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Pachymya
Classification
Phylum:
Mollusca
Class:
Bivalvia
Subclass:
Anomalodesmata
Order:
Pholadomyoida
Superfamily:
Pholadomyacea
Family:
Pholadomyidae
Formal Genus Name and Reference:
Pachymya J. de C. SOWERBY, 1826, p. 1
Type Species:
*P. gigas, M
Images
(Click to enlarge in a new window)
Fig. F14,2a,b. *P. (P.) gigas Sowerby, U.Cret.(Cenoman.), France, 2 a, b, LV ext., and dorsal view of both valves, X0.5 (d'Orbigny, 1843-47)., Fig. F14,2c. P. (P.) austinensis Shumard, L.Cret.(Alb.), USA(Tex.), RV int. showing hinge and pallial line, X0.45 (Stanton, 1947), Fig. F14,2d. P. (P.) latissima (Agassiz), U.Jur.(Oxford), Switz., LV int., showing pallial line, X0.7 (Rollier, 1913).
Synonyms
Geographic Distribution
cosmop.
Age Range
Beginning Stage in Treatise Usage:
M.Trias.
Beginning International Stage:
Anisian
Fraction Up In Beginning Stage:
0
Beginning Date:
246.7
Ending Stage in Treatise Usage:
U.Cret.
Ending International Stage:
Maastrichtian
Fraction Up In Ending Stage:
100
Ending Date:
66.04
Description
Oblong, moderately to strongly inequilateral, with broad, only slightly protruding, almost orthogyrous umbones, posterior gape slight to moderate, most species with umbonal ridge, crossing most inflated part of shell, running diagonally to posteroventral corner, pallial line distant from shell margins, pallial sinus (where known) small or absent, surface unornamented in most species except for fine, radially aligned pustules, but with concentric undulations in some Triassic forms
References
Museum or Author Information
Classification
Phylum:
Mollusca
Class:
Bivalvia
Subclass:
Anomalodesmata
Order:
Pholadomyoida
Superfamily:
Pholadomyacea
Family:
Pholadomyidae
Formal Genus Name and Reference:
Pachymya J. de C. SOWERBY, 1826, p. 1
Type Species:
*P. gigas, M
Images
(Click to enlarge in a new window)
Fig. F14,2a,b. *P. (P.) gigas Sowerby, U.Cret.(Cenoman.), France, 2 a, b, LV ext., and dorsal view of both valves, X0.5 (d'Orbigny, 1843-47)., Fig. F14,2c. P. (P.) austinensis Shumard, L.Cret.(Alb.), USA(Tex.), RV int. showing hinge and pallial line, X0.45 (Stanton, 1947), Fig. F14,2d. P. (P.) latissima (Agassiz), U.Jur.(Oxford), Switz., LV int., showing pallial line, X0.7 (Rollier, 1913).
Synonyms
Geographic Distribution
cosmop.
Age Range
Beginning Stage in Treatise Usage:
M.Trias.
Beginning International Stage:
Anisian
Fraction Up In Beginning Stage:
0
Beginning Date:
246.7
Ending Stage in Treatise Usage:
U.Cret.
Ending International Stage:
Maastrichtian
Fraction Up In Ending Stage:
100
Ending Date:
66.04
Description
Oblong, moderately to strongly inequilateral, with broad, only slightly protruding, almost orthogyrous umbones, posterior gape slight to moderate, most species with umbonal ridge, crossing most inflated part of shell, running diagonally to posteroventral corner, pallial line distant from shell margins, pallial sinus (where known) small or absent, surface unornamented in most species except for fine, radially aligned pustules, but with concentric undulations in some Triassic forms