Glycymeris americana abberans Nicol, 1952

Pliocene, Piacenzian Age, Duplin Formation

Collection Location: Eagle Point Pit, Stokes Sand and Gravel, Darlington County, South Carolina

Dimensions: Length - 65 mm, Height - 49 mm

Identification - Pleiocene Fossils of South-Carolina (1855-1856) (1974 PRI Reprint): Page 51, Plate 17 (Pectunculus transversus)
Tulane Studies in Geology and Paleontology Volume 27 (1995): Page 69, Plate 5

#2261 Limopsacea / Glycymerididae

I sent an email to Dr. Lyle D. Campbell to ask why Glycymeris americana abberans was not included on his Duplin Fm species list, and received the following very informative reply on 1/11/2005:

Glycymeris americana abberans Nicol has previously only been found in deposits which I place in the older Raysor Marl and Goose Creek Limestone formations.  It’s presence in the Eagle Point fauna is one of several reasons I was hesitant to use a Duplin age for the deposit.  However, I am now convinced that Eagle Point is Duplin (the difference is between 3.2 million year old Duplin, and 3.8 million Raysor).  There are a few species like that which I am adding to the Duplin list as the work continues.  Joe Carter interpreted Glycymeris americana abberans as the extreme mutation gradation of the more common form, Glycymeris americana quinquerugata which has one to six folds at the hinge line.  I agree.

Specimen found on 1/20/06:

This is the largest specimen I found that has the characteristics of abberans (it also has the ripples of quinquerugata), 91 mm in height and 100 mm in width.  The wrinkles are very apparent on the first 2/3rds of the shell, but then become obsolete.