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Linnarssonia
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Linnarssonia Walcott, 1885, p. 115, Pegmatreta BELL, 1941, p. 231
Type Species:
Obolella transversa Hartt in DAWSON, 1868, p. 644, OD
Images
(Click to enlarge in a new window)
Fig. 58, 2a-g. L. ophirensis (Walcott), Middle Cambrian, lower Bolaspidella or Bathyuriscus-Elrathia Biozones, Utah, USNM loc. 3e, $a$, dorsal valve interior, X12.5, b, oblique posterior view of dorsal interior, USNM 459693a, x31.7$, c, dorsal valve exterior, USNM 459693b, x13.1$, $d$, ventral valve exterior, X16.7, e, oblique lateral view of ventral exterior, X20, $f$, oblique posterior view of ventral umbo, USNM 459693c, X66.7, $g$, ventral valve interior, USNM 459693d, X25 (new).
Synonyms
Pegmatreta
Geographic Distribution
Germany, Lower Cambrian; Great Britain, Russia (Siberia), Kazakhstan, Kirghizia, Lower Cambrian–Middle Cambrian; Sweden, Norway, ?Lower Cambrian, Middle Cambrian; ?Mexico (Sonora), USA (Utah, Montana, Alaska), Canada, ?China, West Antarctica, Middle Cambrian; Greenland, upper Middle Cambrian; Australia, New Zealand
Age Range
Beginning Stage in Treatise Usage:
Lower Cambrian
Beginning International Stage:
Fortunian
Fraction Up In Beginning Stage:
0
Beginning Date:
538.8
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell subcircular to transversely oval with short, convex posterior margin, ventral valve convex to low subconical, ventral pseudointerarea catacline to procline, rarely apsacline with intertrough, foramen not enclosed within larval shell, dorsal valve gently convex with vestigial, undivided pseudointerarea, apical process high, bosslike, anterior to foramen, dorsal interior with high median ridge and median buttress, anterocentral scars well defined
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Linnarssonia Walcott, 1885, p. 115, Pegmatreta BELL, 1941, p. 231
Type Species:
Obolella transversa Hartt in DAWSON, 1868, p. 644, OD
Images
(Click to enlarge in a new window)
Fig. 58, 2a-g. L. ophirensis (Walcott), Middle Cambrian, lower Bolaspidella or Bathyuriscus-Elrathia Biozones, Utah, USNM loc. 3e, $a$, dorsal valve interior, X12.5, b, oblique posterior view of dorsal interior, USNM 459693a, x31.7$, c, dorsal valve exterior, USNM 459693b, x13.1$, $d$, ventral valve exterior, X16.7, e, oblique lateral view of ventral exterior, X20, $f$, oblique posterior view of ventral umbo, USNM 459693c, X66.7, $g$, ventral valve interior, USNM 459693d, X25 (new).
Synonyms
Pegmatreta
Geographic Distribution
Germany, Lower Cambrian; Great Britain, Russia (Siberia), Kazakhstan, Kirghizia, Lower Cambrian–Middle Cambrian; Sweden, Norway, ?Lower Cambrian, Middle Cambrian; ?Mexico (Sonora), USA (Utah, Montana, Alaska), Canada, ?China, West Antarctica, Middle Cambrian; Greenland, upper Middle Cambrian; Australia, New Zealand
Age Range
Beginning Stage in Treatise Usage:
Lower Cambrian
Beginning International Stage:
Fortunian
Fraction Up In Beginning Stage:
0
Beginning Date:
538.8
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell subcircular to transversely oval with short, convex posterior margin, ventral valve convex to low subconical, ventral pseudointerarea catacline to procline, rarely apsacline with intertrough, foramen not enclosed within larval shell, dorsal valve gently convex with vestigial, undivided pseudointerarea, apical process high, bosslike, anterior to foramen, dorsal interior with high median ridge and median buttress, anterocentral scars well defined