Dimarzipecten brooksvillensis (Mansfield, 1937)
MANSFIELD, W. C. 1937. Mollusks of the Tampa and Suwannee Limestones of Florida. Florida Department of Conservation, State Geological Survey, Geological Bulletin, 15: 1-334, pls. 1-21 [p. 208, pl. 13, figs. 2, 4, 5]
1937 Chlamys (Lyropecten) brooksvillensis Mansfield, 1937
W. C. Mansfield, 1937, plate 13.
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«Shell of moderate size, slightly inequilateral, the posterior side being slightly produced, both valves inflated, the left weakly and the right more strongly. Both valves with about 20 similarly sculptured ribs. Ribs a little narrower than interspaces, strong, rather wide, nearly square in outline, weakly undercut on the sides and sculptured mainly on top with an incised longitudinal line and occasionally on the marginal rihs by two weakly incised lines. Interspaces with one strong medial thread on the distal part of the disk but not present over the beak or early part of the shell. Whole surface of disk concentrically sculptured with marginally raised, rather coarse, scabrous lamellae. There are about 4 of these lamellae to a millimeter on the early part of the shell and 2 to a millillleter on the distal ends of the larger shells. Submargins without any distinct radials but with scabrous concentric sculpture. Right auricle on right valve with a rather deep byssal notch and sculptured with 3 or 4 rather strong scabrous radials. Left auricle raised along dorsal nmrgin and sculptured with about 5 weaker scabrous radials. Auricles on left valve sculptured with scabrous radials.
Dimensions: Holotype, left valve (U. S. National Museum no. 495974), length, 40 mm.; height, 40 mm. Paratype, right valve (U. S. National Museum no. 496234), length, 44 mm.; height, 42 mm. Holotype locality: Station 12322, quarry three-fourths mile soulh-west of Brooksville, Hernando County. Paratype locality: Station 12758, 5.9 miles northeast of Brooksville. Horizon: Suwannee limestone, Oligocene. Occurrence: Station 12318, 5 miles west of Brooksville, Hernando County; station 12757, 10.2 miles Northeast of Brooksville, Hernando County; station 12758, 5.9 miles northeast of Brooksville; station 12321, 3 miles east of Brooksville; station 11116, Blackwater River at Seaboard Air Line Ry. crossing, Hillsborough County; station 10116, bed no. 1 of section at Falling Water, Washington County. (Fragments, identification uncertain.) Chlamys brooksvillensis is similar to C. gabbi Dall, a species reported from Antigua and Anguilla Islands, in the character of sculpture and number of ribs but differs from that species in having more inflated and less oblique shell. An unnamed species from Cedar Grove (station 10046) and from 2½ milles south by cast of Chipley (station 7240), Washington County, Fla., is very closely related to C. brooksvillensis. This species appears to be nearer "Pecten" estrellanus Conrad, the genotype of the section Lyropecten, than to "Pecten" ventricosus Sowerby, the genotype of the section Plagiotecnium» WENDELL CLAY MANSFIELD, 1937
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