CT-Based Descriptions of the Paranasal Complex of Sungir-1, an Upper Paleolithic European

Abstract

Although the intricacies of the underlying processes of paranasal sinus development are still unknown, the docu-mentation of sinus morphology is necessary to fully comprehend the evolutionary history of these structures, and for understanding the complex ontogenetic and phylogenetic processes shaping hominin diversity. As such, the purpose of this study is to present, for the first time, detailed descriptions for internal paranasal structures of the Sungir-1 specimen. The Sungir-1 specimen was scanned via computed tomography (CT) in Moscow, Russia. Us-ing these CT scans, the maxillary and frontal sinuses were semi-automatically segmented and digitally rendered into three-dimensional (3D) models; volumetric data were obtained from these models. Sinus volumes were also obtained from CT scans of another Upper Paleolithic specimen, Mladeč-1, and three morphologically distinct modern human samples (Late Holocene)—West Africans, Mongolians, and Croatians. Volumetric-data was cur-sorily compared to previously published reports for additional Middle and Upper Paleolithic fossils, as well as additional Late Holocene modern human specimens. Overall, Sungir-1 exhibits relatively large maxillary sinuses occupying most of the maxillary body (volumes: right, 24.63cm3;left, 26.18cm3). Initial observations indicate that Sungir’s tall, wide maxillary sinuses are smaller than those of Neanderthals, and likely most similar to those of Mongolians and other Central Asian samples previously described in the literature. Sungir-1’s frontal sinuses are relatively small and simple (volumes: right, 1.51cm3;left, 2.23cm3; combined,3.74cm3)—adding to the complexity of frontal sinus variation already evident in the fossil and modern human record. Studies incorporating shape analyses of these internal structures are currently underway to better understand the position of Sungir-1 relative to diverse modern human groups, as well as any environmental effect.