Rudimentary Fifth Toes, S. keyserlingii (Hasumi)

Rudimentary Fifth Toes (Salamandrella keyserlingii)

Rudimentary fifth toes of the tetradactyl salamander Salamandrella keyserlingii, inhabiting Shaamar, Selenge Province, Mongolia. These fifth toes appeared in both right and left hindlimbs of a juvenile that was hidden in a subterranean burrow with a depth of 25 cm (photographed on 23 July 2005). It is quite rare that the fifth toe of the hindlimb occurs in this species, as well as that of Hynobius hidamontanus. Unlike other tetradactyl salamanders, S. keyserlingii normally has the fifth tarsale, developing to fuse later with the fourth tarsale.