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Department of Invertebrate Zoology

Porcellio scaber

Some terrestrial isopods, like Porcellio scaber shown here, may carry the Isopod Iridescent Virus, or iridovirus, which causes the exoskeleton and internal organs to become blue, violet or purple. The virus eventually affects the health of the animals.

About the List


Compiled by Brian Kensley (*), Marilyn Schotte (*) and Steve Schilling(#)

(*)Department of Invertebrate Zoology
National Museum of Natural History
Smithsonian Institution
Washington, D.C. 20560

(#) formerly, U.S. Environmental Protection Agency
Interagency Taxonomic Information System (ITIS)
401 M Street, SW
Washington, D.C. [Suborder Oniscidea only]

This listing of marine, freshwater and terrestrial isopod species of the world is provided as a service to the public, as part of the Outreach Program of the Department of Invertebrate Zoology, and in keeping with the Smithsonian's mandate for "the increase and diffusion of knowledge."

The list of isopod crustaceans has been compiled from a variety of sources, including numerous individual papers and monographic works, and the collections and catalogues of the National Museum of Natural History, Smithsonian Institution.

Several researchers have generously checked those sections of the list that include the groups with which they are most familiar, or have supplied us with their own lists of their specialty group and/or bibliographies:

Dr. Thomas E. Bowman (deceased), National Museum of Natural History, Smithsonian Institution, (Asellidae in part, Cymothoidae)

Dr. Niel Bruce, Marine Biodiversity & Systematics, National Institute of Water & Atmospheric Research, Wellington, New Zealand (Aegidae, Cirolanidae, Sphaeromatidae)

Dr. Richard Brusca, Ecology & Evolutionary Biology Department, University of Arizona, Tucson, Arizona, U.S.A. (Cirolanidae)

Dr. John C. Markham, Arch Cape Marine Laboratory, Oregon, U.S.A. (Bopyridae)

Dr. Hans-Georg Mueller, Labor fuer Tropische Okosystemforschung, Wetzlar, Germany (Anthuridea, Asellota)

Dr. Gary C. B. Poore, Museum of Victoria, Melbourne, Australia (Anthuridea, Valvifera)

Dr. Fahmida Rafi, Canadian Museum of Nature, Ottawa, Canada (Valvifera).

Dr. Ernest Williams, and Dr. Lucy Bunkley Williams, University of Puerto Rico, Mayaguez, Puerto Rico (Cymothoidae)

Dr. George Wilson, Australian Museum, Sydney, Australia (Asellota, Phreatoicidea in part).

Having compiled a list of about 5,300 marine and freshwater isopod crustaceans of the world (Kensley and Schotte, 1995), we thought that the addition of the terrestrial isopods to the list would create a more valuable taxonomic and biogeographic tool. It quickly became apparent, once we started to compile the names of Oniscidea, that a list of only valid or established taxa could not be assembled, given the state of oniscidean taxonomy. This list is thus intended as a rough guide to the astounding array of names and taxa in the Oniscidea. Synonymy will be rampant in the list. We have tried to use the most current interpretations of some genera and families. Nevertheless, we realize that in no way do we even begin to resolve the taxonomic confusion that reigns in this group. There is uncertainty regarding the familial placement of some genera, and there will certainly be repetition of the same specific name under different genera. There are omissions from the list, either of names of taxa that we've completely missed, or of authors and dates of publication and/or of localities that we have been unable to find. We hope that researchers in this group will be generous and will provide corrections that can be incorporated into updated versions of the list.

Once the initial list had been compiled, Drs. Franco Ferrara and Stefano Taiti (Consiglio Nazionale delle Ricerche, Centro di Studio per la Faunistica ed Ecologia Tropicali, Firenze, Italy) and Andreas Leistikow (Department of Animal Morphology, University of Bielefeld, Germany) generously agreed to check and correct the list at the familial and generic level. In the course of this time-consuming but extremely valuable toil, they also corrected many problems at the specific level. They decline any responsibility, however, for the list at the specific level; to repeat the earlier warning, the list is meant as a rough guide and not as a definitive last word on the group. Note: only Near East/Mediterranean species of Armadillo are regarded as true members of the genus. Those from other parts of the world are suspect, but are included there for the time being.

We hope that perusal of this section of the list will prompt biologists to undertake further taxonomic, biodiversity, and biogeographic investigations. We ourselves have been struck by several features of the list, including the extraordinary proliferation of closely related species and subspecies in some geographic areas; the comprehensive coverage that some geographic areas have received, and the poor to non-existent coverage of others (are there really only 120 species of oniscideans in the contiguous United States and Canada?); the amazing speciosity of some genera like Porcellio, Armadillidium, Cubaris, Trichoniscus; the widespread distribution of some genera and the apparently very retricted distribution of others. These features, plus the fact that the oniscideans are documented as being of value in a variety of pollution studies (e.g. Hopkin & Martin, 1984; Hopkin et al., 1986), we hope will stimulate further comprehensive research on this amazingly adaptable and successful group of arthropods.

All records for the United States are given by state, followed by the abbreviation USA. Cosmopolitan is used as shorthand for "very widely distributed", a category that applies to more than 20 species.

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Organization of the List

The list covers the period from Linnaeus' Systema Naturae (tenth edition, 1758) to present.

The Suborders of the Isopoda are arranged alphabetically: Anthuridea, Asellota, Calabazoidea, Epicaridea, Flabellifera, Gnathiidea, Microcerberidea, Oniscidea, Phreatoicidea, Valvifera.

For the Epicaridea, a complete list of the genera and species of the family Bopyridae is given, courtesy of Dr. John Markham who provided his own species and bibliographic lists. For the rest of the Epicaridea, the compilers did not have sufficient expertise to compile a usable list but are including records as experts make such information available.

Within the Suborder Oniscidea, the Families are arranged alphabetically. Subfamilies have not been used, given the confused state of the taxonomy at the family level. The families used are those listed in Table 2 of Schmalfuss (1989, Monitore Zoologico Italiano, (N.S.), monograph 4, pages 3-27).

Within the suborders, the Families are arranged alphabetically. Subfamilies have not been used, as these were felt to reduce the usefulness and accessibility of the list, a detailed knowledge of the relevant isopod family in the user being a prerequisite.

Within the families, the Genera are arranged alphabetically.

Within the genera, Species and subspecies are arranged alphabetically.

For almost every taxon in the list, its author and date of publication is provided. In many cases, this information has been taken from secondary sources, the original publication not being available.

For every species, the type locality and original generic designation (if this has been changed), are provided. The details of the type locality are generally not given; rather, this category is intended as a quick geographical indicator. Depth records or habitat designations are provided when available, except for the parasitic Bopyridae. In many cases, specific depth records were not provided in the description of the species, although some indication of a depth category was provided. The designation "shallow" in this field means infratidal to 200 m.

For every species or subspecies in the order Oniscidea, some indication of type locality or geographic distribution is provided, generally by state, occasionally by major island or major mountain range. The details of the type locality are not given; rather, this category is intended as a quick geographic indicator. Some abbreviations are used with some consistency in this category:

Abbreviation Full Meaning
Arch. Archipelago
Is. Island
Mts. Mountains
N. North
NSW New South Wales
Pen. Peninsula
R Republic
UAE United Arab Emirates
UK United Kingdom
USA United States of America

An authority list bibliography containing all the references given by author and date in the list, is appended. This list was compiled by Marilyn Schotte, Marie Wallace, Steven Schilling and Brian Kensley. The most recent publications have been used in designating the generic status of species; nevertheless, mistakes have undoubtedly been made, and synonyms and invalid taxa have probably been included. Gaps occur where the relevant information could not be obtained. Users are encouraged to send in corrections and fill gaps, so that the list can be upgraded and improved on a frequent basis. Information should be sent via E-mail to Marilyn Schotte (

This compilation is copyrighted by the Smithsonian Institution, 1996, all rights reserved. It is presented for scholarly use only; copying or redistributing the data in any manner for personal or corporate gain is not permitted.

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Searching the List

To query the list for a term in the categories Suborder, Family, Genus, Species or Type Locality, simply enter the word or part of it in the relevant space and choose an appropriate verb from the pull-down menu. Then click on "submit query". Genus and species names are best queried by selecting "begins with" (the default option) from the pull-down menu. In order to generate a list of genera or species associated with a particular author, enter the author's name into the respective field and select "contains" from the pull-down menu.

For each species record there is an assigned identification number under the field name "Complete information" which refers only to the order in which these records were entered. Clicking on this number brings up a second screen with the same information (in a different format) plus remarks, if any, pertaining to this species.

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