May 7, 2019

 

The following narrative was written prior to Harry Lee's publication 2009.  I delayed including it on LTS because I was working with the Charleston Museum to obtain the topotype material collected by William Mazÿck that Harry had viewed and upon which his conclusions were based.  It has been years, and only last year was it confirmed that this material could not be found in the museum's collection*.

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Costoanachis sparsa (Reeve, 1859) and Costoanachis similis (Ravenel, 1861)

Thoughts by Marlo F. Krisberg in about 2007

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I have struggled with these two species for many years.  At first, I relied upon Abbott (1974), who presented C. sparsa and considered C. similis a dubious species.  I became conflicted when Lyons (1989b) presented his east Florida, Hutchinson Island shells as C. similis.  However, Lyons provided little description and no discussion or consideration of C. sparsa or why he chose to ignore Radwin (1978a & b).  Radwin indicated that C. sparsa was found from Lantana, Florida south.  Lantana is only about 50 miles south of Lyons’ collecting station on Hutchinson Island.  Both Reeve’s description of C. sparsa and Ravenel’s description of C. similis lacks sufficient detail and are inadequate.  Therefore, I’ve relied upon Radwin’s description of C. sparsa to identify my Florida shells.  Now, Harry Lee (2009) has published his perspective on these two shells.  He has adopted C. similis for his northeast Florida shells.  His presentation reads as follows (from personal correspondence rather than direct quote from his book):

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“Costoanachis similis (Ravenel, 1861) [Harry listed several finds from NE Florida at depths from 40-90 ft. and shells from “Scallop tailings.”] Also Brevard, St. Lucie, Palm Beach, and Miami-Dade Cos. (HL). Radwin (1978) incorrectly dismissed Ravenel’s description of Anachis similis as “unclear, ambiguous, and generally inadequate” thus indirectly designating it a nomen dubium. Ravenel compared his species to A. avara, its closest relative, cited the reduction of ribs on the antepenultimate whorl of that species, noted that “generally all of the whorls are regularly ribbed to the apex” in A. similis, and cited its smaller size and colorful markings.  To these characters we may add the wine-colored stain of the nuclear whorls in fresh specimens of A. similis. Illustrated specimen collected very near the type locality in Charleston by Edmund Ravenel’s protégé, William G. Mazÿck and deposited in the Charleston Museum (no. 43.28.9725 in partim). It is rather large: height 10.2 mm.; breadth 4.6 mm. Edmund Ravenel’s types have been lost, not to General Sherman’s torch (Radwin, 1978) but due to other, more mundane, processes (Lee, unpublished; A. Sanders, pers. comm., 1988). A. similis of A. E. Verrill and S. Smith (1873) is actually Costoanachis translirata. L. Perry and Schwengel (1955) applied the name A. similis to a Costoanachis species that is as yet unnamed, and Lyons et al. (1971) seem to have misapplied this binomen to yet another innominate taxon (see next species). Lyons (1989b) correctly identified this species for the first time in the literature since its description. C. sparsa (Reeve, 1859) is a close southern relative; it is more elongate and has a less intricate color pattern. Also, NC (DK).”

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Despite Lee’s feeling that two different species are involved, I have not seen the consistency of characters in the shells from along Florida’s east coast to persuade me that the more northern shell is a different species than the southern shell.   The following comments apply:

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1.  Lee indicates that Radwin (1978) incorrectly dismissed Ravenel’s description of A. similis.  Actually, Radwin did not “dismiss” it, but indicated that “There are 2 apparently undescribed Costoanachis species or subspecies on the Atlantic and Gulf coasts of the United States … and [one] … may be the C. similis of Ravenel.”  However, he concluded that “It is unfortunate that with no existent type, an inadequate description, and no published figure, the assignment of this name to any biological entity is impossible.”   Essentially, Radwin found no reason in the distinguishing characters enumerated by Ravenel for C. similis to separate the Florida shells he studied from Reeve’s C. sparsa.

2. Lee indicates that Ravenel compared his C. similis to A. avara, and noted those characters upon which it differed.  However, these exact characters are the same as would differentiate C. sparsa from C. avara.  Note that Ravenel failed to compare C. similis to C. sparsa.   

3. Lee then adds that “the wine-colored stain of the nuclear whorls in fresh specimens of A. similis” should be added to the characters that differentiate it from C. avara.  I have found the presence of a wine-colored stain at the tip of the protoconch to be extremely variable within the populations I have encountered and almost always present in at least some of most lots of all shells that might arguably be identified as either C. sparsa or C. similis.  I have not found this character to be consistent or reliable.  However, I must disclose that I do not have any deep-water specimens as the ones Lee reported.

4. Lee states that “Lyons (1989b) correctly identified this species [C. similis] for the first time in the literature since its description.”  This reference to Lyons is significant since it appears to be the key reference Malacolog, Mollusca, and Lee cite for validity of C. similis as a distinct species.  However, Lyons simply listed C. similis and provided no description and no discussion of why he chose to identify his shells as C. similis as opposed to C. sparsa or why he chose to ignore Radwin.  His lack of explanation is rather interesting since in his Methods section Lyons stated that “Descriptions and other pertinent information for most species are available in … Abbott (1974).”  Yet, despite that Abbott considered C. similis to be a dubious species; Lyons gave no rationale as to why he used this name rather than Abbott’s C. sparsa.   Lyons reported the results of sampling from nine locations near and off the coast of the Walton Rocks Nuclear Power Plant on Hutchinson Island, St. Lucie County, Florida.  He collected at Walton Rocks (“rocky shore fauna”) near the power plant twice in 1971 and once in 1975.  During the 1975 sampling Lyons collected two living specimens (3.7 mm and 6.4 mm).  Here’s the most interesting circumstance.  Lyons deposited his shells in the Fish and Wildlife Research Institute, St. Petersburg, FL.  I examined the single shell that remains in their collection.  The data slip with the shell identified it as C. sparsa.  But there is also a hand written slip stored in the bottle with the shell with the word “similis.”  Lyons did not publish his findings until 14 years after these shells were collected and many years after both Radwin and Abbott argued that C. similis was nomen dubium.  Yet, he limited his comments to “Costoanachis similis, found only at Walton Rocks during this study, is very common at greater depths on the East Florida Shelf” and provided no explanation as to why he used this name in contradiction with his data slip and despite Radwin’s comments and his acknowledged reliance on Abbott.

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 Lyons’ comment that C. similis “is very common at greater depths on the East Florida Shelf” was particularly              puzzling since two years prior to his publication, Reed and Mikkelsen (1987) reported an extensive survey at four stations (6 m, 27 m, 42 m and 80 m of depth) just 2.5 miles south of Walton Rocks and found no C. similis.  Collecting several times over a year’s period they reported abundant quantities (14, 2, 87 and 55, respectively) of Costoanachis sparsa and four “Costoanachis sp.” at the 42 m station.  They made no mention of C. similis.

 

I find no rationale in Lyons’ report for his use of the name C. similis or why reliance should not be placed upon Radwin’s analysis rather than Lyons’ unsupported use of C. similis. 

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I would also note that in Amelie Scheltema’s 1968 review of C. avara (Say) and A. translirata (Ravenel) she concluded that “A. similis (Ravenel) is considered to be a nomen dubium.”  She stated that “it is impossible from the description to know precisely to what species Ravenel was referring.  The description fits juvenile A. avara as well as a number of small species of Columbellidae.” 

  

        5. Lee concludes by stating that “C. sparsa (Reeve, 1859) is a close southern relative; it is more elongate and has    a less intricate color pattern.”  I cannot address these character differences since I have not examined Lee’s shells to compare with those, I’ve collected from St. Augustine south along Florida’s eastern coast.  However, I have several lots of shells that have been reviewed by Lee and others and identified as either C. sparsa or C. similis.  I have not been able to discern “more elongate” or “color pattern” as consistent characters to distinguish between these lots.  Validation of the “more elongate” character would demand comparison of a significant sample of mature specimens from divergent, but similar habitats to control for the environmental influence on size, and “color pattern” is often a quite variable character over large latitudinal and bathetic ranges, and may be strongly influenced by habitat-unique diet.  

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       6. As noted above, Radwin indicated that “There are 2 apparently undescribed Costoanachis species or subspecies on the Atlantic and Gulf coasts of the United States … and [one] … may be the C. similis of Ravenel. “  And, as also noted above, others have reported Florida shells as Costoanachis sp.   Lee may well be working with shells that are not C. sparsa, but with the poor description and absence of type material or a figure of Ravenel’s C. similis, I find no basis for assuming Lee’s shells are indeed the shell Ravenel named or that any additional characters can be ascribed to C. similis on the assumption that Lee’s shells and Ravenel’s similis are indeed the same.  It seems that at best, if not C. sparsa, Lee’s shells would better be referred to as Costoanachis sp.

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Conclusion    

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Basically, I’ve followed Radwin in considering Ravenel’s description of C. similis as inadequate to serve as a valid species name in the absence of corroboration by type material or drawing.  Although, I also consider Reeve’s description of C. sparsa to be inadequate, it is figured, and type material is available.  Therefore, since I discern no consistent morphological distinctions between the shells identified as C. sparsa or C. similis, I go with Radwin’s classification of C. similis as a nomen dubium and group all my Florida shells that reasonably fit the description under the species name Costoanachis sparsa (Reeve, 1859).  I find no basis to utilize the name Costoanachis similis for shells that are so dissimilar from C. sparsa that the name doesn’t fit, but where no other named Costoanachis does fit.  If this is the case, it would be more appropriate to use the identifier Costoanachis sp. and wait until DNA analysis and/or other research work identifies new species or confirms broader and more inclusive descriptions for shells within existing names.

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References:

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Abbott, R. Tucker. 1974 American Seashells, Second Edition, Van Nostrand Reinhold Company.

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Common and Scientific Names of Aquatic Invertibrates from the United States and Canada:  Mollusks, 2nd Ed., 1998, American Fisheries Society Special Publication 26, Bethesda, Maryland.

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Lee, Harry G.  2009  Marine Shells of Northeast Florida.  Jacksonville Shell Club, Jacksonville, Florida.

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Lyons, William G.  November 1989.  Nearshore Marine Ecology at Hutchinson Island, Florida: 1971-1974, XI. Mollusks.  Florida Marine Research Institute, No. 47.

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Radwin, George E.  April 1978a. The Family Columbellidae in the Western Atlantic Part IIa. – The Pyreninae. The Veliger, 20(2): 119-133.

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Radwin, George E. October 1978b. The Family Columbellidae in the Western Atlantic Part IIb. – The Pyreninae (Continued). The Veliger, 20(4): 328-344.

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Reed, J. K. and P. M. Mikkelsen. 1987. The Molluscan Community Associated With The Scleractinian Coral Oculina varicosa. Bull. Mar. Sci. 40(1): 99-131.

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Rosenberg, G. 2005. Malacolog 4.1.0: A Database of Western Atlantic Marine Mollusca.

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Scheltema, A.E., 1968.  Redescriptions of Anachis avara (Say) and Anachis translirata (Ravenel) with notes on some related species (Prosobranchia, Columbellidae). Breviora 304: 1-19. Dec. 31. [plate 1, fig. 12; as "Anachis sp." Aransas Bay, TX].