Entire Career Spent Studying Fish That Turns Out to Be Misidentified Subspecies of Another Fish

A ichthyologist at the Natural History Museum has learned that the fish species to which he has dedicated twenty-two years of research — including four monographs, sixty-seven peer-reviewed papers, and what he describes as 'the best years of my professional life' — does not exist as a distinct species and is in fact a regional variant of a fish that was correctly described in 1843. Dr. Alistair Langley had built his career on Pseudochromis langleyorum, a small reef fish from the western Indian Ocean that he described as a new species in 2003 based on morphological differences from the closely related Pseudochromis aldabraensis. 'The colour pattern was different,' Dr. Langley explained. 'The meristic counts were slightly different. The habitat preference was slightly different. It met all the criteria for species-level distinction. Or so I believed for twenty-two years.' A genetic analysis published last month by a team in Japan revealed that P. langleyorum falls well within the genetic variation of P. aldabraensis, a species described by Albert Gunther in 1843. The colour and morphological differences, the Japanese team concluded, represent 'phenotypic plasticity associated with local environmental conditions.' 'They are the same fish,' Dr. Langley said, with the measured calm of a man who has had several weeks to process the information. 'Twenty-two years. Four monographs. A species named after my family. And it's a variant. Of a fish described by a man who has been dead since 1914.' Dr. Langley's colleagues have been supportive. 'This happens more often than people realize,' said a fellow systematist. 'The history of ichthyology is littered with species that turned out to be other species having a slightly different day. It doesn't diminish the work. Much.' Dr. Langley has begun a new research program focused on Pseudochromis aldabraensis, 'which is apparently the fish I was studying all along.'