Papilio joanae is a rare butterfly species originally discovered in woodland habitats of the Ozarks region of Missouri.  A positive identification has not been confirmed in many years, but populations are thought to still exist.  Papilio joanae is closely related to Papilio polyxenes (Black Swallowtail) and nearly identical in appearance. Visual field differentiation between the two species is almost impossible and requires DNA testing for accurate identification. Because of the vast similarities, it is thought that P. joanae could possibly be misidentified as P. polyxenes, a common butterfly species, in some situations. 

P. polyxenes were collected and DNA tested from 25 sites in the Ozarks.  Results from this testing did not include any discoveries of P. joanae, but it is thought that misidentification between the two species still exists. DNA testing, as well as field scouting, will continue until populations of P. joanae are discovered and identification confirmed. New testing and scouting methods will be included in ongoing efforts.