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Plaesiomys
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Orthida
Superfamily:
Orthoidea
Family:
Plaesiomyidae
Formal Genus Name and Reference:
Plaesiomys Hall & CLARKE, 1892, p. 196
Type Species:
Orthis subquadrata HALL, 1847, p. 126, OD
Images
(Click to enlarge in a new window)
Fig. 540, $1 a-d$. $* P$. subquadrata (Hall), Ashgill, Indiana, $a, b$, ventral, dorsal exteriors of conjoined pair, x1}$, $c$, ventral interior, x1 . 5, } d$, dorsal interior, X1.5 (Schuchert & Cooper, 1932).
Synonyms
Geographic Distribution
Northern Hemisphere
Age Range
Beginning Stage in Treatise Usage:
Upper Ordovician (Caradoc)
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
Upper Ordovician (Ashgill)
Ending International Stage:
Hirnantian
Fraction Up In Ending Stage:
100
Ending Date:
443.07
Description
Cardinal extremities obtuse, convexoconcave, broadly unisulcate, multicostellate, sporadically lamellose, ventral interarea short, curved, anacline dorsal interarea vestigial, ventral muscle scar without median ridge, posterior pair of quadripartite dorsal adductor scars larger than anterior
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Orthida
Superfamily:
Orthoidea
Family:
Plaesiomyidae
Formal Genus Name and Reference:
Plaesiomys Hall & CLARKE, 1892, p. 196
Type Species:
Orthis subquadrata HALL, 1847, p. 126, OD
Images
(Click to enlarge in a new window)
Fig. 540, $1 a-d$. $* P$. subquadrata (Hall), Ashgill, Indiana, $a, b$, ventral, dorsal exteriors of conjoined pair, x1}$, $c$, ventral interior, x1 . 5, } d$, dorsal interior, X1.5 (Schuchert & Cooper, 1932).
Synonyms
Geographic Distribution
Northern Hemisphere
Age Range
Beginning Stage in Treatise Usage:
Upper Ordovician (Caradoc)
Beginning International Stage:
Sandbian
Fraction Up In Beginning Stage:
0
Beginning Date:
458.18
Ending Stage in Treatise Usage:
Upper Ordovician (Ashgill)
Ending International Stage:
Hirnantian
Fraction Up In Ending Stage:
100
Ending Date:
443.07
Description
Cardinal extremities obtuse, convexoconcave, broadly unisulcate, multicostellate, sporadically lamellose, ventral interarea short, curved, anacline dorsal interarea vestigial, ventral muscle scar without median ridge, posterior pair of quadripartite dorsal adductor scars larger than anterior