A new sea snake has been discovered and described from the Copenhagen museum. The specimen was sitting in a jar since the 1800s, and apparently, it was misidentified and mislabeled. Not until very recently, researchers took a look of the jar and other specimens and determined it to be a different and new species. See the original article here.
Exciting story! Sounded like finding some rare artifact that was thought to be a counterfeit.
I am 101% certain that this incidence of mislabeled specimens turning out to be a species is not a new story. Mis-identification is commonplace for museum specimens. If museums have their collections imaged and made available online, that would greatly facilitate the process of sorting specimens and discovering new species.
See a previous blog entry I wrote about a similar issue of imaging museum collections to accelerate biodiversity discovery.
Writings related to insects, biodiversity and science in general