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Ancistroceras
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Nautiloidea
Order:
Tarphycerida
Family:
Lituitidae
Formal Genus Name and Reference:
Ancistroceras BOLL, 1857, p. 87
Type Species:
Lituites (A. undulatum; M
Images
(Click to enlarge in a new window)
Fig. 267, 1. *A. undulatum BOLL, Pleist. drift, Eu.(Ger.); lat. view, X1 (144).
Synonyms
Strombolituites
Geographic Distribution
Eu. (Balto-Scandia)
Age Range
Beginning Stage in Treatise Usage:
L.Ord. (Arenig.
Beginning International Stage:
Floian
Fraction Up In Beginning Stage:
0
Beginning Date:
477.08
Ending Stage in Treatise Usage:
M.Ord. (Caradoc.)
Ending International Stage:
Katian
Fraction Up In Ending Stage:
66.7
Ending Date:
447.72
Description
Conch weakly annulate, consisting of 1.5 to 2 contiguous or slightly separated compressed whorls and rapidly expanded orthocone (apical angle about 30 degrees) with circular section; growth lines sinuous with pronounced hyponomic sinus adapically, almost straight adorally. Orthocone similar to Rhynchorthoceras but more rapidly expanded, like Holmiceras but lacking sigmoid outline.
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Nautiloidea
Order:
Tarphycerida
Family:
Lituitidae
Formal Genus Name and Reference:
Ancistroceras BOLL, 1857, p. 87
Type Species:
Lituites (A. undulatum; M
Images
(Click to enlarge in a new window)
Fig. 267, 1. *A. undulatum BOLL, Pleist. drift, Eu.(Ger.); lat. view, X1 (144).
Synonyms
Strombolituites
Geographic Distribution
Eu. (Balto-Scandia)
Age Range
Beginning Stage in Treatise Usage:
L.Ord. (Arenig.
Beginning International Stage:
Floian
Fraction Up In Beginning Stage:
0
Beginning Date:
477.08
Ending Stage in Treatise Usage:
M.Ord. (Caradoc.)
Ending International Stage:
Katian
Fraction Up In Ending Stage:
66.7
Ending Date:
447.72
Description
Conch weakly annulate, consisting of 1.5 to 2 contiguous or slightly separated compressed whorls and rapidly expanded orthocone (apical angle about 30 degrees) with circular section; growth lines sinuous with pronounced hyponomic sinus adapically, almost straight adorally. Orthocone similar to Rhynchorthoceras but more rapidly expanded, like Holmiceras but lacking sigmoid outline.