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Mesonomia
Classification
Phylum:
Brachiopoda
Subphylum:
Rhynchonelliformea
Class:
Rhynchonellata
Order:
Pentamerida
Suborder:
Syntrophiidina
Superfamily:
Porambonitoidea
Family:
Huenellidae
Subfamily:
Mesonomiinae
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, X1.66 (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
Subphylum:
Rhynchonelliformea
Class:
Rhynchonellata
Order:
Pentamerida
Suborder:
Syntrophiidina
Superfamily:
Porambonitoidea
Family:
Huenellidae
Subfamily:
Mesonomiinae
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, X1.66 (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