Acris Duméril and Bibron, 1841—CRICKET FROGS
A. crepitans Baird, 1854—Northern Cricket Frog
Three subspecies are named, and have not been formally rejected, though they are infrequently used. Whether these represent arbitrary or historical units is unknown and requires further investigation.
A. c. blanchardi Harper, 1947—Blanchard’s Cricket Frog
A. c. crepitans Baird, 1854—Eastern Cricket Frog
A. c. paludicola Burger, Smith, and Smith, 1949—Coastal
Cricket Frog
A. gryllus (LeConte, 1825)—Southern Cricket Frog
Two nominal subspecies occasionally recognized, although whether they are arbitrary or historical units is arguable.
A. g. dorsalis (Harlan, 1827)—Florida Cricket Frog
A. g. gryllus (LeConte, 1825)—Coastal Plain Cricket Frog

Ascaphus Stejneger, 1899—TAILED FROGS
A. truei Stejneger, 1899—Tailed Frog
Metter (1964, Copeia 1964: 181–195) rejected subspecies but noted extensive geographic variation over relatively short geographic distances, which may indicate the need for further investigation. See Metter (1968, Cat. Am. Amph. Rept. 69) for review.

Bufo Laurenti, 1768—TOADS
B. alvarius Girard, 1859—Colorado River Toad
Reviewed by Fouquette (1970, Cat. Am. Amph. Rept. 93).
B. americanus Holbrook, 1836—American Toad
There is no seeming consensus, or much ongoing work on geographic variation of this taxon, although we suggest that careful evaluation of call and/or molecular data would provide considerable evidence of divergent lineages within the complex. For instance, the status of the nominal subspecies is far from clear, especially against the background of introgressive hybridization, which appears to be relatively common along species boundaries. See comments under Bufo fowleri, B. woodhousii, Bufo hemiophrys, B. baxteri, and B. terrestris.
B. a. americanus Holbrook, 1836—Eastern American Toad
B. a. charlesmithi Bragg, 1954—Dwarf American Toad
B. baxteri Porter, 1968—Wyoming Toad
Recognized as a species, rather than a subspecies, of Bufo hemiophrys by Packard (1971, J. Herpetol. 5: 191–193), and most recently by Smith, Chiszar, Collins, and van Breukelen (1998, Contemp. Herpetol. 1). Nevertheless, Cook (1983, Publ. Nat. Sci. Natl. Mus. Canada 3) considered B. baxteri to be undiagnosable against the background of geographic variation in B. hemiophrys (as B. americanus hemiophrys), and this has not been adequately addressed by subsequent authors.

B. boreas Baird and Girard, 1852—Western Toad
See Schuierer (1963, Herpetologica 18: 262–267). Three nominal subspecies are generally recognized, although the geographic variation within Bufo boreas is poorly studied and may mask a number of cryptic species.
B. b. boreas Baird and Girard, 1852—Boreal Toad
B. b. halophilus Baird and Girard, 1853—California Toad
B. b. nelsoni Stejneger, 1893—Amargosa Toad
B. californicus Camp, 1915—Arroyo Toad
See account (as Bufo microscaphus californicus) by Price and Sullivan (1988, Cat. Am. Amph. Rept. 415). See also Gergus (1998, Herpetologica 54: 317–325) for resurrection and justification.
B. canorus Camp, 1916—Yosemite Toad
Reviewed by Karlstrom (1973, Cat. Am. Amph. Rept. 132).
B. cognatus Say, 1823—Great Plains Toad
Reviewed by Krupa (1990, Cat. Am. Amph. Rept. 457).
B. debilis Girard, 1854—Green Toad
See accounts in Sanders and Smith (1951, Field and Laboratory 19: 141–160) and by Bogert (1962, Am. Mus. Novit. 2100). The nominal subspecies are unlikely to be more than arbitrarily defined sections of clines and therefore indefensible, although this remains to be investigated carefully.
B. d. debilis Girard, 1854—Eastern Green Toad
B. d. insidior Girard, 1854—Western Green Toad
B. exsul Myers, 1942—Black Toad
Considered by some authors to be a subspecies of Bufo boreas. See comments by Schuierer (1963, Herpetologica 18: 262–267).
Bufo fowleri Hinckley, 1882-Fowler's Toad
Green (1996, Israel J. Zool. 42: 95-109), provided a lucid discussion of the problem of interspecific hybridization in the Bufo americanus complex and briefly addressed the unfortunate publication by Sanders (1987, Evol. Hybrid. Spec. N. Am. Indig. Bufonids), in which Sanders recognized a number of dubiously delimited taxa within the Bufo americanus complex (B. hobarti which would be in the synonymy of B. fowleri; B. velatus which Green thought would be in the synonymy of B. fowleri [but see comment under B. woodhousii]; B. copei, which would be in B. americanus, and B. planiorum and B. antecessor, both of which would be in the synonymy of B. woodhousii woodhousii). None have been formally synonymized, but neither have they attracted any recognition by those working on the complex.

B. hemiophrys Cope, 1886—Canadian Toad
See comment associated with Bufo baxteri. Cook (1983, Publ. Nat. Sci. Natl. Mus. Canada 3) regarded Bufo hemiophrys and B. americanus as forming very distinctive subspecies of one species, although subsequent authors (e.g., Green and Pustowka, 1997, Herpetologica 53: 218–228), have regarded the contact zone between these taxa as a hybrid zone between two species—a philosophical rather than a data issue.
B. houstonensis Sanders, 1953—Houston Toad
No geographic variation documented for this endangered species of toad. Reviewed by Brown (1973, Cat. Am. Amph. Rept. 133).
B. marinus (Linnaeus, 1758)—Cane Toad
No subspecies currently diagnosed, although the possibility exists of cryptic species concealed under this name, as one would expect from any nominal species with a range from South Texas and Sonora, Mexico, to Brazil and Peru. Reviewed by Easteal (1986, Cat. Am. Amph. Rept. 395). Relationship with Bufo poeppigii (extralimital) unclear, possibly conspecific.

B. microscaphus Cope, 1867 "1866"—Arizona Toad
See account by Price and Sullivan (1988, Cat. Am. Amph. Rept. 415). See comment under Bufo californicus. Formerly included B. californicus and B. mexicanus (extralimital) as subspecies, which were elevated by Gergus (1998, Herpetologica 54: 317–325).

B. nebulifer Girard, 1843-Gulf Coast Toad
Mendelson (1994, Occas. Pap. Mus. Nat. Hist. Univ. Kansas 166: 1-21; 1997, Herpetologica 53: 14-30) showed that a number of cryptic species were concealed under the name Bufo valliceps and subsequently (Mulcahy and Mendelson, 2000, Mol. Phyl. Evol., 17: 173) recognized that nominal Bufo valliceps was composed of a northern species (Bufo nebulifer) in the USA south to central Veracruz, Mexico, and another (Bufo valliceps) from central Veracruz, Mexico, to Costa Rica. Although the scientific name of the Gulf Coast Toad has changed, and the likelihood remains that Bufo valliceps (sensu stricto) may still hold some surprises, it is unlikely that Bufo nebulifer represents more than one lineage
B. punctatus Baird and Girard, 1852—Red-spotted Toad
On the basis of considerable geographic variation (mostly extralimital) in morphology we suggest that this binominal may represent a composite of geographically vicariant species which might be elucidated with careful evaluation of calls and/or molecular evidence.
B. quercicus Holbrook, 1840—Oak Toad
No geographic variation documented. Reviewed by Ashton and Franz (1979, Cat. Am. Amph. Rept. 222).
B. retiformis Sanders and Smith, 1951—Sonoran Green Toad
No geographic variation reported. Approaches Bufo debilis very closely in Arizona, with no evidence of approaching morphological similarity. Reviewed by Hulse (1978, Cat. Am. Amph. Rept. 207).
B. speciosus Girard, 1854—Texas Toad
No geographic variation reported. Older literature confused this species with Bufo cognatus, B. mexicanus (extralimital), and B. compactilis.
B. terrestris (Bonnaterre, 1789)—Southern Toad
No geographic variation reported as such in the literature, although extensive geographic variation is evident on examination of specimens. Hybrization with Bufo americanus along the Fall Line may have strong effects on geographic variation, although data on this have not been published. Reviewed by Blem (1979, Cat. Am. Amph. Rept. 223).
B. valliceps Wiegmann, 1833—Gulf Coast Toad
Considered to be strongly geographically variable with recognizable subspecies until work by Mendelson (1994, Occas. Pap. Mus. Nat. Hist. Univ. Kansas 166: 1–21; 1997, Herpetologica 53: 14–30) showed that a number of cryptic species were concealed under the name Bufo valliceps. Further cryptic (and not-so-cryptic) species should be expected to be recognized within this complex, although it is unlikely that those populations that occur in the USA will form more than one lineage.
B. woodhousii Girard, 1854-Woodhouse's Toad
See comments under Bufo fowleri. The unjustified emendation of the specific epithet to woodhousei has been used widely. The status of taxa recognized by Sanders (1987, Evol. Hybrid. Spec. N. Am. Indig. Bufonids: 1-110), has not been evaluated closely by any author, although they have neither enjoyed any recognition. Subspecies in this taxon are controversial, with two (B. w. australis and B. w. woodhousii) frequently recognized. A third nominal subspecies, B. w. velatus Bragg and Sanders, 1951 (East Texas Toad) has been suggested (Sullivan, Malmos, and Given, 1996, Copeia, 1996: 274-280), to represent part of a zone of hybridization between Bufo fowleri and Bufo woodhousii so should not be recognized as a taxon until this issue is resolved. Detailed study of calls and molecules will likely prove fruitful within this widely distributed species.
B. w. australis Shannon and Lowe, 1955-Southwestern Woodhouse's Toad
B. w. woodhousii Girard, 1854-Rocky Mountain Toad


Eleutherodactylus Duméril and Bibron, 1841—RAINFROGS
The largest vertebrate genus, but poorly represented in USA. Likely paraphyletic with respect to Ischnocnema, Phrynopus, Barycholos, Euparkerella, Geobatrachus, Holoaden, Adelastes, and Phyzelaphryne (all extralimital).


E. augusti (Dugès, 1879)—Barking Frog
Reviewed by Zweifel (1967, Cat. Am. Amph. Rept. 41). Placed in Hylactophryne by Lynch (1968, Univ. Kansas Publ. Mus. Nat. Hist. 17: 503–515), the combination H. augusti still receives considerable use. Hedges (1989, Biogeography of the West Indies, C. Woods, ed., Sandhill Crane Press) placed Hylactophryne in the synonymy of Eleutherodactylus. The status of the subspecies is unknown.
E. a. cactorum Taylor, 1939 "1938"—Western Barking Frog
E. a. latrans (Cope, 1880)—Balcones Barking Frog
E. coqui Thomas, 1966—Coqui (Introduced)
Introduced into Florida (reports of introduction into Louisiana, USA are based on misinformation; H. A. Dundee, pers. comm.)
E. cystignathoides (Cope, 1878 "1877")— Rio Grande Chirping Frog
Two nominal subspecies named, only one of which enters the USA. The status of these taxa, whether they represent arbitrarily delimited parts of a single population or different lineages is unknown. Formerly placed in Syrrhophus, that nominal genus was placed in the synonymy of Eleutherodactylus by Hedges (1989, Biogeography of the West Indies, C. Woods, ed., Sandhill Crane Press).
E. c. campi (Stejneger, 1915)— Rio Grande Chirping Frog
E. guttilatus (Cope, 1879)—Spotted Chirping Frog
Geographic variation is poorly known. Formerly placed in Syrrhophus, this nominal genus was placed in the synonymy of Eleutherodactylus by Hedges (1989, Biogeography of the West Indies, C. Woods, ed., Sandhill Crane Press). Some authors (e.g. Morafka, 1977, Biogeographica 9: 69) consider E. guttilatus a synonym of E. campi.
E. marnockii (Cope, 1878)—Cliff Chirping Frog
See account by Lynch (1970, Univ. Kansas Publ. Mus. Nat. Hist. 20: 1–45). Geographic variation not well studied, but unlikely to hide any cryptic species. Formerly placed in Syrrhophus, that nominal genus was placed in the synonymy of Eleutherodactylus by Hedges (1989, Biogeography of the West Indies, C. Woods, ed., Sandhill Crane Press). See comment under E. guttilatus.
E. planirostris (Cope, 1862)—Greenhouse Frog (Introduced)
Extralimital subspecies recently elevated to species status.

Gastrophryne Fitzinger, 1843—NORTH AMERICAN NARROW-MOUTHED
TOADS
Reviewed by Nelson (1972, J. Herpetol. 6: 111–137) and Nelson (1973, Cat. Am. Amph. Rept. 134). Monophyly with respect to Hypopachus is not documented.
G. carolinensis (Holbrook, 1836)—Eastern Narrow-mouthed Toad
Reviewed by Nelson (1972, Cat. Am. Amph. Rept. 120); details of distribution in Nelson (1972, J. Herpetol. 6: 125–128).
G. olivacea (Hallowell, 1857 "1856")—Great Plains Narrow-mouthed Toad
Reviewed by Nelson (1972, Cat. Am. Amph. Rept. 122); details of distribution given by Nelson (1972, J. Herpetol. 6: 129–130). Cryptic species possible given the extensive distribution of this species.

Hyla Laurenti, 1768—TREEFROGS
The huge majority of nominal Hyla species are extralimital to this list. It should be noted that no evidence of Hyla monophyly exists, and that the type species of Hyla is H. arborea, a European species with strong morphological similarities to a group of North American species, including H. andersonii and Pseudacris. Therefore, it should be expected that most, if not all of Neotropical "Hyla" will ultimately be transferred to other genera, such as has already taken place with the removal of the former Hyla rubra group to Scinax and the recognition of genera such as Duellmanohyla, Ptychohyla, Pternohyla, Plectrohyla, Trachycephalus, Triprion, Osteocephalus, Tepuihyla, Sphaenorhynchus, Xenohyla, Osteopilus, and Smilisca that clearly are satellites of a paraphyletic Hyla.
H. andersonii Baird, 1854—Pine Barrens Treefrog
The widely disjunct populations have been examined with allozymes and only subtle (no fixed differences) geographic variation was documented (Karlin et al., 1982, Copeia 1982: 175–178).
H. arenicolor Cope, 1866—Canyon Treefrog
Barber (1999, Molec. Ecol. 8: 563–576) recently examined geographic variation in this taxon and suggested it is composed of three cryptic species.
H. avivoca Viosca, 1928—Bird-voiced Treefrog
Smith (1953, Herpetologica 9: 172) discussed geographic variation and recognized two nominal subspecies. Whether these represent arbitrary or historical units is unknown. For discussion see Smith (1966, Cat. Am. Rept. Amph. 28).
H. a. avivoca Viosca, 1928—Western Bird-voiced Treefrog
H. a. ogechiensis Neill, 1948—Eastern Bird-voiced Treefrog
H. chrysoscelis Cope, 1880—Cope’s Gray Treefrog
See comment associated with Hyla versicolor. Hyla chrysoscelis is possibly a composite deserving of considerable more work; see Maxson, Pepper, and Maxson (1977, Science, 197: 1012–13) and Johnson (1966, Texas J. Sci. 18: 361). See comment under H. versicolor. Reviewed by Hoffman (1988, Cat. Am. Amph. Rept. 436).
H. cinerea (Schneider, 1799)—Green Treefrog
Subspecies are occasionally recognized (H. c. cinerea and H. c. evittata) without discussion, and on the basis of a single populationally variable character. See Duellman and Schwartz (1958, Bull. Florida State Mus., Biol. Sci. 3: 241) for discussion and rejection of subspecies.
H. eximia Baird, 1854—Mountain Treefrog
Discussed, in part, by Jameson, Mackey, and Richmond (1966, Proc. California Acad. Sci. 33: 594), by Duellman (1970, Monogr. Mus. Nat. Hist. Univ. Kansas 1: 499–505), and by Blair (1960, Southwest. Nat. 5: 129–135). No subspecies currently recognized, although this is a strong candidate for being composed of several sibling species and considerable undocumented geographic variation is apparent upon casual inspection of specimens. The Arizona Treefrog, Hyla wrightorum, formerly a synonym of H. eximia, has been recognized by some authors (e.g., Sullivan, 1986, Great Bas. Nat. 46: 378–381) but no recent discussion of evidence in support of this has been published.
H. femoralis Bosc, 1800—Pine Woods Treefrog
Reviewed by Hoffman (1988, Cat. Am. Amph. Rept. 436).
H. gratiosa LeConte, 1857 "1856"—Barking Treefrog
Reviewed by Caldwell (1982, Cat. Am. Amph. Rept. 298).
H. squirella Bosc, 1800—Squirrel Treefrog
Reviewed by Martof (1975, Cat. Am. Amph. Rept. 168).
H. versicolor LeConte, 1825—Gray Treefrog
Nominal Hyla versicolor is possibly polyphyletic and further work is needed to elucidate the historical components of this complex. Hyla versicolor and H. chrysoscelis are sibling species that can only be distinguished readily by call, karyotypes, or cell volume. The actual range of each species is poorly understood. Ptacek, Gerhardt, and Sage (1994, Evolution 48: 898–908), suggested that "H. versicolor" is a set of at least three lineages, independently derived from the two documented lineages of "H. chrysoscelis". See also evidence for a single origin of H. versicolor in Ralin, Roman, and Kilpatrick (1983, Herpetologica 39: 212–225).

Hypopachus Keferstein, 1867—SHEEP FROGS
H. variolosus (Cope, 1866)—Sheep Frog
See Nelson (1973, Herpetologica 29: 6–17; 1974, Herpetologica 30: 250–274) for discussion of geographic variation, rejection of subspecies, and synonymy. Although only two species are currently recognized within this genus, very strong geographic variation in coloration, call, and toe structure argues that several species are masquerading under this particular name. Given that the type locality of Hypopachus variolosus is in Costa Rica, one can look forward to the name applied to the U.S. form to change.

Leptodactylus Fitzinger, 1826—NEOTROPICAL GRASS FROGS
L. labialis (Cope, 1878 "1877")—Mexican White-lipped Frog
No report of geographic variation. Reviewed by Heyer (1971, Cat. Am. Amph. Rept. 104; 1978, Sci. Bull. Nat. Hist. Mus. Los Angeles Co. 29: 31) who suggested that Cystignathus labialis Cope, 1877, was a junior synonym of Leptodactylus mystacinus, and that L. fragilis was the appropriate name for this species. This arrangement was rejected by Dubois and Heyer (1992, Copeia 1992: 584–585).

Osteopilus Fitzinger, 1843—WEST INDIAN TREEFROGS
O. septentrionalis (Duméril and Bibron, 1841)— Cuban Treefrog
(Introduced)
Introduced into Florida. Considerable inter-island variation exists in the Caribbean, although this has not been studied closely. Reviewed by Duellman and Crombie (1970, Cat. Am. Amph. Rept. 92) (as Hyla septentrionalis). See also Powell, Passaro, and Henderson (1992, Carib. J. Sci. 28: 234–235). See discussion of species nomenclature by Mittleman (1950, Herpetologica 6: 24–26), in which he suggests that H. septentrionalis Schlegel, 1837, is not a nomen nudum and applies to H. chalconota. If correct, the nomenclature of this species could be expected to change.

Pseudacris Fitzinger, 1843—CHORUS FROGS
Dubois (1981, Monit. Zool. Ital., N.S. 16: 9–65) regarded Pseudacris as a subgenus of Hyla, an arrangement that has not met general acceptance. See comments under Pseudacris regilla, P. ocularis, and P. crucifer.
P. brachyphona (Cope, 1889)—Mountain Chorus Frog
No geographic variation documented. Reviewed by Hoffmann (1980, Cat. Am. Amph. Rept. 234).
P. brimleyi Brandt and Walker, 1933—Brimley’s Chorus Frog
No geographic variation documented. Reviewed by Hoffmann (1983, Cat. Am. Amph. Rept. 311).
P. cadaverina (Cope, 1866)—California Treefrog
Reviewed by Gaudin (1979, Cat. Am. Amph. Rept. 225). Hedges (1986, Syst. Zool. 35: 11) placed former Hyla cadaverina in Pseudacris. Cocroft (1994, Herpetologica 50: 420–437) provided a phylogenetic reanalysis of Pseudacris and disputed Hedges’ results, although Silva (1997, J. Herpetol. 31: 609–613) provided additional evidence and discussion for placing this species within Pseudacris.
P. clarkii (Baird, 1854)—Spotted Chorus Frog
No geographic variation documented. Reviewed by Pierce and Whitehurst (1990, Cat. Am. Amph. Rept. 458).
P. crucifer (Wied-Neuwied, 1838)—Spring Peeper
Transfer to Pseudacris by Hedges (1986, Syst. Zool. 35: 11) was disputed by Cocroft (1994, Herpetologica 50: 420–437) although Silva (1997, J. Herpetol. 31: 609–613) provided additional evidence and discussion for placing this species within Pseudacris. Hardy and Borrough (1986, Bull. Maryland Herpetol. Soc. 22: 80) placed this species in the monotypic Parapseudacris, although this has enjoyed little support. Two nominal subspecies generally recognized, but whether these represent historical or arbitrary elements is not known.
P. c. bartramiana (Harper, 1939)—Southern Spring Peeper
P. c. crucifer (Wied-Neuwied, 1838)—Northern Spring Peeper
P. feriarum (Baird, 1854)—Southeastern Chorus Frog
Removed from the synonymy of Pseudacris triseriata by Hedges (1986, Syst. Zool. 35: 1–21). Platz (1989, Copeia 1989: 704–712) retained P. feriarum and P. kalmi as subspecies of one species but suggested that they might also be distinct species on the basis of data presented by Hedges. The contact zone between these named populations deserves careful scrutiny.
P. f. feriarum (Baird, 1854)—Upland Chorus Frog
P. f. kalmi Harper, 1955—New Jersey Chorus Frog
P. maculata (Agassiz, 1850)—Boreal Chorus Frog
Elevated from subspecies status under Pseudacris triseriata by Platz (1989, Copeia 1989: 704–712) on the basis of widespread sympatry and differences in call structure (see Platz and Forester, 1988, Copeia 1988: 1062–1066). Further study of geographic variation is warranted.
P. nigrita (LeConte, 1825)—Southern Chorus Frog
Two subspecies recognized although the status of these requires evaluation; for discussion see Smith and Smith (1952, Am. Midl. Nat. 48: 165–180) and Schwartz (1957, Am. Mus. Novit. 1838: 1–12).
P. n. nigrita (LeConte, 1825)—Striped Southern Chorus Frog
P. n. verrucosus (Cope, 1878 "1877")—Florida Chorus Frog
P. ocularis (Bosc and Daudin, 1801)—Little Grass Frog
No geographic variation documented, although careful work is warranted. Reviewed, as Limnaoedus ocularis, by Franz and Chantell (1978, Cat. Am. Amph. Rept. 209.). Regarded as a nomen dubium by Nieden (1923, Das Tierreich 46: 36). See nomenclatural discussion by Mittleman (1946, Herpetologica 3: 57–60) who considered Hyla ocularis Bosc and Daudin, 1801, to be a senior synonym of Acris gryllus or A. crepitans. Hedges (1986, Syst. Zool. 35: 11) placed this species in Pseudacris and discussed phylogenetic relationships. Cocroft (1994, Herpetologica 50: 420–437) provided a phylogenetic analysis of Pseudacris that disputed Hedges’ results although Silva (1997, J. Herpetol. 31: 609–613) provided additional evidence and discussion for placing this species within Pseudacris.
P. ornata (Holbrook, 1836)—Ornate Chorus Frog
No geographic variation documented. For discussion see Harper (1937, Am. Midl. Nat. 22: 134–149).
P. regilla (Baird and Girard, 1852)—Pacific Treefrog
Transfer to Pseudacris by Hedges (1986, Syst. Zool. 35: 11) was disputed by Cocroft (1994, Herpetologica 50: 420–437), although Silva (1997, J. Herpetol. 31: 609–613) provided additional evidence and discussion for placing this species within Pseudacris. See Jameson, Mackey, and Richmond (1966, Proc. California Acad. Sci. 33: 551–620) and Duellman (1970, Monogr. Mus. Nat. Hist. Univ. Kansas 1: 484–493). Several nominal subspecies named, though infrequently used in the literature. Whether these represent sibling species or arbitrarily delimited components of geographic variation is unknown. Further investigation is warranted.
P. r. cascadae (Jameson, Mackey, and Richmond, 1966)—Cascade Mountain Treefrog
P. r. curta (Cope, 1867 "1866")—California Pacific Treefrog
P. r. deserticola (Jameson, Mackey, and Richmond, 1966)—Desert Treefrog
P. r. pacifica (Jameson, Mackey, and Richmond, 1966)—Western Oregon Treefrog
P. r. palouse (Jameson, Mackey, and Richmond, 1966)—Eastern Oregon Treefrog
P. r. regilla (Baird and Girard, 1852)—Northern Pacific Treefrog
P. r. sierra (Jameson, Mackey, and Richmond, 1966)—Sierran Treefrog
P. streckeri A. A. Wright and A. H. Wright, 1933—Strecker’s Chorus Frog
Reviewed by Smith (1966, Cat. Am. Amph. Rept. 27).
P. s. illinoensis Smith, 1951—Illinois Chorus Frog
Considered a distinct species, Pseudacris illinoensis by Collins (1997, SSAR Herpetol. Circ. 25) without discussion, presumably because of the broad geographic disjunction from P. streckeri and published mutually diagnostic differences between the nominal races.
P. s. streckeri A. A. Wright and A. H. Wright, 1933—Strecker’s
Chorus Frog
P. triseriata (Wied-Neuwied, 1838)—Western Chorus Frog
See comment under Pseudacris maculata.

Pternohyla Boulenger, 1882—BURROWING TREEFROGS
P. fodiens Boulenger, 1882—Lowland Burrowing Treefrog
No documented geographic variation, although cryptic species are not expected. Reviewed by Trueb (1969, Cat. Am. Amph. Rept. 77).

Rana Linnaeus, 1758—TRUE FROGS
The monophyly of the nominal family (Ranidae Rafinesque, 1814) with respect to the other firmisternal frogs has not been documented, nor is it remotely clear that within that chaotic firmisternal array that Rana is monophyletic, even with the recognition in recent years of many extralimital genera.
R. areolata Baird and Girard, 1852—Crawfish Frog
See comment under Rana capito. Reviewed by Altig and Lohoefener (1983, Cat. Am. Amph. Rept. 324). Geographic variation deserves further study to determine status of the nominal subspecies.
R. a. areolata Baird and Girard, 1852—Southern Crawfish Frog
R. a. circulosa Rice and Davis, 1878—Northern Crawfish Frog
R. aurora Baird and Girard, 1852—Red-legged Frog
Hayes and Miyamoto (1984, Copeia 1984: 1018–1022) suggested that Rana aurora aurora and R. a. draytoni might be distinct species, and this arrangement was adopted by Dubois (1992, Bull. Mens. Soc. Linn. Lyon 61: 322) without discussion. Nevertheless, the distribution of characters is complex and the status of the nominal subspecies/species is not resolved.
R. a. aurora Baird and Girard, 1852—Northern Red-legged Frog
R. a. draytonii Baird and Girard, 1852—California Red-legged Frog
R. berlandieri Baird, 1854—Rio Grande Leopard Frog
Geographic variation is not well documented, and relationships with extralimital Mexican forms (e.g., Rana forreri, R. brownorum) are not well understood.
R. blairi Mecham, Littlejohn, Oldham, Brown, and Brown, 1973—Plains Leopard Frog
Reviewed by Brown (1992, Cat. Am. Amph. Rept. 536). Isolated western populations have not been well explored.
R. boylii Baird, 1854—Foothill Yellow-legged Frog
See Zweifel (1968, Cat. Am. Amph. Rept. 71) for review. Molecular study of geographic variation of this rapidly disappearing species would prove illuminating.
R. capito LeConte, 1855—Gopher Frog
Rana capito is considered by some to be part of R. areolata (but see Case, 1978, Syst. Zool. 27: 299–311, who considered it distinct). Reviewed by Altig and Lohoefener (1983, Cat. Am. Amph. Rept. 324). Recent as-yet-unpublished data argue that based on allozyme data capito and areolata are distinct and sevosa is distinct from the rest of the capito populations. The allozyme data also indicate that the remaining nominal subspecies are arbitrary units (Brian Crother, pers. comm.).
R. c. aesopus Cope, 1886—Florida Gopher Frog
R. c. capito LeConte, 1855—Carolina Gopher Frog
R. c. sevosa Goin and Netting, 1940—Dusky Gopher Frog
R. cascadae Slater, 1939—Cascades Frog
Reviewed by Altig and Dumas (1971, Cat. Am. Amph. Rept. 105). The disjunct populations should be investigated with respect to call and molecular parameters.
R. catesbeiana Shaw, 1802—American Bullfrog
Introduced worldwide, although geographic variation within the USA is poorly documented.
R. chiricahuensis Platz and Mecham, 1979—Chiricahua Leopard Frog
Status of Mexican populations and relationship with Rana montezumae needs study. Platz (1993, J. Herpetol. 27: 160) noted that various lines of evidence suggest that R. chiricahuensis is composed of more than one species, with the central Arizona population notably distinctive. The status of this species with respect to extralimital R. montezumae remains unresolved.
R. clamitans Latreille, 1801—Green Frog
The status of the nominal subspecies requires investigation to determine whether they are arbitrary or evolutionary units.
R. c. clamitans Latreille, 1801—Bronze Frog
R. c. melanota Rafinesque, 1820—Northern Green Frog
R. fisheri Stejneger, 1893—Vegas Valley Leopard Frog
Extinct. See comment under Rana onca.
R. grylio Stejneger, 1901—Pig Frog
R. heckscheri Wright, 1924—River Frog
Reviewed by Sanders (1984, Cat. Am. Amph. Rept. 348).
R. luteiventris Thompson, 1913—Columbia Spotted Frog
Green, Sharbel, Kearsley, and Kaiser (1996, Evolution 50: 374–390) and Cuellar (1996, Biogeographica 72: 145–150) suggested that Rana pretiosa was composed of two sibling species. Subsequently Green, Kaiser, Sharbel, Kearsley, and McAllister (1997, Copeia 1997: 1–8) recognized Rana luteiventris as a distinct species from the eastern and northern form.
R. muscosa Camp, 1917—Mountain Yellow-legged Frog
See Zweifel (1968, Cat. Am. Amph. Rept. 65) for review. Geographic variation warrants detailed study.
R. okaloosae Moler, 1985—Florida Bog Frog
Reviewed by Moler (1993, Cat. Am. Amph. Rept. 561).
R. onca Cope, 1875—Relict Leopard Frog
The status of this taxon is controversial, with some workers regarding the Vegas Valley Leopard Frog, Rana fisheri Stejnejer, 1893 (extinct), as conspecific with the Relict Leopard Frog, R. onca (likely now extinct). Others regard R. fisheri as most closely related to R. chiricahuensis and R. onca to not be a member of the R. chiricahuensis–group. The systematic discussion is not over although the relevant populations may be both extinct. Reviewed by Jennings (1988, Cat. Am. Amph. Rept. 417).
R. palustris LeConte, 1825—Pickerel Frog
Geographic variation studied by Pace (1974, Misc. Publ. Mus. Zool. Univ. Michigan 148: 1–140). Reviewed by Schaaf and Smith (1971, Cat. Am. Amph. Rept. 117). Schaaf and Smith, (1970, Herpetologica, 26: 240–254), reported on geographic variation and although they rejected subspecies did find coherent variation which corresponds to geographic boundaries among more recently recognized species in other taxa. A second look is warranted.
R. pipiens Schreber, 1782—Northern Leopard Frog
Synonymy and discussion in Pace (1974, Misc. Publ. Mus. Zool. Univ. Michigan 148: 1–140). Cryptic species are possible along the western part of the range.
R. pretiosa Baird and Girard, 1853—Oregon Spotted Frog
See comment under Rana luteiventris.
R. septentrionalis Baird, 1854—Mink Frog
Reviewed by Hedeen (1977, Cat. Am. Amph. Rept. 202). Cryptic species are not expected.
R. sphenocephala Cope, 1886—Southern Leopard Frog
Pace (1974, Misc. Publ. Mus. Zool. Univ. Michigan 148: 1–140) revived the older name Rana utricularius Harlan, 1825, for this species, which Pace emended to R. utricularia. Subsequently, the International Commission of Zoological Nomenclature moved (Opinion, 1685, 1992, Bull. Zool. Nomencl., 49: 171–173) to suppress R. utricularia for purposes of priority in favor of R. sphenocephala, leaving the unusual situation where the younger species name sphenochephala has nomenclatural priority over the older subspecies name, utricularia. The status of the nominal subspecies requires detailed examination (see Brown, Smith, and Funk, 1977, Bull. Zool. Nomencl. 33: 199–200; Zug, 1982, Bull. Zool. Nomencl. 39: 80–81; and Uzzell, 1982, Bull. Zool. Nomencl. 39: 83).
R. s. sphenocephala Cope, 1886—Florida Leopard Frog
R. s. utricularia Harlan, 1825—Southern Leopard Frog
R. subaquavocalis Platz, 1993—Ramsey Canyon Leopard Frog
The status of this taxon with respect to populations in Mexico, including Rana montezumae, needs study.
R. sylvatica LeConte, 1825—Wood Frog
Geographic variation requires detailed work, particularly with regard to the status of various isolated populations, of which one in Colorado, Rana maslini Porter, 1969, has been arguably considered a distinct species although this was rejected by Bagdonas and Pettus (1976, J. Herpetol. 10: 105–112). Reviewed by Martof (1970, Cat. Am. Amph. Rept. 86).
R. tarahumarae Boulenger, 1917—Tarahumara Frog
Extinct in the USA although persisting in Mexico.
R. virgatipes Cope, 1891—Carpenter Frog
Reviewed by Gosner and Black (1968, Cat. Am. Amph. Rept. 67). Data presented by Pytel, Herpetologica 42(3):273, suggest that careful evaluation for cryptic species are warranted.
R. yavapaiensis Platz and Frost, 1984—Lowland Leopard Frog

Rhinophrynus Duméril and Bibron, 1841—BURROWING TOADS
R. dorsalis Duméril and Bibron, 1841—Mexican Burrowing Toad
Geographic variation has not been studied in any detail and cryptic lineages are a possibility. Reviewed by Fouquette (1969, Cat. Am. Amph. Rept. 78).

Scaphiopus Holbrook, 1836—NORTH AMERICAN SPADEFOOTS
See comment under Spea.
S. couchii Baird, 1854—Couch’s Spadefoot
Reviewed by Wasserman (1970, Cat. Am. Amph. Rept. 85). Geographic variation is poorly documented.
S. holbrookii (Harlan, 1835)—Eastern Spadefoot
Reviewed by Wasserman (1968, Cat. Am. Amph. Rept. 70) as Scaphiopus holbrookii holbrookii. Frequently considered conspecific with the allopatric and diagnosable S. hurterii.
S. hurterii Strecker, 1910—Hurter’s Spadefoot
Considered by some to be an allopatric, well-differentiated subspecies of Scaphiopus holbrookii, even though it is diagnosable and allopatric. Reviewed by Wasserman (1968, Cat. Am. Amph. Rept. 70) as S. holbrookii hurterii.

Smilisca Cope, 1865—SMILISCAS
For review see Duellman (1968, Cat. Am. Amph. Rept. 58).
S. baudinii (Duméril and Bibron, 1841)—Mexican Treefrog
Reviewed by Duellman (1968, Cat. Am. Amph. Rept. 59). Molecular analysis would likely find interesting marks of history distinguishing the western and eastern Mexican populations although this would be unlikely to affect the appropriate name for the USA population.

Spea Cope, 1866—WESTERN SPADEFOOTS
Tanner (1989, Great Basin Nat. 49: 38–70) and Wiens and Titus (1991, Herpetologica 47: 21–28) removed Spea from the synonymy of Scaphiopus.
S. bombifrons (Cope, 1863)—Plains Spadefoot
Known to hybridize with Spea multiplicatus in parts of their ranges (Brown, 1976, Contrib. Sci. Nat. Hist. Mus. Los Angeles Co. 286). Geographic variation poorly documented.
S. hammondii (Baird, 1859 "1857")—Western Spadefoot
This name formerly covered populations now referred to Spea multiplicata and S. intermontana until separated by Brown (1976, Contrib. Sci. Nat. Hist. Mus. Los Angeles Co. 286). See Tanner (1989, Great Basin Nat. 49:503–510) for discussion, although he continued to retain these species as subspecies of S. hammondi, a position effectively rejected by Wiens and Titus (1991, Herpetologica 47: 21–38).
S. intermontana (Cope, 1883)—Great Basin Spadefoot
Geographic variation very poorly documented, and, according to evidence provided by Titus and Wiens (1991, Herpetologica 47: 21–29), this nominal species may be a paraphyletic composite of at least two species. Reviewed (as Scaphiopus intermontanus) by Hall (1999, Cat. Am. Amph. Rept. 650).
S. multiplicata (Cope, 1863)—Mexican Spadefoot
Considered a species distinct from Spea hammondii by Brown (1976, Contrib. Sci. Nat. Hist. Mus. Los Angeles Co. 286) and by Titus and Wiens (1991, Herpetologica 47: 21–28). Regarded, on the basis of overall similarity, to be conspecific with S. hammondii by Van Devender, Mead, and Rea (1991, Southwest. Nat. 36: 302–314) and by Tanner (1989, Great Bas. Nat. 49: 503–510). Tanner recognized S. h. stagnalis Cope as the northern (Arizona to central Chihuahua) subspecies of his S. hammondii, which is here, on the basis of phylogenetic evidence presented by Titus and Wiens, considered to be part of S. multiplicata. Geographic variation has not been carefully studied and cryptic species are possible.
S. m. stagnalis (Cope, 1875)—New Mexico Spadefoot

Xenopus Wagler, 1827—CLAWED FROGS
X. laevis (Daudin, 1802)—African Clawed Frog (Introduced)
"Xenopus laevis" is clearly a composite of many undescribed species in Africa and the actual identity of introduced populations in the U.S. has not been clearly determined. One can expect the identification of these introduced frogs to change.