coefficient of variation are included. The coefficient of variation (CV = SD/mean) was corrected for a small sample size using the V* parameter, which is calculated as [(1 + 1/4N) × CV] and expressed in percentages. We do not indicate the minimum and maximum variations in terms of volume because this variable is most subject to the state of preservation of the specimens. The average value and the coefficient of variation are much better indicators of the variation for this measurement.

<table><caption>Table S5: Measurements of the endocast of Maba 1 compared with early hominins, *Homo erectus*, *H. neanderthalensis*, and *H. sapiens*</caption><thead><tr><th></th><th>FalCE</th><th>WBE</th><th>MFWE</th><th>MPWE</th><th>Eb-P</th><th>PalCE</th><th>FalCEr</th><th>WBEr</th><th>MFWEr</th><th>MPWEr</th><th>Eb-Pr</th><th>PalCEr</th></tr></thead><tbody><tr><td>MABA</td><td>121.7</td><td>100.7</td><td>115.1</td><td>117.2</td><td>147.1</td><td>51.7</td><td>111.5</td><td>92.3</td><td>105.4</td><td>107.4</td><td>134.8</td><td>47.3</td></tr><tr><td colspan="12">early hominins (n=7)</td></tr><tr><td>Mean</td><td>93.2</td><td>75.7</td><td>83.6</td><td>83.2</td><td>114.8</td><td>38.2</td><td>116.8</td><td>95.0</td><td>104.8</td><td>104.5</td><td>143.9</td><td>47.8</td></tr><tr><td>SD</td><td>6.6</td><td>3.9</td><td>6.3</td><td>3.5</td><td>7.6</td><td>5.3</td><td>5.5</td><td>5.0</td><td>5.2</td><td>5.7</td><td>7.9</td><td>5.7</td></tr><tr><td>Max</td><td>105.2</td><td>80.6</td><td>94.8</td><td>88.8</td><td>129.2</td><td>45.8</td><td>126.0</td><td>103.2</td><td>113.5</td><td>112.8</td><td>154.7</td><td>54.8</td></tr><tr><td>Min</td><td>84.3</td><td>69.3</td><td>76.6</td><td>78.1</td><td>105.0</td><td>30.7</td><td>110.7</td><td>86.7</td><td>95.9</td><td>97.8</td><td>129.6</td><td>41.5</td></tr><tr><td>Azs</td><td>1.7</td><td>2.5</td><td>1.9</td><td>3.7</td><td>1.6</td><td>1.0</td><td>-0.4</td><td>-0.2</td><td>0.0</td><td>0.2</td><td>-0.4</td><td>0.0</td></tr><tr><td colspan="12">Homo erectus (n=13)</td></tr><tr><td>Mean</td><td>120.0</td><td>91.1</td><td>104.5</td><td>106.9</td><td>143.1</td><td>43.0</td><td>119.7</td><td>90.9</td><td>104.4</td><td>106.9</td><td>142.8</td><td>43.0</td></tr><tr><td>SD</td><td>10.6</td><td>7.2</td><td>6.5</td><td>5.4</td><td>10.8</td><td>5.4</td><td>5.4</td><td>3.9</td><td>4.1</td><td>5.0</td><td>4.6</td><td>5.1</td></tr><tr><td>Max</td><td>137.8</td><td>104.5</td><td>113.0</td><td>112.6</td><td>158.7</td><td>53.5</td><td>128.8</td><td>97.7</td><td>112.3</td><td>116.6</td><td>149.4</td><td>52.0</td></tr><tr><td>Min</td><td>102.8</td><td>82.3</td><td>94.1</td><td>97.3</td><td>124.6</td><td>34.9</td><td>108.6</td><td>83.1</td><td>97.2</td><td>100.4</td><td>131.6</td><td>37.2</td></tr><tr><td>Azs</td><td>0.1</td><td>0.6</td><td>0.7</td><td>0.8</td><td>0.2</td><td>0.7</td><td>-0.7</td><td>0.2</td><td>0.1</td><td>0.0</td><td>-0.8</td><td>0.4</td></tr><tr><td colspan="12">Homo neanderthalensis (n=9)</td></tr><tr><td>Mean</td><td>131.1</td><td>102.4</td><td>117.1</td><td>125.6</td><td>155.2</td><td>46.2</td><td>117.1</td><td>91.4</td><td>104.6</td><td>112.1</td><td>138.7</td><td>41.3</td></tr><tr><td>SD</td><td>7.3</td><td>6.2</td><td>5.0</td><td>6.6</td><td>6.9</td><td>3.9</td><td>5.3</td><td>4.1</td><td>3.4</td><td>2.1</td><td>5.8</td><td>3.3</td></tr><tr><td>Max</td><td>142.1</td><td>111.3</td><td>122.2</td><td>135.2</td><td>166.1</td><td>50.0</td><td>128.8</td><td>100.4</td><td>112.1</td><td>114.6</td><td>152.1</td><td>45.8</td></tr><tr><td>Min</td><td>118.2</td><td>91.3</td><td>108.8</td><td>118.0</td><td>142.5</td><td>39.1</td><td>109.8</td><td>86.6</td><td>101.2</td><td>108.8</td><td>132.4</td><td>35.6</td></tr></tbody></table>
<table><thead><tr><th>Azs</th><th>-0.5</th><th>-0.1</th><th>-0.2</th><th>-0.5</th><th>-0.5</th><th>0.6</th><th>-0.4</th><th>0.1</th><th>0.1</th><th>-0.9</th><th>-0.3</th><th>0.8</th></tr></thead><tbody><tr><td colspan="14">Homo sapiens (n=44)</td></tr><tr><td>Mean</td><td>134.2</td><td>99.5</td><td>118.2</td><td>126.4</td><td>156.7</td><td>57.6</td><td>117.8</td><td>87.3</td><td>103.8</td><td>111.0</td><td>137.4</td><td>50.5</td></tr><tr><td>SD</td><td>6.9</td><td>6.5</td><td>9.3</td><td>7.0</td><td>8.3</td><td>9.4</td><td>6.7</td><td>6.6</td><td>9.6</td><td>8.3</td><td>7.0</td><td>7.9</td></tr><tr><td>Max</td><td>152.2</td><td>113.9</td><td>139.0</td><td>138.8</td><td>173.8</td><td>76.8</td><td>135.2</td><td>105.0</td><td>132.4</td><td>135.7</td><td>155.5</td><td>65.7</td></tr><tr><td>Min</td><td>122.2</td><td>85.2</td><td>102.4</td><td>113.5</td><td>138.3</td><td>36.3</td><td>104.1</td><td>74.6</td><td>83.1</td><td>89.7</td><td>119.7</td><td>34.1</td></tr><tr><td>Azs</td><td>-0.9</td><td>0.1</td><td>-0.2</td><td>-0.6</td><td>-0.6</td><td>-0.3</td><td>-0.5</td><td>0.4</td><td>0.1</td><td>-0.2</td><td>-0.1</td><td>-0.2</td></tr></tbody></table>

Notes: Dimensions are in mm or are relative dimensions (with the suffix r). N = number of individuals; SD = standard deviation; Max and Min = maximal and minimal observed values; Azs = adjusted z-score of Maba 1 compared to the other groups.

<table><caption>Table S6: Measurements of the endocast in early hominins, *Homo erectus*, *H. neanderthalensis*, *H. sapiens* (fossils and extant specimens), and some unattributed specimens. Dimensions are in mm or are relative dimensions (with the suffix r).</caption><thead><tr><th></th><th>FalC<br>E</th><th>WB<br>E</th><th>MFW<br>E</th><th>MPW<br>E</th><th>Eb-P</th><th>FalC<br>E</th><th>FalCE<br>r</th><th>WBE<br>r</th><th>MFWE<br>r</th><th>MPWE<br>r</th><th>Eb-<br>Pr</th><th>PalCE<br>r</th></tr></thead><tbody><tr><td>Sts5</td><td>89.2</td><td>76.6</td><td>82.1</td><td>78.1</td><td>109.<br>6</td><td>36.9</td><td>113.5</td><td>97.5</td><td>104.4</td><td>99.4</td><td>139.<br>5</td><td>47.0</td></tr><tr><td>ER K1813</td><td>89.7</td><td>73.6</td><td>76.6</td><td>88.8</td><td>116.<br>8</td><td>43.6</td><td>112.3</td><td>92.2</td><td>95.9</td><td>111.2</td><td>146.<br>2</td><td>54.6</td></tr><tr><td>ER 13750</td><td>94.2</td><td>80.6</td><td>81.9</td><td>80.0</td><td>114.<br>0</td><td>34.6</td><td>120.7</td><td>103.2</td><td>105.0</td><td>102.6</td><td>146.<br>1</td><td>44.3</td></tr><tr><td>ER23000</td><td>94.7</td><td>75.2</td><td>83.5</td><td>82.8</td><td>117.<br>1</td><td>40.0</td><td>120.1</td><td>95.4</td><td>105.9</td><td>105.1</td><td>148.<br>5</td><td>50.7</td></tr><tr><td>OH 16</td><td>95.3</td><td>74.7</td><td>88.7</td><td>84.2</td><td>111.<br>6</td><td>35.7</td><td>110.7</td><td>86.7</td><td>103.0</td><td>97.8</td><td>129.<br>6</td><td>41.5</td></tr><tr><td>ER1805</td><td>105.2</td><td>80.1</td><td>94.8</td><td>85.4</td><td>129.<br>2</td><td>45.8</td><td>126.0</td><td>95.9</td><td>113.5</td><td>102.3</td><td>154.<br>7</td><td>54.8</td></tr><tr><td>Sts60</td><td>84.3</td><td>69.3</td><td>77.8</td><td>83.1</td><td>105.<br>0</td><td>30.7</td><td>114.4</td><td>94.1</td><td>105.6</td><td>112.8</td><td>142.<br>5</td><td>41.6</td></tr><tr><td>K3733</td><td>102.8</td><td>84.4</td><td>101.1</td><td>110.4</td><td>124.<br>6</td><td>39.7</td><td>108.6</td><td>89.2</td><td>106.8</td><td>116.6</td><td>131.<br>6</td><td>41.9</td></tr><tr><td>Sangiran 2</td><td>105.7</td><td>82.3</td><td>94.1</td><td>97.3</td><td>129.<br>8</td><td>39.6</td><td>113.2</td><td>88.2</td><td>100.9</td><td>104.2</td><td>139.<br>0</td><td>42.5</td></tr><tr><td>Sangiran 17</td><td>123.1</td><td>90.3</td><td>106.5</td><td>111.6</td><td>144.<br>8</td><td>37.2</td><td>122.9</td><td>90.2</td><td>106.3</td><td>111.4</td><td>144.<br>6</td><td>37.2</td></tr><tr><td>Sambungmacan 3</td><td>114.2</td><td>86.2</td><td>106.2</td><td>110.5</td><td>138.<br>4</td><td>49.0</td><td>117.5</td><td>88.7</td><td>109.3</td><td>113.7</td><td>142.<br>5</td><td>50.4</td></tr><tr><td>Ngandong 5</td><td>129.8</td><td>95.8</td><td>108.6</td><td>108.1</td><td>154.<br>2</td><td>42.8</td><td>120.5</td><td>88.9</td><td>100.8</td><td>100.4</td><td>143.<br>2</td><td>39.7</td></tr><tr><td>Ngandong 7</td><td>121.7</td><td>93.1</td><td>112.8</td><td>112.6</td><td>141.<br>1</td><td>39.4</td><td>121.1</td><td>92.6</td><td>112.3</td><td>112.1</td><td>140.<br>5</td><td>39.2</td></tr><tr><td>Ngandong 12</td><td>121.0</td><td>96.0</td><td>109.5</td><td>109.0</td><td>153.</td><td>53.5</td><td>117.6</td><td>93.3</td><td>106.4</td><td>105.9</td><td>148.</td><td>52.0</td></tr></tbody></table>
<table><tr><td>Zhoukoudian 1</td><td>135.1</td><td>103.1</td><td>113.0</td><td>111.4</td><td>158.7</td><td>49.1</td><td>127.2</td><td>97.0</td><td>106.4</td><td>104.8</td><td>149.4</td><td>46.2</td></tr><tr><td>Zhoukoudian 2</td><td>122.9</td><td>83.6</td><td>97.8</td><td>103.1</td><td>145.5</td><td>43.4</td><td>122.2</td><td>83.1</td><td>97.2</td><td>102.5</td><td>144.6</td><td>43.1</td></tr><tr><td>Zhoukoudian 3</td><td>114.5</td><td>86.3</td><td>98.6</td><td>99.5</td><td>139.4</td><td>47.9</td><td>117.9</td><td>88.8</td><td>101.5</td><td>102.5</td><td>143.6</td><td>49.4</td></tr><tr><td>Zhoukoudian 10</td><td>137.8</td><td>104.5</td><td>110.5</td><td>111.5</td><td>157.0</td><td>40.2</td><td>128.8</td><td>97.7</td><td>103.3</td><td>104.3</td><td>146.8</td><td>37.6</td></tr><tr><td>Zhoukoudian 12</td><td>122.4</td><td>92.0</td><td>104.4</td><td>105.2</td><td>143.7</td><td>42.3</td><td>121.3</td><td>91.1</td><td>103.4</td><td>104.2</td><td>142.3</td><td>41.9</td></tr><tr><td>ER 3883</td><td>108.9</td><td>86.2</td><td>95.2</td><td>99.5</td><td>129.7</td><td>34.9</td><td>117.1</td><td>92.8</td><td>102.4</td><td>107.1</td><td>139.5</td><td>37.6</td></tr><tr><td>Neandertal</td><td>134.9</td><td>105.1</td><td>117.9</td><td>129.8</td><td>154.2</td><td>41.0</td><td>117.2</td><td>91.4</td><td>102.4</td><td>112.7</td><td>133.9</td><td>35.6</td></tr><tr><td>La Chapelle 1</td><td>134.3</td><td>105.5</td><td>122.2</td><td>132.3</td><td>160.3</td><td>49.3</td><td>114.3</td><td>89.7</td><td>103.9</td><td>112.6</td><td>136.4</td><td>42.0</td></tr><tr><td>Saccopastore</td><td>118.2</td><td>95.7</td><td>113.1</td><td>119.4</td><td>142.5</td><td>45.4</td><td>109.8</td><td>88.9</td><td>105.1</td><td>111.0</td><td>132.4</td><td>42.2</td></tr><tr><td>Monte Circe</td><td>128.7</td><td>111.3</td><td>118.6</td><td>124.5</td><td>150.4</td><td>45.5</td><td>116.1</td><td>100.4</td><td>107.0</td><td>112.3</td><td>135.8</td><td>41.0</td></tr><tr><td>Tabun C1</td><td>126.7</td><td>98.6</td><td>121.4</td><td>118.0</td><td>152.6</td><td>48.9</td><td>116.9</td><td>91.0</td><td>112.1</td><td>109.0</td><td>140.9</td><td>45.2</td></tr><tr><td>Spy1</td><td>124.2</td><td>104.2</td><td>111.0</td><td>118.9</td><td>151.9</td><td>50.0</td><td>113.7</td><td>95.3</td><td>101.6</td><td>108.8</td><td>139.0</td><td>45.8</td></tr><tr><td>Spy10</td><td>134.8</td><td>102.6</td><td>121.7</td><td>131.2</td><td>158.2</td><td>47.5</td><td>116.4</td><td>88.6</td><td>105.1</td><td>113.3</td><td>136.6</td><td>41.0</td></tr><tr><td>La Ferrassie 1 bis</td><td>142.1</td><td>107.4</td><td>119.3</td><td>135.2</td><td>166.1</td><td>49.2</td><td>120.5</td><td>91.0</td><td>101.2</td><td>114.6</td><td>140.9</td><td>41.7</td></tr><tr><td>La Quina5</td><td>135.8</td><td>91.3</td><td>108.8</td><td>120.6</td><td>160.3</td><td>39.1</td><td>128.8</td><td>86.6</td><td>103.1</td><td>114.4</td><td>152.1</td><td>37.1</td></tr><tr><td>1489 (Extant)</td><td>130.9</td><td>90.9</td><td>114.5</td><td>131.5</td><td>159.9</td><td>66.6</td><td>112.8</td><td>78.4</td><td>98.7</td><td>113.4</td><td>137.9</td><td>57.5</td></tr><tr><td>3662 (Extant)</td><td>129.6</td><td>102.5</td><td>120.1</td><td>131.8</td><td>159.2</td><td>60.3</td><td>111.3</td><td>88.0</td><td>103.1</td><td>113.2</td><td>136.7</td><td>51.7</td></tr><tr><td>3663 (Extant)</td><td>122.3</td><td>102.5</td><td>116.7</td><td>125.7</td><td>138.3</td><td>50.0</td><td>105.9</td><td>88.7</td><td>101.0</td><td>108.8</td><td>119.7</td><td>43.3</td></tr><tr><td>3664 (Extant)</td><td>122.2</td><td>101.0</td><td>127.3</td><td>130.6</td><td>147.9</td><td>53.9</td><td>127.1</td><td>105.0</td><td>132.4</td><td>135.7</td><td>153.7</td><td>56.1</td></tr><tr><td>3665 (Extant)</td><td>136.1</td><td>102.0</td><td>132.6</td><td>136.7</td><td>154.5</td><td>46.8</td><td>114.3</td><td>85.6</td><td>111.3</td><td>114.7</td><td>129.7</td><td>39.3</td></tr><tr><td>3666 (Extant)</td><td>146.2</td><td>101.2</td><td>122.1</td><td>138.3</td><td>161.7</td><td>53.5</td><td>122.4</td><td>84.8</td><td>102.3</td><td>115.8</td><td>135.5</td><td>44.8</td></tr></table>
<table>
  <tr>
    <td>3669 (Extant)</td>
    <td>140.1</td>
    <td>106.8</td>
    <td>138.2</td>
    <td>136.7</td>
    <td>158.4</td>
    <td>53.1</td>
    <td>117.1</td>
    <td>89.3</td>
    <td>115.5</td>
    <td>114.3</td>
    <td>132.5</td>
    <td>44.4</td>
  </tr>
  <tr>
    <td>3683 (Extant)</td>
    <td>134.6</td>
    <td>109.0</td>
    <td>126.3</td>
    <td>136.5</td>
    <td>146.6</td>
    <td>41.2</td>
    <td>123.3</td>
    <td>99.9</td>
    <td>115.7</td>
    <td>125.1</td>
    <td>134.4</td>
    <td>37.7</td>
  </tr>
  <tr>
    <td>3684 (Extant)</td>
    <td>141.4</td>
    <td>98.6</td>
    <td>112.7</td>
    <td>128.0</td>
    <td>169.5</td>
    <td>64.7</td>
    <td>111.4</td>
    <td>77.7</td>
    <td>88.8</td>
    <td>100.9</td>
    <td>133.6</td>
    <td>51.0</td>
  </tr>
  <tr>
    <td>3686 (Extant)</td>
    <td>138.3</td>
    <td>91.6</td>
    <td>116.9</td>
    <td>128.8</td>
    <td>167.5</td>
    <td>70.5</td>
    <td>112.7</td>
    <td>74.6</td>
    <td>95.2</td>
    <td>104.9</td>
    <td>136.4</td>
    <td>57.4</td>
  </tr>
  <tr>
    <td>3687 (Extant)</td>
    <td>125.7</td>
    <td>93.2</td>
    <td>113.9</td>
    <td>128.4</td>
    <td>147.6</td>
    <td>56.0</td>
    <td>120.3</td>
    <td>89.2</td>
    <td>109.0</td>
    <td>122.8</td>
    <td>141.2</td>
    <td>53.6</td>
  </tr>
  <tr>
    <td>3688 (Extant)</td>
    <td>128.9</td>
    <td>96.2</td>
    <td>119.5</td>
    <td>123.9</td>
    <td>145.5</td>
    <td>40.1</td>
    <td>112.2</td>
    <td>83.7</td>
    <td>104.0</td>
    <td>107.9</td>
    <td>126.6</td>
    <td>34.9</td>
  </tr>
  <tr>
    <td>3696 (Extant)</td>
    <td>130.0</td>
    <td>89.7</td>
    <td>104.6</td>
    <td>123.6</td>
    <td>152.8</td>
    <td>62.0</td>
    <td>115.0</td>
    <td>79.3</td>
    <td>92.5</td>
    <td>109.3</td>
    <td>135.2</td>
    <td>54.9</td>
  </tr>
  <tr>
    <td>3697 (Extant)</td>
    <td>125.6</td>
    <td>94.3</td>
    <td>115.3</td>
    <td>132.4</td>
    <td>145.9</td>
    <td>51.1</td>
    <td>111.0</td>
    <td>83.3</td>
    <td>101.9</td>
    <td>117.0</td>
    <td>128.9</td>
    <td>45.1</td>
  </tr>
  <tr>
    <td>3699 (Extant)</td>
    <td>125.2</td>
    <td>97.3</td>
    <td>113.2</td>
    <td>126.0</td>
    <td>149.5</td>
    <td>67.8</td>
    <td>110.4</td>
    <td>85.8</td>
    <td>99.8</td>
    <td>111.2</td>
    <td>131.9</td>
    <td>59.8</td>
  </tr>
  <tr>
    <td>3701 (Extant)</td>
    <td>129.0</td>
    <td>85.2</td>
    <td>102.4</td>
    <td>123.8</td>
    <td>148.5</td>
    <td>48.4</td>
    <td>116.5</td>
    <td>77.0</td>
    <td>92.5</td>
    <td>111.8</td>
    <td>134.2</td>
    <td>43.8</td>
  </tr>
  <tr>
    <td>3702 (Extant)</td>
    <td>138.1</td>
    <td>98.3</td>
    <td>116.1</td>
    <td>119.7</td>
    <td>160.6</td>
    <td>57.6</td>
    <td>118.2</td>
    <td>84.1</td>
    <td>99.3</td>
    <td>102.4</td>
    <td>137.4</td>
    <td>49.3</td>
  </tr>
  <tr>
    <td>3705 (Extant)</td>
    <td>136.3</td>
    <td>93.7</td>
    <td>107.3</td>
    <td>116.1</td>
    <td>151.3</td>
    <td>56.7</td>
    <td>127.3</td>
    <td>87.5</td>
    <td>100.2</td>
    <td>108.4</td>
    <td>141.3</td>
    <td>52.9</td>
  </tr>
  <tr>
    <td>3707 (Extant)</td>
    <td>139.5</td>
    <td>104.6</td>
    <td>106.9</td>
    <td>115.4</td>
    <td>170.6</td>
    <td>68.5</td>
    <td>108.4</td>
    <td>81.3</td>
    <td>83.1</td>
    <td>89.7</td>
    <td>132.6</td>
    <td>53.2</td>
  </tr>
  <tr>
    <td>3708 (Extant)</td>
    <td>135.2</td>
    <td>91.3</td>
    <td>108.0</td>
    <td>123.3</td>
    <td>152.3</td>
    <td>51.4</td>
    <td>126.2</td>
    <td>85.2</td>
    <td>100.8</td>
    <td>115.1</td>
    <td>142.1</td>
    <td>48.0</td>
  </tr>
  <tr>
    <td>3709 (Extant)</td>
    <td>134.6</td>
    <td>95.4</td>
    <td>109.4</td>
    <td>118.2</td>
    <td>157.9</td>
    <td>59.8</td>
    <td>124.4</td>
    <td>88.2</td>
    <td>101.1</td>
    <td>109.3</td>
    <td>146.0</td>
    <td>55.3</td>
  </tr>
  <tr>
    <td>9844 (Extant)</td>
    <td>125.4</td>
    <td>95.1</td>
    <td>111.7</td>
    <td>119.0</td>
    <td>153.3</td>
    <td>62.8</td>
    <td>112.6</td>
    <td>85.3</td>
    <td>100.2</td>
    <td>106.8</td>
    <td>137.6</td>
    <td>56.3</td>
  </tr>
  <tr>
    <td>9848 (Extant)</td>
    <td>138.7</td>
    <td>96.3</td>
    <td>113.8</td>
    <td>117.4</td>
    <td>156.3</td>
    <td>51.8</td>
    <td>125.3</td>
    <td>87.0</td>
    <td>102.9</td>
    <td>106.1</td>
    <td>141.2</td>
    <td>46.8</td>
  </tr>
  <tr>
    <td>9852 (Extant)</td>
    <td>128.2</td>
    <td>92.6</td>
    <td>105.8</td>
    <td>113.5</td>
    <td>149.4</td>
    <td>58.4</td>
    <td>120.4</td>
    <td>87.0</td>
    <td>99.3</td>
    <td>106.6</td>
    <td>140.3</td>
    <td>54.9</td>
  </tr>
  <tr>
    <td>9853 (Extant)</td>
    <td>136.4</td>
    <td>91.6</td>
    <td>106.1</td>
    <td>115.8</td>
    <td>155.1</td>
    <td>64.5</td>
    <td>116.0</td>
    <td>77.9</td>
    <td>90.2</td>
    <td>98.4</td>
    <td>131.8</td>
    <td>54.9</td>
  </tr>
  <tr>
    <td>10109 (Extant)</td>
    <td>144.1</td>
    <td>102.0</td>
    <td>124.6</td>
    <td>133.5</td>
    <td>163.1</td>
    <td>51.6</td>
    <td>118.7</td>
    <td>84.0</td>
    <td>102.5</td>
    <td>109.9</td>
    <td>134.3</td>
    <td>42.4</td>
  </tr>
  <tr>
    <td>10113 (Extant)</td>
    <td>136.0</td>
    <td>95.5</td>
    <td>113.2</td>
    <td>124.7</td>
    <td>148.6</td>
    <td>60.8</td>
    <td>127.3</td>
    <td>89.4</td>
    <td>106.0</td>
    <td>116.8</td>
    <td>139.1</td>
    <td>57.0</td>
  </tr>
  <tr>
    <td>12033 (Extant)</td>
    <td>132.0</td>
    <td>97.9</td>
    <td>110.0</td>
    <td>123.1</td>
    <td>157.6</td>
    <td>55.5</td>
    <td>111.8</td>
    <td>82.9</td>
    <td>93.2</td>
    <td>104.3</td>
    <td>133.5</td>
    <td>47.0</td>
  </tr>
</table>
<table>
  <tr>
    <td>21413 (Extant)</td>
    <td>138.2</td>
    <td>97.1</td>
    <td>118.9</td>
    <td>122.3</td>
    <td>157.2</td>
    <td>44.8</td>
    <td>115.2</td>
    <td>80.9</td>
    <td>99.1</td>
    <td>101.9</td>
    <td>131.0</td>
    <td>37.4</td>
  </tr>
  <tr>
    <td>D727 (Extant)</td>
    <td>130.6</td>
    <td>99.6</td>
    <td>124.1</td>
    <td>127.0</td>
    <td>144.8</td>
    <td>42.7</td>
    <td>123.5</td>
    <td>94.2</td>
    <td>117.4</td>
    <td>120.1</td>
    <td>136.9</td>
    <td>40.3</td>
  </tr>
  <tr>
    <td>D728 (Extant)</td>
    <td>132.2</td>
    <td>101.8</td>
    <td>130.3</td>
    <td>127.2</td>
    <td>147.5</td>
    <td>36.3</td>
    <td>124.4</td>
    <td>95.8</td>
    <td>122.6</td>
    <td>119.7</td>
    <td>138.8</td>
    <td>34.1</td>
  </tr>
  <tr>
    <td>D732 (Extant)</td>
    <td>134.2</td>
    <td>106.3</td>
    <td>129.9</td>
    <td>135.7</td>
    <td>153.5</td>
    <td>48.0</td>
    <td>126.5</td>
    <td>100.2</td>
    <td>122.5</td>
    <td>127.9</td>
    <td>144.8</td>
    <td>45.3</td>
  </tr>
  <tr>
    <td>D788 (Extant)</td>
    <td>127.2</td>
    <td>101.5</td>
    <td>124.9</td>
    <td>130.6</td>
    <td>159.5</td>
    <td>62.6</td>
    <td>104.1</td>
    <td>83.1</td>
    <td>102.2</td>
    <td>106.9</td>
    <td>130.6</td>
    <td>51.2</td>
  </tr>
  <tr>
    <td>D789 (Extant)</td>
    <td>142.0</td>
    <td>110.9</td>
    <td>127.7</td>
    <td>132.6</td>
    <td>165.1</td>
    <td>60.7</td>
    <td>112.3</td>
    <td>87.6</td>
    <td>100.9</td>
    <td>104.8</td>
    <td>130.5</td>
    <td>48.0</td>
  </tr>
  <tr>
    <td>D808 (Extant)</td>
    <td>152.2</td>
    <td>113.1</td>
    <td>139.0</td>
    <td>138.8</td>
    <td>163.5</td>
    <td>52.1</td>
    <td>122.2</td>
    <td>90.8</td>
    <td>111.6</td>
    <td>111.4</td>
    <td>131.3</td>
    <td>41.8</td>
  </tr>
  <tr>
    <td>Cro Magnon 1</td>
    <td>131.0</td>
    <td>101.6</td>
    <td>121.9</td>
    <td>134.6</td>
    <td>167.5</td>
    <td>76.8</td>
    <td>109.1</td>
    <td>84.6</td>
    <td>101.6</td>
    <td>112.2</td>
    <td>139.5</td>
    <td>64.0</td>
  </tr>
  <tr>
    <td>Abri Pataud 1</td>
    <td>126.6</td>
    <td>97.6</td>
    <td>114.7</td>
    <td>124.7</td>
    <td>153.5</td>
    <td>58.4</td>
    <td>113.7</td>
    <td>87.7</td>
    <td>103.0</td>
    <td>112.0</td>
    <td>137.9</td>
    <td>52.5</td>
  </tr>
  <tr>
    <td>Skhul 5</td>
    <td>134.6</td>
    <td>102.2</td>
    <td>111.0</td>
    <td>125.7</td>
    <td>155.4</td>
    <td>57.9</td>
    <td>117.1</td>
    <td>88.9</td>
    <td>96.5</td>
    <td>109.3</td>
    <td>135.1</td>
    <td>50.3</td>
  </tr>
  <tr>
    <td>Predmost 10</td>
    <td>134.6</td>
    <td>106.8</td>
    <td>125.4</td>
    <td>131.6</td>
    <td>164.6</td>
    <td>67.5</td>
    <td>118.9</td>
    <td>94.3</td>
    <td>110.7</td>
    <td>116.2</td>
    <td>145.3</td>
    <td>59.6</td>
  </tr>
  <tr>
    <td>Predmost 3</td>
    <td>139.8</td>
    <td>111.1</td>
    <td>128.5</td>
    <td>122.8</td>
    <td>169.4</td>
    <td>69.6</td>
    <td>120.0</td>
    <td>95.4</td>
    <td>110.3</td>
    <td>105.5</td>
    <td>145.5</td>
    <td>59.8</td>
  </tr>
  <tr>
    <td>Dolní Věstonice 1</td>
    <td>134.3</td>
    <td>98.2</td>
    <td>113.5</td>
    <td>122.3</td>
    <td>165.3</td>
    <td>75.2</td>
    <td>117.3</td>
    <td>85.8</td>
    <td>99.1</td>
    <td>106.9</td>
    <td>144.4</td>
    <td>65.7</td>
  </tr>
  <tr>
    <td>Predmost 4</td>
    <td>145.6</td>
    <td>100.8</td>
    <td>123.4</td>
    <td>130.8</td>
    <td>167.5</td>
    <td>66.8</td>
    <td>135.2</td>
    <td>93.6</td>
    <td>114.5</td>
    <td>121.4</td>
    <td>155.5</td>
    <td>62.1</td>
  </tr>
  <tr>
    <td>Predmost 9</td>
    <td>144.7</td>
    <td>113.9</td>
    <td>131.3</td>
    <td>114.8</td>
    <td>173.8</td>
    <td>69.1</td>
    <td>124.9</td>
    <td>98.3</td>
    <td>113.3</td>
    <td>99.1</td>
    <td>150.0</td>
    <td>59.6</td>
  </tr>
  <tr>
    <td>Brno 3</td>
    <td>127.0</td>
    <td>99.5</td>
    <td>106.8</td>
    <td>118.7</td>
    <td>156.4</td>
    <td>60.5</td>
    <td>116.3</td>
    <td>91.1</td>
    <td>97.8</td>
    <td>108.6</td>
    <td>143.2</td>
    <td>55.4</td>
  </tr>
  <tr>
    <td>Djebel Irhoud 1</td>
    <td>117.0</td>
    <td>101.7</td>
    <td>117.3</td>
    <td>125.2</td>
    <td>151.7</td>
    <td>57.0</td>
    <td>107.1</td>
    <td>93.0</td>
    <td>107.3</td>
    <td>114.6</td>
    <td>138.8</td>
    <td>52.2</td>
  </tr>
  <tr>
    <td>Broken Hill 1</td>
    <td>124.1</td>
    <td>99.5</td>
    <td>119.2</td>
    <td>121.0</td>
    <td>149.3</td>
    <td>56.1</td>
    <td>113.0</td>
    <td>90.6</td>
    <td>108.5</td>
    <td>110.2</td>
    <td>136.0</td>
    <td>51.1</td>
  </tr>
  <tr>
    <td>LH 18</td>
    <td>129.3</td>
    <td>104.1</td>
    <td>108.5</td>
    <td>107.4</td>
    <td>159.6</td>
    <td>53.2</td>
    <td>116.5</td>
    <td>93.8</td>
    <td>97.7</td>
    <td>96.7</td>
    <td>143.8</td>
    <td>47.9</td>
  </tr>
  <tr>
    <td>Maba 1</td>
    <td>118.9</td>
    <td>100.7</td>
    <td>115.1</td>
    <td>117.2</td>
    <td>147.1</td>
    <td>55.5</td>
    <td>109.0</td>
    <td>92.3</td>
    <td>105.4</td>
    <td>107.4</td>
    <td>134.8</td>
    <td>50.9</td>
  </tr>
</table>
<figure><img src="image_7.png" /><figcaption>**Figure S1.** The 3D models of Maba 1. a, anterior view; b, posterior view; c, lateral view (right); d, superior view; e, inferior view; f, lateral view (left).</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>**Figure S2.** The CT slice of Maba 1 cranium (cross section along the coronal plane), showing the thickening and thinning caused by the reliefs on the endocranial surface.</figcaption></figure>
<figure><img src="image_9.png" /><figcaption>**Figure S3.** The parietal foramen and its connection with diploic vessel in Maba 1. The figure is from the author's PhD thesis (Hui, 2024).</figcaption></figure>
<figure><img src="image_10.png" /><figcaption>**Figure S4.** The location of landmarks and the overall shape differences described by PC1 and PC2. Note that some points are not visible on the 3D model in this orientation (BEC, indicated here by an arrow, LWP, LWF and LBC) while Right and Left Frontal Poles are superimposed</figcaption></figure>
on the illustrations of shape differences. The cones show the direction of the deformation along
the PCs.

References

Balzeau, A. (2013). Thickened cranial vault and parasagittal keeling: Correlated traits and autapomorphies of *Homo erectus? Journal of Human Evolution*, 64(6), 631–644.

https://doi.org/10.1016/j.jhevol.2013.02.005

Balzeau, A., Albessard-Ball, L., Kubicka, A. M., Filippo, A., Beaudet, A., Santos, E., Bienvenu, T.,
Arsuaga, J.-L., Bartsiokas, A., Berger, L., Bermúdez de Castro, J. M., Brunet, M., Carlson, K. J.,
Daura, J., Gorgoulis, V. G., Grine, F. E., Harvati, K., Hawks, J., Herries, A., Buck, L. T. (2022).
Frontal sinuses and human evolution. *Science Advances*, 8(42), eabp9767.

https://doi.org/10.1126/sciadv.abp9767

Hui, J. (2024). *Comparative anatomy of the diploic vessels in hominids: Implications for the evolutionary history of human cranial blood circulation* [PhD, Sorbonne University].

https://theses.hal.science/tel-04743615

Hui, J., & Balzeau, A. (2023). The diploic venous system in *Homo neanderthalensis* and fossil *Homo sapiens*: A study using high-resolution computed tomography. *American Journal of Biological Anthropology*, 182(3), 412–427. https://doi.org/10.1002/ajpa.24843