Posted: Aug 27 2006
Sphenia fragilis (H. & A. Adams, 1854)
Syn: Sphenia antillensis
Note: As of 7/1/26 WoRMS accepts S. fragilis. The taxonomy of this small clam has been historically complex. Researchers point out that Sphenia dubia (H. C. Lea, 1843) may be synonymous with other species, including Sphenia fragilis. Sphenia dubia represents the earlier described name for these forms in the western Atlantic and is the name for this taxon used by Jaxshells. This presentation follows Coan (1999) and uses S. fragilis, the taxon for which Coan examined specimens from both sides of Florida.
Posted: Aug 12 2009, by Harry Lee:
I believe there are several synonyms for this species. and Sphenia dubia (H. C. Lea, 1843) appears to be the earliest. This, like other nestlers, is quite variable conchologically. Recent shells we attribute to this species cannot be separated from those of this Miocene fossil. S. attenuata Dall, 1898, and Sphenia antillensis Dall and Simpson, 1901 are apparent synonyms from the Pliocene and Recent faunas respectively. Coan (1998) states that the E. Pacific S. fragilis Carpenter, 1857 is synonymous with our (Recent) taxon, which he distinguishes from the above two fossil taxa (Coan, 1999). Observed in abundance attached to wave-dashed intertidal rocks in Flagler Co. (HL!); also St. Lucie (Lyons, 1989b), Pinellas Cos.; NC, GA, Brazoria Co., TX (all in my collection). Enlarges known range for the genus vs. Abbott (1974): “South Padre Is. ...Brazil.”
Coan, E.V., 1998. The eastern Pacific species of Sphenia (Bivalvia: Myidae). Abstracts of the World Congress of Malacology, Washington, DC 25-30 July 1998. Chicago, 1998.
Coan. 1999. The eastern Pacific species of Sphenia (Bivalvia: Myidae). The Nautilus 113(4), pg. 103.