Uncinocythere Hart, 1962
Superfamily: Cytheroidea Baird, 1850
Family: Entocytheridae Hoff, 1942
Subfamily: Entocytherinae Hoff, 1942
One species has been reported from Japan:
1. Uncinocythere occidentalis (Kozloff & Whitman, 1954) 
Invasive
Right side view of a male (top) and female of Uncinocythere occidentalis, length 0.4 mm.
- Additional figures in: Hart & Hart 1974; Smith & Kamiya 2001.
- Habitat: Lakes and rivers.
- Mode of life: Commensal on the signal crayfish Pacifastacus leniusculus trowbridgii, typically found on the gills.
- Reproduction mode: Sexual.
- Known distribution: Hokkaido (Smith & Kamiya 2001). Elsewhere, western USA (Hart & Hart 1974), UK, Spain, France, the Netherlands and Germany (see references in Ohtaka et al. 2017).
- Notes: This is an invasive species in Japan, originating from the USA (Smith & Kamiya 2001).
- References:
- ⚬ Hart, D. G. & Hart, Jr., C. W. 1974. The ostracod family Entocytheridae. The Academy of Natural Sciences of Philadelphia, Monograph 18, 1-239.
- ⚬ Smith, R. J. & Kamiya, T. 2001. The first record of an entocytherid ostracod (Crustacea: Cytheroidea) from Japan. Benthos Research, 56 (2), 57-61.