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Amictocracens
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Amictocracens Henderson & MACKINNON, 1981, p. 295
Type Species:
A. teres, OD
Images
(Click to enlarge in a new window)
Fig. 52, 5a-d. *A. teres, Mailchange Limestone, Goniagnostus nathorsti Biozone, Georgina basin, Queensland, $a$, dorsal valve interior, JCF 10718, x22.5, b, c$, ventral valve exterior, lateral view of both valves, JCF 10719, x35$, $d$, ventral valve interior, JCF 10717, X20.8 (Henderson & MacKinnon, 1981).
Synonyms
Geographic Distribution
Australia (Queensland), New Zealand, ?northern China (Hebei)
Age Range
Beginning Stage in Treatise Usage:
Middle Cambrian
Beginning International Stage:
Wuliuan
Fraction Up In Beginning Stage:
0
Beginning Date:
509
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell subcircular with short, weakly concave posterior margin, ventral valve low, conical, pseudointerarea procline, poorly defined laterally with fine interridge, foramen enclosed within larval shell, dorsal valve weakly convex with poorly defined pseudointerarea, forming concave, undivided plate, apical process forming bosslike projection anterior to internal foramen, dorsal interior with moderately high, triangular, bladelike median septum, dorsal median buttress poorly developed.
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Amictocracens Henderson & MACKINNON, 1981, p. 295
Type Species:
A. teres, OD
Images
(Click to enlarge in a new window)
Fig. 52, 5a-d. *A. teres, Mailchange Limestone, Goniagnostus nathorsti Biozone, Georgina basin, Queensland, $a$, dorsal valve interior, JCF 10718, x22.5, b, c$, ventral valve exterior, lateral view of both valves, JCF 10719, x35$, $d$, ventral valve interior, JCF 10717, X20.8 (Henderson & MacKinnon, 1981).
Synonyms
Geographic Distribution
Australia (Queensland), New Zealand, ?northern China (Hebei)
Age Range
Beginning Stage in Treatise Usage:
Middle Cambrian
Beginning International Stage:
Wuliuan
Fraction Up In Beginning Stage:
0
Beginning Date:
509
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell subcircular with short, weakly concave posterior margin, ventral valve low, conical, pseudointerarea procline, poorly defined laterally with fine interridge, foramen enclosed within larval shell, dorsal valve weakly convex with poorly defined pseudointerarea, forming concave, undivided plate, apical process forming bosslike projection anterior to internal foramen, dorsal interior with moderately high, triangular, bladelike median septum, dorsal median buttress poorly developed.