Method for assessing the development of non‑metric traits of the scapula: humans and modern primates

Abstract

Introduction. The mammalian scapula is a product of complex evolutionary development and bears features of functional specialization of the upper (thoracic) limb. This article presents an osteoscopic program developed for studying the morphology of the scapula in modern humans (Homo sapiens) and adapted for other members of the order Primates.

Materials and methods. The study was conducted using osteological materials: scapulae of modern humans (n=85) from the collection of the Department of Anthropology, Faculty of Biology, Moscow State University, as well as scapulae of other primates (n=193) from the collections of the Zoological Museum and the Museum of Anthropology of Moscow State University. The program includes 16 traits for morphological analysis (including the shape of the glenoid cavity, scapular spine, acromion, and medial border; the position of the spine base; the presence and prominence of ridges and grooves along the lateral border; the shape of the infraglenoid tubercle, etc.) and 7 traits for age identification based on the timing of fusion of accessory ossification centers. All traits are scored using a grading scale.

Results. The study revealed species‑specific morphological features of the glenoid cavity and introduced two new variants (including the “lemuroid” type); expanded the typology of the scapular spine with two additional shape variants; described specific features of the lateral border in galagos, tarsiers, and lorisids; and detailed criteria for describing ridges, grooves, and other structures. The presented scapuloscopic program is accompanied by detailed illustrations.

Conclusion. The osteoscopic program for analyzing human scapulae was significantly enhanced and adapted for studying scapulae of other Primates. The proposed methodology can serve as a foundation for examining scapulae across other mammalian orders and be applied in anthropology, zoology, paleontology, and comparative anatomy. Osteoscopic data may prove valuable for reconstructing locomotor patterns of fossil primates and other mammals, combining the traditions of classical anthropology with modern research methods.

Acknowledgements. The study was conducted under the state assignment of Lomonosov Moscow State University.

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