Posted: Aug 31 2006
Costoanachis sertulariarum (d’Orbigny, 1839) is Costoanachis floridana (Rehder, 1939)
Currently, the shell Abbott presented as C. floridana (#2052) is accepted as C. sertulariarum. Radwin in his paper The Family Columbellidae in the Western Atlantic Part IIa. – The Pyreninae, The Veliger, Vol. 20; No.2, Oct. 1, 1977, presented the two as separate species. However, it is interesting to note that his comments reflected the growing belief that the two may well be the same. He wrote that, “C. floridana actually appears more closely related … to C. sertulariarum. It (C. floridana) may be separated from that species (C. sertulariarum) on the basis of geographic distribution (southern Florida vs. Brasil), its smaller size, more convex spire profile, slight differences in lateral radular dentition and presence of microscopic shell sculpture.” While these characters may differ between the Basilian C. sertulariarum and Rehder’s C. floridana, they are all of a nature that are easily accounted by geographic separation rather than species differentiation, as is the current view. And, indeed, a comparison of images of C. sertulariarum from South America and one from Florida do show only superficial differences (which may well be more attributable to photographic technique and specific subject variations within the population diversity).