Two directions of the burrowing specialization in insectivorous mammals (Talpidae, Chrysochloridae)

Abstract

The transformation of the forelimb musculature in insectivorous mammals was clarified in connection with their digging specialization. The comparative morphological analysis was carried out in five species of moles (Talpidae): Neurotrichus gibbsii; Talpa europaea; Mogera wogura; Scalopus aquaticus; Desmana moschata, and two species of golden moles (Chrysochloridae): Chrysochloris asiatica; Eremitalpa granti. In Т. europaea, during the soil displacement aside the main load falls on the flexors of the shoulder joint, of which the m. teres major is most developed. In golden moles, as in many other mammals, the relative weight of this muscle is significantly less that is connected with a different manner of burrowing. In all moles, in contrast to the gold moles, the maintenance of the permanently extended elbow joint is characteristic during the whole lateral stroke. As a result their olecranon is well developed that allows increasing the lever of the force attachment with relatively weak extensors. Thus, in moles, the relative weight of the m. anconeus longus is less of such in majority of specialized diggers. In both moles and golden moles, the weakness of the muscle parts of the m. flexor digitorum profundus is also observed.