Spyroceras
Temporal range: Devonian
Scientific classification
Kingdom:
Phylum:
Class:
Subclass:
Order:
Family:
Genus:
Spyroceras

Hyatt, 1884

Spyroceras is a genus of pseudorthocerids from the Devonian of North America and Europe, defined by Alpheus Hyatt in 1884. Pseudorthocerids are a kind of orthocertaoid, a taxonomic group within the Nautiloidea. Specifically Spyroceras belongs to the pseudorthocerid family, Spyroceratidae.

Spyroceras had annulated orthocones with straight transverse sutures, transverse or slightly oblique surface annulations, and faintly cyrtoconic apices. Surface ornamentation varies but longitudinal lirae are conspicuous from earliest stage. The siphuncle was central or slightly offset ventrally, and composed of expanded segments typical of the Pseudorthocerida. Cameral and siphonal deposits developed later than in most pseudorthocerids and are thus confined to the apical portion of the phragmocone.

References


    This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.