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Hadrotreta
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Hadrotreta ROWELL, 1966, p. 12
Type Species:
Acrotreta primaea WALCOTT, 1902, p. 593, OD
Images
(Click to enlarge in a new window)
Fig. 57, 1a-f. * H. primaea (Walcott), Pioche Shale, upper Bonnia-Olenellus-pre-Albertella Biozones, Nevada, USNM loc. 316, $a$, dorsal valve exterior, USNM 459692a, x8.3, b$, dorsal valve interior, USNM 459692b, x8.3, c$, anterior view of ventral pseudointerarea, USNM 459692c, $\\times$.5, detail of apical process, USNM 459692d, X13.3 (new), $e$, ventral valve exterior, KUMIP 115512, x15.8$, $f$, ventral valve interior, KUMIP 115525, X15.8 (Rowell, 1980).
Synonyms
Geographic Distribution
USA (Nevada), upper Lower Cambrian–lower Middle Cambrian; Russia (Novaya Zemlya, Altai), Kirghizia, Uzbekistan, Amgaian; Kazakhstan, Amgaian–Mayaian; Australia, lower Amgaian
Age Range
Beginning Stage in Treatise Usage:
upper Lower Cambrian
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell transversely oval with short, rounded posterior margin, ventral apex moderately convex to subconical, ventral pseudointerarea catacline to gently procline with shallow intertrough, foramen not enclosed within larval shell, dorsal valve gently convex with broad, shallow median sulcus, dorsal pseudointerarea narrowly triangular, orthocline to anacline with shallow median groove, apical process forming rounded boss anterior to internal foramen, apical pits immediately lateral of pedicle tube, dorsal median ridge low, mantle canals baculate
References
Museum or Author Information
Classification
Phylum:
Brachiopoda
Class:
Lingulata
Order:
Acrotretida
Superfamily:
Acrotretoidea
Family:
Acrotretidae
Formal Genus Name and Reference:
Hadrotreta ROWELL, 1966, p. 12
Type Species:
Acrotreta primaea WALCOTT, 1902, p. 593, OD
Images
(Click to enlarge in a new window)
Fig. 57, 1a-f. * H. primaea (Walcott), Pioche Shale, upper Bonnia-Olenellus-pre-Albertella Biozones, Nevada, USNM loc. 316, $a$, dorsal valve exterior, USNM 459692a, x8.3, b$, dorsal valve interior, USNM 459692b, x8.3, c$, anterior view of ventral pseudointerarea, USNM 459692c, $\\times$.5, detail of apical process, USNM 459692d, X13.3 (new), $e$, ventral valve exterior, KUMIP 115512, x15.8$, $f$, ventral valve interior, KUMIP 115525, X15.8 (Rowell, 1980).
Synonyms
Geographic Distribution
USA (Nevada), upper Lower Cambrian–lower Middle Cambrian; Russia (Novaya Zemlya, Altai), Kirghizia, Uzbekistan, Amgaian; Kazakhstan, Amgaian–Mayaian; Australia, lower Amgaian
Age Range
Beginning Stage in Treatise Usage:
upper Lower Cambrian
Beginning International Stage:
Guzhangian
Fraction Up In Beginning Stage:
50
Beginning Date:
498.75
Ending Stage in Treatise Usage:
Middle Cambrian
Ending International Stage:
Guzhangian
Fraction Up In Ending Stage:
100
Ending Date:
497
Description
Shell transversely oval with short, rounded posterior margin, ventral apex moderately convex to subconical, ventral pseudointerarea catacline to gently procline with shallow intertrough, foramen not enclosed within larval shell, dorsal valve gently convex with broad, shallow median sulcus, dorsal pseudointerarea narrowly triangular, orthocline to anacline with shallow median groove, apical process forming rounded boss anterior to internal foramen, apical pits immediately lateral of pedicle tube, dorsal median ridge low, mantle canals baculate