In this contribution we describe a new species of burrowing crayfi sh of the genus Parastacus Huxley, 1879 from a swamp forest in southern Brazil and determine its conservation status. Th e distinction of the new species is based on morphology and the mitochondrial DNA marker 16S rRNA. Th e extinction risk was assessed according to the sub-criterion B1 of IUCN that estimates the Extent of Occurrence (EOO). Parastacus tuerkayi sp. nov. is morphologically distinguishable from all species of Parastacus by having three lines of verrucous tubercles on the dorsomesial margin of the cheliped propodus and a suborbital angle exceeding 90°. Th e EOO comprises 647,674 km², and the species is classifi ed as “endangered”. Phylogenetic relationships indicate the distinct position of this new species in relation to the already described species
