Different Level of Intraspecific Variation of the Bony Labyrinth Morphology in Slow- Versus Fast-Moving Primates

作者：Perier Alexandre; Lebrun Renaud; Marivaux Laurent

来源：Journal of Mammalian Evolution, 2016, 23(4): 353-368.

DOI：10.1007/s10914-016-9323-3

• Inner ear
• Semicircular canals
• Intraspecific variation
• Geometric morphometrics
• Primates
• Locomotion

The vestibular system of the inner ear detects the motions of the head and is involved in maintaining balance. For this reason, this organ has been deeply studied and several scientists have tried to link its morphology with the locomotor behavior of an animal. Via high-resolution computed microtomography and geometric morphometric methods, we analyzed the intraspecific variation of the 3D morphology of the bony labyrinth (inner ear) in four species of primates differing in their locomotor adaptations: two being slow-moving taxa (Nycticebus and Perodicticus), and two being fast-moving taxa (Callithrix and Microcebus). Basically, there are very few analyses of the inter-individual variation of this organ in mammals in general, and this approach has never been attempted in primates thus far. Our results show that variation of the bony labyrinth morphology is expressed by the same ways in the different species (e.g., differences in the size, shape, and orientation of the semicircular canals, and in the width and height of the cochlea), but that slow-moving taxa exhibit a higher amount of intraspecific variation than do fast-moving taxa. Our results strengthen support for a previously published hypothesis, according to which a relaxation of the selective pressure applied to the morphology of the bony labyrinth is the likely reason for this higher amount of intraspecific variation in slow-moving taxa, and that it may be related to a reduced functional demand for rapid postural adjustments.

• 出版日期2016-12