In a notice published 5 December 1996 (Federal Register [FR] 61:64481-64485), the United States Fish and Wildlife Service (the "Service") has confirmed its decision to discontinue the practice of maintaining a list of "Category 2" candidate species for endangered or threatened status under the Endangered Species Act of 1973.

Numerous mollusk species are affected. The following table presents mollusk taxa identified as Category 2 candidates in FR 59:58982 ff., 15 November 1994, the most recent publication of such a list. Category 2 species formerly were defined as "taxa for which information now in the possession of the Service indicates that proposing to list as endangered or threatened is possibly appropriate, but for which persuasive data on biological vulnerability and threat are not currently available to support proposed rules" (FR 59:58983).

The Service attempts to justify this action, in part, as follows:

"When the Service first started publishing comprehensive lists of candidates and potential candidates, no comparable list existed because few organizations were tracking species of concern. Now, a number of agencies and organizations track species that may be declining, including State natural resource agencies and Natural Heritage Programs, Federal land-management agencies, the Biological Resources Division of the U.S. Geological Survey (USGS), professional societies, and conservation organizations. The added attention and wider range of focus means that there is vastly superior information available on species of concern than was maintained in the Service's list of category-2 species. Duplicative effort to maintain lists is not the best use of limited endangered species funding.

"The quality of the information supporting the former category-2 list varied considerably, ranging from extremely limited or old data to fairly comprehensive assessments. It is the intent of the Service to work with all interested parties and to use scientifically credible sources of peer-reviewed information, when available, to identify new candidate species.

"The need for a species of concern list extends beyond implementation of the Endangered Species Act. Using the old category-2 list as a "species of concern" list was inappropriate; it is widely believed that sensitive, rare, and declining species are more inclusive than those found in the old category-2 list. Many Divisions of the Fish and Wildlife Service, such as Migratory Birds, Refuges, Endangered Species, Habitat Conservation, Environmental Contaminants, and Fish and Wildlife Management Assistance will continue to work with partners to identify and protect species of concern.

"The result of such collaboration should be a far more comprehensive and reliable accounting of biological resources that are declining or otherwise at risk. This approach is consistent with the purposes of numerous Federal environmental policies and statutes, not just the Act" (FR 61:64481-64482).

The notice goes on to summarize comments and recommendations received in response to the initial proposal to discontinue the list (FR 61:7596-7599, 28 February 1996). It also reiterates the Service's interest in receiving comments and information relating to the biological status and threats of particular taxa that are, or should be, regarded as candidates for protection under the Endangered Species Act.

Under the revised listing system, only those species for which there is enough information (in the opinion of the FWS) to support a listing proposal will be called candidates. These were formerly known as "Category 1" candidate species. A former Category 3, consisting of a mixture of non-candidate species, thought to be either extinct, taxonomically invalid, or too widespread to be considered at risk also no longer exists.

It is too early to assess the effects of these changes in listing procedures. But because the Service formerly encouraged state and local governments to take Category 2 candidates into account in their environmental planning, there is reason to believe that the new classification will significantly lower the level of protection afforded the nation's mollusk fauna.

References:

Cowie, R. H., N. L. Evenhuis, & C. C. Christensen. 1995. Catalog of the native land and freshwater molluscs of the Hawaiian Islands. Backhuys Publishers, Leiden. vi + 248 pp.

Turgeon, D. D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G. Lyons, P. M. Mikkelsen, J. F. Quinn Jr., C. F. E. Roper, G. Rosenberg, B. Roth, M. J. Sweeney, A. H. Scheltema, F. G. Thompson, M. Vecchione, & J. D. Williams. In preparation. Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Mollusks. 2d ed. American Fisheries Society Special Publication.

Table 1. Former United States Fish and Wildlife Service Category 2 candidate mollusk species, from last published list (Federal Register 59:58982, ff., 15 November 1994). Taxon names edited for conformity with current molluscan literature (e.g., Cowie et al., 1995; Turgeon et al., in preparation).

Neritidae: Neritilia hawaiiensis Kay, 1979

Viviparidae: Campeloma decampi (W. G. Binney, 1865); Lioplax cyclostomaformis (Lea, 1841)

Pleuroceridae: Elimia acuta (Lea, 1831); Elimia alabamensis (Lea, 1861); Elimia albanyensis (Lea, 1864); Elimia aterina (Lea, 1863); Elimia bellula (Lea, 1861); Elimia boykiniana (Lea, 1840); Elimia capillaris (Lea, 1861); Elimia crenatella (Lea, 1860); Elimia fascinans (Lea, 1861); Elimia haysiana (Lea, 1843); Elimia hydei (Conrad, 1834); Elimia interrupta (Haldeman, 1840); Elimia interveniens (Lea, 1862); Elimia nassula (Conrad, 1834); Elimia olivula (Conrad, 1834); Elimia porrecta (Lea, 1863); Elimia prestriata (Lea, 1852); Elimia pybasi (Lea, 1862); Elimia strigosa (Lea, 1841); Elimia teres (Lea, 1841); Elimia troostiana (Lea, 1838); Elimia varians (Lea, 1861); Io fluvialis (Say, 1825); Leptoxis ampla (Anthony, 1855); Leptoxis compacta (Anthony, 1854); Leptoxis crassa (Haldeman, 1841); Leptoxis melanoidus (Conrad, 1834); Leptoxis minor (Hinckley, 1912); Leptoxis picta (Conrad, 1834); Leptoxis plicata (Conrad, 1834); Leptoxis praerosa (Say, 1821); Leptoxis taeniata (Conrad, 1834); Leptoxis virgata (Lea, 1841); Lithasia armigera (Say, 1821); Lithasia curta (Lea, 1868); Lithasia duttoniana (Lea, 1841); Lithasia geniculata Haldeman, 1840; Lithasia jayana (Lea, 1841); Lithasia lima (Conrad, 1834); Lithasia salebrosa (Conrad, 1834); Lithasia verrucosa (Rafinesque, 1820); Pleurocera alveare (Conrad, 1834); Pleurocera annulifera (Conrad, 1834); Pleurocera brumbyi (Lea, 1852); Pleurocera corpulenta (Anthony, 1854); Pleurocera curta (Haldeman, 1841); Pleurocera foremani (Lea, 1843); Pleurocera postelli (Lea, 1862); Pleurocera pyrenella (Conrad, 1834); Pleurocera showalteri (Lea, 1862); Pleurocera viridulum (Anthony, 1854); Pleurocera walkeri Goodrich, 1928

Littorinidae: Littorina subrotundata (Carpenter, 1865) [as Algamorda newcombiana (Hemphill, 1877)]

Hydrobiidae: Antrorbis breweri Hershler & Thompson, 1990; Aphaostracon asthenes Thompson, 1968; Aphaostracon monas (Pilsbry, 1899); Aphaostracon pycnum Thompson, 1968; Aphaostracon xynoelictum Thompson, 1968; Cincinnatia helicogyra Thompson, 1968; Cincinnatia mica Thompson, 1968; Cincinnatia monroensis (Dall, 1885); Cincinnatia parva Thompson, 1968; Cincinnatia ponderosa Thompson, 1968; Cincinnatia vanhyningi (Vanatta, 1934); Cincinnatia wekiwae Thompson, 1968; Clappia cahabensis Clench, 1965; Clappia umbilicata (Walker, 1904); Cochliopa texana Pilsbry, 1935; Fluminicola columbianus (Keep, 1887); Fontigens tartarea Hubricht, 1963 [as F. holsingeri Hubricht, 1976]; Fontigens turritella Hubricht, 1976; Lepyrium showalteri (Lea, 1861); Phreatodrobia imitata Herschler & Longley, 1986; Pyrgulopsis, three unnamed spp.; Pyrgulopsis aardahli Hershler, 1989; Pyrgulopsis agarhecta (Thompson, 1969); Pyrgulopsis arizonae (Taylor, 1987) [as Apachecoccus]; Pyrgulopsis avernalis (Pilsbry, 1935) [as Fluminicola]; Pyrgulopsis bacchus Hershler, 1988; Pyrgulopsis bernardina (Taylor, 1987) [as Yaquicoccus]; Pyrgulopsis castor (Thompson, 1977); Pyrgulopsis conica Hershler, 1988; Pyrgulopsis crystalis Hershler & Sada, 1987; Pyrgulopsis davisi (Taylor, 1987) [as "Fontelicella"]; Pyrgulopsis erythropoma (Pilsbry, 1899); Pyrgulopsis fairbanksensis Hershler & Sada, 1987; Pyrgulopsis glandulosa Hershler, 1988; Pyrgulopsis isolata Hershler & Sada, 1987; Pyrgulopsis merriami (Pilsbry & Beecher, 1892) [as Fluminicola]; Pyrgulopsis metcalfi (Taylor, 1987) [as "Fontelicella"]; Pyrgulopsis micrococcus (Pilsbry, 1893); Pyrgulopsis montezumensis Hershler, 1988; Pyrgulopsis morrisoni Hershler, 1988; Pyrgulopsis nanus Hershler & Sada, 1987; Pyrgulopsis ogmorhaphe (Thompson, 1977); Pyrgulopsis olivacea (Pilsbry, 1895); Pyrgulopsis owensensis Hershler, 1989; Pyrgulopsis ozarkensis Hinkley, 1915; Pyrgulopsis pachyta (Thompson, 1977); Pyrgulopsis perturbata Hershler, 1989; Pyrgulopsis pisteri Hershler & Sada, 1987; Pyrgulopsis robusta (Walker, 1908); Pyrgulopsis simplex Hershler, 1988; Pyrgulopsis sola Hershler, 1988; Pyrgulopsis thompsoni Hershler, 1988; Pyrgulopsis trivialis (Taylor, 1987) [as "Fontelicella"]; Pyrgulopsis wongi Hershler, 1989; Somatogyrus amnicoloides Walker, 1915; Somatogyrus aureus Tryon, 1865; Somatogyrus biangulatus Walker, 1906; Somatogyrus constrictus Walker, 1904; Somatogyrus coosaensis Walker, 1904; Somatogyrus crassilabris Walker, 1915; Somatogyrus crassus Walker, 1904; Somatogyrus currierianus (Lea, 1863); Somatogyrus decipiens Walker, 1909; Somatogyrus excavatus Walker, 1906; Somatogyrus hendersoni Walker, 1909; Somatogyrus hinkleyi Walker, 1904; Somatogyrus humerosus Walker, 1906; Somatogyrus nanus Walker, 1904; Somatogyrus obtusus Walker, 1904; Somatogyrus parvulus Tryon, 1865; Somatogyrus pilsbryanus Walker, 1904; Somatogyrus pygmaeus Walker, 1909; Somatogyrus quadratus Walker, 1906; Somatogyrus sargenti Pilsbry, 1895; Somatogyrus strengi Pilsbry & Walker, 1906; Somatogyrus tenax (Thompson, 1969); Somatogyrus tennesseensis Walker, 1906; Somatogyrus virginicus Walker, 1904; Somatogyrus wheeleri Walker, 1915; Stiobia nana Thompson, 1978; Tryonia angulata Hershler & Sada, 1987; Tryonia brunei Taylor, 1987; Tryonia cheatumi (Pilsbry, 1935); Tryonia circumstriata (Leonard & Ho, 1960 [as T. stocktonensis Taylor, 1987]; Tryonia clathrata Stimpson, 1865; Tryonia elata Hershler & Sada, 1987; Tryonia ericae Hershler & Sada, 1987; Tryonia gilae Taylor, 1987; Tryonia imitator (Pilsbry, 1899); Tryonia margae Hershler, 1989; Tryonia quitobaquitae Hershler, 1988; Tryonia robusta Hershler, 1989; Tryonia rowlandsi Hershler, 1989; Tryonia variegata Hershler & Sada, 1987

Assimineidae: Assiminea infima S. S. Berry, 1947

Valvatidae: Valvata virens Tryon, 1863

Acroloxidae: Acroloxus coloradensis (J. Henderson, 1930)

Physidae: Physella microstriata (Chamberlain & E. G. Berry, 1930); Physella spelunca (Turner & Clench, 1925); Physella utahensis (Clench, 1925); Physella zionis (Pilsbry, 1926)

Planorbidae: Amphigyra alabamensis Pilsbry, 1906; Helisoma jacksonense (Henderson, 1932); Neoplanorbis carinatus Walker, 1908; Neoplanorbis smithi Walker, 1908; Neoplanorbis tantillus Pilsbry, 1906; Neoplanorbis umbilicatus Walker, 1908; Planorbella magnifica (Pilsbry, 1903); Planorbella multivolvis (Case, 1847)

Ancylidae: Ferrissia mcneili Walker, 1925; Rhodacme elatior (Anthony, 1855); Rhodacme filosa (Conrad, 1834)

Achatinellidae: Newcombia canaliculata (Baldwin, 1905); Newcombia cumingi (Newcomb, 1853); Newcombia lirata (Pfeiffer, 1853) [as N. plicata "Mighels, 1912-1914" (sic)]; Newcombia perkinsi Sykes, 1896; Newcombia pfeifferi (Newcomb, 1853); Newcombia sulcata (Pfeiffer, 1857); Partulina anceyana (Baldwin, 1895); Partulina carnicolor Baldwin, 1906; Partulina confusa (Sykes, 1900); Partulina crassa (Newcomb, 1854); Partulina crocea (Gulick, 1856); Partulina dolei (Baldwin, 1895); Partulina dubia (Newcomb, 1853); Partulina dwightii (Newcomb, 1855); Partulina fusoidea (Newcomb, 1855); Partulina germana (Newcomb, 1854); Partulina grisea (Newcomb, 1854); Partulina horneri (Baldwin, 1895); Partulina induta (Gulick, 1856); Partulina kaaeana Baldwin, 1906; Partulina lemmoni Baldwin, 1906; Partulina marmorata (Gould, 1847); Partulina mighelsiana (Pfeiffer, 1848); Partulina mucida (Baldwin, 1895); Partulina mutabilis Baldwin, 1908; Partulina natti (Hartman, 1888); Partulina nivea (Baldwin, 1895); Partulina perdix (Reeve, 1850); Partulina physa (Newcomb, 1854); Partulina plumbea (Gulick, 1856); Partulina porcellana (Newcomb, 1853); Partulina proxima (Pease, 1862); Partulina radiata (Gould, 1845); Partulina redfieldi (Newcomb, 1853); Partulina rufa (Newcomb, 1853); Partulina semicarinata (Newcomb, 1854); Partulina splendida (Newcomb, 1853); Partulina subpolita Pilsbry & Cooke, 1912; Partulina talpina (Gulick, 1856) [as P. gouldii (Newcomb, 1853)]; Partulina tappaniana (C.B. Adams, 1851); Partulina terebra (Newcomb, 1853); Partulina tessellata (Newcomb, 1854); Partulina thaanumiana Pilsbry in Pilsbry & Cooke, 1913; Partulina theodorei (Baldwin, 1895); Partulina ustulata (Gulick, 1856); Partulina variabilis (Newcomb, 1854); Partulina virgulata (Mighels, 1845); Partulina winniei Baldwin, 1908; Perdicella carinella Baldwin, 1906; Perdicella fulgurans Sykes, 1900; Perdicella helena (Newcomb, 1853); Perdicella kuhnsi (Pilsbry in Pilsbry & Cooke, 1913); Perdicella maniensis (Pfeiffer, 1856); Perdicella ornata (Newcomb, 1854); Perdicella thwingii (Pilsbry & Cooke, 1914); Perdicella zebra (Newcomb, 1855); Perdicella zebrina (Pfeiffer, 1856)

Amastridae: Carelia, ca. 12 spp.; Laminella sanguinea (Newcomb, 1854); Leptachatina lepida Cooke in Hyatt & Pilsbry, 1910

Partulidae: Partula salifana au, date?; Samoana abbreviata (Mousson, 1869); Samoana conica au, date?; Samoana thurstoni au, date?

Pupillidae: Gastrocopta dalliana dalliana (Sterki, 1898); Vertigo, unnamed sp.; Vertigo alabamensis Clapp, 1915; Vertigo arthuri von Martens, 1882; Vertigo briarensis (Leonard, 1972); Vertigo hebardi Vanatta, 1912; Vertigo hubrichti (Pilsbry, 1934); Vertigo meramacensis (Van Devender, 1979); Vertigo occulta (Leonard, 1972); Vertigo ovata Say, 1822

Helicodiscidae: Helicodiscus diadema Grimm, 1967; Helicodiscus hexodon Hubricht, 1966

Discidae: Discus marmorensis H. B. Baker, 1932; Discus shimekii cockerellii (Pilsbry, 1898)

Oreohelicidae: Oreohelix eurekensis eurekensis J. Henderson and Daniels, 1916; Oreohelix eurekensis uinta Brooks, 1939; Oreohelix florida Pilsbry, 1939; Oreohelix haydeni corrugata J. Henderson and Daniels, 1916; Oreohelix haydeni haydeni (Gabb, 1869); Oreohelix idahoensis idahoensis (Newcomb, 1866); Oreohelix jugalis (Hemphill, 1890); Oreohelix nevadensis S. S. Berry, 1932; Oreohelix parawanensis Gregg, 1941; Oreohelix pilsbryi Ferriss, 1917; Oreohelix strigosa berryi Pilsbry, 1915; Oreohelix strigosa cooperi (W. G. Binney, 1858); Oreohelix strigosa goniogyra Pilsbry, 1934; Oreohelix vortex S. S. Berry, 1932; Oreohelix waltoni Solem, 1975; Oreohelix yavapai Pilsbry, 1905; Radiocentrum avalonense (Hemphill in Pilsbry, 1905)

Arionidae: Binneya notabilis Cooper, 1863

Succineidae: Catinella gelida (Baker, 1927); Succinea, two unnamed spp.; Succinea guamensis au, date?; Succinea piratarum au, date?; Succinea quadrasi au, date?

Trochomorphidae: Trochomorpha apia au, date?

Helicarionidae: Diastole matafaoi H. B. Baker, 1938; Diastole schmeltziana au, date?

Zonitidae: Glyphyalinia clingmani (Dall, 1890); Glyphyalinia pecki Hubricht, 1966; Glyphyalinia raderi (Dall, 1898); Paravitrea aulacogyra (Pilsbry & Ferris, 1906); Paravitrea ceres Hubricht, 1978; Paravitrea ternaria Hubricht, 1978; Paravitrea varidens Hubricht, 1978

Polygyridae: Ashmunella hebardi Pilsbry & Vanatta, 1923; Ashmunella macromphala Vagvolgyi, 1974; Ashmunella pasonis (Drake, 1951); Cryptomastix magnidentata (Pilsbry, 1940); Daedalochila hippocrepis (Pfeiffer, 1848) [as Polygyra]; Euchemotrema hubrichti (Pilsbry, 1940); Euchemotrema leai cheatumi (Fullington, 1974); (?)Fumonelix clingmanica (Pilsbry, 1904) [as Mesodon clingmanicus]; Mesodon trossulus Hubricht, 1966; Millerelix peregrina Rehder, 1932 [as Polygyra]; Patera clenchi (Rehder, 1932); Stenotrema pilsbryi (Ferris, 1900); Triodopsis soelneri (J. B. Henderson, 1907); Vespericola karokorum Talmadge, 1962; Xolotrema occidentale (Pilsbry & Ferriss, 1894) [as Triodopsis occidentalis]

Megomphicidae: Ammonitella yatesii Cooper, 1869

Bradybaenidae: Monadenia circumcarinata (Stearns, 1879); Monadenia fidelis minor (W. G. Binney, 1885); Monadenia fidelis pronotis S. S. Berry, 1931; Monadenia mormonum buttoni (Pilsbry, 1900); Monadenia mormonum hirsuta Pilsbry, 1927; Monadenia setosa Talmadge, 1952; Monadenia troglodytes Hanna & Smith, 1933; Monadenia yosemitensis (Lowe, 1916) [as M. hillebrandi yosemitensis]

Helminthoglyptidae: Eremarionta immaculata (Willett, 1937); Eremarionta millepalmarum (S. S. Berry, 1930); Eremarionta morongoana (S. S. Berry, 1929); Eremarionta rowelli bakerensis (Pilsbry & Lowe, 1934) [as Micrarionta]; Eremarionta rowelli mccoiana (Willett, 1935) [as Micrarionta]; Helminthoglypta allynsmithi Pilsbry, 1939; Helminthoglypta arrosa pomoensis A. G. Smith, 1938; Helminthoglypta callistoderma (Pilsbry, 1917); Helminthoglypta coelata (Bartsch, 1916) [as H. traski coelata]; Helminthoglypta mohaveana S. S. Berry, 1927; Helminthoglypta nickliniana awania (Bartsch, 1919); Helminthoglypta nickliniana bridgesii (Newcomb, 1861); Helminthoglypta sequoicola consors S. S. Berry, 1938; Helminthoglypta stiversiana williamsi A. G. Smith, 1938 [as H. arrosa williamsi]; Maricopella allynsmithi (Gregg & Miller, 1969) [as Sonorella]; Micrarionta facta (Newcomb, 1864); Micrarionta feralis (Hemphill, 1901); Micrarionta gabbi (Newcomb, 1864); Micrarionta opuntia Roth, 1975; Sonorella, unnamed sp.; Sonorella christenseni Fairbanks & Reeder, 1980; Sonorella grahamensis Pilsbry & Ferris, 1919; Sonorella metcalfi Miller, 1976; Sonorella todseni Miller, 1976

Margaritiferidae: Cumberlandia monodonta (Say, 1829); Margaritifera marrianae Johnson, 1983

Unionidae: Alasmidonta arcula (Lea, 1838); Alasmidonta marginata Say, 1818; Alasmidonta varicosa (Lamarck, 1819); Alasmidonta wrightiana (Walker, 1901); Anodonta californiensis Lea, 1852; Anodontoides denigrata (Lea, 1852); Cyprogenia aberti (Conrad, 1850); Disconaias salinasensis (Simpson, 1908); Elliptio, unnamed sp.; Elliptio judithae Clarke, 1986; Elliptio lanceolata (Lea, 1828); Elliptio monroensis (Lea, 1843); Elliptio nigella (Lea, 1852); Elliptio shepardiana (I.Lea, 1834); Elliptio spinosa (Lea, 1836); Elliptio waccamawensis (Lea, 1863); Elliptio waltoni (Wright, 1888); Epioblasma triquetra (Rafinesque, 1820); Fusconaia escambia Clench & Turner, 1956); Fusconaia masoni (Conrad, 1834); Lampsilis australis Simpson, 1900; Lampsilis binominata Simpson, 1900; Lampsilis cariosa (Say, 1817); Lampsilis fullerkati Johnson, 1984; Lampsilis haddletoni Athearn, 1964; Lampsilis rafinesqueana Frierson, 1927; Lampsilis subangulata (Lea, 1840); Lasmigona, unnamed sp.; Lasmigona holstonia (Lea, 1838); Lasmigona subviridis (Conrad, 1835); Leptodea leptodon (Rafinesque, 1820); Lexingtonia dolabelloides (Lea, 1840); Medionidus penicillatus (Lea, 1857); Medionidus simpsonianus Walker, 1905; Medionidus walkeri (Wright 1897); Obovaria rotulata (Wright, 1899); Pleurobema oviforme (Conrad, 1834); Pleurobema pyramidatum (Rafinesque, 1820); Pleurobema pyriforme (Lea, 1857); Pleurobema rubellum (Conrad, 1834); Pleurobema strodeanum (Wright 1898); Pleurobema verum (Lea, 1861); Popenaias popei (Lea, 1857); Potamilus amphichaenus (Frierson, 1898); Ptychobranchus jonesi (van der Schalie, 1934); Ptychobranchus occidentalis (Conrad, 1836); Quadrula cylindrica cylindrica (Say, 1817); Quadrula cylindrica strigillata (Wright, 1898); Quincuncina burkei Walker, 1922; Quincuncina mitchelli (Simpson, 1896); Simpsonaias ambigua (Say, 1825); Toxolasma lividus (Rafinesque, 1831); Toxolasma pullus (Conrad, 1838); Truncilla cognata (Lea, 1860); Villosa choctawensis Athearn, 1964; Villosa fabalis (Lea, 1831); Villosa ortmanni (Walker, 1925); Villosa perpurpurea (Lea, 1861)

Sphaeriidae: Pisidium sanquinichristi Taylor, 1987; Pisidium ultramontanum Prime, 1865

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