Gross Morphology of the Brain and Spinal Cord of the African Pygmy Hedgehog (Atelerix albiventris)

Abstract

The African pygmy hedgehog (Atelerix albiventris) is an insectivorous animal, native to Africa. The central nervous system (CNS) consists of the brain and the spinal cord, protected by the cranium and vertebral column respectively. Assessment of the gross appearance and morphometries of the African pygmy hedgehog CNS were carried out using six adults (3 males and 3 females). The gross examination showed the brains to be lissencephalic, with relatively large olfactory bulbs, similar to that observed in some rodents. The rootlets of the first cervical spinal nerves were observed to emerge before the foramen magnum. Linear measurements were obtained from both the brain and spinal cord. The mean weight of the animals was 199.00 ± 16.09 g, with the males having an average body weight of 183.50 ± 12.02 g and the females 206.80 ± 11.95 g. Although not statistically significant, the males had a higher encephalisation quotient (0.40 ± 0.08) relative to the females 0.36 ± 0.04). The values for the brain weight, length of spinal cord and heights of the telencephalon and diencephalon at different points were higher in the males, while the spinal cord weight, length of brain and cerebellar height were higher in the females. The spinal cord showed slight enlargements at the cervical, thoracic, lumbar and sacral segments. This study aimed to provide baseline data for the study of the gross appearance and neuromorpho-metrics of the hedgehog, with possible application in regional anaesthesiology and comparative wildlife neuroanatomy.

The brain of the tree pangolin (Manis tricuspis). X. The spinal cord

“…The current findings in the tree pangolin would support this notion, as the tree pangolin undergoes a similar flexion of the vertebral column when creating this defensive posture. Despite this, two other species that have modified external defensive structures of the skin (spines and “armor”) and exhibit volvation under threat, the African pygmy hedgehog and the nine‐banded armadillo, have spinal cords that are not shorter than seen typically in mammals (African pygmy hedgehog—Igado et al., 2021; nine‐banded armadillo—Shuddemagen, 1907). Thus, while the mechanical hypothesis of Ashwell (2013) may be applicable to tree pangolins and echidnas, it does not appear to apply to all mammals that use volvation as a defensive mechanism.…”