Spyroceratidae

Not to be confused with Spiroceratidae.

Spyroceratidae
Temporal range: M Silurian - Permian
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: †Pseudorthocerida
Family: †
Shimazu & Obata 1935

Spyroceratidae are defined[1] as Pseudorthocerida with uniformly slender siphuncle segments, longer than wide, that contract sharply near either end, in which endosiphuncular deposits first form a compete annulus before fusing ventrally.

References

  1. ^ Sweet, Walter C. 1964. Nautiloidea -Orthocerida. Treatise on Invertebrate Paleontology, Part K. Geological Soc. of America and Univ of Kansas press
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