''Stygobromus arizonensis'', the Arizona cave amphipod, is a

troglomorphic Troglomorphism is the morphological adaptation of an animal to living in the constant darkness of caves, characterised by features such as loss of pigment, reduced eyesight or blindness, and frequently with attenuated bodies and/or appendages. The ...

species of

amphipod Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descr ...

in family

Crangonyctidae Crangonyctidae is a family of cave-dwelling freshwater amphipod crustaceans. It contains the following genera: *'' Amurocrangonyx'' Sidorov & Holsinger, 2007 *'' Bactrurus'' Hay, 1902 *'' Crangonyx'' Bate, 1859 *'' Lyurella'' Derzhavin, ...

. It is endemic to Arizona in the United States. It is known only from three specimens; two collected at a cave on the Flying "H" Ranch in 1963 and one from a mine near Paradise, Arizona. It has not been collected since then. The main threat to its survival is abstraction of groundwater.

References

Freshwater crustaceans of North America Crustaceans described in 1974 Cave crustaceans Endemic fauna of Arizona Endemic crustaceans of the United States arizonensis {{Amphipod-stub