Geisonoceras Hyatt, 1884

Kröger, Björn, 2013, The cephalopods of the Boda Limestone, Late Ordovician, of Dalarna, Sweden, European Journal of Taxonomy 41, pp. 1-110 : 43-44

publication ID	https://doi.org/10.5852/ejt.2013.41
publication LSID	lsid:zoobank.org:pub:A2F1B9ED-870A-466E-B35E-BD5DA782476E
DOI	https://doi.org/10.5281/zenodo.3815174
persistent identifier	https://treatment.plazi.org/id/AD4D9054-CD4E-6A4D-F036-4696FB76FED0
treatment provided by	Carolina (2020-05-07 19:54:00, last updated by Valdenar 2025-03-03 12:23:23)
scientific name	Geisonoceras Hyatt, 1884
status

Treatment

Genus Geisonoceras Hyatt, 1884

Type species

Orthoceras rivale Barrande, 1866 , Prague Basin, Czech Republic, Ludlovian, Silurian; by original designation.

Diagnosis

Slender longiconic orthocones or slightly cyrtoconic longicones with circular to subcircular cross section; ornamented with broad transverse bands between which are fine growth lines; transverse bands are slightly oblique forming shallow hyponomic sinus; sutures directly transverse or slightly

oblique; siphuncle subcentral; septal necks short orthochoanitic; connecting rings slightly expanding within chambers; weak annulosiphonate deposits concentrated at septal foramen in adapical siphuncular segments; camerae with episeptal and hyposeptal deposits. (Adopted from Sweet 1964c).