Uranoceratidae Explained

The Uranoceratidae is a family of Silurian barrandeoceroids that tend to become uncoiled with age and in which siphuncle segments tend to be expanded into the camerae.^[1]

Description

Shells of uranoceratids are gyroconic. Early stages of a few species are annulated. Later stages of all are smooth or faintly striated or cancellated.^[2] In many, septal necks are straight, but in others recumbent on one side or the other. Connecting rings are thin.

Derivation and content

The Uranoceratidae are derived from Bickmorites. Genera include:

• Uranoceras
• Jolietoceras
• Cumingsoceras, and
• Cliftonoceras.

Notes and References

1. Flower, R.H. & Kummel, B. 1950. A Classification of the Nautiloidea. Journal of Paleontology vol 24, no.5, pp604–616, Sept 1950.
2. Sweet, Walter C, 1964. Nautiloidea - Barrandeocerida, in Treatise on Invertebrate Paleontology, Part K, Geol Soc of America, Teichert & Moore(eds).