Solenochilus
Encyclopedia
Solenochilus, type genus of the Solenochildae (Aipocerataceae) 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. Solenochilus is derived from the Upper Mississppian Acanthonautilus
, principally through evolutionary changes in the siphuncle
.
The siphuncle in both Solenochilus and Acanthonautilus is ventral, running just inside the outer rim of the shell. In both the siphuncle is mostly composed of thin connecting rings. The siphuncle in Solenochilus is wider and has a more sinuous profile than that of Acanthonautilus. Both swing dorsally between septa, but more so in Solenochilus. In both the septal necks are somewhat long and straight on the ventral side but in Solenochilus they are cyrtochoanitic and recumbent on the dorsal side, rather than simply curved back, cyrtochoanitic.
Solenochilus resembles its predecessor, Acanthonautilus, overall, and superficially Permonautilus
from the Clydonautilaceae ;
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...
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. Solenochilus is derived from the Upper Mississppian Acanthonautilus
Acanthonautilus
Acanthonautilus is an extinct genus in the nautilid family Solenochildae from the Upper Mississippian of North America and equivalent strata in Europe, first described by Foord in 1896....
, principally through evolutionary changes in 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...
.
The siphuncle in both Solenochilus and Acanthonautilus is ventral, running just inside the outer rim of the shell. In both the siphuncle is mostly composed of thin connecting rings. The siphuncle in Solenochilus is wider and has a more sinuous profile than that of Acanthonautilus. Both swing dorsally between septa, but more so in Solenochilus. In both the septal necks are somewhat long and straight on the ventral side but in Solenochilus they are cyrtochoanitic and recumbent on the dorsal side, rather than simply curved back, cyrtochoanitic.
Solenochilus resembles its predecessor, Acanthonautilus, overall, and superficially Permonautilus
Permonautilus
Permonautilus is an extinct nautilid from the Upper Permian of Russia, Named and described by Kruglov in 1933. Permonautilus is an involute, globular, spinose member of the Lirocertidae which are included in the Clydonautilaceae. Whorl sections are broad, with a rounded venter...
from the Clydonautilaceae ;
References
- Kummel, B. 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