Megasurcula siogamensis is an extinct species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies. Tohoku University Museum: Megasurcula siogamensis
Distribution Fossils of this marine species have been found in Middle Miocene strata in Japan.
References
Nomura, S. "Miocene Mollusca from Siogama, Northeast Honsyu, Japan." Saito Ho-on Kai Museum, Research Bulletin 6 (1935): 193–234.