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Grammoceras
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Order:
Ammonitida
Superfamily:
Eoderocerataceae
Family:
Hildoceratidae
Formal Genus Name and Reference:
Grammoceras HYATT, 1867
Type Species:
Am. striatulus SOWERBY, 1823
Images
(Click to enlarge in a new window)
Fig. 294,6. *G. (G.) striatulum (Sow.), Eng., holotype, 6a,b, x0.7 (595*)
Synonyms
Pseudogrammoceras, Costigrammoceras, Pseudowalkericeras
Geographic Distribution
Eu.-N.Afr.-Cauc.-N.Persia-Indon.-?Borneo-Spitz.-Can.
Age Range
Beginning Stage in Treatise Usage:
U.Toarc.(jurense z.)
Beginning International Stage:
Toarcian
Fraction Up In Beginning Stage:
50
Beginning Date:
179.45
Ending Stage in Treatise Usage:
U.Toarc.(jurense z.)
Ending International Stage:
Toarcian
Fraction Up In Ending Stage:
100
Ending Date:
174.7
Description
Evolute, umbilical slope gentle, ribbing simple and gently sigmoid
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Order:
Ammonitida
Superfamily:
Eoderocerataceae
Family:
Hildoceratidae
Formal Genus Name and Reference:
Grammoceras HYATT, 1867
Type Species:
Am. striatulus SOWERBY, 1823
Images
(Click to enlarge in a new window)
Fig. 294,6. *G. (G.) striatulum (Sow.), Eng., holotype, 6a,b, x0.7 (595*)
Synonyms
Pseudogrammoceras, Costigrammoceras, Pseudowalkericeras
Geographic Distribution
Eu.-N.Afr.-Cauc.-N.Persia-Indon.-?Borneo-Spitz.-Can.
Age Range
Beginning Stage in Treatise Usage:
U.Toarc.(jurense z.)
Beginning International Stage:
Toarcian
Fraction Up In Beginning Stage:
50
Beginning Date:
179.45
Ending Stage in Treatise Usage:
U.Toarc.(jurense z.)
Ending International Stage:
Toarcian
Fraction Up In Ending Stage:
100
Ending Date:
174.7
Description
Evolute, umbilical slope gentle, ribbing simple and gently sigmoid