doi: 10.1111/joa.13799.
Online ahead of print.
Affiliations
Affiliations
- 1 A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation.
- 2 Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russian Federation.
Item in Clipboard
Ruslan I Belyaev et al.
J Anat.
.
Display options
Format
doi: 10.1111/joa.13799.
Online ahead of print.
Affiliations
- 1 A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russian Federation.
- 2 Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russian Federation.
Item in Clipboard
Display options
Format
Abstract
The vertebral column is a hallmark of vertebrates; it is the structural basis of their body and the locomotor apparatus in particular. Locomotion of any vertebrate animal in its typical habitat is directly associated with functional adaptations of its vertebrae. This study is the first large-scale analysis of mobility throughout the presacral region of the vertebral column covering a majority of extant odd-toed ungulates from 6 genera and 15 species. In this study, we used a previously developed osteometry-based method to calculate available range of motion. We quantified all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). The cervical region in perissodactyls was found to be the most mobile region of the presacral vertebral column in LB and SB. Rhinoceroses and tapirs are characterized by the least mobile necks in SB among odd-toed and even-toed ungulates. Equidae are characterized by very mobile necks, especially in LB. The first intrathoracic joint (T1-T2) in Equidae and Tapiridae is characterized by significantly increased mobility in the sagittal plane compared to the typical thoracic joints and is only slightly less mobile than typical cervical joints. The thoracolumbar part of the vertebral column in odd-toed ungulates is very stiff. Perissodactyls are characterized by frequent fusions of vertebrae with each other with complete loss of mobility. The posterior half of the thoracic region in perissodactyls is characterized by especially stiff intervertebral joints in the SB direction. This is probably associated with hindgut fermentation in perissodactyls: the sagittal stiffness of the posterior thoracic region of the vertebral column is able to passively support the hindgut heavily loaded with roughage. Horses are known as a prime example of a dorsostable galloper among mammals. However, based on SB in the lumbosacral part of the backbone, equids appear to be the least dorsostable among extant perissodactyls; the cumulative SB in equids and tapirs is as low as in the largest representatives of artiodactyls, while in Rhinocerotidae it is even lower representing the minimum across all odd-toed and even-toed ungulates. Morphological features of small Paleogene ancestors of rhinoceroses and equids indicate that dorsostability is a derived feature of perissodactyls and evolved convergently in the three extant families.
Keywords:
Equidae; Perissodactyla; Rhinocerotidae; Tapiridae; gallop; range of motion; vertebral biomechanics.
© 2022 Anatomical Society.
References
REFERENCES
-
-
Alexander, R.M., Dimery, N.J. & Ker, R.F. (1985) Elastic structures in the back and their role in galloping in some mammals. Journal of Zoology (London), 207, 467-482.
-
-
-
Alexander, R.M. & Pond, C.M. (1992) Locomotion and bone strength of the white rhinoceros, Ceratotherium simum. Journal of Zoology, 227, 63-69. Available from: https://doi.org/10.1111/j.1469-7998.1992.tb04344.x
-
-
-
Audigié, F., Pourcelot, P., Degueurce, C., Denoix, J.M. & Geiger, D. (1999) Kinematics of the equine back: flexion-extension movements in sound trotting horses. Equine Veterinary Journal. Supplement, 30, 210-213. Available from: https://doi.org/10.1111/j.2042-3306.1999.tb05219.x
-
-
-
Belyaev, R., Kuznetsov, A. & Prilepskaya, N. (2022b) Figures of various perissodactyls vertebral column. Figshare. Figures. Available from: https://doi.org/10.6084/m9.figshare.21276723
-
-
-
Belyaev, R.I. (2018) Vertical intervertebral mobility in representatives of the odd-toed ungulates (Perissodactyla). Materialy Mezhdunarodnogo molodezhnogo nauchnogo foruma «Lomonosov-2018», 1-2. [In Russian].
-
Cite