Two new species of Thalassina (Decapoda, Thalassinidae) from the Miocene of Japan

Thalassina tsuyamensis ANDO & KISHIMOTO n. sp. is described from the lower to middle Miocene Yoshino Formation of the Katsuta Group in the Okayama Prefecture, Japan. This species is similar to the extant T. saetichelis SAKAI & TURKAY, 2012, but differs in having a lateral subdorsal carina on the dorsal border of the propodus with tubercles extending posterior to the anterior part of pereiopod 1. Thalassina yamato ANDO & KISHIMOTO n. sp. is described from the middle Miocene Kawachi Formation of the Kukinaga Group in the Kagoshima Prefecture, Japan. This new species is closest to the extant T. squamifera DE MAN, 1915. However, it differs from T. squamifera in having a lateral dorsal carina on the dorsal border of the propodus of pereiopod 1 extending to only one-third length and an unarmed dorsal border of the merus of pereiopods 3 to 5.