Posted: Sep 5 2006

Granulina hadria vs ovuliformis, No ovuliformis in Florida

Granulina hadria (Dall, 1889)
Granulina ovuliformis (d’Orbigny, 1841)

Granulina hadria in Florida has been confused with Granulina ovuliformis for a long time. This confusion was not clarified until January 1988 when Gary A. Coovert addressed the matter in Marginellidae of Florida, Part I: Granulina hadria, Marginella Marginalia, Vol. 4, No. 1, a publication of the Dayton Museum of Natural History. He recounts that Dall initially described G. hadria based upon material from “Mud flats at Cedar Key, Florida, Hemphill,” but that Dall did not “figure” the shell nor did he when he again discussed hadria in a 1927 publication. Coovert’s review of the literature revealed that many authors either confused G. hadria with Granulina lachrimula Gould, 1862 or synonymized it with G. ovuliformis. Among these was Abbott in his extremely influential 1974 edition of American Seashells. Unfortunately, while errors in synonymity were common based upon the state of knowledge at the time, such errors become extremely difficult to dispel when the species figured is of the one assigned synonymity and not the instant species being described. This is the case with Abbott. The picture included for G. ovuliformis is actually of G. hadria. Since the two were considered synonymous at the time, this is not surprising. This same error is also reflected in Rehder’s Audubon Field Guide to North American Seashells. G. Hadria was correctly identified and figured in Kaicher card #95, 1973 and most recently in Bob Lipe’s Marginellas and Ross Gundersen’s The Seashells of Sanibel and Captiva Islands.

Coovert studied 35 lots of specimens (33 from Volusia County to the Florida Keys and north along the Florida west coast to Cedar Key, one from St. Joseph Bay, Texas, and one from west of Moroas Point, Mexico). He also examined the only museum lot he could find of specimens with the same data as cited by Dall. He concluded that G. hadria was indeed a separate species from G. ovuliformis and that all records of G. ovuliformis from Florida were mistaken due to the synonymity error and resultant erroneous figuring of G. hadria as G. ovuliformis in so many publications prior to Bob Lipe’s Marginellas. Coovert surmised that “G. hadria appears to be confined to shallow water on the mainland and is not known from any Caribbean island localities.” He believes G. ovuliformis is not found in Florida, but is a Caribbean species.

I have collected extensively over the entire Florida range Coovert described for G. hadria and have only found specimens that match the description for G. hadria. When in doubt I have had specimens examined by Bob Lipe and Harry Lee, and they have consistently confirmed them as G. hadria. I have never found a specimen that conforms to the description for G. ovuliformis and concur with Coovert’s conclusion that G. ovuliformis does not occur in the shallow waters of Florida. I asked Bob Lipe, author of Marginellas and other shell books, to review this discussion. Bob replied, "I have read the article and I agree with you on the hadria."

Following are the best images of G. ovuliformis and G. hadria I could find on the net that conforms to their descriptions. Below the images is a tabulation of some of the key differences between the two as pointed out by Coovert.

G. ovuliformis, North                G. ovuliformis (Original drawing)            G. hadria NE Florida                                                                                                Carolina (2.2 mm)                                                                                         (1.9 mm)  

Photo by David Kirsh                                                                                   

Character                               Hadria                                                                         Ovuliformis
Aperture                 distinctly wider anteriorly                         narrow & uniform throughout, distinctly cresent shaped
Shape                      angulate at shoulder                                 distinctly tear-shaped, evenly rounded at shoulder
Lip                            thickened, fattened at shoulder              thickened, uniform over most of its length
Lip                            significantly arched above apex              not arched at apex, smoothly rounded like teardrop
In side of lip            tiny, indistinct denticules inside              strong dentricules entire length inside of lip

                                  anterior end

                                                                                                 

 

                                                                                                 Coovert described other differences, but they are not visible                                                                                                       on the above images images. G. Hadria’s overall shape                                                                                                                 (especially the distinctive angulate posterior half and arched                                                                                                       posterior lip), thickened lip at shoulder, and lack of denticules                                                                                                     the entire length of the inside of the outer lip are enough to

                                                                                                 distinguish the two.

                                                                                                               Photo by Marlo Krisberg

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