C. dubia

C. dubia may refer to:


 * Calochlaena dubia. a fern species
 * Centaurea dubia, the Tyrol knapweed, a perennial plant species
 * Cercomela dubia, the sombre chat, a bird species found in Ethiopia and Somalia
 * Ceriodaphnia dubia, a species of water flea in the class Branchiopoda
 * Clathrina dubia, a sponge species
 * Clausilia dubia, a species of small, very elongate, left-handed air-breathing land snail species
 * Colias dubia, the dwarf clouded yellow, a small butterfly species found in India
 * Coursetia dubia, a legume species found only in Ecuador