New insights into the variability of upper airway morphology in modern humans.

The biological adaptation of the human lineage to its environment is a recurring question in paleoanthropology. Particularly, how eco-geographic factors (e.g.

Reassessment of the phylogenetic relationships of the late Miocene apes and based on vestibular morphology.

Late Miocene great apes are key to reconstructing the ancestral morphotype from which earliest hominins evolved. Despite consensus that the late Miocene dryopith great apes (Spain) and (Hungary) are closely related (Hominidae), ongoing debate on their phylogenetic relationships with extant apes (stem hominids, hominines, or pongines) complicates our understanding of great ape and human evolution. To clarify this question, we rely on the morphology of the inner ear semicircular canals, which has been shown to be phylogenetically informative.

Comparison of different machine learning approaches to predict dental age using Demirjian's staging approach.

Context: Dental age, one of the indicators of biological age, is inferred by radiological methods. Two of the most commonly used methods are using Demirjian's radiographic stages of permanent teeth excluding the third molar (Demirjian's and Willems' method). The major drawbacks of these methods are that they are based on population-specific conversion tables and may tend to over- or underestimate dental age in other populations.

Hominin diversity in East Asia during the Middle Pleistocene: A premolar endostructural perspective.

Following the recent studies of East Asian mid-Middle to early Late Pleistocene hominin material, a large spectrum of morphological diversity has been recognized and the coexistence of archaic ('Homo erectus-like') and derived ('modern-like') dental morphological patterns has been highlighted. In fact, for most of these Chinese fossils, generally categorized as 'archaic Homo sapiens' or 'post-H. erectus Homo', the taxonomic attribution is a matter of contention.

Are endocasts reliable proxies for brains? A 3D quantitative comparison of the extant human brain and endocast.

Endocasts (i.e., replicas of the inner surface of the bony braincase) constitute a critical proxy for qualifying and quantifying variations in brain shape and organization in extinct taxa.

Volume of unsupported peri-implant soft tissue over time: A cross-sectional observation study.

Statement Of Problem: Supraimplant emergence profile changes have revealed that, when not supported, peri-implant soft tissue collapses. However, this phenomenon has not been described qualitatively and quantitatively in 3 dimensions.

Purpose: The purpose of this cross-sectional clinical study was to analyze changes in the supraimplant emergence profile digitally over time when the peri-implant soft tissue was not supported.

The evolution of the vestibular apparatus in apes and humans.

Phylogenetic relationships among extinct hominoids (apes and humans) are controversial due to pervasive homoplasy and the incompleteness of the fossil record. The bony labyrinth might contribute to this debate, as it displays strong phylogenetic signal among other mammals. However, the potential of the vestibular apparatus for phylogenetic reconstruction among fossil apes remains understudied.

Structural analysis of premolar roots in Middle Pleistocene hominins from China.

This study investigates permanent maxillary and mandibular premolar root structural organization in East Asian Middle Pleistocene hominins. In addition to reporting and analyzing the linear and volumetric properties of the roots, we used a landmark-free approach to both qualify and quantify in 3D premolar root shape variation of Middle Pleistocene hominins in East Asia. Moreover, we focus on some mid-to late East Asian Middle Pleistocene hominin specimens whose taxonomic attribution is unclear.

Cortical bone distribution in the femoral neck of Paranthropus robustus.

Studies of the australopith (Australopithecus and Paranthropus) proximal femur have increasingly integrated information from the local arrangement of the cortical and cancellous bone to allow functional-biomechanical inferences on the locomotor behavioral patterns. In Australopithecus africanus and Paranthropus robustus, the cancellous bone organization at the center of the femoral head shows principal strut orientation similar to that of fossil and recent humans, which indicates that australopiths were human-like in many aspects of their bipedalism. However, by combining outer morphology with superoinferior asymmetry in cortical bone thickness at the base of neck and mid-neck, it has been suggested that, while adapted for terrestrial bipedality, australopiths displayed a slightly altered gait kinematics compared to Homo.

Cochlear shape reveals that the human organ of hearing is sex-typed from birth.

Sex differences in behavioral and neural characteristics can be caused by cultural influences but also by sex-based differences in neurophysiological and sensorimotor features. Since signal-response systems influence decision-making, cooperative and collaborative behaviors, the anatomical or physiological bases for any sex-based difference in sensory mechanisms are important to explore. Here, we use uniform scaling and nonparametric representations of the human cochlea, the main organ of hearing that imprints its adult-like morphology within the petrosal bone from birth.

Efficacy of diffeomorphic surface matching and 3D geometric morphometrics for taxonomic discrimination of Early Pleistocene hominin mandibular molars.

Morphometric assessments of the dentition have played significant roles in hypotheses relating to taxonomic diversity among extinct hominins. In this regard, emphasis has been placed on the statistical appraisal of intraspecific variation to identify morphological criteria that convey maximum discriminatory power. Three-dimensional geometric morphometric (3D GM) approaches that utilize landmarks and semi-landmarks to quantify shape variation have enjoyed increasingly popular use over the past twenty-five years in assessments of the outer enamel surface (OES) and enamel-dentine junction (EDJ) of fossil molars.

A geometric morphometric approach to the study of variation of shovel-shaped incisors.

Objectives: The scoring and analysis of dental nonmetric traits are predominantly accomplished by using the Arizona State University Dental Anthropology System (ASUDAS), a standard protocol based on strict definitions and three-dimensional dental plaques. However, visual scoring, even when controlled by strict definitions of features, visual reference, and the experience of the observer, includes an unavoidable part of subjectivity. In this methodological contribution, we propose a new quantitative geometric morphometric approach to quickly and efficiently assess the variation of shoveling in modern human maxillary central incisors (UI1).

Inner tooth morphology of Homo erectus from Zhoukoudian. New evidence from an old collection housed at Uppsala University, Sweden.

Locality 1, in the Lower Cave of the Zhoukoudian cave complex, China, is one of the most important Middle Pleistocene paleoanthropological and archaeological sites worldwide, with the remains of c. 45 Homo erectus individuals, 98 mammalian taxa, and thousands of lithic tools recovered. Most of the material collected before World War II was lost.

Assessment of automatic segmentation of teeth using a watershed-based method.

Objective: Tooth 3D automatic segmentation (AS) is being actively developed in research and clinical fields. Here, we assess the effect of automatic segmentation using a watershed-based method on the accuracy and reproducibility of 3D reconstructions in volumetric measurements by comparing it with a semi-automatic segmentation(SAS) method that has already been validated.

Methods: The study sample comprised 52 teeth, scanned with micro-CT (41 µm voxel size) and CBCT (76; 200 and 300 µm voxel size).

Intra-individual metameric variation expressed at the enamel-dentine junction of lower post-canine dentition of South African fossil hominins and modern humans.

Objectives: The aim of this study is to compare the degree and patterning of inter- and intra-individual metameric variation in South African australopiths, early Homo and modern humans. Metameric variation likely reflects developmental and taxonomical issues, and could also be used to infer ecological and functional adaptations. However, its patterning along the early hominin postcanine dentition, particularly among South African fossil hominins, remains unexplored.

Further morphological evidence on South African earliest Homo lower postcanine dentition: Enamel thickness and enamel dentine junction.

The appearance of the earliest members of the genus Homo in South Africa represents a key event in human evolution. Although enamel thickness and enamel dentine junction (EDJ) morphology preserve important information about hominin systematics and dietary adaptation, these features have not been sufficiently studied with regard to early Homo. We used micro-CT to compare enamel thickness and EDJ morphology among the mandibular postcanine dentitions of South African early hominins (N = 30) and extant Homo sapiens (N = 26), with special reference to early members of the genus Homo.

Upper third molar internal structural organization and semicircular canal morphology in Plio-Pleistocene South African cercopithecoids.

Despite the abundance of cercopithecoids in the fossil record, especially in South Africa, and the recent development of morphometric approaches, uncertainties regarding the taxonomic identification of isolated cranio-dental specimens remain. Because cercopithecoids, nearly always found in stratigraphic association with hominin remains in Plio-Pleistocene deposits, are considered as sensitive ecological and chronological biomarkers, a significant effort should be made to clarify their palaeobiodiversity by assessing additional reliable morphological diagnostic criteria. Here we test the relevance of both molar crown internal structure and bony labyrinth morphology for discrimination of fossil cercopithecoid species.

Disproportionate Cochlear Length in Genus Homo Shows a High Phylogenetic Signal during Apes' Hearing Evolution.

Changes in lifestyles and body weight affected mammal life-history evolution but little is known about how they shaped species' sensory systems. Since auditory sensitivity impacts communication tasks and environmental acoustic awareness, it may have represented a deciding factor during mammal evolution, including apes. Here, we statistically measure the influence of phylogeny and allometry on the variation of five cochlear morphological features associated with hearing capacities across 22 living and 5 fossil catarrhine species.

The human semicircular canals orientation is more similar to the bonobos than to the chimpanzees.

For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes).