Sphaeorthoceratidae is an extinct family of orthocone cephalopods that lived in the Paleozoic Era. They were similar to the nautiloid Michelinoceras in the apex, but had shorter necks to their septa that were orthochoanitic or suborthochoanitic.[1]
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| Family: | Sphaerorthoceratidae Ristedt, 1968
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The sphaerorthoceratids were significant in cephalopod evolution because they may have given rise to the bactritids, which in turn were the ancestors of ammonoids and coleoids.[2] The family lived in the middle Paleozoic, ranging from the Sheinwoodian age of the Silurian Period to the Famennian age of the Devonian Period, or about 428 to 361 Ma.[3]
References
edit- ^ Kröger, B. (2008). "Nautiloids before and during the origin of ammonoids in a Siluro-Devonian section of the Tafilalt, Anti-Atlas, Morocco". Special Papers in Palaeontology. 79. Palaeontological Association, London: 1–110. ISBN 978-1-4051-8770-1.
- ^ Kröger, B; Mapes, R. H. (2007). "On the origin of bactritoids (Cephalopoda)". Paläontologische Zeitschrift. 81 (3): 316–327. doi:10.1007/BF02990181. S2CID 129091196.
- ^ "Sphaerorthoceratidae - Age Range and Collections". The Paleobiology Database. Retrieved 18 July 2012.