Registry of World Record Size Shells
The Registry of World Record Size Shells is a conchological work listing the largest verified shell specimens of various marine molluscan taxa.
A successor to the Lost Operculum Club List of Champions and World Size Records, it has been published on a semi-regular basis since 1997, changing ownership and publisher a number of times. Originally planned for release every two years, new editions are now published annually. Since 2008 the entire registry has been available online in the form of a searchable database. The registry is continuously expanded and now contains more than 52,000 listings and 93,000 supporting images.
Background
World record size shells—commonly indicated by the acronym 'WRS'—are of broad interest to shell collectors and conchologists. In particular, those of species in the most popular families are often much sought after, and can thus command high prices. Collections of such shells are exhibited at a number of specialist museums, notably the Bailey-Matthews National Shell Museum, which has a dedicated "World Record Size Shells" exhibit. Since volume scales with the cube of length, apparently small differences in stated size—in terms of [|greatest measurable dimension], usually given in mm—can correspond to dramatic differences in the visual appearance of size, something that is often underappreciated by novice collectors.Maximum and minimum sizes are also of interest to malacologists, and may be useful in delimiting closely related species. As an extensive compilation of maximum shell sizes, the registry has found use as a data source for scientific studies.
Overview
Scope
Throughout its history the registry has covered four classes of molluscs: bivalves, cephalopods, gastropods, and scaphopods. Chitons have been excluded because their shells are formed from eight articulated plates and therefore the size of a fixed specimen depends in large part on the preservation method used.Smallest adult sizes have been listed beginning with a few specimens of Cypraeidae and Strombidae in the first edition, and they now additionally encompass a third family: Marginellidae. Separate records for sinistral shells and obviously rostrate cowries are also included. Terrestrial and freshwater species, as well as fossils, are not covered by the registry.
Content
The bulk of the publication—which apart from the cover is unillustrated—comprises a list of taxa and their corresponding world record sizes. Each specimen in the registry is listed alphabetically under its recognised scientific name. This is usually a binomen, but subspecies, varieties and forms are also included. In addition to the shell size, each specimen is listed with its location, owner or repository, and the year it was collected, acquired, or registered.Each print edition has an appendix with an alphabetical listing of entry totals for all private collectors and repositories having ownership of specimens in the registry. In the first edition, the most individual entries belonged to Victor Dan, with 369, closely followed by co-author Don Pisor on 325. This title subsequently went to Tennessee physician and world-renowned collector Pete Stimpson, who for a time held over 2,000 entries in the registry, and whose WRS specimens have been exhibited at museums including the McClung Museum of Natural History and Culture. As of the fifth print edition from 2008, the distinction of having the most WRS entries belonged to Havelet Marine, with 3,244 specimens, compared to Stimpson's 1,963.
Measurements
The registry's rules specify that specimens "should be measured with vernier type calipers and should reflect the greatest measurable dimension of the shell in any direction including any processes of hard shell material produced by the animal and not including attachments, barnacles, coralline algae, or any other encrusting organisms. Long, hair-like periostracum is not to be included." This "greatest measurable dimension" can be at odds with the standard scientific definition of shell length.Shell sizes are given in millimetres and recorded to the nearest, as is standard in conchology. To account for human error and environmental effects, new records are only accepted if they exceed the standing record by at least. This 0.3 mm margin also applies to smallest adult sizes exceeding.
Entries for specimens that tie the standing record can also be submitted. Though not included in the registry, they are kept on file for future use in the event that the current record holder is shown to be misidentified or smaller than originally claimed.
Superlative species
The three largest species in the registry are the bivalves Kuphus polythalamia, Tridacna gigas and Pinna nobilis, with maximum recorded shell sizes of, and, respectively. The fourth largest species, and the largest of all gastropods, is Syrinx aruanus with a maximum length of. There are literature records of an even larger S. aruanus specimen measuring, but these are erroneous and actually refer to the same specimen, which is on display at the Houston Museum of Natural Science. The extinct gastropod Campanile giganteum reached a similar or slightly greater size, while the largest extinct bivalves and especially the largest extinct shelled cephalopods were much larger still. However, only external shells of extant species are covered by the registry. The largest listed cephalopod "shell" is that of Argonauta argo, at, though this is technically an eggcase rather than a true molluscan shell.Adult external shells down to are known, as are fully-grown larval shells as small as . But the smallest end-stage "shells" of all, broadly defined, are likely to be vestigial internal gastropod shells, which could be almost arbitrarily small, perhaps consisting of only a few molecules.
Size verification
For inclusion in the registry, size records must be verified either by a recognised second party or through photographic evidence. Entries may be submitted by regular mail or e-mail; a submission form is included at the back of each print edition. These requirements mean that in some cases older or even current malacological literature may include size records which exceed those found in the registry.In the early years of the registry, shells were sometimes officially measured for world record size status at Conchologists of America conventions, as in 1999 when the measurements were carried out by senior author Kim Hutsell.
History
Progenitors
''Lost Operculum Club List of Champions'' (1950–1987)
Beginning in the mid–20th century, several attempts were made to produce a list of the largest shell specimens. Perhaps the earliest of these was what would eventually become known as the Lost Operculum Club List of Champions, initiated in 1950 by John Q. Burch and Dick Mayhew of the Los Angeles–based Conchological Club of Southern California. Though started as something of a "joke", it soon evolved into a serious endeavour. Its first list, featuring 20 entries, appeared in the January 1950 issue of the Minutes of the Conchological Club of Southern California, opening as follows:Have you ever noticed that when you go to the shell club meeting with a large specimen to show, someone always comes up claiming a larger one at home? So to settle some of the arguments as to who has the largest shell, we are starting a competition. No slogans to write, no box tops to send, just measurements.
In other words we are after the Paul Bunyon of each species represented on the West Coast from Alaska to Panama. To interest everybody, we are including land, fresh water and fossil shells, as well as the marine varieties.
Judging from some of the stories we hear, the measurememnts are made on the scales used by fishermen telling about the one that got away, or on a scale with more than 25.4 mm to the inch.
From the outset, the competition was said to have "created a great deal of interest"; entries for 54 species had already been submitted by the printing of the second list in February 1950. Then known simply as "The Society of the Lost Operculum", a new compilation of records appeared every month until the June 1950 issue, during which time some 150 shells belonging to nearly 125 species were registered. However, with the exception of a small number of specimens submitted by Walter J. Eyerdam for the January 1951 issue, no further updates were published and the project soon became inactive.
During a meeting of the CCSC on 6 January 1959, it was decided that the list would be revived, following a query from then-President Donald Shasky. Shasky volunteered to handle records pertaining to specimens collected south of Cedros Island, Baja California; it was only at the following month's meeting that a volunteer—George Kanakoff —was found for the northern taxa. At subsequent meetings, shells were routinely entered for competition, measured, and displayed for club members; mimeographed copies of the list were also occasionally distributed, showing strong demand. A compilation of all "southern" specimens printed during the list's original run in 1950 appeared—with updated nomenclature—in the March 1959 issue; a complete and up-to-date list was published in the July–August 1959 issue, running to 7 pages. The revival was short-lived, however, as the Minutes soon ceased publication, the 200th and final issue appearing in June 1960.
Between 1966 and 1987, the project was again resurrected, this time being overseen by Bertram C. Draper, Museum Associate at the Natural History Museum of Los Angeles County, a member of the CCSC since 1961, and a specialist in minute shells; it bore at least [|five standalone print publications] during this time. Overall, the Lost Operculum Club List of Champions was limited in scope compared to later efforts, ultimately encompassing only marine species of the Eastern Pacific, from Alaska to Chile. Unlike later publications it notably included a small number of fossil specimens.