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Opikina varia
Taxonomy
Opikina varia was named by Cooper (1956) [Öpikina varia
Rafinesgnina aff. minnesotensis Butts (not Winchell), Alabama Geol. Surv., Special Rep. 14, p. 126, pi. 31, figs. 23, 24, 1926.]. Its type specimen is USNM 117848a, a shell, and it is a 3D body fossil.
Sister species lacking formal opinion data
Synonymy list
| Year | Name and author |
|---|---|
| 1956 | Opikina varia Cooper pp. 922 - 923 figs. Plate 240, A, figures 1-7 |
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
†Opikina varia Cooper 1956
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| G. A. Cooper 1956 | Shell small for the genus, subquadrate to subrectangular in outline, slightly wider than long ; sides gently rounded, subparallel ; anterior margin broadly rounded. Hinge generally equal to or less than the width at the middle. Costellae well differentiated, 2 of the larger size in i mm. at the front margin. Larger costellae separated by 2 to 4 of the finer ones.
Pedicle valve unevenly convex in lateral profile, with the maximum convexity anterior to the middle ; anterior profile moderately domed ; geniculation occurring about II mm. anterior to the beak; angle of geniculation 115° ; visceral region varying in lateral profile from nearly flat to moderately convex ; anterior slope gently convex, short and steep ; sides with short and steep slopes; interior with muscle field to about the middle of the valve. Brachial valve gently concave in the visceral region which extends for about ¼ the length; deepest part anterior to middle ; sides and anterior margin narrow and abruptly bent in the direction of the brachial valve. |