Teeth of a new elasmobranch Karksiodus mirus gen. et sp. nov. were discovered on two levels in the sandstones of the Karksi outcrop (South Estonia), corresponding to the Härma Beds, lower part of the Burtnieki Regional Stage (Givetian, Middle Devonian). These teeth differ from all known Palaeozoic elasmobranch teeth in the presence of a unique wide transversal tube-shaped basal canal, in very fine and dense striation of cusps and in an arched base without well-developed extensions. The order and family of this taxon are notspecified.