The functional and biomechanical modifications of the spine of Scutisorex somereni, the hero shrew: skeletal scaling relationships

Abstract

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.