Halgerda johnsonorum was described from Kwajalein Atoll, where it lives in ledges and caves on the seaward reef slope and surge channels. More than 20 specimens have been found, nearly all at night at depths of 12-20 meters. Sizes range from 20 to 40mm. Halgerda johnsonorum was first reported in the Marshalls from Kwajalein by Carlson & Hoff (2000).
Variation in color is shown in the two animals below, which were found together.
Created 12 December 2006
Updated 5 March 2016