Leucothoidae is a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of amphipods

Amphipoda

Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...

. It contains 138 species in 6 genera:

• Anamixis Stebbing, 1897 – 21 species
• Leucothoe
  Leucothoe (amphipod)
  Leucothoe is a genus of amphipods in the family Leucothoidae. It contains the following species:*Leucothoe acanthopus Schellenberg, 1928*Leucothoe acutilobata Ledoyer, 1978*Leucothoe adelphe White & Thomas, 2009...
  
  Leach, 1814 – 96 species
• Leucothoella Schellenberg, 1928 – 2 species
• Nepanamixis Thomas, 1997 – 4 species
• Paranamixis Schellenberg, 1938 – 13 species
• Paraleucothoe Stebbing, 1899 – 2 species

Males undergo a profound transformation when they reach sexual maturity

Sexual maturity

Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...

, turning from the "leucomorph" state to the "anamorph" state. Before this transformation was recognised in 1983, females and immature males were described in the genus Leucothoides (Leucothoidae), and mature males were described in the genera Anamixis, Paranamixis and Nepanamixis (Anamixidae). The genus Leucothoides may still be used for leucomorphs of species whose anamorph has not yet been identified.