CLASSIFICATION, PHYLOGENY, AND PALEOBIOGEOGRAPHY OF THE NEW SUBFAMILY GIFUELLINAE AND A REVISION OF THE FAMILY NEOSCHWAGERINIDAE (SUPERORDER FUSULINOIDA); GUADALUPIAN (MIDDLE PERMIAN)

摘要

The new subfamily Gifuellinae is composed of two genera, Gifuella Honjo and Gifuelloides n. gen., and is assigned to the family Neoschwagerinidae, superorder Fusulinoida (Foraminifera). This new subfamily is based on extensive and ongoing studies by Kobayashi of fusulinoid material from the Akasaka Limestone of Japan and a careful literature survey. In both Gifuella and Gifuelloides, the spiral wall consists of a uniform tectum and a very fine alveolar keriotheca, which forms a consistent, thin layer that gives rise to the septula. Both genera are characterized by relatively small proloculi. Of the two genera, species of Gifuella are simpler, smaller, and have fewer whorls and they have well-developed, thin, planar primary transverse septula and almost completely lack secondary transverse septula. Species of Gifuelloides are larger, have more whorls, and have only a few secondary transverse septula in their middle and outer whorls. Gifuella sp., previously recorded from Hyogo, Japan, is here named Gifuella harimensis n. sp. The new genus Gifuelloides includes its type species G. larga (Morikawa and Suzuki), and G. hanaokensis (Morikawa and Suzuki).