Acanthonautilus
Encyclopedia
Acanthonautilus is an extinct genus in the nautilid
family Solenochildae (Aipocerataceae) from the Upper Mississippian of North America and equivalent (uL Carb) strata in Europe, first described by Foord in 1896.
Acanthonautilus, like Solenochilus
, has an involute, globular shell of few volutions that enlargens with fair rapidity, with prominent lateral spines extending from the umbilical area at maturity. The siphuncle
in Acanthonautilus is narrower than in Solenochilus and not as sinuous. As with Solenochilus, septal necks on the outer, or ventral, side are straight, but those on the inner, or dosal, side rather than being recumbent are simply curved, cytochoanitic. Most of the siphuncle is thin connecting ring which from the outside is slightly ventrally concave and slightly dorsally convex between septa.
Acanthonautilus may have been derived from Aipoceras, or possibly Asymptoceras and give rise, principally through modification of the siphuncle, to Solenochilus
.
See List of nautiloids
Nautilida
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species...
family Solenochildae (Aipocerataceae) from the Upper Mississippian of North America and equivalent (uL Carb) strata in Europe, first described by Foord in 1896.
Acanthonautilus, like Solenochilus
Solenochilus
Solenochilus, type genus of the Solenochildae is an extinct cosmopotilian nautilid from the Lower Pennsylvanian to the Lower Permian with a rapidly expanding, coiled globular shell with few whorls, from which prominent spines extend laterally from the umbilical area at maturity...
, has an involute, globular shell of few volutions that enlargens with fair rapidity, with prominent lateral spines extending from the umbilical area at maturity. The siphuncle
Siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and Spirula...
in Acanthonautilus is narrower than in Solenochilus and not as sinuous. As with Solenochilus, septal necks on the outer, or ventral, side are straight, but those on the inner, or dosal, side rather than being recumbent are simply curved, cytochoanitic. Most of the siphuncle is thin connecting ring which from the outside is slightly ventrally concave and slightly dorsally convex between septa.
Acanthonautilus may have been derived from Aipoceras, or possibly Asymptoceras and give rise, principally through modification of the siphuncle, to Solenochilus
Solenochilus
Solenochilus, type genus of the Solenochildae is an extinct cosmopotilian nautilid from the Lower Pennsylvanian to the Lower Permian with a rapidly expanding, coiled globular shell with few whorls, from which prominent spines extend laterally from the umbilical area at maturity...
.
References
- Kummel 1964; Nautiloidea-Nautilida, Treatise on Invertebrate PaleontologyTreatise on Invertebrate PaleontologyThe Treatise on Invertebrate Paleontology published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and...
, 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)
See List of nautiloids