Redescription of Bradleya japonica Benson, 1972 (Ostracoda) from the Sea of Japan and the significance of its shell shape from an optical point of view

The marine podocopid ostracod, Bradleya japonica Benson, 1972 is redescribed on the basis of appendages and adult valves. This is the first report describing the appendages of the species. The reflectivity of the shells abruptly increases around an incident angle of 70°, and the reflectivity reaches to ca. 50% around an incident angle of 85° from the possible life position of this animal. Based on optical and morphological analyses, Bradleya japonica has a shell shape that minimizes reflection from the shell under the downwelling light conditions in which it lives.