Chesapecten jeffersonius
NameChesapecten jeffersonius
Scientific NameChesapecten jeffersonius
Common NameJefferson's Scallop
FamilyPectinidae
GenusChesapecten
Speciesjeffersonius
Geographic DistributionFossils are primarily found in the Miocene and Pliocene deposits of the Atlantic Coastal Plain of North America, particularly abundant in Virginia, Maryland, and North Carolina, especially around the Chesapeake Bay region.
Average Size (mm)Commonly ranges from 100 to 150 mm in height, with some specimens exceeding 200 mm. The shells in the image appear to be within this range, with the largest around 150-200 mm.
Identifying FeaturesKey identifying features include its large, fan-shaped shell, the prominent and broad radial ribs (typically 10-18, often 12-15), the convex right valve, and well-developed auricles. The number and character of the ribs are diagnostic for the species within the *Chesapecten* genus. The fossil nature is evident from the preserved texture and color.
Dietfilter-feeder
Raritycommon
Author CitationConrad, 1833
Description
The image displays three fossilized shells of *Chesapecten jeffersonius*, a large extinct scallop. These bivalve shells are distinctly fan-shaped, characterized by prominent, broad, radiating ribs that extend from the umbo to the shell margin. The specimens appear to be the right (upper) valves, which are typically more convex. The largest shell in the center exhibits several small borings, indicative of its fossil nature and past marine life. The shells vary in size, suggesting different growth stages. Their coloration is a muted grey-beige, typical of fossilized remains, with visible growth lines and rib patterns.
