Restudy of a Miocene Bryozoan Species, Microporina articulata notoensis Sakakura, 1936 with Description of Another New Species from the Nanao Calcareous Sandstone

Abstract

Microporina articulata notoensis Sakakura, 1936, from the Nanao Calcareous Sandstone (Middle Miocene) was restudied and raised to species rank, mainly based on the orifice morphology. Sakakura interpreted small depressions along lateral sides of the cryptocyst as additional opesiules, but it is not clear whether they function as opesiules or not, based on the SEM image. This and other Neogene to Recent Microporina species in Japan are compared, and one more species, Microporina iwayaensis sp. nov. is erected.