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Mesonomia
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Pentamerida
Superfamily:
Porambonitoidea
Family:
Huenellidae
Formal Genus Name and Reference:
Mesonomia Ulrich & COOPER, 1936, p. 627
Type Species:
Eoorthis iophon WALCOTT, 1924, p. 507, OD
Images
(Click to enlarge in a new window)
Fig. 626, 1a-b. *M. iophon (Walcott), Tremadoc, Mons Formation, Alberta, Canada, $a$, ventral valve exterior, $b$, dorsal valve exterior, x2$ (Ulrich & Cooper, 1938), Fig. 626, 1c-f. M. magna Cooper, Fort Sill Formation, Oklahoma, USA, $c$, ventral valve interior, $d$, ventral valve, lateral view, $e$, dorsal valve interior, $f$, dorsal valve, anterior view, USNM $116694, \\times 1.66$ (new)
Synonyms
Geographic Distribution
USA, Canada, ?Kazakhstan, ?eastern China
Age Range
Beginning Stage in Treatise Usage:
Upper Cambrian (Drebachian)
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Lower Ordovician (Tremadoc)
Ending International Stage:
Tremadocian
Fraction Up In Ending Stage:
100
Ending Date:
477.08
Description
Fine but distinct costellae, biconvexity weak to moderate, weakly uniplicate, dorsal sulcus reverts to fold early in growth
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Pentamerida
Superfamily:
Porambonitoidea
Family:
Huenellidae
Formal Genus Name and Reference:
Mesonomia Ulrich & COOPER, 1936, p. 627
Type Species:
Eoorthis iophon WALCOTT, 1924, p. 507, OD
Images
(Click to enlarge in a new window)
Fig. 626, 1a-b. *M. iophon (Walcott), Tremadoc, Mons Formation, Alberta, Canada, $a$, ventral valve exterior, $b$, dorsal valve exterior, x2$ (Ulrich & Cooper, 1938), Fig. 626, 1c-f. M. magna Cooper, Fort Sill Formation, Oklahoma, USA, $c$, ventral valve interior, $d$, ventral valve, lateral view, $e$, dorsal valve interior, $f$, dorsal valve, anterior view, USNM $116694, \\times 1.66$ (new)
Synonyms
Geographic Distribution
USA, Canada, ?Kazakhstan, ?eastern China
Age Range
Beginning Stage in Treatise Usage:
Upper Cambrian (Drebachian)
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Lower Ordovician (Tremadoc)
Ending International Stage:
Tremadocian
Fraction Up In Ending Stage:
100
Ending Date:
477.08
Description
Fine but distinct costellae, biconvexity weak to moderate, weakly uniplicate, dorsal sulcus reverts to fold early in growth