Amphipods of the family Leucothoidae are commensals in sponges and ascidians and occur throughout the world's tropical and subtropical marine systems. They exhibit an unusual life history pattern involving two highly dissimilar developmental stages that occur simultaneously in the host.
These two stages are so different they were previously assigned to separate families. Initial, or, "leucomorph" developmental stages (male and female) of different leucothoid species are nearly identical, while the transformed, or "anamorph" stage (always male) is distinct for each species. In a remarkable transformation, leucomorph males pass via a single molt to anamorph males. This transformation is accompanied by a number of extreme morphological changes that explain their placement in separate families prior to this discovery in 1983.
The new species Leucothoe eltoni, was named in honor of the rock musician Sir Elton John. Specifically, in reference to the large shoe-like first gnathopod (see image above) of this species and the oversize boots Elton John wore as the local pinball champion in the movie “Tommy” (1975).
For the experts: A new species of leucothoid amphipod, Leucothoe eltoni sp. n., is described from coral reefs in Raja Ampat, Indonesia where it inhabits the branchial chambers of solitary tunicates. With an inflated first gnathopod superficially resembling the genus Paraleucothoe, this new species has a two-articulate maxilla 1 palp characteristic of the genus Leucothoe. While described from coral reef environments in tropical Indonesia and the Philippines, it is an established invasive species in the Hawaiian Islands. The most likely mode of introduction was a US Navy dry dock transported to Pearl Harbor in 1992 from Subic Bay, Philippines.