A new legume fruit species from the mid-Miocene Climatic Optimum in Japan

Isolated legume fruits from the early-middle Miocene Shimo Formation of the Uchiura Group in Takahama Town, Fukui Prefecture, central Japan, are described in this paper. They are unique in yielding 1-coiled or curved and terete-moniliform shapes with both simple sutures constricting uniformly. A new fossil-species, Leguminocarpum oguruiensis, is designated here. These legume specimens occur together with a number of molluscan fossils that indicate tropical-subtropical shallow marine conditions at the warmest time period during the mid-Miocene Climatic Optimum. The species was probably dispersed by the oceanic currents from southerly areas and inhabited areas with coastal vegetation where warm-temperate forest elements dominated.