Permoceras
Introduction '''''Permoceras''''', the sole member of the family Permoceratidae, is a genus of coiled nautiloids with a smooth, compressed involute shell, whorls higher than wide, earlier whorls hidden from view. The venter is rounded as are the  ventral and umbilical shoulders, the flanks flattened. The siphuncle is ventrally subcentral. The suture, which is most characteristic, has a deep, narrow pointed ventral lobe and large, asymmetrical pointed lobes on either side. ''Permoceras'' is included in the nautilid superfamily, Trigonocerataceae, and is derived from the Mississippian (L Carb) - Triassic Grypoceratidae. ''Permoceras'' was first identified in the Lower Permian of Timur in the East Indies and named by Miller and Collinson in 1953The coiling and whorl structure of ''Permoceras'' almost precisely resembles those of ''Pseudonautilus'' from the Upper Jurassic.
See also * Nautiloid** List of nautiloids
References *  1964; Nautiloidea-Nautilida, Treatise on Invertebrate Paleontology, Part K Nautiliodea, Geological Society  of America and University of Kansas press* Sepkoski, J.J. Jr. 2002.A compendium of fossil marine animal genera. D.J. Jablonski & M.L. Foote (eds.). ''Bulletins of American Paleontology'' '''363''': 1–560.Sepkoski's Online Genus Database (CEPHALOPODA)