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Trigonarca sectilis
Taxonomy
Trigonarca sectilis was named by Packard (1922). Its type specimen is UCMP 12316 and is a 3D body fossil. Its type locality is UCMP loc. 2144, Santa Ana Mountains, which is in a Turonian/Campanian marine horizon in the Ladd Formation of California.
Sister species lacking formal opinion data
Synonymy list
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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.
†Trigonarca sectilis Packard 1922
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| E. L. Packard 1922 | Shell small, trigonal, inequilateral, ventricose, the diameter being nearly equal to length. Anterior extremity short, evenly rounded. Posterior dorsal side of the shell conspicuously flattened; basal margin nearly straight. Beaks small , widely separated. Posterior umbonal ridge sharply marked , extending to the bluntly pointed posterior extremity . The margins of the shell within this area pout, forming the boundary of a groove which extends from the beaks to the ventral margin. Five oblique anterior teeth, and apparently about the same number of posterior teeth on hinge of cotype. The teeth short, and transverse on the middle portion of the plate. Length of type, 43 mm.; height,
45 mm.; diameter, 40 mm. |