Spyroceratidae

Spyroceratidae Temporal range: M Silurian - Permian
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Nautiloidea
Superorder:	Orthoceratoidea
Order:	Pseudorthocerida
Family:	Spyroceratidae 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

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

Notable fossil cephalopods (listed by first occurrence)

Cenozoic

The belemnite-cuttlefish-like Belosaepia

Evolutionary history of cephalopods

Mesozoic

Advanced nautiloids Nautilaceae True ammonites

Early coleoids Proteroctopus Styletoctopus Keuppia Palaeoctopus Paleocirroteuthis

Ceratitid ammonoids late Nautilida

Advanced belemnoids Diplobelids: Diplobelus Belemnites: Belemnites Belemnopsis Belemnotheutis

Palaeozoic

First appearance of long-lasting lineages Goniatite and ceratite ammonoids Probable coleoid ancestor Bactritida Earliest belemnoids: Aulacocerids: Aulacoceras Phragmoteuthids: Phragmoteuthis

Early forms the earliest cephalopod group Ellesmerocerida Orthocones: Endocerida, Orthocerida, Actinocerida Brevicones: Ascocerida, Oncocerida Earliest coiled cephalopods: Tarphycerida Spirulid?: Shimanskya

Octopus Pohlsepia

Cambrian

Earliest unambiguous cephalopods: Plectronocerida
- Plectronoceras
Monoplacophoran-like ancestral forms: Knightoconus
Possible, nude, "stem-group cephalopods": Nectocarididae

This article is issued from Wikipedia - version of the 6/18/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.