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Holcodiscus
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Ammonoidea
Order:
Ammonitida
Suborder:
Ammonitina
Superfamily:
Perisphinctaceae
Family:
Holcodiscidae
Formal Genus Name and Reference:
Holcodiscus UNLIG, 1882a, p. 86, 93
Type Species:
Ammonites caillaudianus ORBIGNY, 1850a, p. 99, OD
Images
(Click to enlarge in a new window)
Fig. 35, 4a, b. *H. caillaudianus (Orbigny), France, X 1 (Kilian, 1889a)
Synonyms
Geographic Distribution
central and southern Europe, California, Mexico
Age Range
Beginning Stage in Treatise Usage:
Lower Cretaceous (Barremian)
Beginning International Stage:
Barremian
Fraction Up In Beginning Stage:
0
Beginning Date:
126.5
Ending Stage in Treatise Usage:
Lower Cretaceous (Barremian)
Ending International Stage:
Barremian
Fraction Up In Ending Stage:
100
Ending Date:
121.4
Description
Circular to rectangular whorl section; fine, low, straight or flexuous, simple or branched ribs, periodically truncated by thin, high, enlarged ribs bearing lateral and ventrolateral tubercles; inner whorls tending to have depressed whorl section and to resemble Olcostephanus.
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Ammonoidea
Order:
Ammonitida
Suborder:
Ammonitina
Superfamily:
Perisphinctaceae
Family:
Holcodiscidae
Formal Genus Name and Reference:
Holcodiscus UNLIG, 1882a, p. 86, 93
Type Species:
Ammonites caillaudianus ORBIGNY, 1850a, p. 99, OD
Images
(Click to enlarge in a new window)
Fig. 35, 4a, b. *H. caillaudianus (Orbigny), France, X 1 (Kilian, 1889a)
Synonyms
Geographic Distribution
central and southern Europe, California, Mexico
Age Range
Beginning Stage in Treatise Usage:
Lower Cretaceous (Barremian)
Beginning International Stage:
Barremian
Fraction Up In Beginning Stage:
0
Beginning Date:
126.5
Ending Stage in Treatise Usage:
Lower Cretaceous (Barremian)
Ending International Stage:
Barremian
Fraction Up In Ending Stage:
100
Ending Date:
121.4
Description
Circular to rectangular whorl section; fine, low, straight or flexuous, simple or branched ribs, periodically truncated by thin, high, enlarged ribs bearing lateral and ventrolateral tubercles; inner whorls tending to have depressed whorl section and to resemble Olcostephanus.