Posted: Feb 11 2007
Terebra concava (Say, 1827) and Terebra vinosa Dall, 1889
Are they the same?
Abbott placed T. vinosa as a synonym for T. concava Say, 1827. However, many treat the two as separate species, including Common and Scientific Names of Aquatic Invertibrates from the United States and Canada: Mollusks, 2nd Ed., 1998, and Sally D. Kaicher, as illustrated on her card 2187. Harry Lee, among the foremost experts on Florida mollusks, noted that "Sally's specimen was not indicated as a museum shell or a type." He further commented that "I'm not certain that the two species are different, but my position nowadays is to separate them." I have been uncertain on this issue since I've never collected any specimens in Florida that clearly fit Abbott's description of T. concava. All mine more closely fit T. vinosa.
According to Abbott, T. concava displays
a large, heavily nodulated or beaded,
swollen spiral cord just below the suture.
Above the suture there is a spiral series
of 20 very small beads per whorl and the
concave middle of the whorl bears about
five microscopic, incised lines. These latter
two characters are apparently absent in
T. vinosa. Rather, the whorls of T. vinosa
below the swollen, subsutural spiral cord
are characterized by axial ribs and spiral
cords that present a somewhat reticulated
appearance with the spiral sculpture some
times predominate. Adjacent are a T. concava
from Cumberland Island, GA, and a
T. vinosa from Cedar Key, FL, for direct
Adjacent is a clearly T. concava from Cumberland Island,
GA. It displays exactly the charaters described by
Abbott. Also shown is a specimen from Tarpon Springs
that displays characters of both T. concava and
T. vinosa. It has the nodulated subsutural cord of both,
the beads above the suture of T. concava and between
the two the reticulated sculpture of T. vinosa instead of
the fine spiral lines of T. concava. It is a specimen like
this one that makes you wonder if T. concava is a
T. vinosa with greatly diminished axial cords (diminished
to the extreme of none) in the middle of the whorl and
the spiral cords also diminished to nonexistent with only
fine lines remaining where grooves would have been
Adjacent is a direct comparison of a T. vinosa (East Beach,
Mullet Key, Pinellas County. 17.5 mm) with Sally's card 2187.
I posted this material on Conch-L and indicated "Your comments
would be very welcome.
The following comments were provided via Conch-L or private
Peggy Williams, author of Shallow Water Turridae of Florida
and the Caribbean, commented,
" I, too separate vinosa, on Bill Lyons' advice. They are very different in appearance and can both be found on the same sand bar in Sarasota Bay."
Linda Brunner, collector, reported,
"Here in the northern Florida panhandle we have T. vinosa, T. protextra, and T. concava. T. protexta is usually a dark purplish brown and T. concava is pale. T. vinosa is dark and fades to a grayish color. T. protexta and T. concava are easy to separate. We use Sally's cards as well as Abbott and several other references. We find these to be distinct species and have worked with Harry and Peggy."
G. Thomas Watters, PhD, Department of Evolution, Ecology and Organismal Biology The Ohio State University Museum of Biological Diversity, in comparing T. vinosa with T. protexta noted,
"The two seem different to me. In vinosa the spiral sculpture seems to predominate, but opposite in protexta.'
2/11/07: When I first posted this topic I had no representations
of T. concava from Florida. Well, Linda Brunner of Panama City on
Florida's panhandle has generously provided me samples of
several species of Terebras from the panhandle, including the
adjacent two (they were so pretty I had to do two) T. concava she
collected on an exposed sand bar, Palm Point, St. Joe Bay, Gulf
County. Many thanks, Linda!
The image with dorsal view is a 15.5 mm specimen, and the image
with ventral view is a 20 mm specimen. Photos by Marlo Krisberg.
And, for comparison adjacent is a T. vinosa Linda collected in a grassy, sandy area at low
tide, St. Andrews Sound, Panama City, Bay County. This is another specimen that makes
you wonder if T. concava and T. vinosa are extremes of the same species. Note that
above the suture there are a spiral series of small beads as in T. concava and the
absence of the pronounced reticulated sculpture of T. vinosa.
Specimen is 17.8 mm. Photo by Marlo Krisberg.
In February 2009 Jo O'Keefe (The O'Keffe Family Website) sent me some unidentified shells. Among them were the following T. concava.
2/24/07 David Kirsh:
Worthwhile discussion. My one T. vinosa is from Redington Shores, Pinellas County, FL.
It's interesting to me that in North Carolina, Terebra concava can be white, tan or pale lilac. Have others found such coloration in states to the south?