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Isognomon
Classification
Phylum:
Mollusca
Class:
Bivalvia
Subclass:
Pteriomorphia
Order:
Pterioida
Suborder:
Pteriina
Superfamily:
Pteriacea
Family:
Isognomonidae
Formal Genus Name and Reference:
Isognomon LIGHTFOOT, 1786, p. 41, 52
Type Species:
Ostrea perna LINNÉ, 1767, p. 1149, M
Images
(Click to enlarge in a new window)
Fig. C50,2a-e. I. (I.) ephippium (Linné), Rec., Mauritius, 2a,b, RV ext., RV int., X0.5 (Cox, n), 2 c-e, early ontogenetic stages, showing hinge teeth later obsolete, much enl. (44).-Fig. C50,2f,g. I. (I.) isognomonoides (Stahl), M.Jur.(Bathon.), 2 f, Switz., RV, X0.7 (Greppin, 1900), 2g, Ger., LV ligamental area, X0.7 (341b).
Synonyms
Geographic Distribution
U.Trias.-Rec., cosmop.
Age Range
Beginning Stage in Treatise Usage:
U.Trias.
Beginning International Stage:
Carnian
Fraction Up In Beginning Stage:
0
Beginning Date:
237
Ending Stage in Treatise Usage:
Rec.
Ending International Stage:
Meghalayan
Fraction Up In Ending Stage:
100
Ending Date:
0
Description
Shell subequivalve, usually higher than long, more or less compressed, of various shapes, umbo directed anteriorly and not protruding above hinge margin, ligamental area broad and flat, scarcely undercut, ligamental grooves numerous, regularly arranged, narrow byssal gape present below beaks, with corresponding reflection of anterior margin
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Bivalvia
Subclass:
Pteriomorphia
Order:
Pterioida
Suborder:
Pteriina
Superfamily:
Pteriacea
Family:
Isognomonidae
Formal Genus Name and Reference:
Isognomon LIGHTFOOT, 1786, p. 41, 52
Type Species:
Ostrea perna LINNÉ, 1767, p. 1149, M
Images
(Click to enlarge in a new window)
Fig. C50,2a-e. I. (I.) ephippium (Linné), Rec., Mauritius, 2a,b, RV ext., RV int., X0.5 (Cox, n), 2 c-e, early ontogenetic stages, showing hinge teeth later obsolete, much enl. (44).-Fig. C50,2f,g. I. (I.) isognomonoides (Stahl), M.Jur.(Bathon.), 2 f, Switz., RV, X0.7 (Greppin, 1900), 2g, Ger., LV ligamental area, X0.7 (341b).
Synonyms
Geographic Distribution
U.Trias.-Rec., cosmop.
Age Range
Beginning Stage in Treatise Usage:
U.Trias.
Beginning International Stage:
Carnian
Fraction Up In Beginning Stage:
0
Beginning Date:
237
Ending Stage in Treatise Usage:
Rec.
Ending International Stage:
Meghalayan
Fraction Up In Ending Stage:
100
Ending Date:
0
Description
Shell subequivalve, usually higher than long, more or less compressed, of various shapes, umbo directed anteriorly and not protruding above hinge margin, ligamental area broad and flat, scarcely undercut, ligamental grooves numerous, regularly arranged, narrow byssal gape present below beaks, with corresponding reflection of anterior margin