Conus (Contraconus)  mitchellorum (Petuch, 1994)

Description ⁽¹⁾: Shell of average size for genus, very elongated and cylind-rical, straight-sided, with modera-tely-low, domed spire; shoulder somewhat rounded, edged with low, wide carina; spire whorls distinctly convex, inflated, with 2 large cords; early whorls strongly coronated; body whorl heavily-sculptured with very numerous, fine spiral cords; spiral cords on anterior one-third largest; aperture narrow.

Holotype: UF66445, Length 63 mm.

Type Locality: Griffin Pit Unit, Griffin Brothers pit, Holey Land area, southwestern Palm Beach County.

Remarks: Contraconus mitchellorum is most similar to, and is the direct descendant of, the older, C. tryoni stratigraphically-lower (Heilprin, 1886) (Plate 96, Figures A, B) from the Cloosahatchee Fauna. The new species differs in being a smaller, more slender and cylind-rical shell with a domed spire and distinctly convex spire whorls, in having stronger spiral sculpture on the body whorl, and in having more strongly-coronated early whorls on the spire. Along with C. heilprini, C. living left-handed cone matcheliorum was probably the last-living left-handed cone.

Etypmology: Named for Mr. and Mrs. Mark (and Lisa) Mitchell of Martin Downs, Florida.

This species “is most similar to, and is the direct descendant of, the older, stratigraphically-lower C.tryoni” (Heilprin, 1886) ^(1,2).

Bibliografia Consultata

• (1) - Petuch, E. J., 1994. Atlas of Florida Fossil Shells (Pliocene and Pliestocene Marine Gastropods).

• (2) - Hendricks (2008) “The Genus Conus (Mollusca: Neogastropoda) in the Plio-Pleistocene of the Southeastern United States”