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Composita
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Athyridida
Superfamily:
Athyridoidea
Family:
Athyrididae
Formal Genus Name and Reference:
Composita BROWN, 1845, p. 131
Type Species:
Spirifer ambiguus SOWERBY, 1822 in 1821-1822, p. 105, OD
Images
(Click to enlarge in a new window)
Fig. 1043, 2a-c. $* C$. ambigua (Sowerby), Viséan, Derbyshire, England, $a-b$, lectotype, dorsal and ventral views, BMNH B 61041, x1.5$ (Brunton, 1980, photographs courtesy of C. H. C. Brunton), $c$, ventral view of dorsal interior showing jugum, approximately x3$ (Davidson, 1861).
Synonyms
Seminula, Gruntathyris
Geographic Distribution
cosmopolitan
Age Range
Beginning Stage in Treatise Usage:
Upper Devonian (Famennian)
Beginning International Stage:
Famennian
Fraction Up In Beginning Stage:
0
Beginning Date:
371.1
Ending Stage in Treatise Usage:
Upper Permian
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Moderately to strongly biconvex, subovate, subpentagonal or subtrigonal shells, commonly widest near midlength, dorsal fold and ventral sulcus variably developed, may extend to umbonal region or be restricted to anterior part, fold may be flat or slightly depressed medianly, anterior commissure uniplicate to parasulcate, ventral beak thick, rounded, foramen large, ovate, in epi- to permesothyridid position, delthyrium completely filled by dorsal umbo without deltidial plates, dorsal foramen infilled other than in early forms.
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Rhynchonellata
Order:
Athyridida
Superfamily:
Athyridoidea
Family:
Athyrididae
Formal Genus Name and Reference:
Composita BROWN, 1845, p. 131
Type Species:
Spirifer ambiguus SOWERBY, 1822 in 1821-1822, p. 105, OD
Images
(Click to enlarge in a new window)
Fig. 1043, 2a-c. $* C$. ambigua (Sowerby), Viséan, Derbyshire, England, $a-b$, lectotype, dorsal and ventral views, BMNH B 61041, x1.5$ (Brunton, 1980, photographs courtesy of C. H. C. Brunton), $c$, ventral view of dorsal interior showing jugum, approximately x3$ (Davidson, 1861).
Synonyms
Seminula, Gruntathyris
Geographic Distribution
cosmopolitan
Age Range
Beginning Stage in Treatise Usage:
Upper Devonian (Famennian)
Beginning International Stage:
Famennian
Fraction Up In Beginning Stage:
0
Beginning Date:
371.1
Ending Stage in Treatise Usage:
Upper Permian
Ending International Stage:
Changhsingian
Fraction Up In Ending Stage:
100
Ending Date:
251.9
Description
Moderately to strongly biconvex, subovate, subpentagonal or subtrigonal shells, commonly widest near midlength, dorsal fold and ventral sulcus variably developed, may extend to umbonal region or be restricted to anterior part, fold may be flat or slightly depressed medianly, anterior commissure uniplicate to parasulcate, ventral beak thick, rounded, foramen large, ovate, in epi- to permesothyridid position, delthyrium completely filled by dorsal umbo without deltidial plates, dorsal foramen infilled other than in early forms.