Posted: Dec 19 2013
Nassarius consensus (Ravenel, 1861), Striate Nassa
I’ve been collecting in Florida for a long, long time and for all that time there has been a group of white (most of the time) Nassarius that created a bit of consternation. Note that Lee (2013) argues that the genus level taxon Uzita H. and A. Adams, 1853 is the proper placement for the ubiquitous and speciose group we’re accustomed to as Nassarius Duméril, 1805. In this presentation I am retaining the use of the more familiar “Nassarius.”
Through the ‘80s and ‘90s Abbott’s (1974) treatment of North American Nassarius dominated. Abbott presented “Nassarius albus (Say, 1826) Variable Nassa” and described it as “this unusually variable species.” He suggested “N. consensus (Ravenel, 1861) is possibly only a form” and specified as synonyms “ambiguus Pulteney, 1799, non Solander, 1766; antillarum Orbigny, 1842;” and others. Abbott did not mention N. paucicostatus (Marrat, 1877), which is also confused as part of this group. Rehder (1981) presented only “Nassarius albus” and made no mention of the “synonymous” names listed by Abbott. Subsequent to Abbott and Rehder workers have given species status to these various taxa, but only Redfern (2001) has presented extensive descriptions, including distinguishing characters, for three of them; namely, N. albus, N. antillarum, and N. paucicostatus. Kaicher (1982) and Lee (1998 and 2009) have also provided tidbits that are helpful in ascertaining observational consistency upon which to draw conclusions.
Because so many workers up to Rehder considered N. albus, the earliest named Western Atlantic Nassarius of this group, to be an “unusually variable species,” and did not distinguish it from the others, we cannot rely upon their descriptions, since they may be inclusive of characters we now would identify with other species. This circumstance has given rise to many presentations of specimens as N. albus that subsequently were considered other (or potentially other) similar taxa, and referred to as N. albus of authors Non Say, meaning labeled as N. albus by workers, but not the same as Say’s N. albus. These could very well have been forms of N. consensus.
The problem is that the early descriptions of many of these taxa were insufficient and lacked comparative distinctions between similar taxa. Good figures were lacking and type material was not preserved or has been lost. It was just too early in the development of scientific methods, too little comprehensive material was available and there was a lack of scientific self-discipline. Many have tried to reconcile these taxa, but these deficiencies have made it impossible for there to be accuracy and, in fact, the many interpretations have just added to the confusion. Until a comprehensive DNA-based analysis is performed, distinct species identified and linked to known type material, neotypes designated for existing species names, and new species identified, if applicable, we will not be able to identify many of Florida’s “white” Nassarius with confidence.
With this presentation (and those to follow), I am attempting to extract from the original descriptions those few descriptive characters that appear to be unique to each species, also utilize those few works that presented a comparative analysis pointing out unique characters, link them to a consistent protoconch, and separate all my little white Florida Nassarius accordingly. I intend to present N. consensus, N. paucicostatus, N. antillarum, N. albus, and those that do not fit and of these. My preliminary conclusion is that all the little white Florida Nassarius are variations of N. consensus, N. paucicostatus, N. albus or are unnamed, and that does not occur in Florida.
Here is a list of the confused taxa in this group:
N. albus (Say, 1826)
No type or figure. From the context of Say’s presentation, it appears his description is based upon a single shell from the “Southern Coast of East Florida,” which he felt was “in no respect different from specimens brought from the West India Islands,” with which he was apparently familiar.
N. consensus (Ravenel, 1861)
No type or figure
N. antillarum (d’Orbigny, 1847)
d’Orbigny’s description is based upon a group of syntypes. However, Kaicher found that only two specimens in the group truly matched d’Orbigny’s description. One of these two is illustrated in Kaicher card 3232. When De Jong & Coomans (1988) examined the nine syntypes present in BMNH they also found that they all did not match d’Orbigny’s description and, as a result, designated d’Orbigny’s figure as the lectotype
N. ambiguus (Pulteney, 1799)
No type or figure. The shell described was of Mediterranean fauna. (Doubtful that this name should be assigned to a western Atlantic shell.) Shells from western Atlantic assigned this name are either variations of one of the others or an unnamed species. Kaicher (1982) and more recently Lee (personal correspondence) have pointed out that "Buccinum ambiguum Pulteney, 1799 is unavailable under the provisions of the Code since it is a primary junior homonym of B. ambiguum Solander ]in Brander, 1766 (28; fig. 56), an available name applied to a fossil from Hampshire, U.K."
N. paucicostatus (Marrat, 1877)
No known authentic illustrations.
N. albus auct. non Say (Kaicher card 3234) and N. albus of authors non Say
These are the many specimens presented as N. albus but which cannot accurately be assigned this name and may be any of the above or as yet are innominate.
These are the many specimens presented as N. albus, but which cannot accurately be assigned this name and may be any of the above or are as yet innominate.
While the above taxa are confused, Ravenel’s description of N. consensus, despite being based upon a single specimen, has sufficient information that it can be
distinguished from the others with a high degree of
confidence. Here is Ravenel’s description.
The two distinguishing characters mentioned by
Ravenel, taken together, which distinguish
N. consensus are:
1. Most importantly, the spiral sculpture is of
“numerous revolving striae.” Striae are very narrowly
incised shallow grooves. Striae appear as incisions on
the surface as opposed to grooves between cords.
The others in this group are characterized as having
2. While color saturation is variable and specimens
are often creamy-white, the vast majority display
“delicate lines more or less grouped, of yellowish
brown” with “a narrow deep brown band” just above the deep groove around the base. The color of the band, which may be quite wide, corresponds to the color of the rest of the shell, but has a deeper saturation.
Once we assign specimens to this taxa based upon the above two characters, we find that the protoconch of N. consensus consists of 3¼ smooth, white to cream colored whorls. This is consistent with the distinctions made by Lee (1998 and 2009) in describing the protoconch of N. consensus as “polyspiral” “of 3.4 … whorls.”
As illustrated in the following gallery, others have reported and illustrated various shapes of N. consensus all consistent with the variations occurring over its range.
Abbott, R. Tucker. 1974 American Seashells, Second Edition, Van Nostrand Reinhold Company.
Brander, G., 1766. Fossilia Hantoniensia collecta, et in Musæo Britannico deposita. London. i-vi + 1-43, plates 1-9.
De Jong, K. M. and Coomans, H. E. 1988. Marine Gastropods from Curacao, Aruba and Bonaire. Institute of Taxonomic Zoology, University of Amsterdam.
Kaicher, S. 1982. Kaicher's Card Catalogue of World-Wide Shells. Pack #31 - Nassariidae Part 1. Privately printed, St. Petersburg FL, 108 cards.
Lee, Harry G. December 1998. Western Atlantic Nassariidae. American Conchologist 26 (4): 18-20.
Lee, H.G. July 2013. Nassa update: Application of the genus-level taxon Uzita H. and A. Adams , 1853 to a large and ubiquitous group of nassariids (Gastropoda: Buccinoidea). Shell-O-Gram 54(4): 6-7.
Redfern, Colin. 2001. Bahamian Seashells: A Thousand Species from Abaco, Bahamas. Bahamianseashells.com, Inc: Boca Raton, Florida.
Rehder, Harald A. 1981. The Audubon Society Field Guide to North American Seashells. Alfred A. Knopf, New York.
This presentation is very long and has 3 galleries. Be sure to scroll down to view Galleries 2 and 3.