The vertebral column of Scutisorex somereni (the hero shrew), and its size and morphology, is probably the most modified among the vertebrates (Kingdon, 1974). We examined the scaling of diameter versus length in the long bones and ribs, and spine mass versus body mass of this species, in comparison to 19 other mammalian taxa (including fossorial species). The ribs of Scutisorex are significantly more robust than any genus examined, and the spine of this species, relative to its body mass, is four times more robust than that reported for any other vertebrate. Paradoxically, the long bones of the limbs of Scutisorex demonstrate no difference in robustness from that predicted for an animal of its body mass. There is no satisfactory ecological, behavioural, or functional explanation for this unique spinal morphology.

The spine of Scutisorex somereni, the hero shrew, is probably the most highly modified among the vertebrates (Kingdon, 1974), yet no description of the accompanying spinal musculature has been published. This paper describes the anatomy and proposed functions of the major epaxial and hypaxial muscle groups of Scutisorex. The unusual vertebral morphology of this species is accompanied by major modifications in some of the spinal muscle groups. The transverse spinalis muscles are the most modified, and this is probably related to the presence of bony interdigitating tubercles on the vertebrae. The longissimus muscles possess long tendons that share attachment with the iliocostalis muscles. The iliopsoas muscles and their sites of attachment are greatly enlarged in comparison to those of Blarina and Rattus. Much of the spinal musculature reflects the highly modified state of the Scutisorex vertebrae. The unique behavioural function of the Scutisorex spinal modification, if any exists, is not known