Phylogenetic significance of a new cheilostome bryozoan species, Dysnoetocella : voigti from the Upper Cretaceous Izumi Group in Shikoku, Japan

Abstract

A new anascan cheilostome bryozoan species, Dysnoetocella? voigti, is described from the Upper Cretaceous Izumi Group in the northwestern part of Shikoku Island, Japan. The zoarium is erect and unjointed, with subcylindrical multilamellar branches. Three types of fine structure are evident in the calcareous skeletal layers from well preserved specimens. The narrow frontal shields of the zooids show ontogenetic thickening, which suggests that the species is an anascan cryptocystidean. The zoarium, consisting of many zooid columns, is reminiscent of some Paleozoic trepostomes. Although the zooid column is sometimes found in the Ascophora, it also occurs rarely in the Anasca.