Chlamys (Lyropecten) pontoni Mansfield, 1932
MANSFIELD, W. C. 1932. Miocene Pelecypods of the Choctawhatchee Formation of Florida. Florida Geological Survey Bulletin, 8: 7-164, pls. 1-34. [p. 59, pl. 10, figs. 1, 2]
«Chlamys (Lyropecten) pontoni Mansfield, n. sp.
Plate 10, figures 1, 2 1916. Pecten Madisonius Say?, Mansfield, U. S. Nat. Mus. Proc., vol. 51, p. 601. (Lilsted from Red Bay)
Shell large, rarther strongly inflated, nearly equivalve and nearly equilateral, the posterior region being slightly more produced. Ornamented with 11 nearly flat to slightly rounded, widely spaced ribs, which are strong on the middle of the disk but weaker on the sides. Interradial spaces and surface of the ribs marked with moderately coarse radial threads which are more prominent between the ribs than on the surface of the ribs. Three to five weak radials lie on the extreme posterior and anterior areas of the disk. Ears partly broken away. Within, the suface distinctly reflects the strong external ribbing.
Holotype (Cat. No. 371613, U. S. N. M.) measures: Length, 137 mm.: height, 130 mm.; semidiameter, 20 mm. Type locality: Station 12047. Vaughan Creek, 1½ to 2 miles from its entrance into Alaqua Creek, Walton County. G. M. Ponton and W. C. Mansfield, collectors. Chlamys (Lyropecten) jeffersonius Say differs from the new specie in having fewer, wider, and more equal-sized ribs. The weaker radials on the anterior and posterior sides of the shell slightly indicate a relationship with the subgenus Nodipecten. Occurrence: Upper middle Miocene: Arca zone — station 12047, type locality (one valve); Red Bay, Walton County (rare). This species is named in honor of Mr. G. M. Ponton, of the Florida Geological Survey.» WENDELL CLAY MANSFIELD, 1932
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W. C. Mansfield, 1932, plate 10.
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