Chesapecten middlesexensis ceccae Ward, 1992
WARD, L. W. 1992. Molluscan bioestratigraphy of the Miocene, Middle Atlantic Coastal Plain of North America. Memoirs of the Virginia Museum of Natural History, 2: 1-159, pls. 1-26. [p. 69, pl. 5, fig. 9]
1992 Chesapecten (Chesapecten) middlesexensis ceccae Ward, 1992
L. W. Ward, 1992, plate 5.
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«Diagnosis. ─ Large, sub-orbicular valves with moderately large, ftnely ribbed auricles, averaging 16 small, finely scaled ribs.
Description. ─ Valves sub-orbicular, moderate in sizefor the genus, with an average of 16 moderate to small ribs. Ribs and interspaces with numerous small striae. Fine scales produced where concentric growth lamellae intersect the radial striae. Right valve deep for the genus, with moderately large auricles and a deep byssal notch. Byssal fasciole shallow with only two small teeth on the active area of the ctenolium of the holotype. Right valve slightly convex near umbo, becoming more noticeably convex in later growth stages. Left valve very deep with the anterior auricle slighdy notched. Interiorly, the valves are thick, with the ribs nearly obscured by the infilling of shell material except near the shell margin. Along the margins, the valves are fluted to correspond to the exterior ribbing. Pallial line is distinct but not impressed. Muscle scar very distinct and deeply impressed on the holotype, as are some of the gill retractor insertions. Resilial insertion deep and triangular. Discussion. ─ Valves of Chesapecten middlesexensis ceccae are found in the upper half of the Claremont Manor Member of the Eastover Formation and differ from C. middlesexensis middlesexensis in being smaller, finer-ribbed, deeper-valved, and thicker-shelled. The new subspecies may represent an ecophenotypic variation within the C. middlesexensis middlesexensis population, but it has distinct characteristics and does not occur with that taxon. Chesapecten m. ceccae is abundant in the upper sandy facies of the Claremont Manor Member from Upper Chippokes Creek to Lower Chippokes Creek, both in Surry County, Va. Type information. ─ Holotype: USNM 258358. Type locality: 0.8 miles below Sloop Point, just above the mouth of Sunken Meadow Creek, Surry County, Va. (USGS locality 26041). Figured specimen. ─ Holotype USNM 258358). Stratigraphic and geographic range. ─ Claremont Manor Member of the Eastover Formation (upper Miocene) in Virginia.» LAUCK W. WARD, 1992
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