First evolutionary insights into the human otolithic system

The human otolithic system (utricle and saccule), housed within the bony vestibule of the inner ear, establishes our sense of balance in conjunction with the semicircular canals. Yet, while the morphological evolution of the semicircular canals is actively explored, comparative morphological analyse...

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Detalles Bibliográficos
Autores: Smith, Christopher M.|||0000-0001-9259-1079, David, Romain|||0000-0003-4073-7456, Almécija, Sergio|||0000-0003-1373-1497, Laitman, Jeffrey T., Hammond, Ashley S.|||0000-0001-8444-0553
Tipo de recurso: artículo
Fecha de publicación:2024
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:301834
Acceso en línea:https://ddd.uab.cat/record/301834
https://dx.doi.org/urn:doi:10.1038/s42003-024-06966-0
Access Level:acceso abierto
Palabra clave:Biological anthropology
Inner ear
Descripción
Sumario:The human otolithic system (utricle and saccule), housed within the bony vestibule of the inner ear, establishes our sense of balance in conjunction with the semicircular canals. Yet, while the morphological evolution of the semicircular canals is actively explored, comparative morphological analyses of the otolithic system are lacking. This is regrettable because functional links with head orientation suggest the otolithic system could be used to track postural change throughout human evolution and across primates more broadly. In this context, we present the first analysis of the evolution of the human otolithic system within an anthropoid primate setting. Using the vestibule as a morphological proxy for the utricle and saccule, we compare humans to 13 other extant anthropoid species, and use phylogenetically-informed methods to find correlations with body size, endocranial flexion, and head-neck posture. Our results, obtained through micro-CT of 136 inner ears, reveal two major evolutionary transitions in hominoids, leading to distinctive vestibular morphology in humans, characterized by otolithic morphology resembling squirrel monkeys (possibly due to reversal), with a pronounced supraovalic fossa. Finally, we find a positional signal embedded in the anthropoid bony vestibule, providing the foundation to further explore the evolution of human head-neck posture using inner ear morphology.