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Protokionoceras
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Nautiloidea
Order:
Orthocerida
Superfamily:
Orthocerataceae
Family:
Geisonoceratidae
Formal Genus Name and Reference:
Protokionoceras Grabau & SHIMER, 1910, p. 58
Type Species:
Orthoceras medullare HALL, 1868, OD
Images
(Click to enlarge in a new window)
Fig. 169, 7. *P. medullare (Hall), M.Sil., USA (Wis.), lat. view, x0.3 (62).
Synonyms
Geographic Distribution
N. Am. (Ill. - Ind.-Me.-Mich.-N.Y.-?Pa.Wis.-Anticosti-Ont.-Que.) -Eu. (Norway) -Australia
Age Range
Beginning Stage in Treatise Usage:
M.Ord.
Beginning International Stage:
Dapingian
Fraction Up In Beginning Stage:
0
Beginning Date:
471.26
Ending Stage in Treatise Usage:
M. Dev.
Ending International Stage:
Givetian
Fraction Up In Ending Stage:
100
Ending Date:
378.9
Description
Moderately expanding orthocones of subcircular section and straight transverse sutures, Surface with cancellate markings produced by intersecting longitudinal and transverse striae or lirae, Siphuncle and cameral deposits in at least some species similar to those of Geisonoceras, these structures not well known in type-species
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Nautiloidea
Order:
Orthocerida
Superfamily:
Orthocerataceae
Family:
Geisonoceratidae
Formal Genus Name and Reference:
Protokionoceras Grabau & SHIMER, 1910, p. 58
Type Species:
Orthoceras medullare HALL, 1868, OD
Images
(Click to enlarge in a new window)
Fig. 169, 7. *P. medullare (Hall), M.Sil., USA (Wis.), lat. view, x0.3 (62).
Synonyms
Geographic Distribution
N. Am. (Ill. - Ind.-Me.-Mich.-N.Y.-?Pa.Wis.-Anticosti-Ont.-Que.) -Eu. (Norway) -Australia
Age Range
Beginning Stage in Treatise Usage:
M.Ord.
Beginning International Stage:
Dapingian
Fraction Up In Beginning Stage:
0
Beginning Date:
471.26
Ending Stage in Treatise Usage:
M. Dev.
Ending International Stage:
Givetian
Fraction Up In Ending Stage:
100
Ending Date:
378.9
Description
Moderately expanding orthocones of subcircular section and straight transverse sutures, Surface with cancellate markings produced by intersecting longitudinal and transverse striae or lirae, Siphuncle and cameral deposits in at least some species similar to those of Geisonoceras, these structures not well known in type-species