Abstract
Ten species of decapod crustaceans are described from the middle Pleistocene Sahama Mud Member of the Hamamatsu Formation, Shizuoka Prefecture, central Japan. The decapod assemblage is dominated by Raphidopus ciliatus Stimpson, 1858, Asthenognathus inaequipes Stimpson, 1858, and Mariaplax sp. Occurrence of Xenophthalmus sp. is not only the first fossil record from Japan but the second fossil evidence for the genus. Raphidopus ciliatus extends the known geologic range into the middle Pleistocene of Japan.
