Species: Bermuda cave amphipod (Pseudoniphargus grandimanus)
Status: Critically Endangered (CR)
Interesting Fact: Juvenile Bermuda cave amphipods are found far closer to the shore than adults.
The Bermuda cave amphipod is a colourless, eyeless amphipod that lacks a rostrum (a forward-projecting spine found between the eyes of most crustaceans). The upper lip is broadly rounded and the lower lip has large inner lobes. Male Bermuda cave amphipods are known to reach lengths of 6.5 to 8 millimetres.
The Bermuda cave amphipod is found in anchialine caves. These are coastal caves that are flooded with seawater via subterranean connections with the ocean. This species has been found in water of varying levels of salt concentration throughout a wide variety of anchialine limestone cave and groundwater habitats. Juvenile Bermuda cave amphipods are found far closer to the sea coast than adults, typically just 11 to 180 metres away, compared to 147 to 853 metres for adults.
Large adults, but notably no specimens carrying eggs, have been found further inland from the sea coast than juveniles. This could indicate a dependence on coastal marine habitats for reproduction, and that juveniles may migrate inland to mature.
The Bermuda cave amphipod is endemic to Bermuda, as its name suggests. Is has been recorded from wells, waterworks and cave waters in Hamilton, St George’s, Devonshire, Paget, Smith’s and Warwick Parishes in Bermuda. Caves in which it has been found include Church, Wonderland, Admiral’s and Government Quarry Caves.
Find out more about the Bermuda cave amphipod at Anchialine Caves and Cave Fauna of the World.
Phoebe Shaw Stewart, ARKive Text Author