evolutionary distinctiveness of the extinct yunnan box turtle cuora yunnanensis revealed by dna from an old museum specimen cuora yunnanensis is an extinct turtle known from 12 specimens collected from yunnan china before 1908 we used ancient dna methods to sequence 1723 base pairs of mitochondrial dna from a museum specimen of c yunnanensis unlike some rare species recently described from the pet trade c yunnanensis represents a lineage that is distinct from other known turtles besides c yunnanensis two other valid species c mccordi c zhoui are unknown in the wild but are supposedly from yunnan intensive field surveys for surviving wild populations of these critically endangered species are urgently needed