Mobula mobular was long described as a Mediterranean endemic, while the very similar Mobula japanica was reported from the Indian, Pacific and Atlantic oceans. Reviews of morphology and genetics published in 2017 found the characters separating the two did not hold up, and japanica was treated as a junior synonym.
The consequence for conservation was immediate rather than cosmetic. A ray assessed as a narrow-range Mediterranean species suddenly had a circumglobal distribution, a far larger population, and exposure to tropical purse-seine and gillnet fisheries that had never been counted against it.
The same round of work collapsed the genus Manta into Mobula, so the manta rays are now formally devil rays. Names of this kind are not trivia: fishery reporting, trade rules and protected-species listings are all written against the name in use at the time, and lag behind revisions.