Among the most diverse of all vertebrate groups with nearly 16,000 described species, freshwater fishes are also the most highly threatened. Body and range size are good predictors of extinction risk, which has the implication that newly described species—usually small in size and with narrow ranges—could be more likely to be threatened.
This study examines the relationship between species traits, publication date and extinction risk in two groups of weakly electric fishes—Mormyroidea and Gymnotiformes. The authors compiled data on body size from FishBase and derived species distributions based on IUCN range maps or GBIF-mediated occurrences for 470 species.
Their analyses revealed that all except one of the larger species are considered Least Concern (LC) or Data Deficient (DD), while all widespread species are listed as LC. The models confirmed that newly-described species are more often small-bodied with narrow ranges and likely to be prone to extinction—especially in the African mormyroids, suggesting that their existence after being described may be short-lived.