The finger tips of an undetermined species of Alpheus (Alpheidae) are recorded from the Shukunohora Facies of the Akeyo Formation (Early Miocene: Burdigalian), the Dainichi Formation (Early Pleistocene: Gelasian) and the Nakoshi Formation (Early Pleistocene: Calabrian). The occurrence of the Shukunohora Facies extends the geologic range for Alpheidae of Japan back to the Early Miocene (Burdigalian).
https://ror.org/0375k5p31 
