914. MIDDLE CARBONIFEROUS BACTRITOIDEA (MOLLUSCA : CEPHALOPODA) FROM THE AKIYOSHI LIMESTONE GROUP, YAMAGUCHI PREFECTURE (MOLLUSCAN PALEONTOLOGY OF THE AKIYOSHI LIMESTONE GROUP-X)

Abstract

A Middle Carboniferous bactritoid fauna is described from the Akiyoshi Limestone Group at Isa, Mine City, Yamaguchi Prefecture. The components of this fauna and those age based on the associated foraminifers are : Bactrites nagatoensis, sp. nov. (Late Bashkirian-Early Moscovian), B. sp. (Late Bashkirian), and Ctenobactrites sp. (Early Moscovian). This is the first detailed systematic report of bactritoids in Japan.