1992 Volume 1992 Issue 166 Pages 1157-1163
A tetragonitid ammonite, Pseudophyllites indra (Forbes) is described based on material from the Orannai Formation in the Soya area of northern Hokkaido and from the Krasnoyarka Formation in the Naiba area of south Sakhalin. P. indra, occurring in the Schlueterella kawadai Subzone of the Metaplacenticeras subtilistriatum Zone, which corresponds to the upper Campanian, has a nearly circular initial chamber in median section, a subellipsoid caecum with weakly constricted base and a ventrally located siphuncle. In various areas of the North Pacific region, the present species first appeared almost synchronously in the upper Campanian. From Santonian to early Campanian times, P. indra was distributed in the Indian region. This evidence shows that this species extended its geographical distribution from the Indian region to the North Pacific region in late Campanian time.