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Lepetopsis peregrina
Taxonomy
Lepetopsis peregrina was named by Newell (1935). It is a 3D body fossil. Its type locality is Fredonia, Olathe Limestone Member, which is in a Missourian carbonate limestone in the Stanton Formation of Kansas.
Synonymy list
| Year | Name and author |
|---|---|
| 1935 | Lepetopsis peregrina Newell pp. 352 - 353 figs. pl. 35 f. 3-7 |
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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.
†Lepetopsis peregrina Newell 1935
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Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| N. D. Newell 1935 | The shell is relatively small, patelli-form, and elongate, with a subelliptical base which is slightly arched from front to back. In mature specimens the apex is nearly central and bluntly rounded, but in small, immature specimens there is coiled tip or nucleus extended toward one end of the shell. Apparently this nucleus is lost by breakage or by abrasion before a mature stage is reached. The lateral margins are subparallel and the sides are somewhat flattened. In some specimens the end nearest the apex has a distinctly concave profile, but in several moderate sized individuals both ends are convex. The shell is not quite symmetrical from a side view in these specimens but commonly the slope which in other individuals is concave is more steeply inclined than the slope at the op-posite end.
There is no trace of radial ornamen-tation in several specimens retaining the shell, but there is a distinct concentric ornamentation consisting of somewhat irregularly bunched growth varices. Since one specimen exhibits a muscle scar across the steeper slope at one end of the shell this end should probably be con-sidered as posterior. By circumstance of the tendency toward concavity at the posterior end and more rapid growth at the anterior margin the growth varices in adult shells are depressed toward the rear so that they pass obliquely back-ward across the sides of the shell. The anterior end of the shell is less steep in profile than the posterior slope and is distinctly convex, with the convexity in-creasing slightly next to the margin. Some shells are slightly narrower at the front than at the rear whereas others have lateral margins that are practically parallel. A remnant of the nucleus occurs in some of the small juveniles. It appears at the apex as a small triangular nub, somewhat wedge-shaped at the anterior end and rounding less abruptly at the posterior end. Probably the nucleus was coiled at the earliest stage but in the 15 specimens at hand it was either broken away and the fracture healed or it was lost by abrasion. There is only one speci-men that shows a trace of the muscle scar. The scar is a U-shaped narrow groove which crosses the posterior end about halfway between the apex and the periphery. The ends of the groove extend forward less than a third of the length of the shell and then become invisible. The following measurements in-dicate the change in dimensions during the stages of growth. |