New and Endangered Species of Blind Cavefish Discovered in Southern Indiana

Deep within the caves of southern Indiana lives a cavefish, born without eyes and with little in the way of pigmentation. Only recently discovered by scientists, this fish is now being called endangered.

The new species is nicknamed the Hoosier cavefish, though its scientific name is Amblyopsis hoosieri. It's the closest relative of a species called A. spelaea which can be found in the longest cave system in the world in Mammoth Cave in Kentucky. The two species are separated by the Ohio River, which also separates the states of Indiana and Kentucky.

The two species differ in small ways, but one of them is that A. spelaea has a knockout mutation in the genetic sequence of rhodopsin, which is a gene that's important in vision. The new species, in contrast, lacks this mutation and maintains a functional rhodopsin gene, despite lacking eyes and vision. It also has distinct morphological differences from A. spelaea. It has a plumper, Bibendum-like body and shorter fins. It also has a smaller mechanosensory neuromasts on papillae, which allows it to sense movement in the dark waters of caves.

The new cavefish is actually the first new cavefish species described from the U.S. in that past 40 years. It possesses some unusual behaviors, as well; females brood their young in their gill chamber, and the fish itself actually has an anus right behind its head.

The findings reveal that new species are being discovered every day, even in places that were thought to be fully explored. Yet steps need to be taken in order to protect these species. As climate change and environmental impacts continue to encroach on species' habitat, it's more important than ever to keep biodiverse regions protected. It's also crucial to continue looking for these species, which may be endangered, before they become extinct.

The findings are published in the journal ZooKeys.