Cyrtorizoceras Hyatt, 1900

Kröger, Björn, 2025, The Lyckholm acme of cephalopods - Review of the late Katian (Vormsi-Pirgu regional stages) Ordovician cephalopods of Estonia, European Journal of Taxonomy 978, pp. 1-169 : 84

publication ID

https://doi.org/10.5852/ejt.2025.978.2801

publication LSID

lsid:zoobank.org:pub:422E6F06-B4C8-4840-854C-811145D88B32

DOI

https://doi.org/10.5281/zenodo.14988533

persistent identifier

https://treatment.plazi.org/id/93268783-9625-7075-FDA0-FCDCFD96FB03

treatment provided by

Plazi (2025-03-07 10:46:31, last updated 2025-03-07 11:32:00)

scientific name

Cyrtorizoceras Hyatt, 1900
status

 

Genus Cyrtorizoceras Hyatt, 1900 View in CoL

Type species

Cyrtoceras minneapolis Clarke, 1897 , from Minneapolis, Minnesota, USA, Platteville Formation, Black River Group, Sandbian; by original designation.

Diagnosis

Compressed cyrtocones; dorsal and ventral profiles diverging constantly adorally; sides converging slightly over mature body chamber; aperture with deep hyponomic sinus; nearly smooth or ornamented with transverse costae; siphuncle subventral, slender; segments slightly expanded, probably empty. (Adopted from Sweet 1964b.)

Clarke J. M. 1897. The Lower Silurian cephalopoda of Minnesota. Minnesota Geology and Natural History Survey 3 (2): 761-812.

Hyatt A. 1900. Cephalopoda. In: Zittel K. A. V. (ed.) Textbook of Paleontology, 1. Second Edition, Translated and Edited by C. R. Eastmann: 502-592. Macmillan and Co, London.

Sweet W. C. 1964 b. Oncocerida. In: Moore R. C. (ed.) Treatise on Invertebrate Paleontology, Part K, Mollusca 3: K 277 - K 319. University of Kansas Press, Boulder, CO.