"Chlamys" indecisus (Dall, 1898)
DALL, W. H. 1898. Contributions to the Tertiary fauna of Florida. Silex Beds of Tampa and the Pliocene Beds of the Caloosahatchie River. Part IV. I. Prionodesmacea: Nucula to Julia. 2. Teleodesmacea: Teredo to Ervilia. Transactions of the Wagner Free Institute of Science of Philadelphia, 3 (4): viii, 571-947 p., pls. 23-35 (pls. 36 and 37 in part 5, 1900) [p. 744, pl. 34, fig. 3]
1898 Pecten (Chlamys) indecisus Dall, 1898
W. H. Dall, 1989, plate 34.
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«Vicksburgian Oligocene at Archer and vicinity, Alachua County; as silicious pseudomorphs at Martin Station, Marion County; at a depth of two hundred and twenty-five feet in the artesian well, Ponce de Leon Hotel, St. Augustine; and in the Tampa limestone of the Hillsborough River, near Tampa, Florida; Dall and Willcox.
Shell thin, moderately convex, ovate, with twenty-six to thirty-four small, low, simple, entire ribs separated by about equal interspaces and having a tendency, especially in the left valve (which is slightly more convex than the other), to become obsolete distally; transverse sculpture only of lines of growth, Camptonectes striation present, more conspicuous in the smoother specimens; ears small, unequal, the posterior smaller; byssal ear with a wellmarked notch and conspicuous fascicle, above which are about six partly scabrous riblets, becoming stronger dorsally; interior lirate, the lirae stronger near the margin; ctenolium present; cardinal crura well developed, cross-striated. Alt. of figured specimen 16, of adult 31, lat. of adult 28 mm. This is a very interesting species which retains the outline of Chlamys while at times it assumes the characters of Amusium. Some specimens are almost ribless, except on the umbones, and in this state the species would belong to the "subgenus" Lissopecten Verrill; in others the ribs are well developed and continuous down to the very margin, which they then crenulate; in which state the shell is a typical Chlamys. In most of its shell characters it is intermediate between the two subgenera, Chlamys and Amusium. Just over the line, and separated from the present species more by its outline than by any other important character, is the shell I have called Amusium ocalanum, all of which, with the aid of A. Lyoni Gabb, form a complete connecting series between the most typical Amusium and undoubted Chlamys.» WILLIAM HEALEY DALL, 1898 |