This catalog lists all published species-group and genus-group names found in the literature, whether available or unavailable according to the International Code of Zoological Nomenclature (ICZN, 1985), that have been applied to the nonmarine gastropod fauna of the Samoan islands. It includes indigenous (including endemic) and artificially introduced terrestrial, freshwater, and brackish-water taxa. The supralittoral Ellobiidae, as pulmonates, are included; but the Siphonariidae, although pulmonates, are intertidal and subtidal, and are therefore excluded as being marine. Extralimital synonyms and unavailable names, i.e., names that have never been applied to Samoan material, are excluded, except in instances where an extralimital name is recognized as a senior synonym of a name previously applied to Samoan material.

The sequence of families follows Vaught (1989), for ease of comparability with the Hawaiian catalog (Cowie et al., 1995), without implying any phylogenetic opinion. Subfamilies (if recognized) appear in alphabetical order within families, as do genera within families/subfamilies, and subgenera within genera. No other supraspecific taxa are used. Assignment of subfamilies, genera, and subgenera within families follows appropriate revisionary works, as indicated under each group. Genus-group synonyms are listed chronologically under the genus-group heading. These synonymies are not exhaustive; extralimital names (i.e., names that as far as could be determined have not been used in combination with Samoan species-group names) are excluded. Misidentifications and incorrect spellings are listed only if confusion might be caused by their omission. All species-group names (valid and invalid, available and unavailable) are listed alphabetically within genera/subgenera. Treatment of species-group names follows the most recent authoritative revisions. Names proposed as "forms", "varieties", etc. and neither already synonymized nor raised to subspecific status are simply listed as infraspecific. Taxa of uncertain placement are listed at the end of the most appropriate taxon.

Strict application of the rules of nomenclature has necessitated the introduction of a very small number of new synonymies, indicated in boldface by "N. syn.". However, no other revisionary work has been attempted and no new taxonomic decisions have been made. For instance, nude names that have never been validated have not been placed in the synonymy of available names, as this would involve taxonomic decisions best left to the appropriate taxonomic specialists and inappropriate herein. This work is simply a nomenclatural catalog.

Family-group and genus-group headings are centered in boldface upper case type. Valid genus-group names are listed flush left in boldface upper case type. Valid, available species-group names are listed flush left in boldface, infraspecific names preceded by a "+". Synonyms, both genus- and species-group, are listed in italics flush left, upper case for genus-group names, lower case for species-group names. In the species-group, junior homonyms for which no synonyms are available as replacement names and for which new names are not provided here are listed in boldface italics flush left. Nomenclaturally unavailable names are listed in plain Roman type, flush left, upper case for genus-group names, lower case for species-group names.

The citation for the original proposal of a genus-group name follows the name. The reference consists of author(s), date of publication and page number (and plate/figure number if these formed part of the original description). Bibliographic and nomenclatural information (citation, synonyms, type species, etc., see below) provided for the nominate subgenus is not repeated if already given for the genus. For species-group names, on the line following the name and indented, the name is given in its original generic combination (including subgenus if in the original description, and using the original spelling, even if incorrect) and with its original status indicated (e.g., subspecies, "var.", as necessary). The name is followed by its author(s), date of publication, page number, and plate/figure number(s). When an author published the same name as new for the same taxon in more than one place, the later citation is given in square brackets following the first citation.

The author/date citation acts as a reference to the work as listed in the Bibliography. If an author published more than one work in the same year, a suffix (a, b, c, etc.), indicating chronological order of publication, is attached to the date in both the catalog text and the Bibliography. Authors’ names containing the terms "de", "le", "van", "von" are cited and alphabetized in the Bibliography by the main name, e.g., "Nerita recluziana Guillou, 1841" in the main body of the catalog, and "Guillou, E. Le. 1841" in the Bibliography.

The date given for a work cited in the catalog is the date of publication. If the date printed in the original work is incorrect, the correct date is placed in square brackets in the Bibliography (Recommendation 22A(5) of the Code), but the brackets are omitted in the text.

The page number cited is that on which the name first appeared. In some instances, the name first appeared in a list or key, with the actual description beginning on a subsequent page. The page numbers of both the list, key, etc., and of the description are cited.

If the current status of a species-group name differs from that in the original description, this is indicated, with appropriate references, in a Remarks section below the standard entry for the species.

If a taxon is mentioned but is not Samoan, e.g., a non-Samoan type species of a genus-group name, the name, author, and date are followed by "not Samoan" in square brackets. The reference is not listed in the Bibliography.

For nomenclaturally available genus-group names, the type species and its method of fixation (following Code Art. 68 and 69) are given following the literature citation. The type species is given in its original combination with correct authorship, date, and spelling. If its citation in fixation of the type species differs from this in any respect, how it differs is indicated in parentheses. The senior synonym, if any, of the type species is given in square brackets.

Homonymy of species-group names is indicated in the Remarks section under the name. In most cases, the junior homonym has already been synonymized with another earlier name, or a replacement name has already been provided from synonymy. In 3 cases (elongata Mousson, 1869 and laevis Baird, 1873, both Assimineidae; montana Cooke & Crampton, 1930, Partulidae) in which a replacement name appears necessary but there are no synonyms, no replacement name is here provided, pending further research.

Unavailable names are listed with full citation and a statement of why the name is unavailable, e.g., "Nom. nud.", "Incorrect original spelling of . . .", etc. No other information is provided except for explanatory details in the Remarks section, if necessary. Obviously incorrect subsequent spellings are not listed but may be mentioned in annotations, for clarity.

Misidentifications are excluded unless inclusion is deemed necessary for clarity (Tornatellinops, Trochonanina). Names of misidentified taxa are italicized but separated from authorship by a colon, e.g., "TROCHONANINA: authors, not Mousson, 1869, misidentification".

Synonyms and unavailable names are cited in their original orthography. Valid names have been changed, if necessary, so that the ending agrees in gender with the genus with which the name is combined herein (Code Art. 31), but only if the species-group name can be construed definitively as adjectival in the original proposal of the name.

Under each family heading, explanatory and other useful information is given. If deemed necessary or useful, such information is also given for genus-group taxa, immediately under the genus-group synonymy. Annotations other than those indicated in the above paragraphs are placed in square brackets immediately following the item to be clarified or, in the case of species-group names if the annotations are more extensive, placed in a Remarks section following the standard entry for the species.

The type locality, quoted exactly as in the original publication, is given for each available species-group name immediately following the author and citation. Any additional or explanatory information regarding the type locality is placed in square brackets following the type locality. If no locality was given, this is simply stated, in square brackets. Location and catalog numbers of type material, if known, are given, following the type locality information. An exhaustive search for type material has not been made; the information provided is largely derived from the literature. This work is not intended as a comprehensive type catalog. Johnson (1964, 1994) provided information on type material for many of the taxa he listed, but ascertaining the true status of these specimens, in many cases probably as lectotypes and paralectotypes, is beyond the scope of this catalog.

Each valid name is followed, on the same line, by abbreviations (see below) in parentheses indicating the island(s) from which the taxon is known. If there is some question about the taxon’s presence on a particular island, the abbreviation for that island is preceded by a "?". If it is not possible to specify particular islands, the catalog simply says "Samoa". If there is a question whether it occurs in Samoa at all, this is indicated by "?Samoan" or "?not Samoan". In some cases, the only locality information available is "Manua" or "Manua Islands". In this case, the catalog says "Manu‘a", without specifying islands. Islands listed for a taxon include all islands for all synonyms as well as for the valid name. Many species that are widespread in the Pacific, as well as some that are more restricted, or perhaps endemic to Samoa, have only been recorded in Samoa from one or a few islands. Although they may occur on other Samoan islands, only those islands reported in the literature are listed. If a taxon has been artificially introduced to Samoa, this is indicated immediately following the list of islands. Island distributions are derived from the original descriptions and from the major monographs mentioned in the introductions to each family, genus, etc., with additional sources indicated under the specific taxa. Spelling of island names and use of diacriticals (except when quoting directly, as for type localities), both in Samoa and elsewhere in the Pacific, follows Motteler (1986).

The following abbreviations are used throughout the catalog:

ISLANDS:
S = Savai‘i
Ap = Apolima
M = Manono
U = ‘Upolu
N = Nu‘utele
Nu = Nu‘ulua
T = Tutuila
A = ‘Aunu‘u
O = Ofu
Ol = Olosega
Ta = Ta‘u
R = Rose
Sw = Swains Island